% Encoding: UTF-8
@COMMENT{BibTeX export based on data in FAU CRIS: https://cris.fau.de/}
@COMMENT{For any questions please write to cris-support@fau.de}
@inproceedings{faucris.108803024,
abstract = {A structural characterisation of the first [01-15] grown 6H SiC crystals is presented. They show a different micro domain structure outside the facetted region as compared to conventionally [0001] grown crystals. It is imposed by the reduced rotational symmetry for this direction which favours the activation of a low number of glide systems.},
author = {Hock, Rainer and et al.},
author_hint = {Seitz C, Herro ZG, Epelbaum BM, Winnacker A, Hock R, Magerl A},
faupublication = {yes},
keywords = {[01-15] growth;crystal growth;defects;x-ray diffraction},
month = {Jan},
pages = {307-310},
peerreviewed = {unknown},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {[01-15] grown {6H} {SiC} bulk crystals investigated by high energy triple axis x-ray diffraction},
volume = {483},
year = {2005}
}
@inproceedings{faucris.272203363,
address = {CHESTER},
author = {Schmidt, E. M. and Krysiak, Yasar and Klar, Paul Benjamin and Palatinus, Lukas and Neder, Reinhard and Goodwin, Andrew L.},
booktitle = {ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES},
doi = {10.1107/s0108767321095994},
faupublication = {yes},
note = {CRIS-Team WoS Importer:2022-04-01},
pages = {C80-C80},
peerreviewed = {unknown},
publisher = {INT UNION CRYSTALLOGRAPHY},
title = {{3D}-{Delta} {PDF} from electron diffraction data},
year = {2021}
}
@article{faucris.108247964,
abstract = {The performance of organic solar cells is determined by the delicate, meticulously optimized bulk-heterojunction microstructure, which consists of finely mixed and relatively separated donor/acceptor regions. Here we demonstrate an abnormal strong burn-in degradation in highly efficient polymer solar cells caused by spinodal demixing of the donor and acceptor phases, which dramatically reduces charge generation and can be attributed to the inherently low miscibility of both materials. Even though the microstructure can be kinetically tuned for achieving high-performance, the inherently low miscibility of donor and acceptor leads to spontaneous phase separation in the solid state, even at room temperature and in the dark. A theoretical calculation of the molecular parameters and construction of the spinodal phase diagrams highlight molecular incompatibilities between the donor and acceptor as a dominant mechanism for burn-in degradation, which is to date the major short-time loss reducing the performance and stability of organic solar cells.},
author = {Li, Ning and Perea, José Darío and Kassar, Thaer and Richter, Moses and Heumüller, Thomas and Matt, Gebhard and Hou, Yi and Güldal, Nusret Sena and Chen, Haiwei and Chen, Shi and Langner, Stefan and Berlinghof, Marvin and Unruh, Tobias and Brabec, Christoph},
doi = {10.1038/ncomms14541},
faupublication = {yes},
journal = {Nature Communications},
peerreviewed = {Yes},
title = {{Abnormal} strong burn-in degradation of highly efficient polymer solar cells caused by spinodal donor-acceptor demixing},
volume = {8},
year = {2017}
}
@article{faucris.122555444,
abstract = {ZnO nanoparticles (NPs) have great potential for their use in, e.g., thin film solar cells due to their electro-optical properties adjustable on the nanoscale. Therefore, the production of well-defined NPs is of major interest. For a targeted production process, the knowledge of the stabilization layer of the NPs during and after their formation is of particular importance. For the study of the stabilizer layer of ZnO NPs prepared in a wet chemical synthesis from zinc acetate, only ex situ studies have been performed so far. An acetate layer bound to the surface of the dried NPs was found; however, an in situ study which addresses the stabilizing layer surrounding the NPs in a native dispersion was missing. By the combination of small angle scattering with neutrons and X-rays (SANS and SAXS) for the same sample, we are now able to observe the acetate shell in situ for the first time. In addition, the changes of this shell could be followed during the ripening process for different temperatures. With increasing size of the ZnO core (dcore) the surrounding shell (dshell) becomes larger, and the acetate concentration within the shell is reduced. For all samples, the shell thickness was found to be larger than the maximum extension of an acetate molecule with acetate concentrations within the shell below 50 vol %. Thus, there is not a monolayer of acetate molecules that covers the NPs but rather a swollen shell of acetate ions. This shell is assumed to hinder the growth of the NPs to larger macrostructures. In addition, we found that the partition coefficient μ between acetate in the shell surrounding the NPs and the total amount of acetate in the solution is about 10% which is in good agreement with ex situ data determined by thermogravimetric analysis.},
author = {Schindler, Torben and Schmiele, Martin and Schmutzler, Tilo and Kassar, Thaer and Segets, Doris and Peukert, Wolfgang and Radulescu, Aurel and Kriele, Armin and Gilles, Ralph and Unruh, Tobias},
doi = {10.1021/acs.langmuir.5b02198},
faupublication = {yes},
journal = {Langmuir},
keywords = {nanoparticle; solar; cell; electroptical; property;},
pages = {10130-10136},
peerreviewed = {Yes},
title = {{A} {Combined} {SAXS}/{SANS} {Study} for the in {Situ} {Characterization} of {Ligand} {Shells} on {Small} {Nanoparticles}: {The} {Case} of {ZnO}},
volume = {31},
year = {2015}
}
@article{faucris.106862844,
abstract = {High efficiency kesterite based solar cells have vigorously raised the research interests in this material. The challenge lies in understanding the formation and co-existence of more than 10 possible by-products during and after the synthesis of Cu2ZnSnS4 (CZTS) and their various different structural and electronic defects. The present contribution shows an in-depth study on the stages of formation and depletion of nanoparticulate CZTS. Employing a hot injection synthesis method, we give direct experimental evidence of the co-existence of cubic, tetragonal and defected CZTS structures and different by-products as a function of time and temperature. SEM, (HR) TEM, XRD, EDX, ICP-OES, Raman spectroscopy and UV-Vis-NIR spectroscopy have been used in order to better evaluate and interpret data for crystal structures and compositions. The obtained understanding on the formation of different phases suggests 250 degrees C as the most favourable synthesis temperature. Based on our study, general strategies can be developed for controlling the amount of formed phases, the by-products and the defects in kesterite and other similar multicomponent nanoparticles as well as in bulk systems.},
author = {Ahmad, Rameez and Brandl, Marco and Distaso, Monica and Herre, Patrick and Spiecker, Erdmann and Hock, Rainer and Peukert, Wolfgang},
doi = {10.1039/c5ce00661a},
faupublication = {yes},
journal = {Crystengcomm},
month = {Jan},
pages = {6972-6984},
peerreviewed = {Yes},
title = {{A} comprehensive study on the mechanism behind formation and depletion of {Cu2ZnSnS4} ({CZTS}) phases},
volume = {17},
year = {2015}
}
@article{faucris.117603684,
abstract = {Atomistic molecular dynamics simulations have become an important source of information for the structure and dynamics of biomembranes at molecular detail difficult to access in experiments. A number of force fields for lipid membrane simulations have been derived in the past; the choice of the most suitable force field is, however, frequently hampered by the availability of parameters for specific lipids. Additionally, the comparison of different quantities among force fields is often aggravated by varying simulation parameters. Here, we compare four atomistic lipid force fields, namely, the united-atom GROMOS54a7 and the all-atom force fields CHARMM36, Slipids, and Lipid14, for a broad range of structural and dynamical properties of saturated and monounsaturated phosphatidylcholine bilayers (DMPC and POPC) as well as for monounsaturated phosphatidylethanolamine bilayers (POPE). Additionally, the ability of the different force fields to describe the gel-liquid crystalline phase transition is compared and their computational efficiency estimated. Moreover, membrane properties like the water flux across the lipid bilayer and lipid acyl chain protrusion probabilities are compared.},
author = {Pluhackova, Kristyna and Kirsch, Sonja and Han, Jing and Sun, Liping and Jiang, Zhenyan and Unruh, Tobias and Böckmann, Rainer},
doi = {10.1021/acs.jpcb.6b01870},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {3888-903},
peerreviewed = {Yes},
title = {{A} {Critical} {Comparison} of {Biomembrane} {Force} {Fields}: {Structure} and {Dynamics} of {Model} {DMPC}, {POPC}, and {POPE} {Bilayers}.},
volume = {120},
year = {2016}
}
@article{faucris.108782124,
abstract = {This work describes solid-state reactions for the formation of the chalcopyrite compounds CuInSe2, CuGaSe2 and Cu(In,Ga)Se-2 on atomic scale. The most important chalcopyrite formation reactions which were identified by the authors by real-time in situ X-ray diffraction in preceding experiments are (A) CuSe + InSe -> CuInSe2, (B) Cu2Se + 2 InSe + Se -> 2 CuInSe2 and (C) Cu2Se + In2Se3 -> 2 CuInSe2. During the selenistaion of a metallic precursor containing gallium a separate fourth reaction occurs: (D) Cu2Se + Ga2Se3 -> 2 CuGaSe2. The quaternary compound is finally formed by interdiffusion of CuInSe2 with CuGaSe2 (E). These five reactions differ in their activation energy and reaction speed. We explain these differences qualitatively by analysing the involved crystal structures for each reaction. It turns out that all reactions involved in the formation of Cu(In,Ga)Se-2 are promoted by epitaxial relations, which facilitates the formation of polycrystalline thin films at temperatures much below those necessary for single crystal growth. Recommendations for the growth of larger grains of Cu(In,Ga)Se-2 containing fewer defects are given. (c) 2006 Elsevier Inc. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Jost S, Hock R, Purwins M},
doi = {10.1016/j.jssc.2006.04.033},
faupublication = {yes},
journal = {Journal of Solid State Chemistry},
keywords = {chalcogenide;crystal growth;epitaxial growth;semiconducting materials;solid state synthesis;ternary compounds;thin films},
pages = {2394-2415},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{A} crystallographic description of experimentally identified formation reactions of {Cu}({In},{Ga}){Se}-2},
volume = {179},
year = {2006}
}
@inproceedings{faucris.241271560,
address = {CHESTER},
author = {Schmidt, Ella and Neder, Reinhard},
booktitle = {ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES},
doi = {10.1107/S2053273319091162},
faupublication = {yes},
month = {Jan},
note = {CRIS-Team WoS Importer:2020-08-07},
pages = {E440-E440},
peerreviewed = {unknown},
publisher = {INT UNION CRYSTALLOGRAPHY},
title = {{A} {DISORDERED} {SUPERSPACE} {APPROACH} {TO} {UNDERSTAND} {HIGHLY} {STRUCTURED} {DIFFUSE} {SCATTERING}},
year = {2019}
}
@article{faucris.108437384,
abstract = {The understanding of porphyrin adsorption on oxide nanoparticles including knowledge about coverages and adsorbate geometries is a prerequisite for the improvement and optimization of hybrid materials. The combination of molecular spectroscopies with small-angle X-ray scattering provides molecular insights into porphyrin adsorption on MgO nanocube dispersions in organic solvents. In particular, we address the influence of terminal carboxyl groups on the adsorption of free base porphyrins, on their chemical binding, on the metalation reaction as well as on the coverage and orientation of adsorbate molecules. We compare the free base form 5,10,15,20-tetraphenyl-21,23H-porphyrin (2HTPP) with the carboxyl-functionalized 5,10,15,20-tetrakis(4-carboxyphenyl)-21,23H-porphyrin (2HTCPP) and show that without carboxylic anchoring groups the free base form metalates on the nanocube surface and adopts a flat-lying adsorbate geometry. The saturation limit for flat-lying adsorption on nanocubes with an average edge length of 6 nm corresponds to 90 14 molecules per particle. This limit is surpassed when 2HTCPP molecules attach via their terminal carboxyl groups to the surface. The resulting upright adsorption geometry suppresses self-metalation, on the one hand, and allows for much higher porphyrin coverages, on the other (at porphyrin concentrations in the stock solution of 2 X 10(-2) mol.L-1). UV-vis diffuse reflectance results are perfectly consistent with conclusions from SAXS data analysis. The experiments reveal concentration dependent 2HTCPP coverages in the range between 0.4 to 1.9 molecules nm(-2) which correspond to the formation of a shell of upright standing porphyrin molecules around the MgO nanocubes. In contrast, after adsorption and metalation of nonfunctionalized 2HTPP the resulting porphyrin shells are in the range of a tenth of a nanometer and thus too thin to be captured by SAXS measurements. Related insights advance our opportunities to prepare well-defined nanohybrids containing highly organized porphyrin films.},
author = {Schneider, Johannes and Kollhoff, Fabian and Schindler, Torben and Bichlmaier, Stephan and Bernardi, Johannes and Unruh, Tobias and Libuda, Jörg and Berger, Thomas and Diwald, Oliver},
doi = {10.1021/acs.jpcc.6b08956},
faupublication = {yes},
journal = {Journal of Physical Chemistry C},
pages = {26879-26888},
peerreviewed = {Yes},
title = {{Adsorption}, {Ordering}, and {Metalation} of {Porphyrins} on {MgO} {Nanocube} {Surfaces}: {The} {Directional} {Role} of {Carboxylic} {Anchoring} {Groups}},
volume = {120},
year = {2016}
}
@article{faucris.108804124,
abstract = {A triple-axis diffractometer for high-energy X-ray diffraction is described. A 450 kV/4.5 kW stationary tungsten X-ray tube serves as the X-ray source. Normally, 220 reflections of thermally annealed Czochralski Si are employed for the monochromator and analyser. Their integrated reflectivity is about ten times higher than the ideal crystal value. With the same material as the sample, and working with the W Kalpha line at 60 keV in symmetric Laue geometry for all axes, the full width at half-maximum (FWHM) values for the longitudinal and transversal resolution are 2.5 x 10(-3) and 1.1 x 10(-4) for DeltaQ/Q, respectively, and the peak intensity for a non-dispersive setting is 3000 counts s(-1). In particular, for a double-axis mode, an energy well above 100 keV from the Bremsstrahlung spectrum can be used readily. High-energy X-rays are distinguished by a high penetration power and materials of several centimetre thickness can be analysed. The feasibility of performing experiments with massive sample environments is demonstrated.},
author = {Hock, Rainer and et al.},
author_hint = {Seitz C, Weisser M, Gomm M, Hock R, Magerl A},
doi = {10.1107/S0021889804023805},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
pages = {901-910},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{A} high-energy triple-axis {X}-ray diffractometer for the study of the structure of bulk crystals},
volume = {37},
year = {2004}
}
@article{faucris.108574444,
abstract = {We present our recent development of a high temperature high pressure cell for neutron scattering. Combining a water cooled Nb1Zr pressure cell body with an internal heating furnace, the sample environment can reach temperatures of up to 1500 K at a pressure of up to 200 MPa at the sample position, with an available sample volume of about 700 mm(3). The cell material Nb1Zr is specifically chosen due to its reasonable mechanical strength at elevated temperatures and fairly small neutron absorption and incoherent scattering cross sections. With this design, an acceptable signal-to-noise ratio of about 10:1 can be achieved. This opens new possibilities for quasielastic neutron scattering studies on different types of neutron spectrometers under high temperature high pressure conditions, which is particularly interesting for geological research on, e.g., water dynamics in silicate melts. (C) 2011 American Institute of Physics. [doi:10.1063/1.3623796]},
author = {Yang, Fan and Kaplonski, Joseph and Unruh, Tobias and Mamontov, Eugene and Meyer, Andreas},
doi = {10.1063/1.3623796},
faupublication = {yes},
journal = {Review of Scientific Instruments},
peerreviewed = {Yes},
title = {{A} high temperature high pressure cell for quasielastic neutron scattering},
volume = {82},
year = {2011}
}
@inproceedings{faucris.222696376,
address = {CHESTER},
author = {Schmidt, Ella and Neder, Reinhard},
booktitle = {ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES},
doi = {10.1107/S2053273318090423},
faupublication = {yes},
note = {CRIS-Team WoS Importer:2019-07-19},
pages = {E316-E317},
peerreviewed = {unknown},
publisher = {INT UNION CRYSTALLOGRAPHY},
title = {{Analysis} of chemical short range order using single crystal diffuse scattering},
year = {2018}
}
@inproceedings{faucris.222698117,
address = {CHESTER},
author = {Hans, Philipp and Neder, Reinhard and Hradil, Klaudia},
booktitle = {ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES},
doi = {10.1107/S2053273318093166},
faupublication = {yes},
note = {CRIS-Team WoS Importer:2019-07-19},
pages = {E141-E141},
peerreviewed = {unknown},
publisher = {INT UNION CRYSTALLOGRAPHY},
title = {{Analysis} of short range phenomena in novel materials using the {PDF}-method},
year = {2018}
}
@article{faucris.123071124,
abstract = {DNA-complexes with platelet-like, cationically modified lipid nanoparticles (cLNPs) are studied with regard to the formation of nanocomposite structures with a sandwich-like arrangement of the DNA and platelets. For this purpose suspensions of platelet-like triglyceride nanocrystals, stabilized by a mixture of two nonionic (lecithin plus polysorbate 80 or poloxamer 188) and one cationic stabilizer dimethyldioctadecylammonium (DODAB), are used. The structure of the platelets in the native suspensions and their DNA-complexes, ranging from the sub-nano to the micron scale, is investigated with small- and wide-angle scattering (SAXS, SANS, WAXS), calorimetry, photon correlation spectroscopy, transmission electron microscopy and computer simulations. The appearance of strong, lamellarly ordered peaks in the SAXS patterns of the DNA-complexes suggests a stacked arrangement of the nanocrystals, with the DNA being partially condensed between the platelets. This finding is supported with computer simulated small-angle scattering patterns of nanocrystal stacks, which can reproduce the measured small-angle scattering patterns on an absolute scale. The influence of the choice of the nonionic stabilizers and the amount of the cationic stabilizer DODAB on the structure of the native suspensions and the inner structure of their DNA-complexes is studied, too. Using high amounts of DODAB, lecithins with saturated acyl chains and polysorbate 80 instead of poloxamer 188 produces thinner nanocrystals, and thus decreases their repeat distances in the nanocomposites. Such nanocomposites could be of interest as DNA carriers, where the triglyceride platelets protect the sandwiched DNA from degradation.},
author = {Schmiele, Martin and Knittel, Charlotte and Unruh, Tobias and Busch, Sebastian and Morhenn, Humphrey and Boesecke, Peter and Funari, Sergio S. and Schweins, Ralf and Lindner, Peter and Westermann, Martin and Steiniger, Frank},
doi = {10.1039/c5cp01241d},
faupublication = {yes},
journal = {Physical Chemistry Chemical Physics},
month = {Jan},
pages = {17939-17956},
peerreviewed = {Yes},
title = {{Analysis} of the structure of nanocomposites of triglyceride platelets and {DNA}},
volume = {17},
year = {2015}
}
@article{faucris.271384333,
abstract = {Adding to the versatile class of ionic liquids, we report the detailed structure and property analysis of a new class of asymmetrically substituted imidazolium salts, offering interesting thermal characteristics, such as liquid crystalline behavior, polymorphism or glass transitions. A scalable general synthetic procedure for N-polyaryl-N’-alkyl-functionalized imidazolium salts with para-substituted linker (L) moieties at the aryl chain, namely [LPhmImHR]+ (L=Br, CN, SMe, CO2Et, OH; m=2, 3; R=C12, PEGn; n=2, 3, 4), was developed. These imidazolium salts were studied by single-crystal X-ray diffraction (SC-XRD), NMR spectroscopy and thermochemical methods (DSC, TGA). Furthermore, these imidazolium salts were used as N-heterocyclic carbene (NHC) ligand precursors for mononuclear, first-row transition metal complexes (MnII, FeII, CoII, NiII, ZnII, CuI, AgI, AuI) and for the dinuclear Ti-supported Fe-NHC complex [(OPy)2Ti(OPh2ImC12)2(FeI2)] (OPy=pyridin-2-ylmethanolate). The complexes were studied concerning their structural and magnetic behavior via multi-nuclear NMR spectroscopy, SC-XRD analyses, variable temperature and field-dependent (VT-VF) SQUID magnetization methods, X-band EPR spectroscopy and, where appropriate, zero-field 57Fe Mössbauer spectroscopy.},
author = {Seidl, Vera and Romero Cordero, Angel Heriberto and Heinemann, Frank Wilhelm and Scheurer, Andreas and Vogel, Carola and Unruh, Tobias and Wasserscheid, Peter and Meyer, Karsten},
doi = {10.1002/chem.202200100},
faupublication = {yes},
journal = {Chemistry - A European Journal},
keywords = {carbene ligands; electronic structure; ionic liquids; solid-state structure; thermal properties},
note = {CRIS-Team Scopus Importer:2022-03-25},
peerreviewed = {Yes},
title = {{A} {New} {Class} of {Task}-{Specific} {Imidazolium} {Salts} and {Ionic} {Liquids} and {Their} {Corresponding} {Transition}-{Metal} {Complexes} for {Immobilization} on {Electrochemically} {Active} {Surfaces}},
year = {2022}
}
@article{faucris.260209712,
abstract = {The transformation from hexagonal close packed (hcp) to face-centered
cubic (fcc) crystal structure upon gaseous nitriding of Co-Cr alloy with
initial hcp crystal structure was investigated. During early stages of
low-temperature nitriding at 400°C, new reflections on the low-angle
side of the hcp-substrate reflections in X-ray diffraction patterns
can be attributed to the formation of hcp phase with an expanded
lattice on the surface. Prolonged nitriding treatment and nitriding at
higher temperatures result in transformation of this expanded hcp into
an expanded fcc. An anisotropic progress of mentioned transformation on
differently-oriented hcp crystallites
is observed. The transformation is slower in hcp orientations with the
highest Schmid factor of the basal slip mode with respect to the
nitriding direction. This is discussed in a view of developed
macrostress in early stages of nitriding and its influence on plastic
anisotropic deformation of hcp variant},
author = {Akhlaghi, Maryam and Martin, Stefan and Dallmann, Johannes and Hock, Rainer and Körner, Carolin and Leineweber, Andreas},
doi = {10.1016/j.scriptamat.2021.114041},
faupublication = {yes},
journal = {Scripta Materialia},
keywords = {Nitriding; Phase transformations; Residual stresses; Metal and alloys; Expanded phase},
peerreviewed = {Yes},
title = {{Anisotropic} nitriding behavior upon formation of expanded hcp in {Co}-{Cr} alloys},
volume = {203},
year = {2021}
}
@article{faucris.239403681,
abstract = {Exploiting small-angle X-ray and neutron scattering (SAXS/SANS) on the same sample volume at the same time provides complementary nanoscale structural information in two different contrast situations. Unlike an independent experimental approach, the truly combined SAXS/SANS experimental approach ensures the exactness of the probed samples, particularly for in situ studies. Here, an advanced portable SAXS system that is dimensionally suitable for installation in the D22 zone of ILL is introduced. The SAXS apparatus is based on a Rigaku switchable copper/molybdenum microfocus rotating-anode X-ray generator and a DECTRIS detector with a changeable sample-to-detector distance of up to 1.6 m in a vacuum chamber. A case study is presented to demonstrate the uniqueness of the newly established method. Temporal structural rearrangements of both the organic stabilizing agent and organically capped gold colloidal particles during gold nanoparticle growth are simultaneously probed, enabling the immediate acquisition of correlated structural information. The new nano-analytical method will open the way for real-time investigations of a wide range of innovative nanomaterials and will enable comprehensive in situ studies on biological systems. The potential development of a fully automated SAXS/SANS system with a common control environment and additional sample environments, permitting a continual and efficient operation of the system by ILL users, is also introduced.},
author = {Metwalli, Ezzeldin and Götz, Klaus and Lages, Sebastian and Bär, Christian and Zech, Tobias and Noll, Dennis and Schuldes, Isabel and Schindler, Torben and Prihoda, Annemarie and Lang, Herbert and Grasser, Jürgen and Jacques, Mark and Didier, Luc and Cyril, Amrouni and Martel, Anne and Porcar, Lionel and Unruh, Tobias},
doi = {10.1107/S1600576720005208},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
note = {CRIS-Team WoS Importer:2020-06-19},
pages = {722-733},
peerreviewed = {Yes},
title = {{A} novel experimental approach for nanostructure analysis: simultaneous small-angle {X}-ray and neutron scattering},
volume = {53},
year = {2020}
}
@article{faucris.244316778,
abstract = {The transition-metal dichalcogenide HfS(2)is a promising alternative semiconductor with adequate band gap and high carrier mobility. However, a controllable growth of continuous HfS(2)films with selectivity for specific surfaces at a low temperature on a large scale has not been demonstrated yet. Herein, HfS(2)films are grown at 100 degrees C by atomic layer deposition (ALD) based on the precursors tetrakis(dimethylamido)hafnium and H2S. In situ vibrational spectroscopy allows for the definition of the temperature range over which (Me2N)(4)Hf chemisorbs as one monolayer. In that range, sequential exposures of the solid surface with (Me2N)(4)Hf and H2S result in self-limiting reactions that yield alternating surface termination with dimethylamide and thiol. Repeating the cycle grows smooth, continuous, stoichiometric films of thicknesses adjustable from angstroms to >100 nm, as demonstrated by spectroscopic ellipsometry, XRR, AFM, UV-vis and Raman spectroscopy, XPS, and TEM. The well-defined surface chemistry enables one to deposit HfS(2)selectively using, for example, patterns generated in molecular self-assembled monolayers. This novel ALD reaction combines several attractive features necessary for integrating HfS(2)into devices.},
author = {Cao, Yuanyuan and Wähler, Tobias and Park, Hyoungwon and Will, Johannes and Prihoda, Annemarie and Moses Badlyan, Narine and Fromm, Lukas and Yokosawa, Tadahiro and Wang, Bingzhe and Guldi, Dirk Michael and Görling, Andreas and Maultzsch, Janina and Unruh, Tobias and Spiecker, Erdmann and Halik, Marcus and Libuda, Jörg and Bachmann, Julien},
doi = {10.1002/admi.202001493},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
keywords = {2D materials; atomic layer deposition; dichalcogenides; hafnium disulfide; thin films},
note = {CRIS-Team Scopus Importer:2020-10-23},
peerreviewed = {Yes},
title = {{Area}-{Selective} {Growth} of {HfS}(2){Thin} {Films} via {Atomic} {Layer} {Deposition} at {Low} {Temperature}},
volume = {7},
year = {2020}
}
@article{faucris.264257687,
abstract = {The transition-metal dichalcogenide HfS(2)is a promising alternative semiconductor with adequate band gap and high carrier mobility. However, a controllable growth of continuous HfS(2)films with selectivity for specific surfaces at a low temperature on a large scale has not been demonstrated yet. Herein, HfS(2)films are grown at 100 degrees C by atomic layer deposition (ALD) based on the precursors tetrakis(dimethylamido)hafnium and H2S. In situ vibrational spectroscopy allows for the definition of the temperature range over which (Me2N)(4)Hf chemisorbs as one monolayer. In that range, sequential exposures of the solid surface with (Me2N)(4)Hf and H2S result in self-limiting reactions that yield alternating surface termination with dimethylamide and thiol. Repeating the cycle grows smooth, continuous, stoichiometric films of thicknesses adjustable from angstroms to >100 nm, as demonstrated by spectroscopic ellipsometry, XRR, AFM, UV-vis and Raman spectroscopy, XPS, and TEM. The well-defined surface chemistry enables one to deposit HfS(2)selectively using, for example, patterns generated in molecular self-assembled monolayers. This novel ALD reaction combines several attractive features necessary for integrating HfS(2)into devices.},
author = {Cao, Yuanyuan and Wähler, Tobias and Park, Hyoungwon and Will, Johannes and Prihoda, Annemarie and Moses Badlyan, Narine and Fromm, Lukas and Yokosawa, Tadahiro and Wang, Bingzhe and Guldi, Dirk Michael and Görling, Andreas and Maultzsch, Janina and Unruh, Tobias and Spiecker, Erdmann and Halik, Marcus and Libuda, Jörg and Bachmann, Julien},
doi = {10.1002/admi.202001493},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
keywords = {2D materials;atomic layer deposition;dichalcogenides;hafnium disulfide;thin films},
peerreviewed = {Yes},
title = {{Area}-{Selective} {Growth} of {HfS}(2){Thin} {Films} via {Atomic} {Layer} {Deposition} at {Low} {Temperature}},
volume = {7},
year = {2020}
}
@article{faucris.108437824,
abstract = {We use Bayesian inference methods to provide fresh insights into the sub-nanosecond dynamics of glycerol, a prototypical glass-forming liquid. To this end, quasielastic neutron scattering data as a function of temperature have been analyzed using a minimal set of underlying physical assumptions. On the basis of this analysis, we establish the unambiguous presence of three distinct dynamical processes in glycerol, namely, translational diffusion of the molecular centre of mass and two additional localized and temperature-independent modes. The neutron data also provide access to the characteristic length scales associated with these motions in a model-independent manner, from which we conclude that the faster (slower) localized motions probe longer (shorter) length scales. Careful Bayesian analysis of the entire scattering law favors a heterogeneous scenario for the microscopic dynamics of glycerol, where molecules undergo either the faster and longer or the slower and shorter localized motions.},
author = {Vispa, Alessandro and Busch, Sebastian and Tamarit, Josep Lluis and Unruh, Tobias and Fernandez-Alonso, Felix and Pardo, Luis Carlos},
doi = {10.1039/c5cp05143f},
faupublication = {yes},
journal = {Physical Chemistry Chemical Physics},
pages = {3975-3981},
peerreviewed = {Yes},
title = {{A} robust comparison of dynamical scenarios in a glass-forming liquid},
volume = {18},
year = {2016}
}
@article{faucris.254611158,
abstract = {The preparation of a highly ordered nanostructured transparent electrode
based on a combination of nanosphere lithography and anodization is
presented. The size of perfectly ordered pore domains is improved by an
order of magnitude with respect to the state of the art. The
concomitantly reduced density of defect pores increases the fraction of
pores that are in good electrical contact with the underlying
transparent conductive substrate. This improvement in structural quality
translates directly and linearly into an improved performance of energy
conversion devices built from such electrodes in a linear manne},
author = {Döhler, Dirk and Triana Merlo, Andres Dario and Büttner, Pascal and Scheler, Florian and Görlitzer, Eric and Harrer, Johannes and Vasileva, Anna A. and Ali, Ezzeldin and Gruber, Wolfgang and Unruh, Tobias and Manshina, Alina A. and Vogel, Nicolas and Bachmann, Julien and Minguez Bacho, Ignacio},
doi = {10.1002/smll.202100487},
faupublication = {yes},
journal = {Small},
keywords = {nanosphere lithography; anodic alumina; antimony sulfide},
peerreviewed = {Yes},
title = {{A} {Self}‐{Ordered} {Nanostructured} {Transparent} {Electrode} of {High} {Structural} {Quality} and {Corresponding} {Functional} {Performance}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/smll.202100487},
volume = {NA},
year = {2021}
}
@article{faucris.108575324,
author = {Boeer, Angelika B. and Barra, Anne-Laure and Chibotaru, Liviu F. and Collison, David and McInnes, Eric and Mole, Richard A. and Simeoni, Giovanna G. and Timco, Grigore A. and Ungur, Liviu and Unruh, Tobias and Winpenny, Richard E. P.},
doi = {10.1002/anie.201100306},
faupublication = {yes},
journal = {Angewandte Chemie International Edition},
keywords = {cluster compounds;cobalt;EPR spectroscopy;inelastic neutron scattering;magnetic properties},
month = {Jan},
pages = {4007-4011},
peerreviewed = {Yes},
title = {{A} {Spectroscopic} {Investigation} of {Magnetic} {Exchange} {Between} {Highly} {Anisotropic} {Spin} {Centers}},
volume = {50},
year = {2011}
}
@article{faucris.107677284,
abstract = {Hybrid organic-inorganic perovskites have emerged as cost-effective and high-performance semiconductors for optoelectronic applications. Precise knowledge of charge carrier mobility and especially the temperature dependence of mobility is therefore of utmost relevance for advancing high-performance materials. Here, the charge carrier mobility in methylammonium lead iodide single crystals is investigated with time of flight technique from 290 to 100 K. A nondispersive transport with an electron mobility of 135 (+/- 20) cm(2)/V s and a hole mobility of 90 (+/- 20) cm(2)/V s is obtained at room temperature. A power-law temperature dependence of mobility, mu alpha T-m, with an exponent m = -2.8 and -2.0, is measured for electrons and holes in the tetragonal phase. The highest electron and hole mobilities measured are 635 (+/- 70) and 415 (+/- 20) cm(2)/V s, respectively. Our results indicate that the scattering of charge carriers with phonons is the limiting factor for carrier mobilities at room temperature.},
author = {Shrestha, Shreetu and Matt, Gebhard and Osvet, Andres and Niesner, Daniel and Hock, Rainer and Brabec, Christoph},
doi = {10.1021/acs.jpcc.8b00341},
faupublication = {yes},
journal = {Journal of Physical Chemistry C},
pages = {5935-5939},
peerreviewed = {Yes},
title = {{Assessing} {Temperature} {Dependence} of {Drift} {Mobility} in {Methylammonium} {Lead} {Iodide} {Perovskite} {Single} {Crystals}},
volume = {122},
year = {2018}
}
@inproceedings{faucris.117820384,
abstract = {Cu-Zn-Sn intermetallic thin films were sputtered on Mo-coated soda-lime glass substrates from elemental targets. Samples representing a wide range of compositions around the 2:1:1 kesterite ratio of the Cu-Zn-Sn material system have been investigated. Crystalline phase content and chemical composition of the metal precursors were characterized by X-ray phase analysis and X-ray fluorescence. The metal precursor films were then processed into metal chalcogenides by rapid thermal processing in sulfur ambient with a maximum process temperature around 500 degrees C. Thin films were investigated by X-ray powder diffraction, X-ray fluorescence and Raman spectroscopy to identify their phase contents as a function of precursor composition and initial intermetallic crystalline phase content. Compositional regions of kesterite crystallization as well as remaining secondary chalcogenide phases were identified. Consequences of the obtained results for the thin film crystallization of Kesterite absorbers for solar cell fabrication by rapid thermal processing of metallic precursors will be discussed. (C) 2012 Elsevier B.V. All rights reserved.},
author = {Wibowo, Rachmat Adhi and Yoo, Hye Sun and Hölzing, Astrid and Lechner, R. and Jost, S. and Palm, J. and Gowtham, M. and Louis, B. and Hock, Rainer},
doi = {10.1016/j.tsf.2012.11.074},
faupublication = {yes},
keywords = {Kesterite;Sulfo-selenization;X-ray diffraction;Intermetallic compounds},
pages = {57-61},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
title = {{A} study of kesterite {Cu2ZnSn}({Se},{S})(4) formation from sputtered {Cu}-{Zn}-{Sn} metal precursors by rapid thermal processing sulfo-selenization of the metal thin films},
volume = {535},
year = {2013}
}
@inproceedings{faucris.108782344,
abstract = {This work describes the influence of sodium doping on the formation reactions of the semiconductor material Cu(In,Ga)Se-2. Assuming the sodium dopant to act as a surface catalyst by formation of sodium polyselenides, we estimate the shift in the reaction enthalpies for the formation of binary selenides. Since the release of selenium from sodium polyselenides is an endothermic process, five of six possible reactions resulting in copper selenides are energetically suppressed whereas all indium and gallium selenides can still be formed exothermically. Furthermore, we have applied the effective heat of formation model on the ternary Cu-In-Se system to predict the first compound being formed during the selenisation of the metallic precursor. Our model predicts that sodium doping does not influence which selenide compound will be formed at first, but that influences consecutive reactions by shifting their reaction enthalpies. (c) 2005 Elsevier B.V. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Jost S, Hock R, Purwins M, Palm J},
doi = {10.1016/j.tsf.2005.11.081},
faupublication = {yes},
keywords = {chalcogenides;thin films;crystal growth;X-ray diffraction;thermodynamic properties},
pages = {147-152},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{A} thermodynamical approach to the formation reactions of sodium-doped {Cu}({In},{Ga}){Se}-2},
volume = {511},
year = {2006}
}
@article{faucris.120518024,
abstract = {The relation between static structure and dynamics as measured through the diffusion coefficients in viscous multicomponent metallic melts is elucidated by the example of the binary alloy Zr(64)Ni(36), by a combination of neutron-scattering experiments and mode-coupling theory of the glass transition. Comparison with a hard-sphere mixture shows that the relation between the different self diffusion coefficients strongly depends on chemical short-range ordering. For the Zr-Ni example, the theory predicts both diffusivities to be practically identical. The kinetics of concentration fluctuations is dramatically slower than that of self-diffusion, but the overall interdiffusion coefficient is equally large or larger due to a purely thermodynamic prefactor. This result is a general feature for non-demixing dense melts, irrespective of chemical short-range order. Copyright (C) EPLA, 2008.},
author = {Voigtmann, Thomas and Meyer, Andreas and Holland-Moritz, Dirk and Stüber, Sebastian and Hansen, Thomas and Unruh, Tobias},
doi = {10.1209/0295-5075/82/66001},
faupublication = {no},
journal = {EPL - Europhysics Letters},
peerreviewed = {Yes},
title = {{Atomic} diffusion mechanisms in a binary metallic melt},
volume = {82},
year = {2008}
}
@article{faucris.106271264,
abstract = {Revelation of unequivocal structural information at the atomic level for complex systems is uniquely important for deeper and generic understanding of the structure property connections and a key challenge in materials science. Here we report an experimental study of the local structure by applying total elastic scattering and Raman scattering analyses to an important non-relaxor ferroelectric solid solution exhibiting the so-called composition-induced morphotropic phase boundary (MPB), where concomitant enhancement of physical properties have been detected. The powerful combination of static and dynamic structural probes enabled us to derive direct correspondence between the atomic-level structural correlations and reported properties. The atomic pair distribution functions obtained from the neutron total scattering experiments were analysed through big-box atom-modelling implementing reverse Monte Carlo method, from which distributions of magnitudes and directions of off-centred cationic displacements were extracted. We found that an enhanced randomness of the displacement-directions for all ferroelectrically active cations combined with a strong dynamical coupling between the A- A nd B-site cations of the perovskite structure, can explain the abrupt amplification of piezoelectric response of the system near MPB. Altogether this provides a more fundamental basis in inferring structure-property connections in similar systems including important implications in designing novel and bespoke material},
author = {Datta, Kaustuv and Neder, Reinhard and Chen, Jun and Neuefeind, Joerg C. and Mihailova, Boriana},
doi = {10.1038/s41598-017-00530-z},
faupublication = {yes},
journal = {Scientific Reports},
peerreviewed = {Yes},
title = {{Atomic}-level structural correlations across the morphotropic phase boundary of a ferroelectric solid solution: {XBiMg1}/{2Ti1}/{2O3}-(1-x){PbTiO3}},
volume = {7},
year = {2017}
}
@article{faucris.108522744,
abstract = {The ferroelectric solid solution (1 - x)Na0.5Bi0.5TiO3-BaTiO3 (NBT-xBT) is a promising material to substitute for the environmentally undesired Pb-based ferroelectrics. The strong enhancement of the dielectric permittivity and piezoelectric coefficients near the morphotropic phase boundary (MPB) in ferroelectric ABO(3)-type solid solutions is commonly related to the existence of a single or several long-range-ordered phases resulting in a complex nanodomain pattern. Here, NBT-xBT is studied by Raman scattering and complementary synchrotron x-ray total elastic scattering to follow the temperature evolution of the mesoscopic-scale structural transformations for x below, at, and slightly above x(MPB). The most remarkable result is that at x similar to x(MPB) the phonon mode involving vibrations of both off-centered A-site Bi and B-site Ti experiences strong softening and damping near the triple-point temperature in the phase diagram, in strong contrast to the compounds with x < x(MPB) or x > x(MPB). The chemically enhanced coupling between the Bi and Ti subsystems at x(MPB) is facilitated by the subtle disturbance of the coupling processes within the Bi subsystem induced by Ba at x(MPB). These mesoscopic-scale structural and dynamic phenomena seem to be significant for the enhanced response functions at the MPB in NBT-xBT.},
author = {Datta, Kaustuv and Richter, Andreas and Göbbels, Matthias and Neder, Reinhard and Mihailova, B.},
doi = {10.1103/PhysRevB.90.064112},
faupublication = {yes},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Atomistic} origin of huge response functions at the morphotropic phase boundary of (1-x){Na0}.{5Bi0}.{5TiO3}-{xBaTiO}(3)},
volume = {90},
year = {2014}
}
@article{faucris.214833529,
abstract = {The operational stability of organic solar cells (OSCs) is the essential barrier to commercialization. Compared to thermally-induced degradation, photo-stability of OSCs is far away from being resolved. Here, we demonstrate that the thermal- and photo-degradation of metastable bulk-heterojunction OSCs are governed by the same mechanism. Understanding the fundamental principles behind this mechanism is of significant importance to fully address the instability issues. Structural incompatibilities between the donor and acceptor molecules are identified as the main origin of the instability. Further, we introduce a top-down approach mainly based on their melting temperature and interaction parameters to rationally screen molecular phase stabilizers from a database with more than 10000 small molecules. Eventually, five chemicals were selected to validate our concept and tested in unstable organic solar cells. 1,4-Piperazine, which possesses a high melting point, good miscibility with polymers and the capability of forming inter-molecular hydrogen bonding, can indeed stabilize the mixed amorphous phases, leading to significantly improved stability of otherwise metastable OSCs.
performance−stability correlation. We demonstrate that four batches of PCE11 with varying crystalline properties can achieve similar high performance in combination with PCBM. Careful device optimization is necessary in each case to properly address the requirements for the quite distinct microstructures. The
bulk-heterojunction (BHJ) microstructure is comprehensively investigated as a function of the macromolecular weight and crystallinity. It is demonstrated that small differences in morphology significantly affect the kinetics and thermodynamic equilibrium of the BHJ microstructure as well as the photostability and thermal stability of the PCE11:PCBM solar cells
the place of the event in real time that is in situ. An early concept of this method has already been
suggested in 1944 by Abrams and McBain [1] and could be realized nearly 60 years later in 2003 by
Williamson et al. [2]. Since that, much effort has been put into characterizing various reactions in
material, biological, and electrochemical systems.
Anisotropic core-shell nanostructures are highly attractive for plasmonic applications like e.g. sensors,
light guiding or labeling, because their plasmon resonance frequency can be variably adjusted over a
wide spectral range via a simple variation of the shell thickness as already shown by Becker et al. [3].
Here we apply LCTEM to induce and to investigate the growth of silver-shell from aqueous silver nitrate
(AgNO3) solution on cetrimonium bromide (CTAB) stabilized gold nanorods. For this purpose, a new,
simplified liquid cell design is utilized, which is not only capable being used for conventional, but also for
analytic TEM techniques like energy dispersive x-ray spectroscopy (EDXS) and electron tomography. To
achieve that, the fluid is enclosed between a structured silicon nitride membrane and a second few layer
graphene membrane, leaving one side of the cell plane, as shown elsewhere [4]. For the experiments, a
conventional TEM specimen holder is used together with a Philips CM 30 and a FEI Titan³ Themis, both
operated at 300 kV.
It could be shown that silver bromide (AgBr) is forming, which components are originating from CTAB
and AgNO3. AgBr is subsequently being reduced by solvated electrons acting as reducing agent. These
free electrons are generated intrinsically by electron beam irradiation of the aqueous solution. The silver
atoms can then nucleate and crystallize at different nucleation centers. One possible nucleation center is
the surface of the present gold nanorods, where an epitaxial, defect free growth of a silver shell can be
observed (cf. Fig. 1 and Fig. 2). The whole process is slowed down compared to bulk reactions because
of the confinement of the solution to a narrow channel and thus because of a higher liquid viscosity
hindering diffusion. Nevertheless, the growth rate of silver perpendicular to the longitudinal direction of
the nanorods is considerably higher compared to the growth rate in the parallel direction. Furthermore, a
dose dependent and reversible layer-by-layer dissolution of AgBr particles, acting as silver sources, is
observable (cf. Fig. 3). Here, the reduction, and thus the annihilation of solvated silver ions at higher
electron dose rate conditions shifting the solubility product to nonequilibrium state, so that AgBr dissolves
to restore this equilibrium. In contrast to this process, counter reactions prevail at lower dose conditions.
Here, the formation of silver ions is favored until the solubility is being exceeded and crystallization of
AgBr takes place.
The experiments done within this study show that this new liquid cell design is appropriate for solving
material scientific issues. In particular, the planar surface of the liquid cell as well as the large viewing
areas allow for improved performance of analytical TEM techniques like EDXS and electron tomography
making the cell architecture capable of more comprehensive investigations into complex material
systems.
2. Although the isosteric heats of adsorption derived from these isotherms are rather similar, of the order of 30 kJ/mol H2, Inelastic Neutron Scattering (INS) of adsorbed dihydrogen and Fourier-Transformed Infra-Red (FTIR) spectroscopy measurements of adsorbed CO and NO reveal that copper is encountered in two oxidation states. At least two types of Cu(I) ions are clearly detected as well as some heterogeneity of the Cu(II) species. The number of these Cu species is different in the two investigated ZSM-5 materials and depends on the Cu exchange level. With the aid of DFT model cluster calculations we find that under different coordination environments, determined by the Al distribution, both mono- and divalent Cu ions could bind H2 with a different strength. Unprecedentedly, we found that Cu-ions compensating two Al atoms, i.e. formally Cu(II) species, relatively far apart from each other, may behave very similarly to the monovalent Cu-species or alternatively viewed – as Cu(I) species that compensate for two framework Al-atoms. Such Cu-species also form stable η2 dihydrogen complexes.},
author = {Georgiev, P. A. and Drenchev, N. and Hadjiivanov, K. I. and Ollivier, J. and Unruh, Tobias and Albinati, A.},
doi = {10.1016/j.ijhydene.2021.05.166},
faupublication = {yes},
journal = {International Journal of Hydrogen Energy},
keywords = {Catalysis; DFT modelling; Hydrogen adsorption; MFI zeolite; Spectroscopic characterisation},
note = {CRIS-Team Scopus Importer:2021-07-16},
peerreviewed = {Yes},
title = {{Dynamics} of bound states of dihydrogen at {Cu}({I}) and {Cu}({II}) species coordinated near one and two zeolite framework aluminium atoms: {A} combined sorption, {INS}, {IR} and {DFT} study},
year = {2021}
}
@article{faucris.108700724,
abstract = {The temporal development of strain relaxation is monitored during and immediately after heteroepitaxy by x-ray diffraction with high resolution in strain and time. ZnSe layers on (001)GaAs with thicknesses just a little above the onset of plastic relaxation reveal inhomogeneous, partial relaxation which continues with a time constant of 50 s immediately after the stop of layer growth. A model of generation, glide, and blocking of dislocations well explains the observation that the degree of relaxation finally reached after growth stop is determined by the density of dislocations rapidly generated prior to it.},
author = {Horbaschk, M. and Benkert, A. and Schumacher, C. and Brunner, K. and Neder, Reinhard},
doi = {10.1063/1.3143630},
faupublication = {yes},
journal = {Applied Physics Letters},
keywords = {dislocation density;gallium arsenide;plasticity;semiconductor epitaxial layers;stress relaxation;X-ray diffraction;zinc compounds},
peerreviewed = {Yes},
title = {{Dynamics} of strain relaxation studied by in situ x-ray diffraction immediately after layer heteroepitaxy},
volume = {94},
year = {2009}
}
@article{faucris.120561364,
abstract = {The freezing behavior of water confined in compacted charged and uncharged clays (montmorillonite in Na-and Ca-forms, illite in Na-and Ca-forms, kaolinite and pyrophyllite) was investigated by neutron scattering. Firstly, the amount of frozen (immobile) water was measured as a function of temperature at the IN16 backscattering spectrometer, Institute Laue-Langevin (ILL). Water in uncharged, partly hydrophobic (kaolinite) and fully hydrophobic (pyrophyllite) clays exhibited a similar freezing and melting behavior to that of bulk water. In contrast, water in charged clays which are hydrophilic could be significantly supercooled. To observe the water dynamics in these clays, further experiments were performed using quasielastic neutron scattering. At temperatures of 250, 260 and 270 K the diffusive motion of water could still be observed, but with a strong reduction in the water mobility as compared with the values obtained above 273 K. The diffusion coefficients followed a non-Arrhenius temperature dependence well described by the Vogel-Fulcher-Tammann and the fractional power relations. The fits revealed that Na-and Ca-montmorillonite and Ca-illite have similar Vogel-Fulcher-Tammann temperatures (T-VFT, often referred to as the glass transition temperature) of similar to 120 K and similar temperatures at which the water undergoes the 'strong-fragile' transition, T-s similar to 210 K. On the other hand, Na-illite had significantly larger values of T-VFT similar to 180 K and T-s similar to 240 K. Surprisingly, Ca-illite has a similar freezing behavior of water to that of montmorillonites, even though it has a rather different structure. We attribute this to the stronger hydration of Ca ions as compared with the Na ions occurring in the illite clays.},
author = {González Sánchez, Fátima and Juranyi, Fanni and Gimmi, Thomas and Van Loon, Luc R. and Seydel, Tilo and Unruh, Tobias},
doi = {10.1088/0953-8984/20/41/415102},
faupublication = {no},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{Dynamics} of supercooled water in highly compacted clays studied by neutron scattering},
volume = {20},
year = {2008}
}
@article{faucris.107738444,
abstract = {We investigate the dynamics of water absorbed in amorphous and semicrystalline aromatic polyamide copolymers. The combination of dielectric spectroscopy and quasi-elastic neutron scattering experiments allows us to characterize the water dynamics over a wide range of temperatures (dielectric spectroscopy) and at microscopic length scales (neutron scattering). The dielectric investigation evidences two relaxations associated with water motions: a fast process corresponding to motions of loosely bonded water molecules and a slower process corresponding to motions of amide-water complexes. While the slower process presents the characteristic Arrhenius temperature dependence of a secondary local relaxation over the whole temperature range, the fast process shows a crossover from Arrhenius to Vogel-Fulcher-Tamman (VFT) behavior at T approximate to 225 K, characteristic of confined water dynamics. The microscopic investigation by neutron scattering shows than in the VFT regime of the fast process the dynamics present a diffusive nature similar to bulk water. A large distribution of diffusion coefficients indicates possible differences in the connectivity of the hydrogen bond network. Diffusive heterogeneous dynamics can arise from a nonuniform distribution of water. The confinement effect of the polymer matrix is detected as a considerable reduction of the diffusion coefficient of water with respect to bulk. The presence of a crystalline phase results in a slowing down of both the fast and slow processes involving water motions. This could give a hint to the presence of a rigid amorphous phase in the semicrystalline material.},
author = {Laurati, M. and Sotta, P. and Long, D. R. and Fillot, L. A. and Arbe, Arantxa and Alegria, A. and Embs, Jan Peter and Unruh, Tobias and Schneider, Gerald J. and Colmenero, Juan},
doi = {10.1021/ma202368x},
faupublication = {yes},
journal = {Macromolecules},
pages = {1676-1687},
peerreviewed = {Yes},
title = {{Dynamics} of {Water} {Absorbed} in {Polyamides}},
volume = {45},
year = {2012}
}
@article{faucris.108581044,
abstract = {Casein proteins belong to the class of natively disordered proteins. The existence of disordered biologically active proteins questions the assumption that a well-folded structure is required for function. A hypothesis generally put forward is that the unstructured nature of these proteins results from the functional need of a higher flexibility. This interplay between structure and dynamics was investigated in a series of time-of-flight neutron scattering experiments, performed on casein proteins, as well as on three well-folded proteins with distinct secondary structures, namely, myoglobin (alpha), lysozyme (alpha/beta) and concanavalin A (beta). To illustrate the subtraction of the solvent contribution from the scattering spectra, we used the dynamic susceptibility spectra emphasizing the high frequency part of the spectrum, where the solvent dominates. The quality of the procedure is checked by comparing the corrected spectra to those of the dry and hydrated protein with negligible solvent contamination. Results of spectra analysis reveal differences in motional amplitudes of well-folded proteins, where beta-sheet structures appear to be more rigid than a cluster of alpha-helices. The disordered caseins display the largest conformational displacements. Moreover their global diffusion rates deviate from the expected dependence, suggesting further large-scale conformational motions.},
author = {Gaspar, A. M. and Appavou, Marie-Sousai and Busch, Sebastian and Unruh, Tobias and Doster, Wolfgang},
doi = {10.1007/s00249-008-0266-3},
faupublication = {no},
journal = {European Biophysics Journal},
pages = {573-582},
peerreviewed = {Yes},
title = {{Dynamics} of well-folded and natively disordered proteins in solution: a time-of-flight neutron scattering study},
volume = {37},
year = {2008}
}
@article{faucris.122413544,
abstract = {Effective engineering of surface ligands in semiconductor nanocrystals can facilitate the electronic interaction between the individual nanocrystals, making them promising for low-cost optoelectronic applications. Here, the use of high purity CuZnSnS (CZTS) nanocrystals as the photoactive layer and hole-transporting material is reported in low-temperature solution-processed solar cells. The high purity CZTS nanocrystals are prepared by engineering the surface ligands of CZTS nanocrystals, capped originally with the long-chain organic ligand oleylamine. After ligand removal, CZTS nanocrystals show substantial improvement in photoconductivity and mobility, displaying also an appreciable photoresponse in a simple heterojunction solar cell architecture. More notably, CZTS nanocrystals exhibit excellent hole-transporting properties as interface layer in perovskite solar cells, yielding power conversion efficiency (PCE) of 15.4% with excellent fill factor (FF) of 81%. These findings underscore the importance of removing undesired surface ligands in nanocrystalline optoelectronic devices, and demonstrate the great potential of CZTS nanocrystals as both active and passive material for the realization of low-cost efficient solar cells.},
author = {Khanzada, Laraib Sarfraz and Levchuk, Ievgen and Hou, Yi and Azimi, Seyed Hamed and Osvet, Andres and Ahmad, Rameez and Brandl, Marco and Herre, Patrick and Distaso, Monica and Hock, Rainer and Peukert, Wolfgang and Batentschuk, Miroslaw and Brabec, Christoph},
doi = {10.1002/adfm.201603441},
faupublication = {yes},
journal = {Advanced Functional Materials},
keywords = {CZTS solar cells; HTM; Inorganic nanocrystals; Ligand exchange; Perovskite},
pages = {8300-8306},
peerreviewed = {unknown},
title = {{Effective} {Ligand} {Engineering} of the {Cu2ZnSnS4} {Nanocrystal} {Surface} for {Increasing} {Hole} {Transport} {Efficiency} in {Perovskite} {Solar} {Cells}},
volume = {26},
year = {2016}
}
@article{faucris.271020495,
abstract = {Some studies have speculated that the concentration of bromide ions plays a crucial role in the surfactant density surrounding gold nanorods (AuNR). Small-angle X-ray and neutron scattering (SAXS and SANS) experiments were conducted to analyze any influence the bromide ions might have on the stabilization layer and the aggregation behavior of the ligand CTAB molecules in general. The AuNR were immersed in solutions containing a fixed CTA+ concentration of 2 mM and varying bromide ion concentrations from 0 to 22 mM. A patchy AuNR stabilization shell at low bromide ion concentrations was found, contrary to previously published SANS studies on the AuNR stabilization shell. However, with increasing bromide ion concentration, the density of the stabilization shell increases asymptotically toward a closed/collapsed bilayer configuration. AuNR grown under similar conditions show higher anisotropy with larger bromide ion concentrations. Both results indicate that anisotropic growth strongly depends on a sufficiently dense stabilization layer established by high bromide ion concentrations.},
author = {Zech, Tobias and Schmutzler, Tilo and Noll, Dennis and Appavou, Marie-Sousai and Unruh, Tobias},
doi = {10.1021/acs.langmuir.1c02733},
faupublication = {yes},
journal = {Langmuir},
note = {CRIS-Team WoS Importer:2022-03-18},
pages = {2227-2237},
peerreviewed = {Yes},
title = {{Effect} of {Bromide} on the {Surfactant} {Stabilization} {Layer} {Density} of {Gold} {Nanorods}},
volume = {38},
year = {2022}
}
@article{faucris.106630304,
abstract = {Explored was the effect of mechanical activation on ignition and combustion of Ti-BN and Ti-SiC-C blends. Activated blends and combustion products were characterized by high-precision XRD and SEM. SHS in the systems under study was found to proceed in a mode of solid flame (no melted intermedi-ates/products). © 2011 Allerton Press, Inc.},
author = {Shkodich, N. F. and Rogachev, A. S. and Vadchenko, S. G. and Sachkova, N. V. and Neder, Reinhard and Magerl, Andreas},
doi = {10.3103/S1061386211030113},
faupublication = {yes},
journal = {International Journal of Self-Propagating High-Temperature Synthesis},
keywords = {Combustion; Ignition; Mechanical activation; SHS; Ti-BN; Ti-SiC-C},
pages = {191-199},
peerreviewed = {unknown},
title = {{Effect} of mechanical activation on ignition and combustion of {Ti}-{BN} and {Ti}-{SiC}-{C} blends},
volume = {20},
year = {2011}
}
@article{faucris.112660284,
abstract = {Self-assembled monolayer field-effect transistors (SAMFETs) are not only a promising type of organic electronic device but also allow detailed analyses of structure-property correlations. The influence of the morphology on the charge transport is particularly pronounced, due to the confined monolayer of 2D-\textgreekp-stacked organic semiconductor molecules. The morphology, in turn, is governed by relatively weak van-der-Waals interactions and is thus prone to dynamic structural fluctuations. Accordingly, combining electronic and physical characterization and time-averaged X-ray analyses with the dynamic information available at atomic resolution from simulations allows us to characterize self-assembled monolayer (SAM) based devices in great detail. For this purpose, we have constructed transistors based on SAMs of two molecules that consist of the organic p-type semiconductor benzothieno[3,2-b][1]benzothiophene (BTBT), linked to a C11 or C12 alkylphosphonic acid. Both molecules form ordered SAMs; however, our experiments show that the size of the crystalline domains and the charge-transport properties vary considerably in the two systems. These findings were confirmed by molecular dynamics (MD) simulations and semiempirical molecular-orbital electronic-structure calculations, performed on snapshots from the MD simulations at different times, revealing, in atomistic detail, how the charge transport in organic semiconductors is influenced and limited by dynamic disorder.},
author = {Schmaltz, Thomas and Gothe, Bastian and Krause, Andreas and Leitherer, Susanne and Steinrück, Hans-Georg and Thoss, Michael and Clark, Timothy and Halik, Marcus},
doi = {10.1021/acsnano.7b02394},
faupublication = {yes},
journal = {Acs Nano},
peerreviewed = {Yes},
title = {{Effect} of {Structure} and {Disorder} on the {Charge} {Transport} in {Defined} {Self}-{Assembled} {Monolayers} of {Organic} {Semiconductors}},
url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.7b02394},
year = {2017}
}
@article{faucris.214066172,
abstract = {Organic solar cells (OSCs) based on non-fullerene acceptors (NFAs) have developed very fast in recent years.
A proper balance among power conversion efficiency (PCE), stability,
and production cost needs further elaboration. Here we investigate the
industrial viability of highly efficient OSCs based on several representative NFAs. The most stable OSCs exhibit PCE of ∼8% along with extrapolated T 80 lifetime
(80% of the initial PCE) of over 11,000 hr under equivalent 1 sun
illumination, which would lead to a very impressive operational lifetime approaching 10 years.
Photo-stability is strongly dependent on the end-group and side-chain
engineering of the NFAs. Breaking of conjugation during photo-aging
leads to increased energetic traps. Fluorination of the end-group
stabilizes molecules against light soaking, while adding methyl groups
shows an opposite trend. Side-chain modification can significantly
influence the morphological stability. Reducing synthetic complexity of
this class of NFAs will ultimately push the organic photovoltaics
technology into real-life applications. © 2018 Elsevier Inc.
We investigate the industrial viability of highly efficient organic solar cells (OSCs) based on several representative non-fullerene acceptors
(NFAs) by taking into consideration the three essential parameters:
power conversion efficiency, photo-stability, and materials cost.
End-group and side-chain modifications of NFAs strongly influence
long-term photo-stability. Promising extrapolated operational lifetime approaching 10 years
has been demonstrated with the most stable system. Industrial figure of
merit (i-FoM) analysis highlights the importance of lowering the
synthetic complexity of the NFAs for commercialization of this
technology. © 2018 Elsevier Inc.
Organic solar cells with non-fullerene acceptors (NFAs) have developed rapidly in recent years.
Breakthroughs in power conversion efficiency (PCE) have significantly
raised the confidence in the community for commercialization of this
technology. In the phase of developing new materials via molecular
engineering, more attention should be paid on industrial figure of merit
(i-FoM), which considers the balance of PCE, stability, and production
cost. Here we investigate industrial viability of highly efficient organic solar cells based
on several representative NFAs. Molecular engineering on both
end-groups and side chains significantly influences the long-term
stability of organic solar cells
by altering the intrinsic chemical stability of the molecules under
light soaking as well as morphological stability. Promising lifetime approaching 10 years
is demonstrated in stable candidates. Reducing synthetic complexity is
highlighted in order to push this technology into real-life appli},
author = {Du, Xiaoyan and Heumüller, Thomas and Gruber, Wolfgang and Classen, Andrej and Unruh, Tobias and Li, Ning and Brabec, Christoph},
doi = {10.1016/j.joule.2018.09.001},
faupublication = {yes},
journal = {Joule},
keywords = {non-fullerene acceptors; organic photovoltaics; device operational stability; industrial figure of merit; bulk-heterojunction morphology},
pages = {215-226},
peerreviewed = {unknown},
title = {{Efficient} {Polymer} {Solar} {Cells} {Based} on {Non}-fullerene {Acceptors} with {Potential} {Device} {Lifetime} {Approaching} 10 {Years}},
volume = {3},
year = {2019}
}
@article{faucris.273564258,
abstract = {Structural characterization of powder samples via total scattering methods, in either real or reciprocal space, must take into account the effect of particle shape. Here, the shape contribution of a set of ideally isolated particles to the small-angle scattering (SAS) component of the intensity profile is modelled using the shape function [Svergun & Koch (2003). Rep. Prog. Phys. 66, 17351782]. The shape function is obtained by orientational averaging of common volume functions (CVFs) for a discrete set of directions. The effects of particle size and size dispersity are accounted for via scaling of the CVFs and their convolution with the underlying probability distribution. The method is applied to shapes with CVFs expressed analytically or by using discrete tables. The accurate calculation of SAS particle shape contributions up to large momentum transfer demonstrates the reliability and flexibility of modelling shape functions from sets of CVFs. The algorithm presented here is computationally efficient and can be directly incorporated into existing routines for analysis of powder total scattering data.},
author = {Leonardi, Alberto and Neder, Reinhard and Engel, Michael},
doi = {10.1107/S1600576722001261},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
note = {CRIS-Team WoS Importer:2022-04-22},
pages = {329-339},
peerreviewed = {Yes},
title = {{Efficient} solution of particle shape functions for the analysis of powder total scattering data},
volume = {55},
year = {2022}
}
@inproceedings{faucris.118012224,
author = {Göbbels, Matthias and Hock, Rainer and Magerl, Andreas and Mashkina, Elena and Demin, A.G. and et al.},
author_hint = {Mashkina Elena, L.A.Dunyushkina, A.K.Demin, Göbbels Matthias, Hock Rainer, Magerl Andreas},
booktitle = {Proceeding of Fifth European Solid Oxide Fuel Cell Forum},
faupublication = {yes},
note = {UnivIS-Import:2015-04-16:Pub.2002.nat.dphy.IAP.LK.electr{\_}32},
pages = {695-699},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Electrical} {Conductivity} in {BaTi1}-{xFexO3}-d system},
venue = {Luzern},
volume = {2},
year = {2002}
}
@article{faucris.119230584,
abstract = {Polycrystalline samples of HxNb2O5 were prepared by electrochemical reduction of pressed and sintered powder samples of the H-Nb2O5 modification. The hydrogen content of the bronze was determined by redox titration. The electrode potential showed that the bronze is thermodynamically unstable with respect to decomposition into Nb2O5 and gaseous hydrogen. The hydrogen loss obeys a second order rate law. The electrode potential fulfills Nernst's law with a square dependence on the hydrogen content. The specific resistance of H0.18Nb2O5 determined by four-point de measurements amounts to rho(30 degrees C) = (0.0110 +/- 0.0015) Omega cm. The protonic conductivity of the bronze was substantiated by polarization experiments and the diffusion coefficient of H-. (D approximate to 5 x 10(-9) cm(2)/sec) was estimated from the rate law of the depolarization voltage. (C) 1995 Academic Press, Inc.},
author = {Schwitzgebel, Günter and Unruh, Tobias},
faupublication = {no},
journal = {Journal of Solid State Chemistry},
pages = {260-264},
peerreviewed = {Yes},
title = {{ELECTROCHEMICAL} {INVESTIGATIONS} {OF} {POLYCRYSTALLINE} {HXNB2O5}},
volume = {115},
year = {1995}
}
@article{faucris.108784764,
abstract = {The crystal structure and disorder phenomena of AlBO, an aluminum borate from the mullite-type family, were studied using automated diffraction tomography (ADT), a recently established method for collection and analysis of electron diffraction data. AlBO, prepared by sol-gel approach, crystallizes in the monoclinic space group C2/m. The ab initio structure determination based on three-dimensional electron diffraction data from single ordered crystals reveals that edge-connected AlO octahedra expanding along the b axis constitute the backbone. The ordered structure (A) was confirmed by TEM and HAADF-STEM images. Furthermore, disordered crystals with diffuse scattering along the b axis are observed. Analysis of the modulation pattern implies a mean superstructure (AAB) with a threefold b axis, where B corresponds to an A layer shifted by ½a and ½c. Diffraction patterns simulated for the AAB sequence including additional stacking disorder are in good agreement with experimental electron diffraction pattern},
author = {Zhao, Haishuang and Krysiak, Yasar and Hoffmann, Kristin and Barton, Bastian and Molina-Luna, Leopoldo and Neder, Reinhard and Kleebe, Hans-Joachim and Gesing, Thorsten M. and Schneider, Hartmut and Fischer, Reinhard X. and Kolb, Ute},
doi = {10.1016/j.jssc.2017.02.023},
faupublication = {yes},
journal = {Journal of Solid State Chemistry},
keywords = {Aluminum borate; Crystal structure determination; Disorder; Electron diffraction; Superstructure},
pages = {114-123},
peerreviewed = {unknown},
title = {{Elucidating} structural order and disorder phenomena in mullite-type {Al4B2O9} by automated electron diffraction tomography},
volume = {249},
year = {2017}
}
@article{faucris.107396124,
author = {Klein, Stefanie and Kizaloglu, Melek and Portilla Berlanga, Luis and Park, Hyoungwon and Rejek, Tobias and Hümmer, Julian and Meyer, Karsten and Hock, Rainer and Distel, Luitpold and Halik, Marcus and Kryschi, Carola},
doi = {10.1002/smll.201704111},
faupublication = {yes},
journal = {Small},
peerreviewed = {unknown},
title = {{Enhanced} {In} {Vitro} {Biocompatibility} and {Water} {Dispersibility} of {Magnetite} and {Cobalt} {Ferrite} {Nanoparticles} {Employed} as {ROS} {Formation} {Enhancer} in {Radiation} {Cancer} {Therapy}},
url = {https://onlinelibrary.wiley.com/doi/full/10.1002/smll.201704111},
year = {2018}
}
@article{faucris.108701164,
abstract = {The detailed structural characterization of nanoparticles is a very important issue since it enables a precise understanding of their electronic, optical and magnetic properties. Here we introduce a new method for modeling the structure of very small particles by means of powder X-ray diffraction. Using thioglycerol-capped ZnO nanoparticles with a diameter of less than 3 nm as an example we demonstrate that our ensemble modeling method is superior to standard XRD methods like, e. g., Rietveld refinement. Besides fundamental properties (size, anisotropic shape and atomic structure) more sophisticated properties like imperfections in the lattice, a size distribution as well as strain and relaxation effects in the particles and-in particular-at their surface (surface relaxation effects) can be obtained. Ensemble properties, i.e., distributions of the particle size and other properties, can also be investigated which makes this method superior to imaging techniques like (high resolution) transmission electron microscopy or atomic force microscopy, in particular for very small nanoparticles. For the particles under study an excellent agreement of calculated and experimental X-ray diffraction patterns could be obtained with an ensemble of anisotropic polyhedral particles of three dominant sizes, wurtzite structure and a significant relaxation of Zn atoms close to the surface.},
author = {Niederdraenk, Franziska and Seufert, Knud and Stahl, Andreas and Bhalerao-Panajkar, Rohini S. and Marathe, Sonali and Kulkarni, Sulabha K. and Neder, Reinhard and Kumpf, Christian},
doi = {10.1039/c0cp00758g},
faupublication = {yes},
journal = {Physical Chemistry Chemical Physics},
month = {Jan},
pages = {498-505},
peerreviewed = {Yes},
title = {{Ensemble} modeling of very small {ZnO} nanoparticles},
volume = {13},
year = {2011}
}
@article{faucris.242412181,
abstract = {Metal-halide-perovskites revolutionized the field of thin-film semiconductor technology, due to their favorable optoelectronic properties and facile solution processing. Further improvements of perovskite thin-film devices require structural coherence on the atomic scale. Such perfection is achieved by epitaxial growth, a method that is based on the use of high-end deposition chambers. Here epitaxial growth is enabled via a approximate to 1000 times cheaper device, a single nozzle inkjet printer. By printing, single-crystal micro- and nanostructure arrays and crystalline coherent thin films are obtained on selected substrates. The hetero-epitaxial structures of methylammonium PbBr(3)grown on lattice matching substrates exhibit similar luminescence as bulk single crystals, but the crystals phase transitions are shifted to lower temperatures, indicating a structural stabilization due to interfacial lattice anchoring by the substrates. Thus, the inkjet-printing of metal-halide perovskites provides improved material characteristics in a highly economical way, as a future cheap competitor to the high-end semiconductor growth technologies.},
author = {Sytnyk, Mykhailo and Yousefi-Amin, Amir Abbas and Freund, Tim and Prihoda, Annemarie and Götz, Klaus and Unruh, Tobias and Harreiß, Christina and Will, Johannes and Spiecker, Erdmann and Levchuk, Jevgen and Osvet, Andres and Brabec, Christoph and Künecke, Ulrike and Wellmann, Peter and Volobuev, Valentin V. and Korczak, Jędrzej and Szczerbakow, Andrzej and Story, Tomasz and Simbrunner, Clemens and Springholz, Gunther and Wechsler, Daniel and Lytken, Ole and Lotter, Sebastian and Kampmann, Felix and Maultzsch, Janina and Singh, Kamalpreet and Voznyy, Oleksandr and Heiß, Wolfgang},
doi = {10.1002/adfm.202004612},
faupublication = {yes},
journal = {Advanced Functional Materials},
keywords = {epitaxial growth;inkjet printing;metal-halide-perovskites;single-crystal-microstructures},
note = {CRIS-Team Scopus Importer:2020-09-11},
peerreviewed = {Yes},
title = {{Epitaxial} {Metal} {Halide} {Perovskites} by {Inkjet}-{Printing} on {Various} {Substrates}},
volume = {30},
year = {2020}
}
@article{faucris.106805204,
abstract = {Current-voltage hysteresis is a major issue for normal architecture organo-halide perovskite
solar cells. In this manuscript we reveal a several Å thick Methylammonium Iodide (MAI) rich
interface between the perovskite and the metal oxide. Surface functionalization via selfassembled
monolayers (SAMs) allowed us to control the composition of the interface
monolayer from Pb poor to Pb rich, which in parallel suppresses hysteresis in perovskite
solar cells. The bulk of the perovskite films is not affected by the interface engineering and
remains highly crystalline in surface normal direction over the whole film thickness. The subnm
structural modifications of the buried interface were revealed by x-ray reflectivity (XRR),
which is most sensitive to monitor changes in the mass density of only several Å thin
interfacial layers as a function of substrate functionalization. From Kelvin probe force
microscopy (KPFM) on a solar cell cross section study, we further demonstrate local
variations of the potential on different electron transporting layers (ETLs) within a solar cell.
Based on these findings we present a unifying model explaining hysteresis in perovskite solar
cells, giving for the first time insight into one crucial aspect of hysteresis and paving the way
for new strategies in the fields of perovskite based opto-electronic devices.},
author = {Will, Johannes and Hou, Yi and Scheiner, Simon and Pinkert, Ute and Hermes, Ilka M. and Weber, Stefan A.L. and Hirsch, Andreas and Halik, Marcus and Brabec, Christoph and Unruh, Tobias},
doi = {10.1021/acsami.7b15904},
faupublication = {yes},
journal = {ACS Applied Materials and Interfaces},
keywords = {perovskite solar cell, hysteresis, buried interface, x-ray reflectivity, Kelvin probe force microscopy},
month = {Jan},
pages = {5511-5518},
peerreviewed = {Yes},
title = {{Evidence} of {Tailoring} the {Interfacial} {Chemical} {Composition} in {Normal} {Structure} {Hybrid} {Organohalide} {Perovskites} by a {Self}-{Assembled} {Monolayer}},
url = {https://pubs.acs.org/doi/abs/10.1021/acsami.7b15904},
volume = {10},
year = {2018}
}
@article{faucris.108581924,
abstract = {Crystal structure, specific heat, thermal expansion, magnetic susceptibility and electrical resistivity studies of the heavy fermion system CeNi9-xCuxGe4 (0 <= x <= 1) reveal a continuous tuning of the ground state by Ni/Cu substitution from an effectively fourfold-degenerate non-magnetic Kondo ground state of CeNi9Ge4 (with pronounced non-Fermi-liquid features) towards a magnetically ordered, effectively twofold-degenerate ground state in CeNi8CuGe4 with T-N = 175 +/- 5 mK. Quantum critical behavior, C/T proportional to chi proportional to - ln T, is observed for x congruent to 0.4. Hitherto, CeNi9-xCuxGe4 represents the first system where a substitution-driven quantum phase transition is connected not only with changes of the relative strength of the Kondo effect and RKKY interaction, but also with a reduction of the effective crystal field ground state degeneracy.},
author = {Peyker, Ludwig and Gold, Christian and Scheidt, Ernst-Wilhelm and Scherer, Wolfgang and Donath, J. G. and Gegenwart, Philipp and Mayr, Franz and Unruh, Tobias and Eyert, Volker and Bauer, Ernst and Michor, Herwig},
doi = {10.1088/0953-8984/21/23/235604},
faupublication = {no},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{Evolution} of quantum criticality in {CeNi9}-{xCuxGe4}},
volume = {21},
year = {2009}
}
@article{faucris.209563547,
abstract = {The core‐shell structure of colloids surrounded by ligands is of great
importance for their later application as it can significantly alter the
chemical and physical properties of the nanoparticles (NPs). A
combination of small angle X‐ray and neutron scattering (SAXS/SANS) in
the native solution with additional ex situ measurements (titration‐UV)
was applied to study the NP/ligand interface of ZnO NPs after
functionalization with catechol derivatives. Based on SAXS data, it was
found that within the multimodal particle size distribution the fraction
of agglomerates is shifted to smaller sizes and nearly disappeared upon
the binding of ethyl 3,4‐dihydroxybenzoate (CAT) molecules. This is
ascribed to improved stabilization at the primary particle level by CAT
molecules. By combining the neutron scattering contrast with the input
of bound CAT molecules from a previously developed titration‐UV method,
the heterogeneous composition of the ligand shell became accessible for
the first tim},
author = {Schindler, Torben and Lin, Wei and Schmutzler, Tilo and Lindner, Peter and Peukert, Wolfgang and Segets, Doris and Unruh, Tobias},
doi = {10.1002/cnma.201800465},
faupublication = {yes},
journal = {ChemNanoMat},
keywords = {quantum dots; Raman spectroscopy; core-shell; nanoparticles; small angle scattering},
pages = {1-9},
peerreviewed = {Yes},
title = {{Evolution} of the {Ligand} {Shell} {Around} {Small} {ZnO} {Nanoparticles} {During} the {Exchange} of {Acetate} by {Catechol}: {A} {Small} {Angle} {Scattering} {Study}},
volume = {4},
year = {2018}
}
@article{faucris.239402941,
abstract = {A fast and exact algorithm to calculate the powder pair distribution function (PDF) for the case of periodic structures is presented. The new algorithm calculates the PDF by a detour via reciprocal space. The calculated normalized total powder diffraction pattern is transferred into the PDF via the sine Fourier transform. The calculation of the PDF via the powder pattern avoids the conventional simplification of X-ray and electron atomic form factors. It is thus exact for these types of radiation, as is the conventional calculation for the case of neutron diffraction. The new algorithm further improves the calculation speed. Additional advantages are the improved detection of errors in the primary data, the handling of preferred orientation, the ease of treatment of magnetic scattering and a large improvement to accommodate more complex instrumental resolution functions.},
author = {Neder, Reinhard and Proffen, Thomas},
doi = {10.1107/S1600576720004616},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
note = {CRIS-Team WoS Importer:2020-06-19},
pages = {710-721},
peerreviewed = {Yes},
title = {{Exact} and fast calculation of the {X}-ray pair distribution function},
volume = {53},
year = {2020}
}
@article{faucris.107684104,
abstract = {Herein, various dispersions of MoS2 obtained by means of liquid phase exfoliation are spectroscopically, (spectro-) electrochemically, and microscopically characterized. At the core of these studies are transient absorption assays. Importantly, small-angle X-ray scattering measurements are employed to corroborate the exfoliated character of the MoS2 flakes in dispersion, on the one hand, and to correlate the results with TEM, AFM, and Raman characterization in the solid state, on the other. It is, then, demonstrated that transient absorption spectroscopy responds sensitively not only to changes in the sample preparation but also to instrumental and environmental parameters. It is documented that the spectroscopic features and their underlying lifetimes are tuneable on the femto-, pico-, and nanosecond scales by changing, for example, the centrifugation speed, the pump fluence, or the temperature. In other words, transient absorption spectroscopy provides an in situ method to quantitatively characterize liquid dispersions of MoS2 without facing the problems of reaggregated samples due to their drying for microscopic assays. The most far reaching results stem from resonantly and nonresonantly changing the pump fluence to characterize either single- or multiple-excited-state species such as excitons, trions, and bi-/multiexcitons and to follow their formation and deactivation pattern.},
author = {Wibmer, Leonie and Lages, Sebastian and Unruh, Tobias and Guldi, Dirk Michael},
doi = {10.1002/adma.201706702},
faupublication = {yes},
journal = {Advanced Materials},
keywords = {2D materials;MoS2;pump-probe spectroscopy;small-angle X-ray scattering (SAXS)},
peerreviewed = {Yes},
title = {{Excitons} and {Trions} in {One}-{Photon}- and {Two}-{Photon}-{Excited} {MoS2}: {A} {Study} in {Dispersions}},
volume = {30},
year = {2018}
}
@article{faucris.113874244,
abstract = {The recently presented LOPLS-AA all-atom force field for long hydrocarbon chains, based on the OPLS-AA force field, was extended to alcohols, esters, and glyceryl monooleate (GMO) lipids as a model lipid. Dihedral angles were fitted against high level ab initio calculations, and ester charges were increased to improve their hydration properties. Additionally, the ester Lennard-Jones parameters were readjusted to reproduce experimental liquid bulk properties, densities, and heats of vaporization. This extension enabled the setup of LOPLS-AA parameters for GMO molecules. The properties of the lipid force field were tested for the liquid-crystalline phase of a GMO bilayer. The obtained area per lipid for GMO is in good agreement with experiment. Additionally, the lipid dynamics on the subpicosecond to the nanosecond time scale is in excellent agreement with results from time-of-flight (TOF) quasielastic neutron scattering (QENS) experiments on a multilamellar monoolein system, enabling here for the first time the critical evaluation of the short-time dynamics obtained from a molecular dynamics simulation of a membrane system.},
author = {Pluhackova, Kristyna and Morhenn, Humphrey and Lautner, Lisa and Lohstroh, Wiebke and Nemkovski, Kirill and Unruh, Tobias and Böckmann, Rainer},
doi = {10.1021/acs.jpcb.5b08569},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {15287-99},
peerreviewed = {Yes},
title = {{Extension} of the {LOPLS}-{AA} {Force} {Field} for {Alcohols}, {Esters}, and {Monoolein} {Bilayers} and its {Validation} by {Neutron} {Scattering} {Experiments}.},
volume = {119},
year = {2015}
}
@article{faucris.243325339,
abstract = {Proccessible FePt3 alloy nanoparticles with sizes smaller than 50 nm open the avenue to novel magnetic sensor, catalytic and biomedical applications. Our research objective was to establish a highly scalable synthesis technique for production of single-crystalline FePt3 alloy nanoparticles. We have elaborated a one-pot thermal decomposition technique for the synthesis of superparamagnetic FePt3 nanoparticles (FePt3 NPs) with mean sizes of 10 nm. Subsequent tiron coating provided water solubility of the FePt3 NPs and further processibility as bidental ligands enable binding to catalyst surfaces, smart substrates or biosensors. The chemical composition, structure, morphology, magnetic, optical and crystallographic properties of the FePt3 NPs were examined using high resolution transmission electron microscopy, high angle annular dark field-scanning transmission electron microscopy, scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy mapping, Fourier transform infrared-attenuated total reflection, X-ray powder diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometry and UV–Vis absorption spectroscopy.
Co-10 at% and -15 at% Cr with the
stable hexagonal close packed (hcp) crystal structure at room
temperature have been subjected to gaseous nitriding treatment using
nitriding temperatures of 400 °C and 450 °C far below the austenite start temperature. Using X-ray and electron backscatter diffraction
(EBSD), structural changes as a result of nitrogen incorporation into
the initial hcp lattice can be divided into the following steps: (i)
expansion of the lattice due to N uptake yielding hcp (hcpexp) at nitriding temperature of 400 °C, (ii) gradual transformation of hcpexp into an expanded face-centered cubic phase (fccexp)
by increasing time at 400 °C/ or temperature to 450 °C (mixture of two
phases), (iii) development of stable nitrided layer containing fccexp using moderate nitriding times up to 3 h at 450 °C and (iv) decomposition of fccexp layer into CrN nitrides
and less expanded austenite and the reverse transformation from fcc to
hcp at near-surface regions at 450 °C after prolonged nitriding time of
24 h. Due to occurrence of step (iv), the square-root treatment-time
dependence of the nitrided layer thickness breaks down. Nitrogen-depth
profiles obtained for Co-15 at% Cr by glow-discharge optical emission spectroscopy (GDOES) along with the Non-Rutherford MeV proton backscattering spectrometry reveal a nitrogen supersaturation of around 20 at% at surface-adjacent areas in hcpexp. A relatively large unit volume expansion has been recognized for hcpexp with a change of c/a ratio of around 0.6%. Hardness-depth profiles obtained for nitrided Co-10 at% and -15 at% Cr alloys using nanoindentation evidence an increase in hardness inside the nitrided layer, compared to the untreated core.
},
author = {Akhlaghi, Maryam and Hock, Rainer and Dallmann, Johannes and Krapf, Anna and Merle, Benoit and Hofsäss, Hans and Körner, Carolin and Leineweber, Andreas},
doi = {10.1016/j.jallcom.2022.164535},
faupublication = {yes},
journal = {Journal of Alloys and Compounds},
keywords = {Nitride materials; Precipitation; Phase transitions; Rutherford backscattering, scanning electron microscopy, SEM; X-ray diffraction},
peerreviewed = {Yes},
title = {{Gaseous} nitriding of {Co}-10 at% and -15 at% {Cr} alloys at 400 °{C} and 450 °{C}},
volume = {907},
year = {2022}
}
@article{faucris.216852496,
abstract = {Optical cavities are widely used to enhance the interaction between atoms and light. Typical designs using a geometrically symmetric structure in the near-concentric regime face a tradeoff between mechanical stability and high single-atom cooperativity. To overcome this limitation, we design and implement a geometrically asymmetric standing-wave cavity. This structure, with mirrors of very different radii of curvature, allows strong atom-light coupling while exhibiting good stability against misalignment. We observe effective cooperativities ranging from ηeff=10 to ηeff=0.2 by shifting the location of the atoms in the cavity mode. By loading Yb171 atoms directly from a mirror magneto-optical trap into a one-dimensional optical lattice along the cavity mode, we produce atomic ensembles with collective cooperativities up to Nη=2×104. This system opens a way to preparing spin squeezing for an optical lattice clock and to accessing a range of nonclassical collective states.},
author = {Kawasaki, Akio and Braverman, Boris and Pedrozo-Penafiel, Edwin and Shu, Chi and Colombo, Simone and Li, Zeyang and Ozel, Ozge and Chen, Wenlan and Salvi, Leonardo and Heinz, André and Levonian, David and Akamatsu, Daisuke and Xiao, Yanhong and Vuletic, Vladan},
doi = {10.1103/PhysRevA.99.013437},
faupublication = {yes},
journal = {Physical Review A},
month = {Jan},
note = {CRIS-Team Scopus Importer:2019-05-02},
peerreviewed = {Yes},
title = {{Geometrically} asymmetric optical cavity for strong atom-photon coupling},
volume = {99},
year = {2019}
}
@article{faucris.117606324,
abstract = {Silicon carbide as a material for electronic devices still has Substantial problems concerning its structural quality and defects. It has been shown that dopants call have a big influence on structural properties like poly-type stability and dislocation statistics [1]. We will discuss the effect of an isoelectronic dopant in silicon carbide. Germanium, being a member of the 4(th) group in the periodic table of elements like silicon and carbon, will not influence the electrical properties of the material such as e.g. aluminum. In Our experiments we reached concentrations of up to 1*10(20) cm(-3). We have observed all impact on the polytype stability during sublimation growth with in-situ germanium incorporation. We investigated all influence on the dislocation statistics during growth and, hence, varying germanium concentration. We found only a slight decrease in mobility during Hall measurements but no severe changes in electrical properties of the materia},
author = {Hens, Philip and Künecke, Ulrike and Konias, Katja and Hock, Rainer and Wellmann, Peter},
doi = {10.4028/www.scientific.net/MSF.615-617.11},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {Bulk Growth; Dislocation; EDX; Germanium; Hall; Lattice Parameter},
month = {Jan},
pages = {11-14},
peerreviewed = {Yes},
title = {{Germanium} {Incorporation} during {PVT} {Bulk} {Growth} of {Silicon} {Carbide}},
volume = {615-617},
year = {2009}
}
@article{faucris.106868784,
abstract = {The oxygen precipitation of highly (17.5 m Omega cm) and moderately (4.5 Omega cm) boron (B) doped silicon (Si) crystals at 780 degrees C is investigated by following in-situ the evolution of diffraction Pendellosung oscillations. All samples show an initial diffusion-driven growth process which may change over into Ostwald ripening. For the highly doped sample and involving a nucleation step at 450 degrees C for 30 h, the precipitate density rho is enhanced by a factor of 8 as compared to the moderately doped sample. The influence of a high B concentration on rho is dramatically higher for the samples directly heated to 780 degrees C, where an enhancement factor of 80 is found. Considering Ostwald ripening as a second growth regime reveals consistent ripening rates and surface energies sigma with those found at 900 degrees C in a previous publication. (c) 2014 AIP Publishing LLC.},
author = {Will, Johannes and Gröschel, Alexander and Bergmann, Christoph and Weißer, Matthias and Magerl, Andreas},
doi = {10.1063/1.4896184},
faupublication = {yes},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Growth} and nucleation regimes in boron doped silicon by dynamical x-ray diffraction},
volume = {105},
year = {2014}
}
@article{faucris.108582144,
abstract = {The two binary clathrates with vacancies (square) Rb8Sn44 square(2) and Cs8Sn44 square(2) have been examined using powder inelastic neutron scattering (INS). Rattling energies of Rb and Cs are found to be similar by both experiment and calculations, h omega(Cs) =h omega(Rb)vertical bar(Exp) = 0.98(1) and h omega(Cs) =h omega(Rb)vertical bar(Calc) = 1.0, despite the significant mass difference: m(Cs)/m(Rb) = 1.6, which shows that guest-host interaction is non-negligible for the studied system. For Rb8Sn44 square(2), a low energy phonon mode is observed at approximate to 3.5 meV, below the phonon mode which in the literature is attributed to the guest atom. The 3.5 meV mode is interpreted to have significant spectral weight of Sn host atoms based on temperature dependence and comparison with published theoretical phonon calculations. The record of low thermal conductivity of the tin clathrates can be attributed to the host structure dynamics rather than the guest atom rattling. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793081]},
author = {Christensen, Sebastian and Bjerg, Lasse and Kaltzoglou, Andreas and Juranyi, Fanni and Fässler, Thomas and Unruh, Tobias and Christensen, Mogens},
doi = {10.1063/1.4793081},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Guest} host interaction and low energy host structure dynamics in tin clathrates},
volume = {113},
year = {2013}
}
@article{faucris.108583024,
abstract = {The vibrational dynamics of vitreous germanium diselenide (v-GeSe2), an amorphous glass belonging to the family of continuous random network forming glasses, has been investigated by means of inelastic neutron scattering. We employed three different neutron spectrometers, each of them providing different energy resolutions and spanning different portions of the energy-wave-vector ((h) over bar omega,Q) plane, which partially overlap so that complementary information can be obtained. Two well-defined peaks are resolved in the dynamic structure factor in a broad Q region, below and above the position of the first sharp diffraction peak in the static structure factor. The low-lying excitation is nondispersive and located around the boson peak frequency. The high-frequency mode presents a pseudoperiodic behavior and it can be associated to the high-frequency counterpart of the longitudinal acoustic (LA) mode. In the low-Q region this mode shows a positive dispersion of its apparent sound velocity and an attenuation which follows a Q(2) law. The combined use of a set of appropriate instruments allows an accurate determination of the nonergodicity parameter f(Q). The LA dispersion curve of v-GeSe2 is similar to that measured in other glasses where a second excitation appears in the spectra. On the contrary other glass forming materials, where this second mode is not detected, present a sinusoidal-like dispersion curve with a deeper minimum in the second pseudo-Brillouin zone.},
author = {Orsingher, Laura and Baldi, Giacomo and Fontana, Aldo and Bove, Livia E. and Unruh, Tobias and Orecchini, A. and Petrillo, Caterina and Violini, N. and Sacchetti, Francesco},
doi = {10.1103/PhysRevB.82.115201},
faupublication = {no},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{High}-frequency dynamics of vitreous {GeSe2}},
volume = {82},
year = {2010}
}
@article{faucris.318014905,
abstract = {Unraveling the two-dimensional (2D) structural ordering of colloidal particles assembled at a flat surface is essential for understanding and optimizing their physical properties. So far, grazing-incidence small-angle X-ray scattering (GISAXS) has been widely used to determine crystallographic information on 2D self-assembled structures of nanosize objects. However, solving the structure of 2D lattices consisting of micrometer (μm)-sized objects still remains a challenge using scattering methods. Here, a model 2D SCALMS (supported catalytically active liquid metal solution) template is fabricated from μm-sized polystyrene (PS) spheres that form a monolayer on top of the flat solid support. GISAXS patterns of the sample were collected for rotation angles around its surface normal in steps of 3°. For every rotation angle, different Bragg-type interference maxima along the out-of-plane (qz) direction were observed. On the basis of simulations of GISXAS patterns of single domains of ordered particle arrangements using the distorted wave Born approximation (DWBA) and validation against a simple geometrical scattering model, the interference maxima could nicely be interpreted to originate from a monolayer of the μm-sized spherical particles which are arranged in domains of hexagonal 2D paracrystalline order. This novel GISAXS evaluation technique serves as a proof of principle for determining the μm-size periodicity of 2D crystalline domains and demonstrates its potential to spatially resolve the relative orientations of such domains with respect to a reference direction.},
author = {Maiti, Santanu and Senavirathna, L. N. and Minguez Bacho, Ignacio and Menath, Johannes and Gruber, W. and Vogel, Nicolas and Bachmann, Julien and Unruh, Tobias},
doi = {10.1021/acs.langmuir.3c02219},
faupublication = {yes},
journal = {Langmuir},
month = {Jan},
note = {CRIS-Team Scopus Importer:2024-02-09},
pages = {1185-1194},
peerreviewed = {Yes},
title = {{Highly} {Ordered} {Monolayers} of μm-{Sized} {Polystyrene} {Spheres} {Studied} by {Grazing}-{Incidence} {Small}-{Angle} {X}-ray {Scattering}, {Simulations}, and {Geometrical} {Calculations}},
volume = {40},
year = {2024}
}
@article{faucris.272775513,
abstract = {High-quality epitaxial growth of oriented microcrystallites on a semiconductor substrate is demonstrated here for formamidinium lead bromide perovskite, by drop casting of precursor solutions in air. The microcrystallites exhibit green photoluminescence at room temperature, as well as lasing with low thresholds. Lasing is observed even though the substrate is fully opaque at the lasing wavelengths, and even though it has a higher refractive index as the perovskite active material. Moreover, the lasing is stable for more than 109 excitation pulses, which is more than what is previously achieved for devices kept in the air. Such highly stable lasing under pulsed excitation represents an important step towards continuous mode operation or even electrical excitation in future perovskite-based devices.},
author = {Afify, Hany A. and Sytnyk, Mykhailo and Rehm, Viktor and Barabash, Anastasiia and Mashkov, Oleksandr and Osvet, Andres and Volobuev, Valentine V. and Korczak, Jędrzej and Szczerbakow, Andrzej and Story, Tomasz and Götz, Klaus and Unruh, Tobias and Schüßlbauer, Christoph and Thiel, Dominik and Ullrich, Tobias and Guldi, Dirk Michael and Brabec, Christoph and Heiß, Wolfgang},
doi = {10.1002/adom.202200237},
faupublication = {yes},
journal = {Advanced Optical Materials},
keywords = {halide perovskites; lasing; microresonators; solution epitaxy},
note = {CRIS-Team Scopus Importer:2022-04-14},
peerreviewed = {Yes},
title = {{Highly} {Stable} {Lasing} from {Solution}-{Epitaxially} {Grown} {Formamidinium}-{Lead}-{Bromide} {Micro}-{Resonators}},
year = {2022}
}
@article{faucris.111515184,
abstract = {Lead halide perovskite semiconductors are in general known to have an inherently high X-ray absorption cross-section and a significantly higher carrier mobility than any other low-temperature solution-processed semiconductor. So far, the processing of several-hundred-micrometres-thick high-quality crystalline perovskite films over a large area has been unresolved for efficient X-ray detection. In this Article, we present a mechanical sintering process to fabricate polycrystalline methyl ammonium lead triiodide perovskite (MAPbI(3)) wafers with millimetre thickness and well-defined crystallinity. Benchmarking of the MAPbI(3) wafers against state-of-the-art CdTe detectors reveals competitive conversion efficiencies of 2,527 mu C Gy(air)(-1) cm(-2) under 70 kV(p) X-ray exposure. The high ambipolar mobility-lifetime product of 2 x 10(-4) cm(2) V-1 is suggested to be responsible for this exceptionally high sensitivity. Our findings inform a new generation of highly efficient and low-cost X-ray detectors based on perovskite wafer},
author = {Shrestha, Shreetu and Fischer, Rene and Matt, Gebhard and Feldner, Patrick and Michel, Thilo and Osvet, Andres and Levchuk, Ievgen and Merle, Benoit and Golkar, Saeedeh and Chen, Haiwei and Tedde, Sandro F. and Schmidt, Oliver and Hock, Rainer and Ruehrig, Manfred and Göken, Mathias and Heiß, Wolfgang and Anton, Gisela and Brabec, Christoph},
doi = {10.1038/NPHOTON.2017.94},
faupublication = {yes},
journal = {Nature Photonics},
pages = {436-+},
peerreviewed = {Yes},
title = {{High}-performance direct conversion {X}-ray detectors based on sintered hybrid lead triiodide perovskite wafers},
volume = {11},
year = {2017}
}
@inproceedings{faucris.233440623,
abstract = {The search for an ideal X-ray sensitive
photo-conductor is an ongoing task since the most semiconductors do not
absorb high energy radiation effectively. However, the latter is an
intrinsic property of the lead-halide perovskites semiconductors due to
high radiation attenuation by the lead and halide ions combined with
there good charge transport properties.
In this presentation we will review our latest efforts utilizing organic-inorganic (MAPbI3) as well as a pure inorganic metal-halide perovkite (CsPbBr3)
for X-ray to current converters. We demonstrate a sintering as well as a
melting process which leads to the formation of several hundred µm
thick and crystalline samples. Most notable for these samples are the
good charge transport properties and unusual high mobility- lifetime
products (~1E-3 cm^2/V).
The achieved X-ray to current conversation rate up to 2500 µC/Gycm2
is on par to the current state-of-the-art Cd(Zn)Te detector technology
and our findings inform on a low-cost scaleable technology for the next
generation of high energy detector technology.
},
author = {Matt, Gebhard and Levchuk, Ievgen and Knüttel, Judith and Shrestha, Shreetu and Dallmann, Johannes and Hock, Rainer and Heiß, Wolfgang and Brabec, Christoph},
booktitle = {nanoGe Fall Meeting 2019},
date = {2019-11-04/2019-11-05},
doi = {10.29363/nanoge.ngfm.2019.142},
faupublication = {yes},
peerreviewed = {unknown},
title = {{High} {Performance} {X}-ray to {Current} {Converters} {Fabricated} {Via} {Sintering} or {Melting} of a {Metal}-halide {Perovskite}},
venue = {Berlin},
year = {2019}
}
@article{faucris.108585224,
abstract = {We investigated the dynamics of confined water indifferent hydrated cement pastes With minimized contributions of capillary water. It was found that the water motions are extremely reduced compared to those of bulk water The onset of water mobility, which was modified by the local environment, was investigated with elastic temperature scans using the high-resolution neutron backscattering instrument SPHERES Using a Cauchy-Lorenz distribution. the quasi-elastic signal observed in the spectra obtained by the backscattering spectrometer was analyzed, leading to the identification of rotational motions with relaxation times of 0 3 ns Additionally, neutron spin echo (NSE) spectroscopy was used to measure the water diffusion over the local network of pores The motions observed in the NSE time scale were characterized by diffusion constants ranging from 0 6 to 1 1 x 10(-9) m(2) s(-1) most likely related to water molecules removed from the interface In summary, our results indicate that the local diffusion observed in the gel pores of hardened cement pastes is on the order of that found in deeply supercooled water Finally, the importance of the magnetic properties of cement pastes were discussed in relation to the observation of a quasi-elastic signal on the dried sample spectra measured using the time-of-flight spectrometer},
author = {Bordallo, Heloisa Nunes and Aldridge, Laurence P. and Fouquet, Peter and Pardo, Luis Carlos and Unruh, Tobias and Wuttke, Joachim and Yokaichiya, Fabiano},
doi = {10.1021/am900332n},
faupublication = {no},
journal = {ACS Applied Materials and Interfaces},
keywords = {cement paste;pore structure;neutron scattering;water dynamics;water diffusion;magnetic relaxation},
pages = {2154-2162},
peerreviewed = {Yes},
title = {{Hindered} {Water} {Motions} in {Hardened} {Cement} {Pastes} {Investigated} over {Broad} {Time} and {Length} {Scales}},
volume = {1},
year = {2009}
}
@article{faucris.120872444,
abstract = {We investigated molecular motions on a picosecond timescale of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) model membranes as a function of hydration by using elastic and quasielastic neutron scattering. Two different hydrations corresponding to approximately nine and twelve water molecules per lipid were studied, the latter being the fully hydrated state. In our study, we focused on head group motions by using chain deuterated lipids. Information on in-plane and out-of-plane motions could be extracted by using solid supported DMPC multilayers. Our studies confirm and complete former investigations by Konig et al. [J. Phys. II (France) 2, 1589 (1992)] and Rheinstadter et al. [Phys. Rev. Lett. 101, 248106 (2008)] who described the dynamics of lipid membranes, but did not explore the influence of hydration on the head group dynamics as presented here. From the elastic data, a clear shift of the main phase transition from the P-beta ripple phase to the L-alpha liquid phase was observed. Decreasing water content moves the transition temperature to higher temperatures. The quasielastic data permit a closer investigation of the different types of head group motion of the two samples. Two different models are needed to fit the elastic incoherent structure factor and corresponding radii were calculated. The presented data show the strong influence hydration has on the head group mobility of DMPC. (C) 2010 American Institute of Physics. [doi:10.1063/1.3495973]},
author = {Trapp, Marcus and Gutberlet, Thomas and Juranyi, Fanni and Unruh, Tobias and Demé, Bruno and Tehei, Moeava and Peters, Judith},
doi = {10.1063/1.3495973},
faupublication = {no},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{Hydration} dependent studies of highly aligned multilayer lipid membranes by neutron scattering},
volume = {133},
year = {2010}
}
@article{faucris.265711868,
abstract = {Herein we systematically investigate the influence of hydrogenation time and temperature on defects formation, structural changes, and co-catalyst free photocatalytic activity for epitaxially grown anatase thin films on strontium titanate single crystals. The photocatalytic activity trend of the anatase epi layers is similar to that of anatase powders and brookite single crystals in reported recent literature, that is, the H2 evolution rate exhibits a typical maximum upon hydrogenation under moderate annealing temperatures (500 °C). By combining surface sensitive X-ray diffraction methods and analytical high-resolution electron microscopy techniques we reveal quantitatively the oxygen loss from the epi-layer ascribed to the hydrogenation (H2 reduction) treatment. We observe specific physicochemical changes associated with the introduction of oxygen vacancies: (i) the formation of a nanoscale strained crystal surface, (ii) the agglomeration of point defects in the bulk of the anatase epi layer, and (iii) a transition towards a Ti2O3 like symmetry at the film surface, i.e. an evident oxygen deficiency at the epi layer surface in particular prominent for the most active sample as a function of the hydrogenation parameters. These extensive experimental findings allow us to propose an empirical model, which links detrimental and beneficial effects of Ti3+ centers and oxygen vacancies in the bulk and at the surface and their abundance to an optimum point defect configuration for water splitting via “grey” anatase.},
author = {Will, Johannes and Wierzbicka, Ewa and Wu, Mingjian and Götz, Klaus and Yokosawa, Tadahiro and Liu, Ning and Tesler, Alexander and Stiller, Markus and Unruh, Tobias and Altomare, Marco and Schmuki, Patrik and Spiecker, Erdmann},
doi = {10.1039/D1TA04809K},
faupublication = {yes},
journal = {Journal of Materials Chemistry A},
peerreviewed = {Yes},
title = {{Hydrogenated} anatase {TiO2} single crystals: defects formation and structural changes as microscopic origin of co-catalyst free photocatalytic {H2} evolution activity},
year = {2021}
}
@article{faucris.307282493,
abstract = {Mixed lead and tin (Pb/Sn) hybrid perovskites exhibit a great potential in fabricating all-perovskite tandem devices due to their easily tunable bandgaps. However, the energy deficit and instability in Pb/Sn perovskite solar cells (PSCs) constrain their practical applications, which renders defect passivation engineering indispensable to develop highly efficient and long-term stable PSCs. Herein, the mechanisms of strain tailoring and defect passivation in Pb/Sn PSCs by 2D ligands are investigated. The 2D ligands include electroneutral cations with long alkyl chain (LAC), iodates with relatively short alkyl chain (SAC) and their mixtures. This study reveals that LAC ligands facilitate the relaxation of tensile strain in perovskite films while SAC ligands cause strain buildup. By mixing LAC/SAC ligands, tensile strain in perovskite films can be balanced which improves solar cell performance. PSCs with admixed β-guanidinopropionic acid (GUA)/phenethylammonium iodide (PEAI) exhibit enhanced open circuit voltage and fill factor, which is attributed to reduced nonradiative recombination losses in the bulk and at the interfaces. Furthermore, the operational stability of PSCs is slightly improved by the mixed 2D ligands. This work reveals the mechanisms of 2D ligands in strain tailoring and defect passivation toward efficient and stable narrow-bandgap PSCs.},
author = {Zhang, Kaicheng and Vincze, Andrej and Metwalli, Ezzeldin and Zhang, Jiyun and Liu, Chao and Meng, Wei and Zhang, Boxue and Tian, Jingjing and Heumüller, Thomas and Xie, Zhiqiang and Luo, Junsheng and Osvet, Andres and Unruh, Tobias and Lüer, Larry and Li, Ning and Brabec, Christoph},
doi = {10.1002/adfm.202303455},
faupublication = {yes},
journal = {Advanced Functional Materials},
keywords = {2D ligand passivation; energy losses; lead/tin perovskite solar cells; stability; strain tailoring},
note = {CRIS-Team Scopus Importer:2023-07-07},
peerreviewed = {Yes},
title = {{Impact} of {2D} {Ligands} on {Lattice} {Strain} and {Energy} {Losses} in {Narrow}-{Bandgap} {Lead}–{Tin} {Perovskite} {Solar} {Cells}},
year = {2023}
}
@article{faucris.108585884,
abstract = {A combination of quasielastic neutron scattering (QNS) and molecular-dynamics (MD) simulation is used to modify an embedded atom method (EAM) potential for Ti with respect to the description of melt properties and crystallization from the melt. In the MD simulation, the EAM model is optimized such that agreement with accurate data of self-diffusion coefficients from QNS is achieved. As a result the density and the melting temperature are in good agreement with experiment.},
author = {Horbach, Jürgen and Rozas, Roberto and Unruh, Tobias and Meyer, Andreas},
doi = {10.1103/PhysRevB.80.212203},
faupublication = {no},
journal = {Physical Review B},
keywords = {crystallisation;liquid metals;liquid theory;melting;molecular dynamics method;neutron diffraction;self-diffusion;titanium},
peerreviewed = {Yes},
title = {{Improvement} of computer simulation models for metallic melts via quasielastic neutron scattering: {A} case study of liquid titanium},
volume = {80},
year = {2009}
}
@article{faucris.119751324,
abstract = {In this work, we present and support the positive influence of 1,8-diiodooctane (DIO) as processing additive for the fabrication of solution processed near infrared (NIR) organic photodiodes (OPDs) based on the spray-coated blend of [6,6]phenyl-C70-butyric acid methyl ester (PC70BM) and poly[(2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-diox-opyrrolo[3,4-c]pyrrole-1,4-diyl)-alt-([2,2’:5′,2″-terthiophene]-5,5″-diyl)] (PDPP3T). Transmission electron microscopy (TEM) analysis show that the use of DIO improves donor–acceptor interfaces in the bulk heterojunction (BHJ) layer. Besides the enhancement of electron/hole transport pathways that leads to higher efficiencies, it reduces significantly the roughness of spray coated layers. The External Quantum Efficiency (EQE) is increased up to 35% at 900 nm and the dark current is decreased one order of magnitude in comparison to the reference down to 20 nA/cm2 at -5 V. The OPD's detectivity is increased from 1.66×1011 Jones to 3.34×1012 Jones and the linearity response is improved. A comprehensive morphological and electro-optical characterization of the generated layers and devices is the main focus of this work.},
author = {Montenegro Benavides, Cindy and Rechberger, Stefanie and Spiecker, Erdmann and Berlinghof, Marvin and Unruh, Tobias and Biele, Markus and Schmidt, Oliver and Brabec, Christoph and Tedde, Sandro F.},
doi = {10.1016/j.orgel.2017.12.022},
faupublication = {yes},
journal = {Organic Electronics},
keywords = {DIO additive, organic photodetectors, spray coating, BHJ morphology},
pages = {21-26},
peerreviewed = {Yes},
title = {{Improving} spray coated organic photodetectors performance by using 1,8-diiodooctane as processing additive},
year = {2018}
}
@article{faucris.107774524,
abstract = {We present measurements of the vibrational spectrum of a binary niobium-phosphate glass in the THz frequency range using inelastic neutron and Raman scattering. The spectra of these glasses show a low-frequency enhancement of the vibrational density of states ("boson peak"). Using a recently developed theory of vibrational excitations in disordered solids we are able to reconcile the measured neutron and Raman spectra using fluctuating elastic and Pockels constants as a model concept. As the spontaneous Raman susceptibility is a key parameter for Raman amplification our results suggest a significant gain profile for application of niobium-phosphate glasses in Raman amplifiers. (C) 2010 Elsevier B.V. All rights reserved.},
author = {Unruh, Tobias and Schulte, Alfons and Guo, Y. and Schirmacher, Walter and Schmid, B.},
doi = {10.1016/j.jnoncrysol.2010.06.073},
faupublication = {no},
journal = {Journal of Non-Crystalline Solids},
keywords = {Raman scattering;Neutron scattering;Raman gain;Boson peak},
month = {Jan},
pages = {506-509},
peerreviewed = {Yes},
title = {{Inelastic} neutron and low-frequency {Raman} scattering in a niobium-phosphate glass for {Raman} gain applications},
volume = {357},
year = {2011}
}
@article{faucris.108586104,
abstract = {We investigate the low-frequency enhancement of vibrational excitations ('boson peak') in niobium-phosphate glasses through the combination of inelastic neutron and polarization-resolved Raman scattering. The spectra of these glasses reveal an enhancement of the vibrational density of states and of the cross section for spontaneous Raman scattering in the frequency range below 150 cm(-1). A recent theoretical model that is based on fluctuating elastic and elasto-optic (Pockels) constants provides a unified description of the measured neutron and Raman spectra, including the depolarization ratio.},
author = {Schulte, Alfons and Schirmacher, Walter and Schmid, B. and Unruh, Tobias},
doi = {10.1088/0953-8984/23/25/254212},
faupublication = {yes},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{Inelastic} neutron and low-frequency {Raman} scattering in niobium-phosphate glasses: the role of spatially fluctuating elastic and elasto-optic constants},
volume = {23},
year = {2011}
}
@article{faucris.121547844,
abstract = {The synthesis, crystal structure and magnetic characterisation by magnetisation and inelastic neutron scattering (INS) of a mixed-valent Mn-10 supertetrahedral aggregate [(Mn6Mn4II)-Mn-III(mu(4)-O)(4)(mu(3)-N-3)(3)(mu(3)-Br)-(Hmpt)(6)(Br)]Br-0.7(N-3)(0.3)center dot 2MeOH center dot 3MeCN (1) (H(3)mpt = 3-methylpentan-1,3,5-triol) is reported. The magnetic core of the molecule can be described as an octahedron of six S=2 Mn-III ions with four faces, each capped by a S=5/2 Mn-II ion such as to form the supertetrahedron. Unlike most related complexes, the molecular symmetry is slightly reduced from approximately T-d to C-3. The magnetic data reveal a total spin of S=22 in the ground state due to ferromagnetic exchange couplings within the molecule. The combined INS and magnetic data permits the accurate determination of the exchange coupling constants. Two types are found. The couplings between the Mn-III ions in the inner octahedron are characterised by J(a)=18.4(3) K, whereas the couplings between the apical Mn-II ions to the neighbouring Mn-III ions are given by J(b)=7.3(2) K. The significantly larger coupling strength J(a) as compared to J(b), and the near-T-d symmetry have profound consequences on the energy spectrum, which are discussed and carefully analysed. In particular, the observed INS spectra can consistently be reproduced by a simplified model in which the inner octahedron is replaced by one large spin of length S-0=12. This model provides intuitive insight into the structure of the magnetic spectrum. Additionally, the magnetic excitations at low temperature are analysed within the frame of ferromagnetic linear spin-wave theory, which permits an analytical calculation of the energy levels. For ferromagnetic clusters, a close analogy to the Huckel method of electronic structure calculation can be drawn, which allows one to grasp the results of the spin-wave theory or the magnetic excitation spectrum, respectively, in a chemical language.},
author = {Stuiber, Stefan and Wu, Gang and Nehrkorn, Joscha and Dreiser, Jan and Lan, Yanhua and Novitchi, Ghenadie and Anson, Christopher E. and Unruh, Tobias and Powell, Anni K. and Waldmann, Oliver},
doi = {10.1002/chem.201100500},
faupublication = {yes},
journal = {Chemistry - A European Journal},
keywords = {coordination clusters;inelastic neutron scattering;magnetic properties;manganese;spin-wave theory},
pages = {9094-9106},
peerreviewed = {Yes},
title = {{Inelastic} {Neutron} {Scattering} on an {Mn}-10 {Supertetrahedron}: {Assessment} of {Exchange} {Coupling} {Constants}, {Ferromagnetic} {Spin} {Waves} and an {Analogy} to the {Huckel} {Method}},
volume = {17},
year = {2011}
}
@article{faucris.108586324,
abstract = {Liquid germanium exhibits a change in the bonding character from being more covalent to more metallic while heating. We used quasielastic neutron scattering to measure the absolute value of self-diffusion coefficients in this liquid. Compared to other monoatomic liquids, such as liquid Ni or Ti, the self-diffusivity is an order faster near the melting temperature and shows a non-Arrhenius-like behavior. Above 1325 K, the activation energy for self-diffusion is low and obeys Stokes-Einstein relation. Even though the packing density of liquid germanium is less than that of simple metallic melts such as Pb or Sn, the temperature dependence of self-diffusivity does not exhibit D proportional to T(n)(n similar or equal to 2) form, which is observed for uncorrelated binary collisions of hard-spheres.},
author = {Chathoth, Suresh Mavila and Damaschke, Bernd and Unruh, Tobias and Samwer, Konrad},
doi = {10.1063/1.3139753},
faupublication = {no},
journal = {Applied Physics Letters},
keywords = {germanium;liquid metals;melting;neutron diffraction;self-diffusion},
peerreviewed = {Yes},
title = {{Influence} of structural changes on diffusion in liquid germanium},
volume = {94},
year = {2009}
}
@article{faucris.200237077,
abstract = {We report on the tailoring of ZnO nanoparticle (NP) surfaces by catechol derivatives (CAT) with different functionalities: tert-butyl
group (tertCAT), hydrogen (pyroCAT), aromatic ring (naphCAT), ester
group (esterCAT), and nitro group (nitroCAT). The influence of
electron-donating/-withdrawing properties on enthalpy of ligand binding
(ΔH) was resolved and subsequently linked with optical
properties. First, as confirmed by ultraviolet/visible (UV/vis) and
Fourier transform infrared (FT-IR) spectroscopy results, all CAT
molecules chemisorbed to ZnO NPs, independent of the distinct
functionality. Interestingly, the ζ-potentials of ZnO after
functionalization shifted to more negative values. Then, isothermal
titration calorimetry (ITC) and a mass-based method were applied to
resolve the heat release during ligand binding and the adsorption
isotherm, respectively. However, both heat- and mass-based approaches
alone did not fully resolve the binding enthalpy of each molecule
adsorbing to the ZnO surface. This is mainly due to the fact that the
Langmuir model oversimplifies the underlying adsorption mechanism, at
least for some of the tested CAT molecules. Therefore, a new,
fitting-free approach was developed to directly access the adsorption
enthalpy per molecule during functionalization by dividing the heat
release measured via ITC by the amount of bound molecules determined
from the adsorption isotherm. Finally, the efficiency of quenching the
visible emission caused by ligand binding was investigated by
photoluminescence (PL) spectroscopy, which turned out to follow the same
trend as the binding enthalpy. Thus, the functionality of ligand
molecules governs the binding enthalpy to the particle surface, which in
turn, at least in the current case of ZnO, is an important parameter
for the quenching of visible emission. We believe that establishing such
correlations is an important step toward a more general way of
selecting and designing ligand molecules for surface functionalization.
This allows developing strategies for tailored colloidal surfaces beyond
empirically driven formulation on a case by case basi},
author = {Segets, Doris and Lin, Wei and Schmidt, Jochen and Peukert, Wolfgang and Mahler, Michael and Schindler, Torben and Unruh, Tobias and Meyer, Bernd},
doi = {10.1021/acs.langmuir.7b03079},
faupublication = {yes},
journal = {Langmuir},
keywords = {functionalization; nanoparticle; photoluminesence;},
pages = {13581-13589},
peerreviewed = {Yes},
title = {{Influence} of {Tail} {Groups} during {Functionalization} of {ZnO} {Nanoparticles} on {Binding} {Enthalpies} and {Photoluminescence}},
volume = {33},
year = {2017}
}
@article{faucris.226138550,
author = {Harreiß, Christina and Langner, Stefan and Berlinghof, Marvin and Rechberger, Stefanie and Will, Johannes and Unruh, Tobias and Brabec, Christoph and Spiecker, Erdmann},
doi = {10.1017/S143192761901119X},
faupublication = {yes},
journal = {Microscopy and Microanalysis},
pages = {2092-2093},
peerreviewed = {Yes},
title = {{In} {Situ} and {Ex} {Situ} {Energy}-{Filtered} {Transmission} {Electron} {Microscopy} {Studies} on the {Nanomorpholgy} {Evolution} of {Organic} {Bulk} {Heterojunction} {Solar} {Cells}},
volume = {25},
year = {2019}
}
@article{faucris.112883804,
abstract = {Recently, in situ characterization methods have attracted increasing attention, especially in organic photovoltaics (OPV) field, since they provide greater insight into the mechanism of film formation, thus help to identify optimized processing conditions used to process the most efficient organic bulk-heterojunction thin films. In combination with various powerful X-ray-based characterization methods, several studies observed the morphological changes under the influence of different processing conditions. In this review, we summarize the fundamentals and implementation of X-ray-based and optical characterization methods, utilized in in situ mode and introduce the reader a better overview of the information acquired from a given technique in terms of microstructure formation in OPV. While we give a chronological development of in situ characterization methods in the field of OPV, we discuss the interplay between thermodynamics of solutions and drying kinetics of different types of organic blends. © 2017 Materials Research Society.},
author = {Güldal, Nusret Sena and Kassar, Thaer and Berlinghof, Marvin and Unruh, Tobias and Brabec, Christoph},
doi = {10.1557/jmr.2017.190},
faupublication = {yes},
journal = {Journal of Materials Research},
keywords = {Characterization; Drying; Heterojunctions; Microstructure; Thermodynamics; Thin films, Characterization methods; In-situ characterization; Microstructure formation; Optical characterization; Organic bulk heterojunctions; Organic photovoltaics; Photovoltaic; Thermodynamics of solutions, In situ processing},
pages = {1855-1879},
peerreviewed = {Yes},
title = {{In} situ characterization methods for evaluating microstructure formation and drying kinetics of solution-processed organic bulk-heterojunction films},
volume = {32},
year = {2017}
}
@article{faucris.117591584,
abstract = {In this work the first PVT grown in-situ erbium doped SiC bulk crystal, to our knowledge, is presented. The crystal was characterised by secondary ion mass spectrometry (SIMS) and photoluminescence measurements. SIMS investigations show erbium concentrations in the range of 1.1 (.) 10" cm(-3) to 2.9 (.) 10(14) cm(-3). photoluminescence measurements between 1450 run and 1650 nm were conducted at 19 K, 77 K and 300 K. A distinct luminescence at 1540 nm corresponding to the 4 I-4(13/2) --> I-4(15/2) transition was detected even at room temperature. In the investigated temperature range, luminescence intensity shows only, a slight decrease of 16 %. Measurements with different laser powers suggest a saturation of erbium related luminescence in our experimental condition},
author = {Müller, Ralf and Desperrier, Patrick and Seitz, Christoph and Weißer, Matthias and Magerl, Andreas and Maier, Manfred and Winnacker, Albrecht and Wellmann, Peter},
doi = {10.4028/www.scientific.net/MSF.457-460.723},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {Erbium; PVT Method; Rare Earth Doping; SiC Bulk Growth},
month = {Jan},
pages = {723-726},
peerreviewed = {Yes},
title = {{In}-situ {Er}-doping of {SiC} bulk single crystals},
volume = {457-460},
year = {2004}
}
@inproceedings{faucris.118675084,
abstract = {The chemical reactions during rapid thermal processing of stacked elemental layers were investigated by angle-dispersive in situ X-ray diffraction. With a time resolution of 5 diffractograms per minute four different solid state reactions resulting in ternary chalcopyrites were identified: (A) CuSe + InSe -> CuInSe2, (B) Cu2Se + 2InSe + Se -> 2CuInSe(2), (C) Cu2Se + In2Se3 -> 2CuInSe(2), (D) Cu2Se + Ga2Se3 -> 2CuGaSe(2). All these reactions form pure tenary chalcopyrites. The reaction resulting in the mixed crystal Cu(In,Ga)Se-2 starts not before (B) has begun. The reaction speed of (A) and the fraction of CuInSe2 formed by (B) depend on Na-doping and Se-pressure, (C) takes place only, if the reaction paths (A) and (B) are suppressed. Reaction (D) is observed only, if 25% In is replaced by Ga in the precursor. The diffractograms were evaluated by Rietveld refinement to give the phase contents of the samples as a function of reaction time. (c) 2005 Elsevier Ltd. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Hock R, Weber A, Purwins M, Palm J, Probst V},
doi = {10.1016/j.jpcs.2005.09.025},
faupublication = {yes},
keywords = {chalcogenides;thin films;crystal growth;x-ray diffraction;phase transitions},
pages = {1903-1907},
peerreviewed = {unknown},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{In} situ investigation of the formation of {Cu}({In},{Ga}){Se}-2 from selemsed metallic precursors by {X}-ray diffraction - {The} impact of {Gallium}, {Sodium} and {Selenium} excess},
volume = {66},
year = {2005}
}
@article{faucris.108980564,
abstract = {We report on a combined ultra-fast in situ SAXS and WAXS study along a free-jet providing insight into the evolution of the morphology and crystalline structure of CdS quantum dots in the very early stage of nucleation between 100 μs and 2.5 ms with a time resolution down to 10 μs. Accessing this yet unexplored time regime provides direct evidence of a two-step mechanism via formation of prenucleation clusters followed by nanoparticle nucleation from coalescing precursors. Using ab initio calculations, the latter species is identified as Cd13S4(SH)18 clusters, the stability of which results from a compact surface and inner structure.},
author = {Schiener, Andreas and Magerl, Andreas and Krach, A. and Seifert, Soenke and Steinrück, Hans-Georg and Zagorac, Jelena and Zahn, D. and Weihrich, R.},
doi = {10.1039/c5nr01602a},
faupublication = {yes},
journal = {Nanoscale},
pages = {11328-11333},
peerreviewed = {unknown},
title = {{In} situ investigation of two-step nucleation and growth of {CdS} nanoparticles from solution},
volume = {7},
year = {2015}
}
@inproceedings{faucris.106869004,
abstract = {The time dependent agglomeration of oxygen in silicon at an annealing temperature of 650 degrees C is followed in-situ via the variation of the thickness-dependent Pendellosung fringes. The measurement of the 400-reflection of a wedge shaped sample with the characteristic tungsten K-alpha 1-line at 59.31 keV allows to observe changes of the static Debye-Waller factor of about 0.001%. Within the model of spherical precipitates and the classical theory of diffusion-driven precipitation we determine from this a diffusion constant 4.7x10(-15) cm(2)/s for oxygen in silicon at 650 degrees C which appears enhanced by a factor of 2.4 as compared to normal oxygen diffusion. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim},
author = {Will, Johannes and Gröschel, Alexander and Bergmann, Christoph and Magerl, Andreas},
doi = {10.1002/pssc.201200064},
faupublication = {yes},
keywords = {silicon;oxygen precipitation;dynamical X-ray diffraction},
month = {Jan},
pages = {1920-1923},
peerreviewed = {unknown},
title = {{In}-situ measurement of thickness-dependent {Pendellosung} oscillations from a precipitation process in silicon at 650 degrees {C}},
volume = {9},
year = {2012}
}
@article{faucris.108587864,
abstract = {DxNb2O5 is thermodynamically unstable. Therefore, neutron diffraction measurements were performed in the electrochemical cell used for the intercalation of deuterium into sintered Nb2O5 powder samples. Diffraction patterns were recorded at equilibrium potentials of -443, -428 -332 and -197 mV vs. NHE (corresponding to x = 0.232, x = 0.23, x = 0.21 and x = 0.06). The structural changes in Nb2O5 caused by the deuterium insertion are small but could be determined reproducibly. The lattice parameters of the host lattice exhibit a characteristic dependence on the deuterium content of the bronze. A model has been developed for the partially inhomogeneous distribution of the deuterium in the Nb2O5 unit cell, which explains the changes of the peak intensities observed in the low angle region (6 degrees less than or equal to 2 theta less than or equal to 18 degrees).},
author = {Unruh, Tobias and Schwitzgebel, Günter and Ritter, Clemens},
faupublication = {no},
journal = {Zeitschrift für Naturforschung Section B-A Journal of Chemical Sciences},
keywords = {neutron diffraction;electrochemical cell;niobium-(V)-oxide;niobium hydrogen bronze;hydrogen distribution},
pages = {557-561},
peerreviewed = {Yes},
title = {{In} situ neutron diffraction on {DxNb2O5}},
volume = {53},
year = {1998}
}
@article{faucris.123225344,
abstract = {This work reports on the in-situ observation of a polytype switch during physical vapor transport (PVT) growth of bulk SiC crystals by x-ray diffraction. A standard PVT reactor for 2 '' and 3 '' bulk growth was set up in a high-energy x-ray diffraction lab. Due to the high penetration depth of the high-energy x-ray beam no modification of the PVT reactor was necessary in order to measure Laue diffraction patterns of the growing crystal with good signal to noise ratio. We report for the first time upon the in-situ observation of polytype switching during SiC bulk PVT growt},
author = {Wellmann, Peter and Konias, Katja and Hens, Philip and Hock, Rainer and Magerl, Andreas},
doi = {10.4028/www.scientific.net/MSF.615-617.23},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {bulk crystal growth; physical vapor transport; in-situ growth control; polytypes},
month = {Jan},
pages = {23-26},
peerreviewed = {Yes},
title = {{In}-situ {Observation} of {Polytype} {Switches} {During} {SiC} {PVT} {Bulk} {Growth} by {High} {Energy} {X}-ray {Diffraction}},
volume = {615-617},
year = {2009}
}
@inproceedings{faucris.106869224,
abstract = {The measurement of Pendellosungs oscillations was used to observe the time dependent nucleation of oxygen in a Czochralski grown single crystal at 750 degrees C. It is shown, that the theoretical approach of the statistical dynamical theory describes the data well. Within the framework of this theory it is possible to determine the static Debye-Waller-factor as a function of the annealing time by evaluating the mean value of the Bragg intensity and the period length. The temperature influence on the Pendellosungs distance was corrected for by measurement of a Float-zone sample at the same temperature.},
author = {Will, Johannes and Gröschel, Alexander and Bergmann, Christoph and Magerl, Andreas},
doi = {10.4028/www.scientific.net/SSP.178-179.353},
faupublication = {yes},
keywords = {Silicon;static Debye-Waller factor;statistical dynamical theory;single crystal diffraction;oxygen nucleation;in-situ;X-Ray;wedge shaped geometry;annealing},
month = {Jan},
pages = {353-359},
peerreviewed = {unknown},
title = {{In}-{Situ} observation of the oxygen nucleation in silicon with {X}-{Ray} single crystal diffraction},
volume = {178-179},
year = {2011}
}
@article{faucris.117542304,
abstract = {In this work CuInSe (CISe) thin films were fabricated by rapid thermal processing of printed CuIn nanoparticles and thermally evaporated selenium as precursor layer. Research is focused on real-time investigations such as in-situ X-ray diffraction and dynamic scanning calorimetry. These measurements show CISe formation starting at 300 C. Significant amount of intermediate phases as reported for state-of-the-art rapid thermal processing of stacked elemental layer was not observed. The morphology of the nanoparticulate layers was examined by field emission scanning electron microscopy. Grain size developed from nanosized binary CuIn nanoparticles to microsized CISe grains. Porosity decreases in the temperature range from 340 C to 540 C. © 2012 Elsevier B.V.},
author = {Möckel, Stefan and Hölzing, Astrid and Hock, Rainer and Wellmann, Peter},
doi = {10.1016/j.tsf.2012.11.081},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {Chalcopyrite; CuInSe2; Dynamic scanning calorimetry; Intermetallic nanoparticles; Real-time investigation; XRD},
pages = {133-137},
peerreviewed = {Yes},
title = {{In}-situ phase formation study of copper indium diselenide absorber layers from {CuIn} nanoparticles and evaporated selenium},
volume = {535},
year = {2013}
}
@article{faucris.107442104,
abstract = {Properties of small semiconductor nanoparticles (NPs) are strongly governed by their size. Precise characterization is a key requirement for tailored dispersities and thus for high-quality devices. Results of a careful analysis of particle size distributions (PSDs) of ZnO are presented combining advantages of UV/vis absorption spectroscopy, analytical ultracentrifugation, and small-angle X-ray scattering (SAXS). Our study reveals that careful cross-validation of these different methods is mandatory to end up with reliable resolution. PSDs of ZnO NPs are multimodal on a size range of 2-8 nm, a finding that is not yet sufficiently addressed. In the second part of our work the evolution of PSDs was studied using in situ SAXS. General principles for the appearance of multimodalities covering a temperature range between 15 and 45 °C were found which are solely determined by the aging state indicated by the size of the medium-sized fraction. Whenever this fraction exceeds a critical diameter, a new multimodality is identified, independent of the particular time-temperature combination. A fraction of larger particles aggregates first before a fraction of smaller particles is detected. Fixed multimodalities have not yet been addressed adequately and could only be evidenced due to careful size analysis.},
author = {Schindler, Torben and Walter, Johannes and Peukert, Wolfgang and Segets, Doris and Unruh, Tobias},
doi = {10.1021/acs.jpcb.5b08005},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {15370-15380},
peerreviewed = {Yes},
title = {{In} {Situ} {Study} on the {Evolution} of {Multimodal} {Particle} {Size} {Distributions} of {ZnO} {Quantum} {Dots}: {Some} {General} {Rules} for the {Occurrence} of {Multimodalities}},
volume = {119},
year = {2015}
}
@article{faucris.106817524,
abstract = {Kesterite CuZnSnS(CZTS) is a promising material for thin film solar cell applications. The biggest advantages of this compound lie in the abundance and non-toxicity of the contained elements. Low temperature hot injection synthesis can provide an economic way to produce CZTS nanoparticles for application in solution processed solar cells. Powder X-ray diffraction (PXRD) measurements on the as-synthesised particles suggest that the crystal structure is cubic and can be best described as sphalerite-like. This means that the cations in the CZTS are statistically distributed on the cation sites of the crystal lattice rather than well-ordered like in the tetragonal kesterite structure. An in-situ PXRD measurement while annealing the particles up to 550 °C revealed a recrystallization process that transforms the structure from cubic to tetragonal meaning an ordering of the cations.},
author = {Brandl, Marco and Ahmad, Rameez and Distaso, Monica and Azimi, Seyed Hamed and Hou, Yi and Peukert, Wolfgang and Brabec, Christoph and Hock, Rainer},
doi = {10.1016/j.tsf.2014.10.077},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {Copper zinc tin sulphide; Cubic phase; Hot-injection synthesis; In-situ; Phase transition; Tetragonal phase; X-ray diffraction},
pages = {269-271},
peerreviewed = {Yes},
title = {{In}-situ {X}-ray diffraction analysis of the recrystallization process in {Cu2ZnSnS4nanoparticles} synthesised by hot-injection},
volume = {582},
year = {2015}
}
@article{faucris.213328320,
abstract = {Kesterite Cu2ZnSnS4 (CZTS) is a promisingmaterial for thin film solar cell applications. The biggest advantages of this compound lie in the abundance and non-toxicity of the contained elements. Low temperature hot injection synthesis can provide an economic way to produce CZTS nanoparticles for application in solution processed solar cells. Powder X-ray diffraction (PXRD) measurements on the as-synthesised particles suggest that the crystal structure is cubic and can be best described as sphalerite-like. This means that the cations in the CZTS are statistically distributed on the cation sites of the crystal lattice rather than well-ordered like in the tetragonal kesterite structure. An in-situ PXRD measurement while annealing the particles up to 550 °C revealed a recrystallization process that transforms the structure from cubic to tetragonal meaning an ordering of the cations.},
author = {Brandl, Marco and Ahmad, Rameez and Distaso, Monica and Azimi, Hamed and Hou, Yi and Peukert, Wolfgang and Brabec, Christoph and Hock, Rainer},
doi = {10.1016/j.tsf.2014.10.077},
faupublication = {yes},
journal = {Thin Solid Films},
note = {EAM Import::2019-03-13},
pages = {269-271},
peerreviewed = {Yes},
title = {{In}-{Situ} {X}-ray {Diffraction} {Analysis} of the {Recrystallization} {Process} in {Cu2ZnSnS4} {Nano} {Particles} {Synthesized} by {Hot}-{Injection}},
volume = {582},
year = {2015}
}
@article{faucris.117574644,
abstract = {A standard inductively heated PVT growth furnace modified for diffraction experiments with high energy x-rays in focussing Laue geometry was built. The growth furnace will be placed in front of a tungsten anode high energy x-ray source. The Laue diffraction pattern of the growing crystal can be detected on a CCD camera detector. Evolution of crystalline defects as a function of the growth process parameters will be infered from the diffraction experiments. The furnace design and results of first test measurements serving as proof of concept are reporte},
author = {Konias, Katja and Hock, Rainer and Stockmeier, Matthias and Wellmann, Peter and Miller, Michael and Ossege, Stefan and Magerl, Andreas},
doi = {10.4028/www.scientific.net/MSF.556-557.267},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {PVT; crystal growth; growth furnace; x-ray diffraction; high energy x-rays; focussing Laue geometry; defects},
month = {Jan},
pages = {267-270},
peerreviewed = {Yes},
title = {{In}-situ {X}-ray measurements of defect generation during {PVT} growth of {SiC}},
volume = {556-557},
year = {2007}
}
@article{faucris.108527804,
abstract = {Cu2ZnSnS4 nanoparticles have been produced by a facile and high-yield wet-chemical method at low synthesis temperature. In order to remove the organic residues the synthesis was followed by a pre-annealing procedure at 250 degrees C in nitrogen atmosphere. Data evaluation of ex-situ XRD measurements on the pre-annealed sample showed, that the diffraction pattern of the as-synthesized powder can be well modeled by diffraction of a hexagonal and a disordered cubic CZTS structure. The CZTS nanoparticles were annealed under nitrogen atmosphere up to 550 degrees C without and with the addition of selenium powder and diffraction patterns were recorded in-situ as a function of temperature in order to investigate the structural phase transitions during the re-crystallization and selenization of the powders. The in-situ XRD measurements showed a structural phase transition into the tetragonal CZTS structure for pure CZTS and with the addition of selenium. With the addition of selenium, an exchange reaction between sulfur and selenium during the heating process was observed by the shift in the diffraction peaks and subsequent refinement of the lattice parameters of the crystal structures. (C) 2016 Elsevier B.V. All rights reserved.},
author = {Sayed, Mohamed H. and Brandl, Marco and Chory, Christine and Hammer-Riedel, Ingo and Parisi, Juergen and Guetay, Levent and Hock, Rainer},
doi = {10.1016/j.jallcom.2016.05.313},
faupublication = {yes},
journal = {Journal of Alloys and Compounds},
keywords = {CZTS nanoparticles;In-situ XRD;Structural phase transition;Selenization},
pages = {24-29},
peerreviewed = {Yes},
title = {{In}-situ {XRD} investigation of re-crystallization and selenization of {CZTS} nanoparticles},
volume = {686},
year = {2016}
}
@article{faucris.107394144,
abstract = {CZTS nanoparticles produced by a wet-chemical method were mixed with different proportions of Selenium powder to observe the sulfur selenium exchange reaction during selenization and the effect of the varying Selenium supply on the tetragonal ordering and recrystallization of the originally disordered cubic structure. Evaluation of the diffraction angle shift of the reflections in in-situ XRD measurements during the selenization process yields the temperature dependent composition of the CZTSSe. The presence of selenium in small to medium amounts seems to benefit the ordering of the cations as well as the crystallite growth, whereas very high proportions seem to reverse the positive effects. (C) 2017 Elsevier B.V. All rights reserved.},
author = {Brandl, Marco and Sayed, Mohamed H. and Chory, Christine and Hammer-Riedel, Ingo and Parisi, Juergen and Hock, Rainer and Guetay, Levent},
doi = {10.1016/j.jallcom.2017.04.199},
faupublication = {yes},
journal = {Journal of Alloys and Compounds},
keywords = {CZTS nanoparticles;In-situ XRD;Structural phase transition;Selenization},
pages = {35-38},
peerreviewed = {unknown},
title = {{In}-situ {XRD} investigation of selenization of {CZTS} nanoparticles},
volume = {714},
year = {2017}
}
@article{faucris.108806324,
abstract = {The eight-beam case of the Si-888 reflection in backscattering has been studied by scanning the eight simultaneously excited reflections Si 888, Si 088, Si 880, Si 808, Si 800, Si 080, Si 008 and Si 000 in wavelength and two independent rocking angles. Largely different widths of the individual reflection profiles found are explained from the Ewald representation as suggested by kinematic diffraction theory. The intensity profiles demonstrate a coupling of the eight simultaneously excited wave fields as expected from dynamic diffraction theory.},
author = {Hock, Rainer and et al.},
author_hint = {Haubold S, Liss KD, Hock R, Magerl A, Lorenzen M, Krisch M},
faupublication = {yes},
journal = {Zeitschrift für Kristallographie},
keywords = {multi beam diffraction;backscattering;eight beam case;dynamical diffraction;X-ray diffraction},
month = {Jan},
pages = {81-87},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Intensity} distribution of the eight-beam case of the {Si}-888 reflection in backscattering geometry},
volume = {219},
year = {2004}
}
@article{faucris.108588084,
abstract = {Hydrogen molecules adsorbed in the nickel, cobalt, and magnesium analogs of the CPO-27 metal-organic framework at low loadings interact significantly more strongly than those adsorbed successively as a consequence of the strong interaction of hydrogen with the coordinatively unsaturated metal cations in the framework.},
author = {Dietzel, Pascal D. C. and Georgiev, Peter A. and Eckert, Juergen and Blom, Richard and Strässle, Thierry and Unruh, Tobias},
doi = {10.1039/c0cc00091d},
faupublication = {no},
journal = {Chemical Communications},
month = {Jan},
pages = {4962-4964},
peerreviewed = {Yes},
title = {{Interaction} of hydrogen with accessible metal sites in the metal-organic frameworks {M}-2(dhtp) ({CPO}-27-{M}; {M} = {Ni}, {Co}, {Mg})},
volume = {46},
year = {2010}
}
@article{faucris.244598221,
abstract = {The mechanism behind the stability of organic nanoparticles prepared by liquid antisolvent (LAS) precipitation without a specific stabilizing agent is poorly understood. In this work, we propose that the organic solvent used in the LAS process rapidly forms a molecular stabilizing layer at the interface of the nanoparticles with the aqueous dispersion medium. To confirm this hypothesis, n-octadecyltrichlorosilane (OTS)-functionalized silicon wafers in contact with water-solvent mixtures were used as a flat model system mimicking the solid-liquid interface of the organic nanoparticles. We studied the equilibrium structure of the interface by X-ray reflectometry (XRR) for water-solvent mixtures (methanol, ethanol, 1-propanol, 2-propanol, acetone, and tetrahydrofuran). The formation of an organic solvent-rich layer at the solid-liquid interface was observed. The layer thickness increases with the organic solvent concentration and correlates with the polar and hydrogen bond fraction of Hansen solubility parameters. We developed a self-consistent adsorption model via complementing adsorption isotherms obtained from XRR data with molecular dynamics simulations.},
author = {Prihoda, Annemarie and Will, Johannes and Duchstein, Patrick and Becit, Bahanur and Lossin, Felix and Schindler, Torben and Berlinghof, Marvin and Steinrück, Hans Georg and Bertram, Florian and Zahn, Dirk and Unruh, Tobias},
doi = {10.1021/acs.langmuir.0c02745},
faupublication = {yes},
journal = {Langmuir},
note = {CRIS-Team Scopus Importer:2020-10-30},
pages = {12077-12086},
peerreviewed = {Yes},
title = {{Interface} between {Water}-{Solvent} {Mixtures} and a {Hydrophobic} {Surface}},
volume = {36},
year = {2020}
}
@article{faucris.108085824,
abstract = {Mixed self-assembled monolayers of C60-functionalized and different long-chained insulating phosphonic acids provide molecular scale non-volatile memory dielectrics for low-voltage organic thin-film transistors. The memory retention depends on the insulation of the C60 moiety and can be improved by embedding into the insulating SAM matrix and covering by corresponding insulating molecules.},
author = {Khassanov, Artöm and Schmaltz, Thomas and Steinrück, Hans-Peter and Magerl, Andreas and Hirsch, Andreas and Halik, Marcus},
doi = {10.1002/admi.201400238},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
pages = {n/a},
peerreviewed = {Yes},
title = {{Interface} {Engineering} of {Molecular} {Charge} {Storage} {Dielectric} {Layers} for {Organic} {Thin}-{Film} {Memory} {Transistors}},
url = {http://onlinelibrary.wiley.com/doi/10.1002/admi.201400238/abstract},
volume = {1},
year = {2014}
}
@article{faucris.224994707,
abstract = {A multipurpose interconnection layer based on poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS), and d-sorbitol for monolithic perovskite/silicon tandem solar cells is introduced. The interconnection of independently processed silicon and perovskite subcells is a simple add-on lamination step, alleviating common fabrication complexities of tandem devices. It is demonstrated experimentally and theoretically that PEDOT:PSS is an ideal building block for manipulating the mechanical and electrical functionality of the charge recombination layer by controlling the microstructure on the nano- and mesoscale. It is elucidated that the optimal functionality of the recombination layer relies on a gradient in the d-sorbitol dopant distribution that modulates the orientation of PEDOT across the PEDOT:PSS film. Using this modified PEDOT:PSS composite, a monolithic two-terminal perovskite/silicon tandem solar cell with a steady-state efficiency of 21.0%, a fill factor of 80.4%, and negligible open circuit voltage losses compared to single-junction devices is shown. The versatility of this approach is further validated by presenting a laminated two-terminal monolithic perovskite/organic tandem solar cell with 11.7% power conversion efficiency. It is envisioned that this lamination concept can be applied for the pairing of multiple photovoltaic and other thin film technologies, creating a universal platform that facilitates mass production of tandem devices with high efficiency.},
author = {Ramírez Quiroz, César Omar and Spyropoulos, Georgios and Salvador, Michael and Roch, Loïc M. and Berlinghof, Marvin and Darío Perea, José and Forberich, Karen and Dion-Bertrand, Laura Isabelle and Schrenker, Nadine J. and Classen, Andrej and Gasparini, Nicola and Chistiakova, Ganna and Mews, Mathias and Korte, Lars and Rech, Bernd and Li, Ning and Hauke, Frank and Spiecker, Erdmann and Ameri, Tayebeh and Albrecht, Steve and Abellán, Gonzalo and León, Salvador and Unruh, Tobias and Hirsch, Andreas and Aspuru-Guzik, Alán and Brabec, Christoph},
doi = {10.1002/adfm.201901476},
faupublication = {yes},
journal = {Advanced Functional Materials},
keywords = {density functional theory; lamination; molecular dynamics; monolithic tandem; perovskite/silicon; transparent-conductive-adhesive},
pages = {1901476},
peerreviewed = {Yes},
title = {{Interface} {Molecular} {Engineering} for {Laminated} {Monolithic} {Perovskite}/{Silicon} {Tandem} {Solar} {Cells} with 80.4% {Fill} {Factor}},
volume = {29},
year = {2019}
}
@article{faucris.123461844,
abstract = {A pegmatite from Diethensdorf, Saxonian Granulite Massif, Germany, contains fine-grained aggregates of at least three different varieties of niobian rutile and a (W, Sc)-rich ferrocolumbite. In addition, rutile I occurs as larger grains. Electron microprobe analyses of niobian rutile gave compositions close to the general formula (Fe,Mn)(x)(Nb,Ta)(2x)Ti3-3xO6 with Nb and Fe contents decreasing in the order rutile I --> rutile 2 --> rutile 3 and Ti increasing accordingly. The substitution of (Ti,Sn) by Fe + (Nb,Ta) is 35-32 at% in rutile 1, 28-26 at% in rutile 2, and 24-19 at% in rutile 3. The intergrown ferrocolumbite has Ta/(Nb + Ta) ratios of <0.10 and Mn/(Fe + Mn) ratios <0.25, and shows unusually high contents Of Sc2O3 and WO3 (UP to 4.0 and 8.8 wt%, respectively). Powder Xray diffraction (XRD) analysis with Guinier and Bragg-Brentano methods identified at least three rutile phases (herein termed A, 13, and C) with cell volumes decreasing with the Nb (+ Ta, W) contents. Nb/Ti ratios of rutiles estimated from Rietveld refinements roughly conform to the results of electron microprobe analysis. The cation distribution in the ferrocolumbite was refined on the basis of a two-scatterer model at sites 8d and 4c in space group Pbcn, leading to ordering of the heavy atoms on site 8d. Textural evidence suggests that the fine-grained intergrowths of ferrocolumbite + rutile 2 + rutile 3 (+ rutile 1) were formed by exsolution from a precursor phase that most probably was not rutile 1.},
author = {Hock, Rainer and et al.},
author_hint = {Okrusch M, Hock R, Schussler U, Brummer A, Baier M, Theisinger H},
faupublication = {yes},
journal = {American Mineralogist},
pages = {986-995},
peerreviewed = {unknown},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Intergrown} niobian rutile phases with {Sc}- and {W}-rich ferrocolumbite: {An} electron-microprobe and {Rietveld} study},
volume = {88},
year = {2003}
}
@article{faucris.123196304,
abstract = {A combined in-situ investigation using X-ray diffraction and differential scanning calorimetry during annealing was carried out to investigate the formation of intermetallic compounds in the stacked elemental layers and to reveal its influences on the crystallization of kesterite Cu2ZnSnSe4. The Mo/Cu/Zn, Mo/Cu/Sn/Zn, Mo/Cu/Zn/Se and Mo/Cu/Sn/Zn/Se stacked films were prepared with a composition resembling a typical kesterite Cu-poor and Zn-rich metallic composition. In-situ experiments during annealing of pure metallic stacked films reveal a dynamic intermetallic compounds formation of Cu5Zn8 -> CuZn -> Cu2Zn -> Cu3Zn and Cu6Sn5 -> Cu41Sn11. The Cu-Zn and Cu5Zn8 layer formed at the interface of metals/Se may prevent the stacked metallic layers from selenization below 320 degrees C. On the other side, the dynamic formation of Cu-Zn phases in the stacked films is found to be an origin of a ZnSe gradual formation starting from 320 degrees C. Phase analysis suggests that the ternary Cu2SnSe3 phase forms almost immediately after the formation of Cu2Se and SnSe. The formation of Cu2SnSe3 is indicated by the consumption of SnSe by the Cu2Se which occurs at 530-540 degrees C. Crystallization of kesterite takes place above 540 degrees C. On a phenomenological basis of present results, consequences for the thin film kesterite fabrication for solar cell application are discussed. (C) 2013 Elsevier B.V. All rights reserved.},
author = {Wibowo, Rachmat Adhi and Möckel, Stefan and Yoo, Hye Sun and Hetzner, Christina and Hölzing, Astrid and Wellmann, Peter and Hock, Rainer},
doi = {10.1016/j.matchemphys.2013.07.021},
faupublication = {yes},
journal = {Materials Chemistry and Physics},
keywords = {Intermetallic compounds; Thin films; Annealing; Sputtering; Differential scanning calorimetry (DSC)},
pages = {311-317},
peerreviewed = {Yes},
title = {{Intermetallic} compounds dynamic formation during annealing of stacked elemental layers and its influences on the crystallization of {Cu2ZnSnSe4} films},
volume = {142},
year = {2013}
}
@article{faucris.228167155,
abstract = {Antisolvent precipitation (AP) is a low-cost and less-invasive preparation alternative for organic nanoparticles compared to top-down methods such as high-pressure homogenization or milling. Here we report on particularly small organic nanoparticles (NPs) prepared by AP. It has been found for various materials that these NPs in their liquid state exhibit a significant degree of molecular order at their interface toward the dispersion medium including ubiquinones (coenzyme Q10), triglycerides (trimyristin, tripalmitin), and alkanes (tetracosane). This finding is independent of the use of a stabilizer in the formulation. While this is obviously a quite general interfacial structuring effect, the respective structural details of specific NPs systems might differ. Here, a detailed structural characterization of very small liquid coenzyme Q10 (Q10) NPs is presented as a particular example for this phenomenon. The Q10 NPs have been prepared by AP in the presence of two different stabilizers, sodium dodecyl sulfate (SDS) and pentaethylene glycol monododecyl ether (C12E5), respectively, and without any stabilizer. The NPs' size is initially analyzed by photon correlation spectroscopy (PCS). The SDS-stabilized Q10 NPs have been studied further by differential scanning calorimetry (DSC), small-angle X-ray and neutron scattering (SAXS, SANS), wide-angle X-ray scattering (WAXS), and cryogenic transmission electron microscopy (CryoTEM). A simultaneous analysis of SAXS and contrast variation SANS studies revealed the molecular arrangement within the interface between the NPs and the dispersion medium. The Q10 NPs stabilized by SDS and C12E5, respectively, are small (down to 19.9 nm) and stable (for at least 16 months) even when no stabilizer is used. The SDS-stabilized Q10 NPs reported here, are therewith, to the best of our knowledge, the smallest organic NPs which have been reported to be prepared by AP so far. In particular, these NPs exhibit a core-shell structure consisting of an amorphous Q10 core and a surrounding shell, which is mainly composed of oriented Q10 molecules and aligned SDS molecules. This structure suggests a significant amphiphilic behavior and a rather unexpected stabilizing role of Q10 molecules.},
author = {Schuldes, Isabel and Noll, Dennis and Schindler, Torben and Zech, Tobias and Götz, Klaus and Appavou, Marie Sousai and Boesecke, Peter and Steiniger, Frank and Schulz, Peter and Unruh, Tobias},
doi = {10.1021/acs.langmuir.9b00944},
faupublication = {yes},
journal = {Langmuir},
note = {CRIS-Team Scopus Importer:2019-10-22},
pages = {13578-13587},
peerreviewed = {Yes},
title = {{Internal} {Structure} of {Nanometer}-{Sized} {Droplets} {Prepared} by {Antisolvent} {Precipitation}},
volume = {35},
year = {2019}
}
@article{faucris.224628092,
abstract = {Single-crystal diffuse scattering is generally interpreted using correlation parameters that describe probabilities for certain configurations on a local scale. In this paper we present an interpretation of diffuse maxima using a disordered superspace approach. In (D + d)-dimensional superspace two modulation functions are disordered along the superspace axis a(s,i) for i = 1, . . . , D, while the periodicity along the internal dimensions is maintained. This simple approach allows the generation of substitutionally disordered model structures that show diffuse maxima of any width at any position in reciprocal space. The extinction rules that are introduced by superspace symmetry are also fulfilled by the diffuse maxima from structures generated using the disordered superspace approach. In this paper we demonstrate the disordered superspace approach using a simple two-dimensional binary substitutionally disordered system. The extension of the approach to (3 + d)-dimensional superspace is trivial. The treatment of displacement and magnetic disorder as well as size-effect-like distortions in a similar manner is possible.},
author = {Schmidt, Ella and Neder, Reinhard},
doi = {10.1103/PhysRevB.100.054201},
faupublication = {yes},
journal = {Physical Review B},
note = {CRIS-Team WoS Importer:2019-08-16},
peerreviewed = {Yes},
title = {{Interpretation} of diffuse scattering using superspace crystallography},
volume = {100},
year = {2019}
}
@article{faucris.108588524,
abstract = {Triglyceride nanocrystals in aqueous dispersion produced by high-pressure melt homogenization exhibit platelet-like shapes and clear but broadened Bragg reflections in the small-angle scattering regime. Because the particle thickness, the thickness of the stabilizer layer, the length scale of the crystalline structure of the nanoparticles and often the interparticle distances are of the same order of magnitude, the scattering of these structures mutually interferes. This leads to complicated small-angle scattering patterns which exhibit a lot of features, but it is not straightforward to discover the contained information on the structure of the system. In this contribution, a scattering model for such systems will be described, which is based on the kinematic scattering theory of X-rays. Using this scattering model an X-ray powder pattern simulation analysis is introduced to gain information on tripalmitin nanosuspensions which have been investigated by synchrotron small-angle X-ray scattering. It will be demonstrated that the results of this method provide a consistent description of all structural details mentioned above. In particular, information on the extension and the molecular packing density of the stabilizer layers can be achieved because these layers exhibit a comparatively large scattering contrast.},
author = {Unruh, Tobias},
doi = {10.1107/S0021889807044378},
faupublication = {no},
journal = {Journal of Applied Crystallography},
pages = {1008-1018},
peerreviewed = {Yes},
title = {{Interpretation} of small-angle {X}-ray scattering patterns of crystalline triglyceride nanoparticles in dispersion},
volume = {40},
year = {2007}
}
@article{faucris.106532184,
abstract = {We present quasielastic neutron scattering results on hydrous silica, sodium aluminosilicate, and sodium trisilicate melts with 10 mol% total water content, studied at high temperature under high pressure. Combining neutron time-of-flight spectrometry with neutron backscattering, intrinsic, microscopic proton dynamics is investigated on a time scale from 0.2 ps up to 1 ns between 850 K and 1250 K. All three hydrous silicate melts exhibit a relatively slow proton dynamics, although the melt viscosity is drastically reduced upon water dissolution. The self-diffusion coefficient of proton in the hydrous sodium trisilicate melt is on the order of 10(-11) m(2) s(-1), two orders of magnitude slower than the sodium dynamics in the corresponding anhydrous melt. The proton dynamics in hydrous silica and albite is not faster than that time scale. We show that the transport mechanism involves not only-OH but also molecular water species. All protons are mobile during the transport of the water instead of diffusion of a specific water speciation. These characteristics of the proton structural relaxation in the melt can be attributed to a transport in a complex H-bonding environment. (C) 2017 Elsevier B.V. All rights reserved.},
author = {Yang, F. and Hess, K. -U. and Unruh, Tobias and Mamontov, Eugene and Dingwell, D. B. and Meyer, Andreas},
doi = {10.1016/j.chemgeo.2017.01.009},
faupublication = {no},
journal = {Chemical Geology},
keywords = {Hydrous silicate melts;Intrinsic proton dynamics;High temperature high pressure;Quasielastic neutron scattering},
pages = {152-159},
peerreviewed = {Yes},
title = {{Intrinsic} proton dynamics in hydrous silicate melts as seen by quasielastic neutron scattering at elevated temperature and pressure},
volume = {461},
year = {2017}
}
@inproceedings{faucris.247645982,
abstract = {For a commercial photovoltaic product not only the efficiency under
standard test conditions (1000 W/m², AM1.5, Tcell=25°C) but also the
performance under different operating conditions in the field is of
importance. In this contribution, first results and the current status
of a new project for Yield maximized Cu(In,Ga)(S,Se)2 thin film solar
modules by deliberately controlled parameters of performance ratio
(MyCIGS)2 are presented. In a comprehensive approach MyCIGS covers the
combination of material and process variations in the different device
layers, material characterisation of these layers, opto-electrical
characterisation of the resulting devices, device and performance
simulation and finally outdoor module testing to identify and optimize
the key contributors for the performance ratio. With Avancis and the
Helmholtz-Zentrum Berlin, the MyCIGS project comprises two partners that
can supply completely processed cell or module samples or the single
layers starting from the back electrode and thus allowing for a large
field of possible process and material variations. Material
characterisation is done by all project partners with a focus at the
University of Erlangen on absorber characterisation via X-ray
diffraction, scanning electron microscopy and photoluminescence. With
the various characterisation techniques the absorber composition and its
grading with absorber thickness, quality of module patterning, optical
properties and electrical properties of the complete device are
investigated. Material and device characterisation are the basis for a
TCAD3 device model by the University of Oldenburg to also allow for a
simulation-based approach to optimise the different contributors to
performance ratio. The impact of the tested process variations on the
parameters of performance ratio is tested indoor and also outdoor on two
newly installed field test setups in Munich and Berlin. In a first
experimental series, various process parameters have been investigated:
composition of the back electrode, composition of the absorber (Ga-poor
and S-poor versus Ga-rich and S-rich), buffer material and ilayer. In
this contribution we will show the results of the absorber variation in
more detai},
author = {Weber, Alfons and Lechner, Robert and Grünsteidl, Stefan and Borowski, Peter and Schubbert, Christian and Dalibor, Thomas and Heise, Stephan J. and Ohland, Joerg and Savchenko, Iievgeniia and Ahmed, Hamsa and Hirwa, Hippolyte and Parisi, Juergen and Klenk, Reiner and Reyes-Figueroa, Pablo and Farias Basulto, Guillermo and Aghaei, Mohammadreza and Ulbrich, Carolin and Waack, Erik and Hock, Rainer and Dallmann, Johannes and Künecke, Ulrike and Schuster, Matthias and Wellmann, Peter},
booktitle = {EU PVSEC},
date = {2020-09-07/2020-09-11},
faupublication = {yes},
keywords = {solar cells; CIGSe; characterization; outdoor test; performance},
peerreviewed = {unknown},
title = {{Investigating} and {Improving} {Performance} {Ratio} of {Cu}({In},{Ga})({S},{Se})2 {Photovoltaic} {Devices}},
venue = {Marseille},
year = {2020}
}
@article{faucris.269701324,
abstract = {Increased usage of gold nanorods (AuNRs) in various biosensing and medical applications requires tight size and morphology control. This is often achieved by tuning the aggregation behavior of the stabilizing ligand cetrimonium bromide (CTAB). Because the role of CTAB during AuNR growth is still a matter of debate, simultaneous small-angle X-ray and neutron scattering experiments (SAXS/SANS) and measurements are performed. The SAXS/SANS measurements have enabled an instantaneous correlation between the size of evolving AuNR and the nanostructure of guiding CTAB moieties. Upon modifying the aggregation behavior of CTAB micelles by adding hexanol or pentanol as inert additives in the precursor solution, a marked change in reaction kinetics is observed. Alcohol-modified CTAB nanostructures have improved AuNR size uniformity compared to those prepared in alcohol-free CTAB solutions, which are attributed to different growth modes. The change in reaction kinetics is linked to a changed stabilization mechanism of reactants and nascent AuNR facilitated by CTAB micelles.},
author = {Zech, Tobias and Metwalli, Ezzeldin and Götz, Klaus and Schuldes, Isabel and Porcar, Lionel and Unruh, Tobias},
doi = {10.1002/ppsc.202100172},
faupublication = {yes},
journal = {Particle & Particle Systems Characterization},
note = {CRIS-Team WoS Importer:2022-02-18},
peerreviewed = {Yes},
title = {{Investigating} {Growth} of {Gold} {Nanorods} by {Simultaneous} {Small}-{Angle} {X}-{Ray} and {Neutron} {Scattering}},
year = {2022}
}
@article{faucris.108460924,
abstract = {Simulations of H-2 sorption were performed in a metal organic framework (MOF) consisting of Zn2+ ions coordinated to 1,2,4-triazole and tetrafluoroterephthalate ligands (denoted [Zn(trz)(tftph)] in this work). The simulated H-2 Sorption isotherms reported in this work are consistent with the experimental data for the state points considered. The experimental H-2 isosteric heat of adsorption (Q(st)) values for this MOP are approximately 8.0 KJ mol(-1) for the considered loading range, which is in the proximity of those determined from simulation. The experimental inelastic neutron scattering (INS) spectra for H-2 in [Zn(trz)(tftph)] reveal at least two peaks that occur at low energies, which corresponds to high barriers to rotation for the respective sites. The most favorable sorption site in the MOF was identified from the simulations as sorption in the vicinity of a metal coordinated H2O molecule, an exposed fluorine atom, and a carboxylate oxygen atom in a confined region in the framework. Secondary sorption was observed between the fluorine atoms of adjacent tetrafluoroterephthalate ligands. The H-2 molecule at the primary sorption site in [Zn(trz)(tftph)] exhibits a rotational barrier that exceeds that for most neutral MOFs with open-metal sites according to an empirical phenomenological model, and this was further validated by calculating the rotational potential energy surface for H-2 at this site.},
author = {Forrest, Katherine A. and Pham, Tony and Georgiev, Peter A. and Pinzan, Florian and Cioce, Christian R. and Unruh, Tobias and Eckert, Juergen and Space, Brian},
doi = {10.1021/acs.langmuir.5b01664},
faupublication = {yes},
journal = {Langmuir},
pages = {7328-7336},
peerreviewed = {Yes},
title = {{Investigating} {H}-2 {Sorption} in a {Fluorinated} {Metal}-{Organic} {Framework} with {Small} {Pores} {Through} {Molecular} {Simulation} and {Inelastic} {Neutron} {Scattering}},
volume = {31},
year = {2015}
}
@inproceedings{faucris.115759204,
author = {Magerl, Andreas and Hock, Rainer and et al.},
author_hint = {Wolff Maximilian, Magerl Andreas, Hock Rainer, BN. Frick , H. Zabel},
booktitle = {The ILL Millenium Symposium 2001},
faupublication = {yes},
note = {UnivIS-Import:2015-04-16:Pub.2001.nat.dphy.IAP.LK.wirdna},
pages = {100},
peerreviewed = {unknown},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Investigation} of sheared liquids by neutron backscattering and reflectivity},
venue = {Grenoble},
year = {2001}
}
@article{faucris.115894504,
abstract = {We have investigated by neutron scattering structural and dynamical properties of water solutions of the triblock copolymer P85 under shear. To this end a shear cell that suits the requirements for neutron backscattering and another for reflectivity experiments have been built. In reflectivity measurements we find the polymer concentration (nominal concentration of 33% by weight) to vary right at the surface between 12% and 52% for hydrophilic or hydrophobic coated silicon wavers, for temperatures between 18°C and 73°C and for shear rates up to 2500 s-1. Additional structural changes deeper in the bulk are also observed. On the backscattering instrument (IN 10 at ILL) we find that the liquid appears to stick to the plates of the shear cell, implying an unusual macroscopic velocity distribution that differs from that found earlier for lubrication oils. We report further on changes of the quasielastic line width in the direction of the shear gradient for different temperatures and shear rates.},
author = {Magerl, Andreas and Hock, Rainer and et al.},
author_hint = {Wolff Maximilian, Magerl Andreas, Hock Rainer, B. Frick , H. Zabel},
doi = {10.1007/s003390201885},
faupublication = {yes},
journal = {Applied Physics A-Materials Science & Processing},
note = {UnivIS-Import:2015-03-09:Pub.2002.nat.dphy.IAP.LK.invest},
pages = {????},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Investigation} of sheared liquids by neutron backscattering and reflectivity},
volume = {A},
year = {2002}
}
@inproceedings{faucris.108635384,
abstract = {The pentanary chalcogenide Cu2ZnSn(S,Se)(4) (CZTSSe) compound is attracting considerable attention as a low-cost and high-efficient solar cell. The band gap can be tuned by adding Se to pure kesterite Cu2ZnSnS4, which influences the crystallization kinetics. The investigation of the crystallization of the pure selenium (Se) compound Cu2ZnSnSe4 can be helpful in understanding the reaction path between the elements of CZTSSe. Sputtered Cu-poor intermetallic Cu-Zn-Sn precursors were deposited on Mo-coated polyimide foil and sequentially capped by a thermally evaporated Se layer. Two different amounts of Se were deposited: amount that exactly matches the composition of Cu2ZnSnSe4; and that corresponding to twofold excess of the compound's element ratio. These two compositions were chosen to investigate influences of the amount of Se on the reaction path and kinetics. Also, the reaction of pure metallic Sn with Se was studied by stacking Sn layers on Mo-coated foils for observing a Sn-loss phenomenon. It was also deposited with two different amounts of Se matching approximately the compositions of SnSe and SnSe2. Time-resolved X-ray diffraction was employed to measure the solid state reactions while increasing the sample temperature up to 550 degrees C at a rate of 0.5 K/s in an evacuated reaction chamber. After the experiment, sample is analyzed by Raman spectroscopy to distinguish the CZTSe from secondary phases. (C) 2013 Elsevier B.V. All rights reserved.},
author = {Yoo, Hye Sun and Wibowo, Rachmat Adhi and Hölzing, Astrid and Lechner, R. and Palm, J. and Jost, S. and Gowtham, M. and Sorin, F. and Louis, B. and Hock, Rainer},
doi = {10.1016/j.tsf.2013.01.054},
faupublication = {yes},
keywords = {Cu2ZnSnSe(4);CZTSe;SnSe;Sputtering;Formation reaction;In-situ XRD;Raman},
pages = {73-77},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
title = {{Investigation} of the solid state reactions by time-resolved {X}-ray diffraction while crystallizing kesterite {Cu2ZnSnSe4} thin films},
volume = {535},
year = {2013}
}
@article{faucris.108588744,
abstract = {Conclusions. Parallel alignment of tripalmitin nanoplatelets is a completely reversible and concentration-dependent effect that can be attributed to the overlap of the exclusion volumes of the anisometric particles. The usefulness of this effect might be explored for the formulation of drug delivery systems.},
author = {Illing, Andreas and Unruh, Tobias and Koch, Michel},
faupublication = {no},
journal = {Pharmaceutical Research},
keywords = {nanoparticles;particle self-assembly;small-angle X-ray scattering;stacked lamellae;tripalmitin},
pages = {592-597},
peerreviewed = {Yes},
title = {{Investigation} on particle self-assembly in solid lipid-based colloidal drug carrier systems},
volume = {21},
year = {2004}
}
@article{faucris.108589624,
abstract = {The flow behavior of low concentrated dispersions of solid lipid nanoparticles consisting of either trimyristin, tripalmitin or tristearin and different ionic and nonionic stabilizer blends were investigated using a rheometer with cone and plate apparatus and an Ubbelohde type capillary viscometer. The data demonstrate a remarkable influence of the matrix material, the stabilizer composition and the presence of small amounts of sodium chloride on the formulations' rheological properties. A significant increase in dispersion viscosity was found in the triglyceride sequence trimyristin < tripalmitin < tristearin. This effect can be clearly attributed to an increase in particle shape anisometry with increasing length of the lipid's fatty acid chains. Surfactants, which are present during the crystallization of the dispersed lipid seem to have an additional effect on the nanoparticle shape. Beyond this, ionic surfactants and other salts affect the dispersion viscosity by altering the dimension of the electrical double layer ("second electroviscous effect"). (C) 2004 Elsevier B.V. All rights reserved.},
author = {Unruh, Tobias and Illing, Andreas},
doi = {10.1016/j.ijpharm.2004.07.017},
faupublication = {no},
journal = {International Journal of Pharmaceutics},
keywords = {solid lipid nanoparticles;rheology;particle shape;second electroviscous effect},
pages = {123-131},
peerreviewed = {Yes},
title = {{Investigation} on the flow behavior of dispersions of solid triglyceride nanoparticles},
volume = {284},
year = {2004}
}
@article{faucris.120872884,
abstract = {Suspensions of triglyceride nanoparticles have been proposed as carrier systems for intravenous administration of poorly water soluble drugs. Such nanosuspensions can easily be produced by homogenization of the melted triglyceride in an aqueous phase. Using special emulsifier blends it is possible to obtain suspensions with an average size of the recrystallized particles below 100 nm (photon correlation spectroscopy z-average). As can be observed by transmission electron microscopy the particles are very thin platelets with thicknesses in the range of only a few molecular layers. Nanoparticles of saturated monoacid triglycerides (smaller than 200 nm) exhibit uncommon melting behaviour, which is expressed in their differential scanning calorimetry curve by multiple endothermal peaks over a temperature range of about 10 degreesC. This effect was attributed earlier to the particle thickness distribution in the suspension rather than to polymorphic transitions since all the material exists in the stable P modification. Here we present experimental investigations on the correlation between the melting behaviour of trilaurin nanosuspensions and the particle thickness distribution determined by analysis of difference X-ray diffraction patterns recorded at progressively higher temperatures in the melting range of the particles. Because of the weak X-ray scattering of the systems investigated synchrotron radiation was used besides conventional sources. The Fourier analysis of the difference diffraction patterns is described in detail and the advantages and difficulties in using this method are discussed. It was observed that the molting temperatures of the nanoparticles increase with increasing particle thicknesses. Simultaneously a decrease in the interplanar (001) spacing with increasing particle thickness was found.},
author = {Unruh, Tobias and Bunjes, Heike and Westesen, Kirsten and Koch, Michel},
faupublication = {no},
journal = {Colloid and Polymer Science},
keywords = {trilaurin;nanoparticles;single-line Fourier analysis;broadening of X-ray reflections;difference diffraction patterns},
pages = {398-403},
peerreviewed = {Yes},
title = {{Investigations} on the melting behaviour of triglyceride nanoparticles},
volume = {279},
year = {2001}
}
@article{faucris.223107885,
abstract = {With incoherent quasielastic neutron scattering self-diffusion coefficients D-s in pure iron, and iron-carbon alloys containing 8.7 at% and 16.9 at% carbon have been measured. At the melting point D-s in liquid iron is 2.8(1) x 10(-9) m(2) s(-1). For the close-to-eutectic Fe83.1C16.9 composition D-s = 1.33(12) x 10(-9) m(2) s(-1) at T-liq = 1432 K. Contradicting conclusions drawn from literature values of tracer diffusion experiments the addition of carbon has only a minor effect on the iron mobility: at a given temperature the self-diffusion coefficient in Fe83.1C16.9 is only 10% larger than in liquid iron, although mixing has a drastic effect on liquidus temperature and phase behavior.},
author = {Meyer, A. and Hennig, L. and Kargl, F. and Unruh, Tobias},
doi = {10.1088/1361-648X/ab2855},
faupublication = {yes},
journal = {Journal of Physics: Condensed Matter},
note = {CRIS-Team WoS Importer:2019-07-26},
pages = {395401},
peerreviewed = {Yes},
title = {{Iron} self diffusion in liquid pure iron and iron-carbon alloys},
volume = {31},
year = {2019}
}
@article{faucris.294847899,
abstract = {Isolated active sites have great potential to be highly efficient and stable in heterogeneous catalysis, while enabling low costs due to the low transition metal content. Herein, we present results on the synthesis, first catalytic trials, and characterization of the Ga9Rh2 phase and the hitherto not-studied Ga3Rh phase. We used XRD and TEM for structural characterization, and with XPS, EDX we accessed the chemical composition and electronic structure of the intermetallic compounds. In combination with catalytic tests of these phases in the challenging propane dehydrogenation and by DFT calculations, we obtain a comprehensive picture of these novel catalyst materials. Their specific crystallographic structure leads to isolated Rhodium sites, which is proposed to be the decisive factor for the catalytic properties of the systems.},
author = {Wittkämper, Haiko and Hock, Rainer and Weißer, Matthias and Dallmann, Johannes and Vogel, Carola and Raman, Narayanan and Tacardi, Nicola and Haumann, Marco and Wasserscheid, Peter and Hsieh, Tzung En and Maisel, Sven and Moritz, Michael and Wichmann, Christoph and Frisch, Johannes and Gorgoi, Mihaela and Wilks, Regan G. and Bär, Marcus and Wu, Mingjian and Spiecker, Erdmann and Görling, Andreas and Unruh, Tobias and Steinrück, Hans-Peter and Papp, Christian},
doi = {10.1038/s41598-023-31157-y},
faupublication = {yes},
journal = {Scientific Reports},
note = {CRIS-Team Scopus Importer:2023-03-31},
pages = {4458-},
peerreviewed = {Yes},
title = {{Isolated} {Rh} atoms in dehydrogenation catalysis},
volume = {13},
year = {2023}
}
@inproceedings{faucris.108806544,
abstract = {The paper examines the kinetics of the electric field induced, first-order transition from the commensurate to the ferro-electric phase in thiourea (SC(NH2)(2)) at 170 K. The satellite reflection from the modulated phase, locked in with a wave vector q = 1/9b* disappears when the phase transition is induced by a static electric field E-c along the a-axis. In order to study the kinetics of the phase transition, an oscillating electric voltage of rectangular shape was applied to the sample and photon events were acquired separately for ON- and OFF-field half-periods. Results received in a series of measurements at different amplitudes between 0 and 500 V and frequencies between 0.125 and 512 Hz lead to the conclusion that a slow and a fast relaxation time play a role for the OFF --> ON and the ON --> OFF transitions, respectively. Further, the highest frequency at which the phase transformation still follows the switching of the electric field depends linearly on the applied field amplitude. A qualitative explanation of the experimental results is given in terms of nucleation and growth of specific ferro-electric domains.},
author = {Hock, Rainer and et al.},
author_hint = {Liss KD, Kaiser M, Hlinka J, Denoyer F, Hock R, Currat R},
faupublication = {yes},
pages = {A172-A176},
peerreviewed = {unknown},
publisher = {IOP PUBLISHING LTD},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Kinetics} of the field induced commensurate to ferro-electric phase transition in thiourea},
volume = {36},
year = {2003}
}
@inproceedings{faucris.122624304,
abstract = {The reaction kinetics of stacked layers of binary In-, Ga- and Cu-selenides is investigated by differential thermal analysis using different constant heating rates. We found that the kinetics of the formation of CuInSe2 depends on the binary selenides being present. The kinetic parameters of the reactive crystallization of CuInSe2 and CuGaSe2 were derived. (c) 2005 Elsevier B.V. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Purwins M, Weber A, Berwian P, Muller G, Hergert F, Jost S, Hock R},
doi = {10.1016/j.jcrysgro.2005.11.054},
faupublication = {yes},
keywords = {kinetics;in-situ monitoring;thermal analysis;CuGaSe2;CuInSe2},
month = {Jan},
pages = {408-413},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE BV},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Kinetics} of the reactive crystallization of {CuInSe2} and {CuGaSe2} chalcopyrite films for solar cell applications},
volume = {287},
year = {2006}
}
@article{faucris.262688745,
abstract = {Novel preparative approaches towards lamellar nanocomposites of carbon and inorganic materials are relevant for a broad range of technological applications. Here, we describe how to utilize the co-assembly of a liquid-crystalline hexaphenylene amphiphile and an aluminosilicate precursor to prepare carbon-aluminosilicate nanocomposites with controlled lamellar orientation and macroscopic order. To this end, the shear-induced alignment of a precursor phase of the two components resulted in thin films comprising lamellae with periodicities on the order of the molecular length scale, an "edge-on" orientation relative to the substrate and parallel to the shearing direction with order on the centimeter length scale. The lamellar structure, orientation, and macroscopic alignment were preserved in the subsequent pyrolysis that yielded the corresponding carbon-aluminosilicate nanocomposites.},
author = {Paripovic, Dragana and Hartmann, Lucia and Steinrück, Hans-Georg and Magerl, Andreas and Li-Destri, Giovanni and Fontana, Yannik and Fontcuberta I Morral, Anna and Oveisi, Emad and Bomal, Enzo and Frauenrath, Holger},
doi = {10.1039/d1nr00807b},
faupublication = {yes},
journal = {Nanoscale},
note = {CRIS-Team WoS Importer:2021-08-13},
peerreviewed = {Yes},
title = {{Lamellar} carbon-aluminosilicate nanocomposites with macroscopic orientation},
year = {2021}
}
@article{faucris.118592144,
abstract = {SiC crystals grown by the physical vapour transport process along the [001] direction show a curvature of the crystal growth front in correspondence with the shape of the isotherms. A large radius for the curvature of the isotherms enhances the formation of an extended facet. Under the facet, the lattice planes are flat with a high crystal quality as expressed by rocking-curve half widths of 0.022 degrees. In the non-faceted region, the lattice planes become bent, following the shape of the isotherms with a radius of typically 0.5 to 0.8 m and an increased rocking-curve half width of 0.3 degrees. A reduction of the growth rate from 300 mu m h(-1) to 70 mu m h(-1) does not affect this behaviour significantly. The lattice-plane curvature and the development of the facet are predominantly affected by the shape of the isotherms. For crystals grown in the [015] direction, the lattice planes adjust only in a one-dimensional manner to the isotherms. In all cases, the lattice-plane curvature results from the formation of a high density of small-angle grain boundaries. They are generated by the condensation of dislocations with Burgers vectors in the ab plane.},
author = {Hock, Rainer and et al.},
author_hint = {Seitz C, Herro ZG, Epelbaum BM, Hock R, Magerl A},
doi = {10.1107/S002188980503298X},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
pages = {17-23},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Lattice}-plane curvature and small-angle grain boundaries in {SiC} bulk crystals},
volume = {39},
year = {2006}
}
@article{faucris.107241464,
abstract = {Quantum size-confined CHNHPbX (X = Br and I) perovskite nanoplatelets with remarkably high photoluminescence quantum yield (up to 90%) were synthesized by ligand-assisted re-precipitation. Thickness-tunability was realized by varying the oleylamine and oleic acid ligand ratio. This method allows tailoring the nanoplatelet thickness by adjusting the number of unit cell monolayers. Broadly tunable emission wavelengths (450-730 nm) are achieved via the pronounced quantum size effect without anion-halide mixing.},
author = {Levchuk, Ievgen and Herre, Patrick and Brandl, Marco and Osvet, Andres and Hock, Rainer and Peukert, Wolfgang and Schweizer, Peter and Spiecker, Erdmann and Batentschuk, Miroslaw and Brabec, Christoph},
doi = {10.1039/c6cc09266g},
faupublication = {yes},
journal = {Chemical Communications},
month = {Jan},
pages = {244-247},
peerreviewed = {unknown},
title = {{Ligand}-assisted thickness tailoring of highly luminescent colloidal {CH3NH3PbX3} ({X} = {Br} and {I}) perovskite nanoplatelets},
volume = {53},
year = {2017}
}
@article{faucris.245900749,
abstract = {Lipids and proteins, as essential components of biological cell membranes, exhibit a significant degree of freedom for different kinds of motions including lateral long-range mobility. Due to their interactions, they not only preserve the cellular membrane but also contribute to many important cellular functions as e.g., signal transport or molecular exchange of the cell with its surrounding. Many of these processes take place on a short time (up to some nanoseconds) and length scale (up to some nanometers) which is perfectly accessible by quasielastic neutron scattering (QENS) experiments and molecular dynamics (MD) simulations. In order to probe the influence of a peptide, a transmembrane sequence of the transferrin receptor (TFRC) protein, on the dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) large unilamellar vesicles (LUVs) on a nanosecond time scale, high-resolution QENS experiments and complementary MD simulations have been utilized. By using different scattering contrasts in the experiment (chain-deuterated lipids and protonated lipids, respectively), a model could be developed which allows to examine the lipid and peptide dynamics separately. The experimental results revealed a restricted lipid lateral mobility in the presence of the TFRC transmembrane peptides. Also the apparent self-diffusion coefficient of the lateral movement of the peptide molecules could be determined quantitatively for the probed short-time regime. The findings could be confirmed very precisely by MD simulations. Furthermore, the article presents an estimation for the radius of influence of the peptides on the lipid long-range dynamics which could be determined by consistently combining results from experiment and simulation.},
author = {Ebersberger, Lisa and Schindler, Torben and Kirsch, Sonja and Pluhackova, Kristyna and Schambony, Alexandra and Seydel, Tilo and Böckmann, Rainer and Unruh, Tobias},
doi = {10.3389/fcell.2020.579388},
faupublication = {yes},
journal = {Frontiers in Cell and Developmental Biology},
note = {CRIS-Team WoS Importer:2020-11-27},
peerreviewed = {Yes},
title = {{Lipid} {Dynamics} in {Membranes} {Slowed} {Down} by {Transmembrane} {Proteins}},
volume = {8},
year = {2020}
}
@article{faucris.122815924,
abstract = {The presence of liquid crystalline phases in suspensions of solid lipid nanoparticles can increase the risk of their gelling upon administration through fine needles. Here we study the formation of liquid crystalline phases in aqueous suspensions of platelet-like shaped solid lipid nanoparticles. A native lecithin-stabilized trimyristin (20 wt %) suspension was investigated at different dilution levels by small-angle X-ray scattering (SAXS) and visual inspection of their birefringence between two crossed polarizers. For trimyristin concentrations phi(MMM) < 6 wt %, the dispersed platelets are well separated from each other whereas they start to self-assemble into stacked lamellae for 6 wt % <= phi(MMM) < 12 wt %. For phi(MMM) >= 12 wt %, the SAXS patterns become increasingly anisotropic, which is a signature of an evolving formation of a preferred orientation of the platelets on a microscopic scale. Simultaneously, the suspensions become birefringent, which proves the existence of an anisotropic liquid crystalline phase formed in the still low viscous liquid suspensions. Spatially resolved SAXS scans and polarization microscopy indicate rather small domains in the (sub)micrometer size range in the nematic liquid crystalline phase and the presence of birefringent droplets (tactoids). The observed critical concentrations for the formation of stacks and the liquid crystalline phase are significantly higher as for equivalent suspensions prepared from triglycerides with longer chains. This can be explained with the lower aspect ratio of trimyristin platelets. Special emphasis is put on the isotropic-liquid crystalline phase transition as a function of the ionic strength of the dispersion medium and phi(MMM). Higher salt concentrations allow shifting of the phase transition to higher trimyristin concentrations. This can be attributed to a partial screening of the repulsive forces between the platelets, which allows higher packing densities within the platelet stacks and of remaining isolated platelets.},
author = {Gehrer, Simone and Schmiele, Martin and Westermann, Martin and Steiniger, Frank and Unruh, Tobias},
doi = {10.1021/jp506787v},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {11387-11396},
peerreviewed = {Yes},
title = {{Liquid} {Crystalline} {Phase} {Formation} in {Suspensions} of {Solid} {Trimyristin} {Nanoparticles}},
volume = {118},
year = {2014}
}
@article{faucris.120104204,
abstract = {Considering the atomic scatterng cross sections for neutrons they are an excellent tool to investigate lubrication problems. Two different shear cells have been built to investigate both the dynamics and structural properties of liquids under shear: one cell has been optimised for quasielastic and inelastic neutron scattering while another one has been designed for reflectivity and diffraction work. The dynamical aspects have been studied on the high-resolution backscattering instrument (INI16 at Institut Laue-Langevin (ILL)). Data with a commercial motor oil as a sample have been taken in contact with an aluminium boundary showing directly the developing anisotropy of diffusion under shear. Furthermore within the same set-up it has been possible to monitor the macroscopic velocity distribution including surface slip. In addition, a diffraction experiment has been carried out, demonstrating from a measurement of the position and the profile of the graphite 002 reflection that the ordering of macroscopic graphite particles in a flowing liquid can be studied with neutrons and an ordering with a tilt angle of the particles of 5° to the flow has been determined.},
author = {Magerl, Andreas and Hock, Rainer and et al.},
author_hint = {Wolff Maximilian, Hock Rainer, Magerl Andreas, B. Frick , H. Zabel},
faupublication = {yes},
journal = {Materials Research Society Symposium - Proceedings},
note = {UnivIS-Import:2015-03-09:Pub.2002.nat.dphy.IAP.LK.liquid},
pages = {????},
peerreviewed = {unknown},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Liquids} under shear explored by neutron scattering: {A} problem in lubrication},
volume = {710},
year = {2002}
}
@article{faucris.108589844,
abstract = {Raman gain for all-optical amplification depends significantly on the cross section for spontaneous Raman scattering. We present measurements of the Raman spectrum of binary niobium-phosphate glasses in the frequency range from 5 to 1300 cm(-1). The spectra of these glasses show a low-frequency enhancement of the vibrational density of states ('Boson peak') suggesting a significant gain profile for application in Raman amplifiers as well as providing an additional mechanism for Raman gain. To separate the effects of density of states from the light-vibration coupling we carried out an inelastic neutron scattering investigation of 40Nb(2)O(5)-60NaPO(3) using the time-of-flight spectrometer (TOFrOF) at the FRM II neutron source in Munich. The Boson peak appears between 40 and 70 cm(-1) as an increase of the reduced density of states over the flat Debye approximation. Possible mechanisms contributing to the low-frequency excitations such as disorder-induced irregular vibrational states are discussed. (C) 2008 Elsevier B.V. All rights reserved.},
author = {Schulte, Alfons and Guo, Y. and Schirmacher, Walter and Unruh, Tobias and Cardinal, Thierry},
doi = {10.1016/j.vibspec.2007.12.014},
faupublication = {no},
journal = {Vibrational Spectroscopy},
keywords = {Raman spectroscopy;Boson peak;Raman gain;neutron scattering},
pages = {12-15},
peerreviewed = {Yes},
title = {{Low}-frequency vibrational excitations in a niobium-phosphate glass for {Raman} gain applications},
volume = {48},
year = {2008}
}
@article{faucris.113963344,
abstract = {In this work an all nanoparticulate precursor for application in Cu(InGa)Sesolar cell absorbers is presented. Binary Cu-In nanoparticles, Cu-Ga powder and elemental Se nanoparticles were mixed in dispersion and deposited on Mo-coated substrates. Research was focused on Cu(InGa)Selayer formation kinetics, phase composition characterised by differential scanning calorimetry and in-situ X-ray diffraction (XRD). Furthermore phase composition and morphology were studied by ex-situ XRD, Raman spectroscopy and scanning electron microscopy. The results revealed a fast consumption of the precursor and the formation of CuInSebelow 340 °C. Binary secondary phases were not observed at any temperature.},
author = {Möckel, Stefan and Wernicke, Tobias and Arzig, Matthias and Köder, Philipp and Brandl, Marco and Ahmad, Rameez and Distaso, Monica and Peukert, Wolfgang and Hock, Rainer and Wellmann, Peter},
doi = {10.1016/j.tsf.2014.11.060},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {Low-temperature; Copper indium gallium diselenide; Chalcopyrite; Nanoparticulate precursors; In-situ X-ray diffraction; Bimetallic nanoparticles},
pages = {60-68},
peerreviewed = {Yes},
title = {{Low} temperature formation of {CuIn1} - {xGaxSe2solar} cell absorbers by all printed multiple species nanoparticulate {Se} + {Cu}-{In} + {Cu}-{Ga} precursors},
volume = {582},
year = {2015}
}
@article{faucris.106819064,
abstract = {The production of high-performance, solution-processed kesterite Cu2ZnSn(Sx,Se1-x)4 (CZTSSe) solar cells typically relies on high-temperature crystallization processes in chalcogen-containing atmosphere and often on the use of environmentally harmful solvents, which could hinder the widespread adoption of this technology. We report a method for processing selenium free Cu2ZnSnS4 (CZTS) solar cells based on a short annealing step at temperatures as low as 350 °C using a molecular based precursor, fully avoiding highly toxic solvents and high-temperature sulfurization. We show that a simple device structure consisting of ITO/CZTS/CdS/Al and comprising an extremely thin absorber layer (∼110 nm) achieves a current density of 8.6 mA/cm2. Over the course of 400 days under ambient conditions encapsulated devices retain close to 100% of their original efficiency. Using impedance spectroscopy and photoinduced charge carrier extraction by linearly increasing voltage (photo-CELIV), we demonstrate that reduced charge carrier mobility is one limiting parameter of low-temperature CZTS photovoltaics. These results may inform less energy demanding strategies for the production of CZTS optoelectronic layers compatible with large-scale processing techniques.},
author = {Hou, Yi and Azimi, Seyed Hamed and Gasparini, Nicola and Savador, Michael and Chen, Wei and Khanzada, Laraib Sarfraz and Brandl, Marco and Hock, Rainer and Brabec, Christoph},
doi = {10.1021/acsami.5b04468},
faupublication = {yes},
journal = {ACS Applied Materials and Interfaces},
keywords = {CZTS; device stability; kesterite solar cells; low-temperature processing; molecular based precursor},
pages = {21100-21106},
peerreviewed = {unknown},
title = {{Low}-{Temperature} {Solution}-{Processed} {Kesterite} {Solar} {Cell} {Based} on in {Situ} {Deposition} of {Ultrathin} {Absorber} {Layer}},
volume = {7},
year = {2015}
}
@article{faucris.120314744,
abstract = {Self-assembled monolayer field-effect transistors (SAMFETs) of BTBT functionalized phosphonic acids are fabricated. The molecular design enables device operation with charge carrier mobilities up to 10 cm V s and for the first time SAMFETs which operate on rough, flexible PEN substrates even under mechanical substrate bending. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
author = {Schmaltz, Thomas and Amin, Atefeh Y. and Khassanov, Artöm and Meyer-Friedrichsen, Timo and Steinrück, Hans-Georg and Magerl, Andreas and Segura, Juan Jose and Voitchovsky, Kislon and Stellacci, Francesco and Halik, Marcus},
doi = {10.1002/adma.201301176},
faupublication = {yes},
journal = {Advanced Materials},
pages = {4511-4514},
peerreviewed = {Yes},
title = {{Low}-{Voltage} {Self}-{Assembled} {Monolayer} {Field}-{Effect} {Transistors} on {Flexible} {Substrates}},
url = {http://onlinelibrary.wiley.com/doi/10.1002/adma.201301176/abstract},
volume = {25},
year = {2013}
}
@article{faucris.119568284,
abstract = {Kagome lattice types have been of intense interest as idealized examples of extended frustrated spin systems. Here we demonstrate how the use of neutron diffraction and inelastic neutron scattering coupled with spin wave theory calculations can be used to elucidate the complex magnetic interactions of extended spin networks. We show that the magnetic properties of the coordination polymer Mn-3(1,2,4-(O2C)(3)C6H3)(2), a highly distorted kagome lattice, have been erroneously characterized as a canted antiferromagnet in previous works. Our results demonstrate that, although the magnetic structure is ferrimagnetic, with a net magnetic moment, frustration persists in the system. We conclude by, showing that the conventions Goodenough-Kanamori rules, which are often applied to similar magnetic exchange interactions, are not relevant in this case.},
author = {Mole, Richard A. and Greene, Stephen and Henry, Paul F. and Humphrey, Simon M. and Rule, Kirrily C. and Unruh, Tobias and Weldon, Gerald F. and Yu, Dehong and Stride, John A. and Wood, Paul T.},
doi = {10.1021/acs.inorgchem.7b00597},
faupublication = {yes},
journal = {Inorganic Chemistry},
pages = {7851-7860},
peerreviewed = {Yes},
title = {{Magnetic} {Properties} of the {Distorted} {Kagome} {Lattice} {Mn}-3(1,2,4-{O2C})(3){C6H3})(2)},
volume = {56},
year = {2017}
}
@article{faucris.107522404,
author = {Bonakdar, Navid and Gerum, Richard and Kuhn, Michael and Spörrer, Marina and Lippert, Anna Helena and Schneider, Werner and Aifantis, Katerina E. and Fabry, Ben},
doi = {10.1038/nmat4689},
faupublication = {yes},
journal = {Nature Materials},
pages = {1090-4},
peerreviewed = {Yes},
title = {{Mechanical} plasticity of cells},
volume = {15},
year = {2016}
}
@article{faucris.262987923,
abstract = {Despite recent efforts to understand homeostasis in epithelial tissues, there are many unknowns surrounding this steady state. It is considered to be regulated by mechanoresponse, but unlike for single cells, this idea remains heavily debated for tissues. Here, we show that changes in matrix stiffness induce a nonequilibrium transition from tubular to squamous Madin-Darby Canine Kidney II tissues. Nonetheless, despite different cell morphologies and densities, all homeostatic tissues display equivalent topologies, which, hence, must be actively targeted and regulated. On the contrary, the mechanoresponse induces dramatic changes in the large-scale organization of the colonies. On stiff gels, this yields an unreported cooperative state of motile cells displaying higher densities than in the arrested homeostatic state, which suggests a more complex relation between cell density and motility than previously anticipated. Our results unequivocally relate the mechanosensitive properties of individual cells to the evolving macroscopic structures, an effect that could be important for understanding the emergent pathologies of living tissues.},
author = {Kaliman, Sara and Hubert, Maxime and Wollnik, Carina and Nuic, Lovro and Vurnek, Damir and Gehrer, Simone and Lovrić, Jakov and Dudziak, Diana and Rehfeldt, Florian and Smith, Ana-Suncana},
doi = {10.1103/PhysRevX.11.031029},
faupublication = {yes},
journal = {Physical Review X},
note = {CRIS-Team WoS Importer:2021-08-20},
peerreviewed = {Yes},
title = {{Mechanical} {Regulation} of {Epithelial} {Tissue} {Homeostasis}},
volume = {11},
year = {2021}
}
@article{faucris.112651484,
abstract = {The memory effect in organic thin film transistors is described with a dielectric hybrid material composed of selectively localized charge trapping titania nanoparticles in a polystyrene-b-polyethyleneoxide (PS-b-PEO) diblock copolymer film. Upon solvent annealing in toluene atmosphere, the films readily form nanophase-separated features of PEO cylinders in a matrix of PS. X-ray reflectivity (XRR) investigations reveal that the TiO2 particles are selectively distributed in the top half of the hybrid layers. Applied in organic thin film transistor devices with 2-tridecyl-[1]benzothieno[3,2-b][1]benzothiophen (mono-C13-BTBT) semiconductor, the hybrid layers induce clockwise drain current hysteresis with promising memory ratio, long-term stability, and endurance. The occurrence of nonvolatile charge trapping directly relates to the hierarchically assembled nanostructure of the nanoparticles in the block copolymer since reference devices with PS homopolymers blended with TiO2 are found to be hysteresis free. Morphological characterization of the hybrid dielectric layers by atomic force microscopy and XRR experiments is presented to shed light on the internal electron density distribution. The layers are subsequently tested in capacitor stacks and transistors.},
author = {Kirschner, Johannes and Will, Johannes and Rejek, Tobias and Portilla Berlanga, Luis and Berlinghof, Marvin and Schweizer, Peter and Spiecker, Erdmann and Steinrück, Hans-Georg and Unruh, Tobias and Halik, Marcus},
doi = {10.1002/admi.201700230},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
peerreviewed = {Yes},
title = {{Memory} {Effect} of {Self}-{Assembled} {PS}-b-{PEO} {Block} {Copolymer} {Films} with {Selectively} {Embedded} {Functionalized} {TiO2} {Nanoparticles}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/admi.201700230/full},
year = {2017}
}
@article{faucris.121190344,
abstract = {A range of compelling information on the local structure and dynamics of the ferroelectric perovskite-type (ABO3) system (1-x)PbTiO3-xBiScO3 has been revealed through analyzing room-temperature x-ray pair distribution functions and temperature-dependent Raman scattering data for compositions ranging across the morphotropic phase boundary (MPB). Raman scattering data have provided exclusive evidence for distinct dynamical responses from the A-site Pb/Bi and the B-site Ti/Sc cations as a function of composition and temperature. Both pair distribution function and Raman scattering analyses indicate improved coherence between the A-site and B-site off-center displacements for x above the MPB composition. The distinguishable dynamical features were spotted between two sets of compositional range from which x=0.34 could be assigned as a critical composition of "local" MPB: the composition at which the pathway of mesoscopic-scale temperature-driven coupling and transformation processes changes. This differs from the previous reports based on the analysis of the average structure, suggesting the response function of a system may not necessarily follow the evolution of the average structure from which however the MPB has so far been ascribed for a particular system. The individual features of the cations revealed here will further help in understanding the structure-property correlations for similar ferroelectric solid solutions.},
author = {Datta, Kaustuv and Richter, Andreas and Göbbels, Matthias and Neder, Reinhard and Mihailova, Boriana},
doi = {10.1103/PhysRevB.92.024107},
faupublication = {yes},
journal = {Physical Review B - Condensed Matter and Materials Physics},
peerreviewed = {unknown},
title = {{Mesoscopic}-scale structure and dynamics near the morphotropic phase boundary of (1-x){PbTiO3}-{xBiScO3}},
volume = {92},
year = {2015}
}
@article{faucris.108462244,
abstract = {Aqueous suspensions of platelet-like shaped tripalmitin nanocrystals are studied here at high tripalmitin concentrations (10 wt % tripalmitin) for the first time by a combination of small-angle X-ray and neutron scattering (SAXS and SANS). The suspensions are stabilized by different lecithins, namely, DLPC, DOPC, and the lecithin blend S100. At such high concentrations the platelets start to self-assemble in stacks, which causes interference maxima at low Q-values in the SAXS and SANS patterns, respectively. It is found that the stack-related interference maxima are more pronounced for the suspension stabilized with DOPC and in particular DLPC, compared to suspensions stabilized by S100. By use of the X-ray and neutron powder pattern simulation analysis (XNPPSA), the SAXS and SANS patterns of the native tripalmitin suspensions could only be reproduced simultaneously when assuming the presence of both isolated nanocrystals and stacks of nanocrystals of different size in the simulation model of the dispersions. By a fit of the simulated SAXS and SANS patterns to the experimental data, a distribution of the stack sizes and their volume fractions is determined. The volume fraction of stacklike platelet assemblies is found to rise from 70% for S100-stabilized suspensions to almost 100% for the DLPC-stabilized suspensions. The distribution of the platelet thicknesses could be determined with molecular resolution from a combined analysis of the SAXS and SANS patterns of the corresponding diluted tripalmitin (3 wt %) suspensions. In accordance with microcalorimetric data, it could be concluded that the platelets in the suspensions stabilized with DOPC, and in particular DLPC, are significantly thinner than those stabilized with S100. The DLPC-stabilized suspensions exhibit a significantly narrower platelet thickness distribution compared to DOPC- and S100-stabilized suspensions. The smaller thicknesses for the DLPC- and DOPC-stabilized platelets explain their higher tendency to self-assemble in stacks. The finding that the nanoparticles of the suspension stabilized by the saturated lecithin DLPC crystallize in the stable beta-tripalmitin modification with its characteristic platelet-like shape is surprising and can be explained by the fact that the main phase transformation temperature for DLPC is, as for unsaturated lecithins like DOPC and S100, well below the crystallization temperature of the supercooled tripalmitin emulsion droplets.},
author = {Schmiele, Martin and Schindler, Torben and Westermann, Martin and Steiniger, Frank and Radulescu, Aurel and Kriele, Armin and Gilles, Ralph and Unruh, Tobias},
doi = {10.1021/jp502580a},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {8808-8818},
peerreviewed = {Yes},
title = {{Mesoscopic} {Structures} of {Triglyceride} {Nanosuspensions} {Studied} by {Small}-{Angle} {X}-ray and {Neutron} {Scattering} and {Computer} {Simulations}},
volume = {118},
year = {2014}
}
@article{faucris.106817304,
abstract = {The methyl group rotation of coenzyme Q(10) confined in nanosized droplets was studied using quasielastic neutron scattering (QENS). Q(10) as an oligoisoprene derivative with ten isoprene units can easily be supercooled in nanodroplets. Fixed window scans and QENS spectra at several temperatures of glassy Q(10) were recorded to study the methyl group rotation which can be described by a logarithmic Gaussian distribution of hopping rates for temperatures below the glass transition temperature (T(g)approximate to 200 K). A mean activation energy of 4.8 kJ/mol with a distribution width of 2.1 kJ/mol was obtained from the evaluation of the QENS spectra. A corresponding analysis of a fixed window scan yielded an average activation energy of 5.1 kJ/mol with a distribution width of 1.8 kJ/mol. The results are compared and discussed with those of chain deuterated polyisoprene-d(5). For polycrystalline Q(10), the QENS spectra could be described by the same model yielding a similar average activation energy as found for glassy Q(10). However, no temperature dependence of the distribution width was observed. Based on the performed low-temperature measurements, the correlation times for the methyl group rotation were extrapolated to temperatures of liquid Q(10). The complex dynamics of liquid Q(10) could be described by a model yielding an apparent diffusion coefficient, the jump rate of the methyl groups, as well as an overall molecular rotational diffusion coefficient. The correlation times of the methyl group rotation in liquid Q(10) at a given temperature T(0) coincide with values determined in the glassy phase and extrapolated to T(0). (C) 2008 American Institute of Physics.},
author = {Smuda, Christoph and Busch, Sebastian and Wagner, Bernd and Unruh, Tobias},
doi = {10.1063/1.2967188},
faupublication = {no},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{Methyl} group dynamics in glassy, polycrystalline, and liquid coenzyme {Q}(10) studied by quasielastic neutron scattering},
volume = {129},
year = {2008}
}
@article{faucris.120873324,
abstract = {We present a quasi-elastic neutron scattering (QENS) study on the methyl group dynamics of ubiquinone Q(0) in the solid and liquid state. For solid ubiquinone Q(0), the dynamics can be described with three Lorentzian functions in the framework of a jump model among three equidistant sites on a circle. According to the known molecular structure of Q(0) in the solid state, this is consistent with three nonequivalent methyl groups in the molecule. From the temperature-dependent analysis of the QENS spectra, the activation energies were determined. The barrier heights could be evaluated from librational bands in the inelastic part of the spectra. The results from neutron spectroscopy are compared to Gaussian 03 calculations leading to an assignment of the activation energies to the different methyl groups in Q(0). The dynamics of Q(0) in the liquid state is evaluated with a scattering function taking into account three different molecular motions. It is demonstrated that the temperature dependence of the long-range diffusion and isotropic rotational diffusion exhibit an Arrhenius-like behavior, whereas the process of methyl group rotation in the liquid phase is virtually free of a barrier.},
author = {Smuda, Christoph and Busch, Sebastian and Schellenberg, René and Unruh, Tobias},
doi = {10.1021/jp807601g},
faupublication = {no},
journal = {Journal of Physical Chemistry B},
month = {Jan},
pages = {916-922},
peerreviewed = {Yes},
title = {{Methyl} {Group} {Dynamics} in {Polycrystalline} and {Liquid} {Ubiquinone} {Q}(0) {Studied} by {Neutron} {Scattering}},
volume = {113},
year = {2009}
}
@article{faucris.108590064,
abstract = {We present a study of the dynamics and structural changes for trans-1,2-dichloroethylene between high-and low-density liquids using neutron-scattering techniques (diffraction, small-angle neutron scattering, and time of flight spectroscopy) and molecular-dynamics simulations. We show that changes in the short-range ordering of molecules goes along with a change in the molecular dynamics: both structure and dynamics of the high-density liquid are more cooperative than those of the low-density liquid. The microscopic mechanism underlying the cooperative motions in the high-density liquid has been found to be related to the backscattering of molecules due to a strong correlation of molecular ordering.},
author = {Rovira-Esteva, Muriel and Murugan, A. and Pardo, Luis Carlos and Busch, Sebastian and Ruiz-Martin, M. D. and Appavou, Marie-Sousai and Tamarit, Josep Lluis and Smuda, Christoph and Unruh, Tobias and Bermejo, F. J. and Cuello, G. J. and Rzoska, S. J.},
doi = {10.1103/PhysRevB.81.092202},
faupublication = {no},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Microscopic} structures and dynamics of high- and low-density liquid trans-1,2-dichloroethylene},
volume = {81},
year = {2010}
}
@article{faucris.106869664,
abstract = {Annealed Czochralski Silicon wafers containing SiOx precipitates have been studied by high energy X-ray diffraction in a defocused Laue setup using a laboratory tungsten tube. The energy dispersive evaluation of the diffracted Bragg intensity of the 220 reflection within the framework of the statistical dynamical theory yields the static Debye-Waller factor E of the crystal, which gives access to the strain induced by the SiOx precipitates. The results are correlated with precipitate densities and sizes determined from transmission electron microscopy measurements of equivalent wafers. This allows for the determination of the constrained linear misfit epsilon between precipitate and crystal lattice. For samples with octahedral precipitates the values ranging from epsilon=0.39 (+0.28/-0.12) to epsilon=0.48 (+0.34/-0.16) indicate that self-interstitials emitted into the matrix during precipitate growth contribute to the lattice strain. In this case, the expected value calculated from literature values is epsilon=0.26 +/- 0.05. Further, the precise evaluation of Pendellosung oscillations in the diffracted Bragg intensity of as-grown wafers reveals a thermal Debye-Waller parameter for the 220 reflection B-220(293 K) of 0.5582 +/- 0.0039 angstrom(2) for a structure factor based on spherically symmetric scattering contributions. (C) 2014 AIP Publishing LLC.},
author = {Gröschel, Alexander and Will, Johannes and Bergmann, Christoph and Magerl, Andreas},
doi = {10.1063/1.4883998},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Misfit} strain of oxygen precipitates in {Czochralski} silicon studied with energy-dispersive {X}-ray diffraction},
volume = {115},
year = {2014}
}
@article{faucris.230333431,
abstract = {Precise control over the ratio of perylene bisimide (PBI) monomers and aggregates, immobilized on alumina nanoparticle (NP) surfaces, is demonstrated. Towards this goal, phosphonic acid functionalized PBI derivatives (PA-PBI) are shown to self-assemble into stoichiometrically mixed monolayers featuring aliphatic, glycolic, or fluorinated phosphonic acid ligands, serving as imbedding matrix (PA-M) to afford core-shell NPs. Different but, nevertheless, defined PBI monomer/aggregate composition is achieved by either the variation in the PA-PBI to PA-M ratios, or the utilization of different PA-Ms. Various steady-state as well as time-resolved spectroscopy techniques are applied to probe the core-shell NPs with respect to changes in their optical properties upon variations in the shell composition. To this end, the ratio between monomer and excimer-like emission assists in deriving information on the self-assembled monolayer composition, local ordering, and corresponding aggregate content. With the help of X-ray reflectivity measurements, accompanied by molecular dynamics simulations, the built-up of the particle shells, in general, and the PBI aggregation behavior, in particular, are explored in depth.},
author = {Henkel, Christian and Wittmann, Judith and Träg, Johannes and Will, Johannes and Stiegler, Lisa and Strohriegl, Peter and Hirsch, Andreas and Unruh, Tobias and Zahn, Dirk and Halik, Marcus and Guldi, Dirk Michael},
doi = {10.1002/smll.201903729},
faupublication = {yes},
journal = {Small},
note = {CRIS-Team WoS Importer:2019-12-10},
pages = {1903729},
peerreviewed = {Yes},
title = {{Mixed} {Organic} {Ligand} {Shells}: {Controlling} the {Nanoparticle} {Surface} {Morphology} toward {Tuning} the {Optoelectronic} {Properties}},
volume = {16},
year = {2020}
}
@article{faucris.120562684,
author = {Busch, Sebastian and Smuda, Christoph and Pardo, Luis Carlos and Unruh, Tobias},
doi = {10.1021/ja907581s},
faupublication = {no},
journal = {Journal of the American Chemical Society},
pages = {3232-3233},
peerreviewed = {Yes},
title = {{Molecular} {Mechanism} of {Long}-{Range} {Diffusion} in {Phospholipid} {Membranes} {Studied} by {Quasielastic} {Neutron} {Scattering}},
volume = {132},
year = {2010}
}
@article{faucris.221878619,
abstract = {This paper introduces a new experimental method to monitor the evolving intra-particle, nanometre-scale response during hydro-mechanical tests on undisturbed wet clay samples using small angle X-ray scattering (SAXS). The method uses a newly developed miniature plane-strain one-dimensional compression cell that facilitates simultaneous full-field surface displacement measurements using digital image correlation and SAXS measurements. The 60–120 s acquisition times offered by SAXS at synchrotron facilities are beneficial to study time-dependent mechanisms in clays. The experimental results presented indicate that, for the natural sensitive clay tested in this work, no significant structural changes occur at the intra-particle scale during loading, even when large strains are measured at the macro-scale. In addition, changes that are observed at this scale occur after the end of perturbation, i.e. the creation of new intra-particle structures. Further information is obtained on the orientation evolution of the fabric by the comparative analysis of the individual mineral component response.},
author = {Birmpilis, Georgios and Hall, Stephen A. and Lages, Sebastian and Dijkstra, Jelke},
doi = {10.1007/s11440-019-00832-8},
faupublication = {yes},
journal = {Acta Geotechnica},
keywords = {Clay; DIC; Directional anisotropy; Nanoscale; Real-time; SAXS},
note = {CRIS-Team Scopus Importer:2019-07-09},
peerreviewed = {Yes},
title = {{Monitoring} of the nano-structure response of natural clay under mechanical perturbation using small angle {X}-ray scattering and digital image correlation},
year = {2019}
}
@article{faucris.204524632,
abstract = {In the present work, a new solution processed nanohybrid system comprising of single-wall carbon nanotubes (SWCNTs) loaded by PbS quantum dots (QD) capped with an epitaxial ligand shell of methylammonium lead iodide perovskite clusters (MA4PbI6) is designed and fabricated. Attachment of PbS/PbI6 QDs on the surface of SWCNT is followed and evidenced by performing Fourier Transform Infrared Spectroscopy, X-ray photoelectron spectroscopy, and Field Emission Scanning Electron Microscopy. The steady state and dynamic photoluminescence results reveal efficient charge transfer from photo-excited PbS/PbI6 to SWCNTs. Very low amount (0.3 wt.%) of the as-synthesized PbS/PbI6-SWCNT is further incorporated into a polymeric solar cell containing P3HT and PC61BM and exhibits a power conversion efficiency improvement of around 15% compared to the P3HT:PC61BM bulk heterojunction reference solar cell. Significantly, loading perovskite capped PbS QDs on the surface of SWCNT works more efficient rather than incorporating PbS/PbI6 or SWCNT separately onto the composition of the photoactive layer. While PbS/PbI6 broaden the absorption window of photoactive layer and enhance the photon harvesting, their loading on the SWCNT has a significant influence on the faster exciton splitting by efficient electron transfer as well as keeping the desired crystallinity and nanoscale morphology of host matrix upon addition of QDs.},
author = {Soltani, Rezvan and Katbab, Ali Asghar and Sytnyk, Mykhailo and Amin, Atefeh Y. and Killilea, Niall Andrew and Berlinghof, Marvin and Ahmadloo, Farzaneh and Osvet, Andres and Unruh, Tobias and Heiß, Wolfgang and Ameri, Tayebeh},
doi = {10.1002/solr.201700043},
faupublication = {yes},
journal = {Solar RRL},
pages = {1700043},
peerreviewed = {Yes},
title = {{Morphology}-{Controlled} {Organic} {Solar} {Cells} {Improved} by a {Nanohybrid} {System} of {Single} {Wall} {Carbon} {Nanotubes}
{Sensitized} by {PbS} {Core}/{Perovskite} {Epitaxial} {Ligand} {Shell} {Quantum} {Dots}},
volume = {1},
year = {2017}
}
@article{faucris.209470913,
abstract = {The tuning of the optical properties of pyrene, immobilized on alumina
nanoparticle surfaces, is demonstrated. To this end, phosphonic acid
functionalized pyrene derivatives are shown to self‐assemble into
stoichiometrically mixed monolayers featuring hydrophilic, hydrophobic,
or fluorophilic phosphonic acid ligands and to form defined core–shell
hybrids depending on the molecular mixing ratio and the nature of the
ligand monomer, excimer, or mutual emission of both evolved. The
spectroscopic observations are explained by the respective mobility of
the dye molecules with respect to their fixed, specific anchor points
and the resulting probability to form excimers and are supported by
molecular dynamic simulations, X‐ray reflectivity measurements, and
temperature‐dependent steady‐state fluorescence assays. In terms of an
additional tuning of the emission color change and/or the on‐off
switching of the fluorescence, the formation of core–shell–shell system
is carried out by applying amphiphiles. The general concept is fully
transferable to demobilized films of nanoparticles, thereby enabling a
switchable solid‐state surfac},
author = {Wittmann, Judith and Stiegler, Lisa and Henkel, Christian and Träg, Johannes and Götz, Klaus and Unruh, Tobias and Zahn, Dirk and Hirsch, Andreas and Guldi, Dirk Michael and Halik, Marcus},
doi = {10.1002/admi.201801930},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
pages = {1801930},
peerreviewed = {Yes},
title = {{Multifunctional} and {Tunable} {Surfaces} {Based} on {Pyrene} {Functionalized} {Nanoparticles}},
url = {https://onlinelibrary.wiley.com/doi/10.1002/admi.201801930},
volume = {6},
year = {2019}
}
@article{faucris.225562077,
abstract = {The magnetism of the mixed-valence high-spin cluster [Mn18SrO8(N3)7Cl(MedhmpH)12(MeCN)6]Cl2 (1) exhibiting intramolecular ferromagnetic interactions was studied using inelastic neutron scattering (INS), and reliable values for the exchange coupling constants were determined based on the quality of simultaneous fits to the INS and magnetic data. The challenge of the huge size of the Hilbert space (3 375 000) and many exchange coupling constants (7 assuming a C3 symmetry) generally encountered in large spin clusters was resolved as follows: (a) The results of the restricted Hilbert space ferromagnetic cluster spin wave theory were compared to the experimental spectroscopic data. The observed INS transitions were thus assigned to spin wave excitations in a bounded ferromagnetic spin cluster and moreover could be visualized in a straightforward way based on this theory. (b) Simultaneously, Quantum Monte Carlo (QMC) calculations of the temperature-dependent magnetic susceptibility with the same parameter set were compared to the experimental data. Application of state-of-the-art QMC algorithms, as available in the open source ALPS package, in ferromagnetic clusters avoids the full Hamiltonian diagonalization without sacrificing calculation accuracy of the magnetic susceptibility down to the lowest temperatures, which was crucial for the successful analysis. The combined fits revealed two exchange-coupling models with equally good overall agreement to the data. Our preferred model was inspired by magnetostructural correlations and is consistent with them. The model involves three different exchange interactions, one describing the interaction between the core MnIII spins Ja = 14.3(1.0) K and two interactions linking the core and the peripheral MnII spins: Jb = 8.3(4) K and J6 = 3.6(4) K. The use of open-source QMC software and our systematic approach to fitting multiple sets of data obtained by different experimental techniques are described in detail and are generally applicable for understanding large ferromagnetically coupled clusters.},
author = {Nekuruh, Siyavash and Nehrkorn, Joscha and Prsa, Krunoslav and Dreiser, Jan and Ako, Ayuk M. and Anson, Christopher E. and Unruh, Tobias and Powell, Annie K. and Waldmann, Oliver},
doi = {10.1021/acs.inorgchem.9b02134},
faupublication = {no},
journal = {Inorganic Chemistry},
note = {CRIS-Team Scopus Importer:2019-09-03},
pages = {11256-11268},
peerreviewed = {No},
title = {{Multimodeling} {Approach} to {Ferromagnetic} {Spin}-{Wave} {Excitations} in the {High}-{Spin} {Cluster} {Mn18Sr} {Observed} by {Inelastic} {Neutron} {Scattering}},
volume = {58},
year = {2019}
}
@article{faucris.106801244,
abstract = {High efficiency polymer:fullerene photovoltaic device layers self-assemble with hierarchical features from ångströms to 100's of nanometers. The feature size, shape, composition, orientation, and order all contribute to device efficiency and are simultaneously difficult to study due to poor contrast between carbon based materials. This study seeks to increase device efficiency and simplify morphology measurements by replacing the typical fullerene acceptor with endohedral fullerene LuN@PC BEH. The metal atoms give excellent scattering contrast for electron beam and X-ray experiments. Additionally, LuN@PC BEH has a lower electron affinity than standard fullerenes, which can raise the open circuit voltage of photovoltaic devices. Electron microscopy techniques are used to produce a detailed account of morphology evolution in mixtures of Lu 3 N@PC 80 BEH with the record breaking donor polymer, PTB7 and coated using solvent mixtures. We demonstrate that common solvent additives like 1,8-diiodooctane or chloronapthalene do not improve the morphology of endohedral fullerene devices as expected. The poor device performance is attributed to the lack of mutual miscibility between this particular polymer:fullerene combination and to co-crystallization of Lu 3 N@PC 80 BEH with 1,8-diiodooctane. This negative result explains why solvent additives mixtures are not necessarily a morphology cure-all.},
author = {Roehling, John D. and Baran, Derya and Sit, Joseph and Kassar, Thaer and Ameri, Tayebeh and Unruh, Tobias and Brabec, Christoph and Moule, Adam J.},
doi = {10.1038/srep30915},
faupublication = {yes},
journal = {Scientific Reports},
peerreviewed = {Yes},
title = {{Nanoscale} {Morphology} of {PTB7} {Based} {Organic} {Photovoltaics} as a {Function} of {Fullerene} {Size}},
volume = {6},
year = {2016}
}
@article{faucris.122535864,
abstract = {X-ray reflectivity measurements of increasingly more complex interfaces involving silicon (001) substrates reveal the existence of a thin low-density layer intruding between the single-crystalline silicon and the amorphous native SiO terminating it. The importance of accounting for this layer in modeling silicon/liquid interfaces and silicon-supported monolayers is demonstrated by comparing fits of the measured reflectivity curves by models including and excluding this layer. The inclusion of this layer, with 6-8 missing electrons per silicon unit cell area, consistent with one missing oxygen atom whose bonds remain hydrogen passivated, is found to be particularly important for an accurate and high-resolution determination of the surface normal density profile from reflectivities spanning extended momentum transfer ranges, now measurable at modern third-generation synchrotron source},
author = {Steinrück, Hans-Georg and Schiener, Andreas and Schindler, Torben and Will, Johannes and Magerl, Andreas and Konovalov, Oleg and Li Destri, Giovanni and Seeck, Oliver and Mezger, Markus and Haddad, Julia and Deutsch, Moshe and Checco, Antonio and Ocko, Benjamin},
doi = {10.1021/nn5056223},
faupublication = {yes},
journal = {ACS nano},
keywords = {native silicon oxide; self-Assembled monolayers; thin films; X-ray reflectivity},
pages = {12676-12681},
peerreviewed = {Yes},
title = {{Nanoscale} structure of {Si}/{SiO2}/organics interfaces},
volume = {8},
year = {2014}
}
@article{faucris.123363284,
abstract = {We present a compact electrostatic levitator as a sample environment for high quality neutron scattering experiments on melts. By this containerless approach we are able to investigate chemically highly reactive melts in a broad temperature range from high temperatures down to very low temperatures in the metastable liquid. The sample volume typical for former electrostatic levitation facilities was increased by one order of magnitude to a sample diameter of 6 mm. A minimized amount of scattering material in the vicinity of the neutron beam results in a low background of the device and thus in a significantly improved signal-to-noise ratio. Even in these large samples the temperature gradient induced by laser heating is less than 20 K. As a first result the Ni self-diffusion coefficient in Zr64Ni36 was measured by quasielastic neutron scattering at the time-of-flight spectrometer TOFTOF at the FRM II as a function of temperature. At an undercooling of 167 K below the melting point deviations from an Arrhenius-type temperature dependence as observed in bulk metallic glass forming alloys become evident. Neutron diffraction experiments were performed at the high flux diffractometer D20 at the ILL. With a neutron wavelength of 0.94 angstrom a high quality total structure factor of Zr64Ni36 wasmeasured in a broad temperature range at wave numbers between 0.6 and 12 angstrom(-1).},
author = {Kordel, Tobias and Holland-Moritz, Dirk and Yang, Fan and Peters, Judith and Unruh, Tobias and Hansen, Thomas and Meyer, Andreas},
doi = {10.1103/PhysRevB.83.104205},
faupublication = {yes},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Neutron} scattering experiments on liquid droplets using electrostatic levitation},
volume = {83},
year = {2011}
}
@article{faucris.108590284,
abstract = {Poly(ethylene oxide) confined in an anodic aluminum oxide solid matrix has been studied by different neutron scattering techniques in the momentum transfer (Q) range 0.2 < Q=vertical bar Q vertical bar < 1.9 A degrees(-1). The cylindrical pores of the matrix present a diameter (40 nm) much smaller than their length (150 mu m) and are parallel and hexagonally ordered. In particular, we investigated the neutron intensity scattered for two orientations of the sample with respect to the incident beam, for which the Q direction was either parallel or perpendicular to the pores for a scattering angle of 90 degrees. Diffuse neutron scattering at room temperature has shown that the aluminum oxide has amorphous structure and the polymer in the nanoporous matrix is partially crystallized. Concerning the dynamical behavior, for Q < 1 A degrees(-1), the spectra show Rouse-like motions indistinguishable from those in the bulk within the uncertainties. In the high-Q limit we observe a slowing down of the dynamics with respect to the bulk behavior that evidences an effect of confinement. This effect is more pronounced for molecular displacements perpendicular to the pore axis than for parallel displacements. Our results clearly rule out the strong corset effect proposed for this polymer from nuclear magnetic resonance (NMR) studies and can be rationalized by assuming that the interactions with the pore walls affect one to two adjacent monomer monolayers.},
author = {Krutyeva, Margarita and Martin, Jaime and Arbe, Arantxa and Colmenero, Juan and Mijangos, Carmen and Schneider, Gerald J. and Unruh, Tobias and Su, Yixi and Richter, Dieter},
doi = {10.1063/1.3258329},
faupublication = {no},
journal = {Journal of Chemical Physics},
keywords = {aluminium compounds;anodes;monolayers;neutron diffraction;nuclear magnetic resonance;polymer melts;polymers},
peerreviewed = {Yes},
title = {{Neutron} scattering study of the dynamics of a polymer melt under nanoscopic confinement},
volume = {131},
year = {2009}
}
@article{faucris.119986504,
abstract = {We present a systematic study of the crystal-field interactions in the LiRF4 (R = Gd, Ho, Er, Tm, and Yb) family of rare-earth magnets. Using detailed inelastic neutron scattering measurements, we have been able to quantify the transition energies and wave functions for each system. This allows us to quantitatively describe the high-temperature susceptibility measurements for the series of materials and make predictions based on a mean-field approach for the low-temperature thermal and quantum phase transitions. We show that coupling between crystal field and phonon states leads to line-shape broadening in LiTmF4 and level splitting in LiYbF4. Furthermore, using high-resolution neutron scattering from LiHoF4, we find anomalous broadening of crystal-field excitations which we attribute to magnetoelastic coupling.},
author = {Babkevich, P. and Finco, A. and Jeong, M. and Piazza, B. Dalla and Kovacevic, I. and Klughertz, G. and Kraemer, K. W. and Kraemer, C. and Adroja, D. T. and Goremychkin, E. and Unruh, Tobias and Straessle, T. and Di Lieto, A. and Jensen, Jens and Ronnow, H. M.},
doi = {10.1103/PhysRevB.92.144422},
faupublication = {yes},
journal = {Physical Review B},
peerreviewed = {Yes},
title = {{Neutron} spectroscopic study of crystal-field excitations and the effect of the crystal field on dipolar magnetism in {LiRF4} ({R} = {Gd}, {Ho}, {Er}, {Tm}, and {Yb})},
volume = {92},
year = {2015}
}
@article{faucris.123363724,
author = {Teixeira, S. C. M. and Zaccai, G. and Ankner, J. and Bellissent-Funel, M. C. and Bewley, R. and Blakeley, M. P. and Callow, P. and Coates, L. and Dahint, R. and Dalgliesh, R. and Dencher, N. A. and Forsyth, V. T. and Fragneto, G. and Frick, Bernhard and Gilles, R. and Gutberlet, Thomas and Haertlein, M. and Hauss, Thomas and Haeussler, W. and Heller, W. T. and Herwig, Kenneth and Holderer, O. and Juranyi, F. and Kampmann, R. and Knott, R. and Krueger, S. and Langan, Paul and Lechner, R. E. and Lynn, G. and Majkrzak, C. and May, R. P. and Meilleur, F. and Mo, Y. and Mortensen, Kell and Myles, D. A. A. and Natali, F. and Neylon, C. and Niimura, N. and Ollivier, J. and Ostermann, A. and Peters, J. and Pieper, J. and Ruehm, A. and Schwahn, D. and Shibata, K. and Soper, A. K. and Straessle, Th. and Suzuki, J. and Tanaka, I. and Tehei, M. and Timmins, P. and Torikai, N. and Unruh, Tobias and Urban, Volker and Vavrin, R. and Weiss, K.},
doi = {10.1016/j.chemphys.2008.04.007},
faupublication = {no},
journal = {Chemical Physics},
pages = {170-170},
peerreviewed = {Yes},
title = {{New} sources and instrumentation for neutrons in biology},
volume = {351},
year = {2008}
}
@article{faucris.238592677,
abstract = {This study made use of a recently developed combination of advanced methods to reveal the atomic structure of a disordered nanocrystalline zeolite using exit wave reconstruction, automated diffraction tomography, disorder modelling and diffraction pattern simulation. By applying these methods, it was possible to determine the so far unknown structures of the hydrous layer silicate RUB-6 and the related zeolite-like material RUB-5. The structures of RUB-5 and RUB-6 contain the same dense layer-like building units (LLBUs). In the case of RUB-5, these building units are interconnected via additional SiO4/2 tetrahedra, giving rise to a framework structure with a 2D pore system consisting of intersecting 8-ring channels. In contrast, RUB-6 contains these LLBUs as separate silicate layers terminated by silanol/siloxy groups. Both RUB-6 and RUB-5 show stacking disorder with intergrowths of different polymorphs. The unique structure of RUB-6, together with the possibility for an interlayer expansion reaction to form RUB-5, make it a promising candidate for interlayer expansion with various metal sources to include catalytically active reaction centres.},
author = {Krysiak, Yasar and Marler, Bernd and Barton, Bastian and Plana-Ruiz, Sergi and Gies, Hermann and Neder, Reinhard and Kolba, Ute},
doi = {10.1107/S2052252520003991},
faupublication = {yes},
journal = {IUCrJ},
keywords = {3D electron diffraction; computational modelling; diffuse scattering; electron crystallography; exit wave reconstruction; framework-structured solids; inorganic materials.; microporous materials; polymorph prediction; stacking faults},
note = {CRIS-Team Scopus Importer:2020-05-22},
pages = {522-534},
peerreviewed = {Yes},
title = {{New} zeolite-like {RUB}-5 and its related hydrous layer silicate {RUB}-6 structurally characterized by electron microscopy},
volume = {7},
year = {2020}
}
@article{faucris.220874980,
abstract = {Gold nanorods (AuNRs) are of interest for many applications, since their absorption in the regime of visible light can easily be tuned by their exact shape. To produce these AuNRs, a two-step synthesis that starts from small seed particles is used. These seed particles are stabilized by cetyltrimethyl-ammonium bromide (CTAB), which forms micelles at the used concentration (0.1 mol/L). In this work, the influence of the micelle morphology on the stabilization of these seed particles and the consequences on the formation of AuNRs is reported. The elongation of CTAB micelles by the addition of n-hexanol leads to much more stable seed particle dispersions and thus less polydisperse AuNRs. In contrast, a higher number of micelles compared to pure CTAB dispersions result from the addition of n-pentanol. This promotes the formation of larger seed particles and leads to lower yields of AuNRs. The gold nanoparticles are characterized by UV-vis-NIR absorption spectroscopy, transmission electron microscopy, and small-angle X-ray scattering (SAXS). The morphology of the micelles has been determined by a combination of SAXS and small-angle neutron scattering (SANS). The experimental results were used to calculate the collision kinetics of seed particles by using an improved approach of classical coagulation theory to consider the anisotropy of the micelles. The combination of these experiments with the calculations strongly supports the mechanistic model-that these gold seed particles are not stabilized by a CTAB bilayer but by the micelles itself. For the first time, the influence of the micellar size and shape on the stabilization mechanism of noble metal nanoparticles could be clarified. Theses findings contribute to the development of targeted design routes for distinct nanoparticle morphologies by the use of suitable dispersions.},
author = {Schmutzler, Tilo and Schindler, Torben and Zech, Tobias and Lages, Sebastian and Thoma, Martin and Appavou, Marie-Sousai and Peukert, Wolfgang and Spiecker, Erdmann and Unruh, Tobias},
doi = {10.1021/acsanm.9b00510},
faupublication = {yes},
journal = {ACS Applied Nano Materials},
note = {CRIS-Team WoS Importer:2019-06-18},
pages = {3206-3219},
peerreviewed = {Yes},
title = {n-{Hexanol} {Enhances} the {Cetyltrimethylammonium} {Bromide} {Stabilization} of {Small} {Gold} {Nanoparticles} and {Promotes} the {Growth} of {Gold} {Nanorods}},
volume = {2},
year = {2019}
}
@article{faucris.120874864,
abstract = {The nickel self-diffusion coefficient in Si-Ni melts was measured for compositions up to 20 at. % Ni in a temperature range from 270 K below to 200 K above the liquidus temperature by using quasielastic neutron scattering in combination with electromagnetic levitation. Ni self-diffusion coefficients are in the order of 10(-8) m(2)/s, fairly independent of the Ni concentration. Diffusion coefficients calculated from viscosity data of pure liquid silicon via the Stokes-Einstein relation compare well with the Ni self-diffusion obtained here, indicating a strong correlation between the mobility of the silicon and nickel atoms. (C) 2008 American Institute of Physics.},
author = {Pommrich, Ines and Meyer, Andreas and Holland-Moritz, Dirk and Unruh, Tobias},
doi = {10.1063/1.2947592},
faupublication = {no},
journal = {Applied Physics Letters},
peerreviewed = {Yes},
title = {{Nickel} self-diffusion in silicon-rich {Si}-{Ni} melts},
volume = {92},
year = {2008}
}
@article{faucris.108590944,
abstract = {This work presents investigations on the Ni self-diffusion coefficient in Al-Ni melts forming the technological relevant intermetallic phases Al50Ni50 and Al25Ni75 by quasielastic neutron scattering. We found that the Ni self-diffusivity at constant temperature is nearly independent of the composition within the composition range between 0 and 50 at. % Al. This may be a result of the small composition dependence of the atomic volume observed in the same range of composition.},
author = {Stüber, Sebastian and Holland-Moritz, Dirk and Unruh, Tobias and Meyer, Andreas},
doi = {10.1103/PhysRevB.81.024204},
faupublication = {no},
journal = {Physical Review B},
month = {Jan},
peerreviewed = {Yes},
title = {{Ni} self-diffusion in refractory {Al}-{Ni} melts},
volume = {81},
year = {2010}
}
@article{faucris.200927688,
abstract = {Snowman-shaped Au-Fe3O4 nanoheterodimers were synthesized by thermal decomposition of iron oleate on presynthesized Au nanoparticles. Subsequently performed ligand exchange with nitrosyl tetrafluoroborate provided water solubility and enabled X-ray-induced NO release. These Au-Fe3O4 nanoheterodimers combine high-Z material with catalytically active Fe3O4 surfaces and, moreover, plasmonic properties with superparamagnetic performance. We could establish synergetic interactions between X-radiation and both the Au and Fe3O4 surfaces, which resulted in the simultaneous production of the nitric oxide radical at the Fe3O4 surface and the superoxide radical at the Au surface. The surface-confined reaction between these radicals generated peroxynitrite. This highly reactive species may cause nitration of mitochondrial proteins and lipid peroxidation and induce DNA strand breaks. Therefore, high concentrations of peroxynitrite are expected to give rise to severe cellular energetic derangements and thereupon entail rapid cell death. As providing a common platform for X-ray-induced formation of the highly superoxide, and peroxynitrite, nitrosyl tetrafluoroborate functionalized Au-Fe3O4 nanosnowmen were shown to exhibit excellent performance as X-ray-enhancing agents in radiation therapy.},
author = {Klein, Stefanie and Harreiß, Christina and Menter, Christina and Hümmer, Julian and Distel, Luitpold and Meyer, Karsten and Hock, Rainer and Kryschi, Carola},
doi = {10.1021/acsami.8b03660},
faupublication = {yes},
journal = {ACS Applied Materials and Interfaces},
keywords = {Au-Fe3O4 nanoheterodimers;nitrosyl tetrafluoroborate coating;radiation therapy;reactive oxygen species;reactive nitrogen species},
pages = {17071-17080},
peerreviewed = {Yes},
title = {{NOBF4}-{Functionalized} {Au}-{Fe3O4} {Nanoheterodimers} for {Radiation} {Therapy}: {Synergy} {Effect} {Due} to {Simultaneous} {Reactive} {Oxygen} and {Nitrogen} {Species} {Formation}},
volume = {10},
year = {2018}
}
@article{faucris.108591164,
abstract = {Low-dimensional and frustrated magnetic systems often show interesting quantum phenomena. The use of large moments such as S = 5/2 within such materials is uncommon, partly due to the evidence that the large manifold of states associated with these centres results in pseudo-classical behaviour. Here we report on the inelastic neutron scattering of Mn-2(OD)(2)(C4O4), a well-isolated chain with next nearest neighbour interactions. We observe a magnetic excitation spectrum below 30 K whose characteristics resemble those of quantum spin singlets. Inelastic neutron scattering from a powdered sample is shown to yield a great deal of information about the nature of these effects.},
author = {Mole, Richard A. and Stride, John A. and Unruh, Tobias and Wood, Paul T.},
doi = {10.1088/0953-8984/21/7/076003},
faupublication = {no},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{Non}-classical behaviour in an {S}=5/2 chain with next nearest neighbour interactions observed from the inelastic neutron scattering of {Mn}-2({OD})(2)({C4O4})},
volume = {21},
year = {2009}
}
@article{faucris.110195624,
abstract = {We have investigated thermally induced strain in the SiC crystal lattice during physical vapor transport bulk growth. Using high energy x-ray diffraction lattice plane bending was observed in-situ during growth. With increasing growth rate increasing lattice plane bending and, hence, strain was observed. A comparison with numerical modeling of the growth process shows that the latter is related to the heat of crystallization which needs to be dissipated from the crystal growth front. The related temperature gradient as driving force for the dissipation of the heat of crystallization causes lattice plane bending. Optimization of the growth process needs to consider such effect},
author = {Hock, Rainer and Konias, Katja and Perdicaro, Laura Maria Stella and Magerl, Andreas and Hens, Philip and Wellmann, Peter},
doi = {10.4028/www.scientific.net/MSF.645-648.29},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {Bulk Crystal Growth; PVT Growth},
month = {Jan},
pages = {29-32},
peerreviewed = {Yes},
title = {{Observation} of lattice plane bending during {SiC} {PVT} bulk growth using in-situ high energy x-ray diffraction},
volume = {645-648},
year = {2010}
}
@article{faucris.121675444,
abstract = {The differential scanning calorimetry thermograms of suspensions of trimyristin nanoparticles in the stable P-polymorph display several melting events. Particle thickness distributions obtained by analysis of difference X-ray diffraction patterns recorded during melting reveal that these discrete events correspond to the melting of classes of particles differing in thickness by only one unit cell. A large increase in lattice constants with decreasing particle thickness was observed, indicating that classical surface thermodynamics is not applicable to particles consisting of only a few molecular layers.},
author = {Unruh, Tobias and Bunjes, Heike and Westesen, Kirsten and Koch, Michel},
faupublication = {no},
journal = {Journal of Physical Chemistry B},
pages = {10373-10377},
peerreviewed = {Yes},
title = {{Observation} of size-dependent melting in lipid nanoparticles},
volume = {103},
year = {1999}
}
@article{faucris.240665183,
abstract = {Despite rapidly growing interest in the application of mesocrystals in
catalysis, energy storage, and sensing, the understanding of mesocrystal
formation mechanisms remains a relatively unexplored field, due to the
time and space overlapping of different reaction steps, namely, the
nucleation and growth of solid phase and, possibly, their self-assembly
in 3D superstructures. In particular, the role of polymers used as
templating matrices requires more in-depth investigation. Here, ZnO–PVP
mesocrystals are used as a model system and their formation from
molecular precursors is followed with simultaneous in situ
dynamic light scattering (DLS) and turbidity measurements. The formation
of 10 nm primary building blocks during the early stages of the
synthesis and their subsequent oriented attachment into 200–1200 nm
mesocrystalline superstructures are both directly observed with in situ
DLS. The primary particle concentration at which oriented attachment
(OA) begins to occur at an observable rate is proportional to the
colloidal primary particle stability and is compared for different
synthesis conditions with inline turbidity measurements. Synthesis with
higher PVP concentrations and molecular weights results in increasingly
sterically stabilized primary particles and the formation of larger
ZnO–PVP mesospheres. The larger diameter of mesocrystals synthesized at
higher PVP educt concentrations is attributed to partial screening of
(electrostatic repulsive) interparticle interactions between
mesocrystals and primary particles by attached surface PV},
author = {Embrechts, Heidemarie and Zhang, Siqi and Hock, Rainer and Peukert, Wolfgang and Distaso, Monica},
doi = {10.1021/acs.cgd.9b01523},
faupublication = {yes},
journal = {Crystal Growth & Design},
keywords = {Oxides; Nanoparticles; Dynamic light scattering; Chemical synthesis; Metal oxide nanoparticles},
pages = {1266-1275},
peerreviewed = {Yes},
title = {{Observing} {Oriented} {Attachment} during {Mesocrystal} {Growth} with in {Situ} {Dynamic} {Light} {Scattering} ({DLS})},
volume = {20},
year = {2020}
}
@article{faucris.262183111,
abstract = {Semiconducting self-assembled monolayers (SAMs) represent highly relevant components for the fabrication of organic thin-film electronics because they enable the precise formation of active it-conjugates in terms of orientation and layer thickness. In this work, we demonstrate self-assembled monolayer field-effect transistors (SAMFETs) composed of phosphonic acid oligomers of 3-hexylthiophene (oligothiophenes-OT) with systematic variations of thiophene repeating units (5, 10, and 20). The devices exhibit stable lateral charge transport with increased mobility as a function of thiophene unit counts. Importantly, our work reveals the packing and intermolecular order of varied-chain-length SAMs at the molecular scale via X-ray reflectivity (XRR) and quantitative X-ray photoelectron spectroscopy (XPS). Short oligomers (OT5-PA and OT10-PA) arrange almost perpendicular to the substrate, forming highly ordered SAMs, whereas the long-chain OT20-PA exhibits a folded structure. By tuning the molecular order in the monolayers via the SAM substitution reaction, the OT20-PA devices show a tripling in mobility.},
author = {Zhao, Baolin and Gothe, Bastian and Groh, Arthur and Schmaltz, Thomas and Will, Johannes and Steinrueck, Hans-Georg and Unruh, Tobias and Mecking, Stefan and Halik, Marcus},
doi = {10.1021/acsami.1c05764},
faupublication = {yes},
journal = {ACS Applied Materials and Interfaces},
note = {CRIS-Team WoS Importer:2021-07-30},
pages = {32461-32466},
peerreviewed = {Yes},
title = {{Oligothiophene} {Phosphonic} {Acids} for {Self}-{Assembled} {Monolayer} {Field}-{Effect} {Transistors}},
volume = {13},
year = {2021}
}
@article{faucris.123225564,
abstract = {The thermal expansion coefficients of the hexagonal SiC polytypes 4H and 6H and with Al and N dopants have been determined for temperatures between 300 and 1770 K. Further, a set of the room temperature lattice parameters in dependence on doping with N, Al, and B has been obtained. Data for the thermal expansion were taken on a triple axis diffractometer for high energy x rays with a photon energy of 60 keV, which allows the use of large single crystals with a volume of at least 6x6x6 mm(3) without the need to consider absorption. The room temperature measurements for samples with different dopants have been performed on a four-circle diffractometer. The thermal expansion coefficients along the a- and c-directions, alpha(11) and alpha(33), increase from 3x10(-6) K(-1) at 300 K to 6x10(-6) K(-1) at 1750 K. It is found that alpha(11) and alpha(33) are isotropic within 10(7) K(-1). At high temperatures both coefficients for doped samples are similar to 0.2x10(-6) and 0.3x10(-6) K(-1) lower than for the undoped material.},
author = {Stockmeier, Matthias and Müller, Robin and Sakwe, Aloysius and Wellmann, Peter and Magerl, Andreas},
doi = {10.1063/1.3074301},
faupublication = {yes},
journal = {Journal of Applied Physics},
keywords = {Silicon Carbide; 4H SiC; 6H SiC; thermal expansion coefficients; x-ray diffraction},
peerreviewed = {Yes},
title = {{On} the lattice parameters of silicon carbide},
volume = {105},
year = {2009}
}
@article{faucris.115278724,
abstract = {In order to realize a versatile high throughput production of micro-optical elements, UV-curable polymer composites containing titanium dioxide nanoparticles were prepared and characterized. The composites are based on an industrial prototype epoxy polymer. Titanium dioxide nanoparticles smaller than 10 nm were synthesized by the nonaqueous sol method and in situ sterically stabilized by three different organic surfactants. The composites exhibit high transparency. Distinct alteration of optical transmission properties for visible light and near IR wavelength range could be avoided by adaption of the stabilizing organic surfactant. Most importantly, the refractive index (RI) of the composites that depends on the fraction of incorporated inorganic nanoparticles could be directly tuned. E.g. the RI at a wavelength of 635 nm of a composite containing 23 wt% titanium dioxide nanoparticles is increased to 1.626, with respect to a value of 1.542 for the pure polymer. Furthermore, it could be demonstrated that the prepared inorganic-organic nanocomposites are well suited for the direct fabrication of low-cost micro-optical elements by nanoimprint lithography. A low response of the optical composite properties to temperature treatment up to 220°C with a shrinkage of only about 4% ensures its application for integrated micro-optical elements in industrial production.},
author = {Landwehr, J. and Fader, R. and Rumler, Maximilian and Rommel, Mathias and Bauer, Anton and Frey, Lothar and Simon, B. and Fodor, B. and Petrik, P. and Schiener, Andreas and Winter, Benjamin and Spiecker, Erdmann},
doi = {10.1088/0957-4484/25/50/505301},
faupublication = {yes},
journal = {Nanotechnology},
keywords = {Composite materials; Refractive index matching; Substrate conformal imprint lithography; TiO; UV polymers},
note = {UnivIS-Import:2015-04-14:Pub.2014.tech.IE.LEB.optica},
pages = {Article number 505301},
peerreviewed = {unknown},
title = {{Optical} polymers with tunable refractive index for nanoimprint technologies},
volume = {25},
year = {2014}
}
@article{faucris.110149644,
abstract = {Roll-to-roll deposition techniques for the fabrication of chalcopyrite solar cells are of major interest and are a promising alternative to state of the art vacuum processes. However, for roll-to-roll processes the preparation of precursor materials like nanoparticle inks is a crucial point. In this work a study on the preparation technique of copper-indium intermetallic nanoparticles was conducted. The preparation of the nanoparticles is based on the chemical reduction of copper and indium cations with sodium borohydride. Different parameters are discussed regarding their influence on (1) size and shape of the nanoparticles, (2) Cu/In ratio within the synthesised nanoparticles and (3) yield of the synthesis. Results show a strong dependency of the Cu/In ratio of the nanoparticles and the yield of the synthesis on the synthesis parameters. The influence of different parameters like (a) the ratio of metal cations to BH anions, (b) the Cu/In cation ratio within the precursor solution and (c) the dropping rate of the copper-indium precursor solution are discussed. The Cu/In ratio within the nanoparticles can mainly be controlled by the Cu/In cation ratio and the dropping rate of the copper-indium precursor solution. The yield of the synthesis shows saturation behaviour depending on the ratio of metal cations to BH anions. Shape and size of the nanoparticles are independent of the varied parameters. © 2013 Materials Research Societ},
author = {Schuster, Matthias and Möckel, Stefan and Wibowo, Rachmat Adhi and Hock, Rainer and Wellmann, Peter},
doi = {10.1557/opl.2013.980},
faupublication = {yes},
journal = {Materials Research Society Symposium - Proceedings},
keywords = {nanoscale; alloy; chemical synthesis},
pages = {203-208},
peerreviewed = {Yes},
title = {{Optimising} the parameters for the synthesis of {CuIn}-nanoparticles by chemical reduction method for chalcopyrite thin film precursors},
volume = {1538},
year = {2013}
}
@article{faucris.124083344,
abstract = {In order to reduce the residual stress caused by the mismatch of thermal expansion coefficients of 3C-SiC layers grown on Si after cooling down to room temperature, the growth temperature was reduced from usually above 1300 degrees C to 1200 degrees C. Epitaxial layers with high crystalline quality were grown on 1 x 1 cm(2) (100) Si substrates. The layers were evaluated by means of x-ray diffraction (XRD), Raman measurements, scanning electron microscopy and atomic force microscopy. Full width at half maximum values of 0.19 degrees for XRD rocking curve measurements of the (200) 3C-SiC peak were achieved, indicating high crystalline quality of the layers and epitaxial growth. For optimized growth at 1200 degrees C a high C/Si-ratio, on-axis substrates and a layer thickness of over 1 mu m are necessary. (C) 2015 Elsevier B.V. All rights reserved.},
author = {Wilhelm, Martin and Rieth, Marcel and Brandl, Marco and Wibowo, Rachmat Adhi and Hock, Rainer and Wellmann, Peter},
doi = {10.1016/j.tsf.2015.01.049},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {Cubic silicon carbide; Heteroepitaxy; X-ray diffraction; Raman spectroscopy},
pages = {88-93},
peerreviewed = {Yes},
title = {{Optimization} of growth parameters for growth of high quality heteroepitaxial {3C}-{SiC} films at 1200 degrees {C}},
volume = {577},
year = {2015}
}
@inproceedings{faucris.123293324,
abstract = {Organometallic halide perovskites CH3NH3BX3 (B= Pb, Sn, Ge; X = I, Br, Cl) have become one of the most promising semiconductors for solar cell applications, reaching power conversion efficiencies beyond 20%. Improving our ability to harness the full potential of organometal halide perovskites requires the development of more reliable synthesis routines of well defined, reproducible and defect free reference systems allowing to study the fundamental photo-physical processes. In this study we present size and band gap engineering for organo-lead perovskites crystallites with various shapes and sizes ranging from the 5 nm regime all the way to 1 cm. Colloidal nano-crystals, micro-crystlline particles as well as single crystals are demonstrated with excellent purity and control in shape and size are demonstrated. The structural, optical and photo-physical properties of these reference materials are investigated and analyzed as function of their size and shape.},
author = {Levchuk, Ievgen and Högl, Florian and Brandl, Marco and Osvet, Andres and Herre, Patrick and Hock, Rainer and Schweizer, Peter and Spiecker, Erdmann and Batentschuk, Miroslaw and Brabec, Christoph and Peukert, Wolfgang},
booktitle = {SPIE Nanoscience + Engineering, 2016},
date = {2016-11-08},
doi = {10.1117/12.2237101},
faupublication = {yes},
keywords = {particle; crystal; organometal; optoelectronics;},
pages = {9919 - 9919 - 1},
peerreviewed = {unknown},
title = {{Organometallic} perovskites for optoelectronic applications ({Conference} {Presentation})},
venue = {San Diego, California},
volume = {9919},
year = {2016}
}
@article{faucris.213434346,
abstract = {There is a strong market driven need for processing organic photovoltaics from eco-friendly solvents. Water-dispersed organic semiconducting nanoparticles (NPs) satisfy these premises convincingly. However, the necessity of surfactants, which are inevitable for stabilizing NPs, is a major obstacle towards realizing competitive power conversion efficiencies for water-processed devices. Here, we report on a concept for minimizing the adverse impact of surfactants on solar cell performance. A poloxamer facilitates the purification of organic semiconducting NPs through stripping excess surfactants from aqueous dispersion. The use of surfactant-stripped NPs based on poly(3-hexylthiophene) / non-fullerene acceptor leads to a device efficiency and stability comparable to the one from devices processed by halogenated solvents. A record efficiency of 7.5% is achieved for NP devices based on a low-band gap polymer system. This elegant approach opens an avenue that future organic photovoltaics processing may be indeed based on non-toxic water-based nanoparticle inks.},
author = {Xie, Chen and Heumüller, Thomas and Gruber, Wolfgang and Tang, Xiaofeng and Classen, Andrej and Schuldes, Isabel and Bidwell, Matthew and Späth, Andreas and Fink, Rainer and Unruh, Tobias and Mcculloch, Iain and Li, Ning and Brabec, Christoph},
doi = {10.1038/s41467-018-07807-5},
faupublication = {yes},
journal = {Nature Communications},
keywords = {microstructure-recombination correlation; organic photovoltaics;
polymer-fullerene nanoparticles; water processed},
peerreviewed = {Yes},
title = {{Overcoming} efficiency and stability limits in water-processing nanoparticular organic photovoltaics by minimizing microstructure defects},
volume = {8},
year = {2018}
}
@article{faucris.123735744,
abstract = {Solution-processed organic solar cells with promising photovoltaic performance and extraordinary high thermal stability are achieved by employing novel fullerene-based acceptors in combination with two state-of-the-art polymer donors. The findings demonstrated in this work underline the necessity and importance of novel acceptor design rules for highly efficient organic solar cells with excellent device stability.},
author = {Zhang, Chaohong and Mumyatov, Alexander and Langner, Stefan and Perea Ospina, Jose Dario and Kassar, Thaer and Min, Jie and Ke, Lili and Chen, Haiwei and Gerasimov, Kirill L. and Anokhin, Denis V. and Ivanov, Dimitri A. and Ameri, Tayebeh and Osvet, Andres and Susarova, Diana K. and Unruh, Tobias and Li, Ning and Troshin, Pavel and Brabec, Christoph},
doi = {10.1002/aenm.201601204},
faupublication = {yes},
journal = {Advanced Energy Materials},
keywords = {Miscibility; Morphological analysis; Novel fullerene-based acceptors; Organic photovoltaics; Thermal stability},
peerreviewed = {unknown},
title = {{Overcoming} the {Thermal} {Instability} of {Efficient} {Polymer} {Solar} {Cells} by {Employing} {Novel} {Fullerene}-{Based} {Acceptors}},
volume = {7},
year = {2017}
}
@article{faucris.107068104,
abstract = {Aggregation and neurotoxicity of misfolded alpha-synuclein (?Syn) are crucial mechanisms for progressive dopaminergic neurodegeneration associated with Parkinson's disease (PD). Posttranslational modifications (PTMs) of ?Syn caused by oxidative stress, including modification by 4-hydroxy-2-nonenal (HNE-?Syn), nitration (n-?Syn), and oxidation (o-?Syn), have been implicated to promote oligomerization of ?Syn. However, it is yet unclear if these PTMs lead to different types of oligomeric intermediates. Moreover, little is known about which PTM-derived ?Syn species exerts toxicity to dopaminergic cells. In this study, we directly compared aggregation characteristics of HNE-?Syn, n-?Syn, and o-?Syn. Generally, all of them promoted ?Syn oligomerization. Particularly, HNE-?Syn and n-?Syn were more prone to forming oligomers than unmodified ?Syn. Moreover, these PTMs prevented the formation of amyloid-like fibrils, although HNE-?Syn and o-?Syn were able to generate protofibrillar structures. The cellular effects associated with distinct PTMs were studied by exposing modified ?Syn to dopaminergic Lund human mesencephalic (LUHMES) neurons. The cellular toxicity of HNE-?Syn was significantly higher than other PTM species. Furthermore, we tested the toxicity of HNE-?Syn in dopaminergic LUHMES cells and other cell types with low tyrosine hydroxylase (TH) expression, and additionally analyzed the loss of TH-immunoreactive cells in HNE-?Syn-treated LUHMES cells. We observed a selective toxicity of HNE-?Syn to neurons with higher TH expression. Further mechanistic studies showed that HNE-modification apparently increased the interaction of extracellular ?Syn with neurons. Moreover, exposure of differentiated LUHMES cells to HNE-?Syn triggered the production of intracellular reactive oxygen species, preceding neuronal cell death. Antioxidant treatment effectively protected cells from the damage triggered by HNE-?Syn. Our findings suggest a specific pathological effect of HNE-?Syn on dopaminergic neurons.},
author = {Xiang, Wei and Schlachetzki, Johannes and Helling, Stefan and Bussmann, Julia C. and Berlinghof, Marvin and Schäffer, Tilman and Marcus, Katrin and Winkler, Jürgen and Klucken, Jochen and Becker, Cord-Michael and Klucken, Jochen},
doi = {10.1016/j.mcn.2013.01.004},
faupublication = {yes},
journal = {Molecular and Cellular Neuroscience},
note = {EVALuna2:4685},
pages = {71-83},
peerreviewed = {Yes},
title = {{Oxidative} stress-induced posttranslational modifications of alpha-synuclein: specific modification of alpha-synuclein by 4-hydroxy-2-nonenal increases dopaminergic toxicity},
volume = {54},
year = {2013}
}
@article{faucris.107812804,
abstract = {Thickness dependent Pendellösung oscillations are highly sensitive to strain fields from defects in a host crystal. Based on this, we present a novel technique to measure the precipitation kinetics of oxygen in silicon already at its early stage of clustering at high temperatures. At 900 °C, precipitates with a radius smaller than 4 nm and with a density of 1 ± 0.5 × 10 1/cm were observed. The technique was calibrated by complementary scanning transmission electron microscope and energy dispersive X-ray measurements in the range of normal diffusivity yielding a diffusion constant of 1.7 ± 0.1 × 10 - 12 cm / s, which is close to the literature value of 2.074 × 10 - 12 cm / s. The measurements have been made with the characteristic K-line of a high voltage tungsten X-ray tube at 59.31 keV, which provides the opportunity to illuminate through complex sample environments like high temperature scattering furnaces. © 2013 American Institute of Physics.},
author = {Will, Johannes and Gröschel, Alexander and Kot, Dawid and Bergmann, Christoph and Steinrück, Hans-Georg and Schubert, M. A. and Kissinger, Gurdrun and Magerl, Andreas},
doi = {10.1063/1.4792747},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Oxygen} diffusivity in silicon derived from dynamical {X}-ray diffraction},
volume = {113},
year = {2013}
}
@article{faucris.124025924,
abstract = {The dynamics of long range translation and local motions of oxygen in SrTi0.2 Fe0.8 O3-δ have been studied by electrical conductivity and quasielastic neutron scattering. The activation energy of the translational ionic diffusion measured by electrical conductivity is 0.97 eV for T>900°C. Both quasielastic linewidths and quasielastic intensities in neutron scattering show the presence of two motions. The Q independences indicate a localized character for these oxygen diffusion modes with activation energies of 0.43 and 0.27 eV for the "fast" and the "slow" local jumps, respectively. A model for the local oxygen motion is proposed involving oxygen jumps in the (0 k 0) plane either directly to the next unit cell or performing detours combining two and two site jumps resulting in the same final momentum transfer. © 2006 The American Physical Society.},
author = {Mashkina, Elena and Magerl, Andreas and Ollivier, Jacques and Göbbels, Matthias and Seifert, Friedrich},
faupublication = {yes},
journal = {Physical Review B - Condensed Matter and Materials Physics},
note = {UnivIS-Import:2015-03-09:Pub.2006.nat.dgeo.IGM.LM.oxygen},
pages = {214106},
peerreviewed = {unknown},
title = {{Oxygen} mobility in the perovskite {SrTi1}-{xFexO3}-ð (x = 0.8)},
volume = {74},
year = {2006}
}
@article{faucris.244847757,
abstract = {In this study, we compare the real-time oxygen (O) precipitation kinetics of heavily germanium (Ge)-doped Czochralski-silicon (Cz-Si) at 900 °C - under different pre-annealing conditions - with those of undoped Cz-Si. We follow in situ the evolution of the Bragg intensity in Laue transmission geometry at elevated temperature and identify both diffusion-driven growth and Ostwald ripening of the O precipitates. We build on our past results, where we observed that although Ge-doping at 800 °C facilitates grown-in precipitates, it has no influence on the nucleation rate. Our present results indicate that within a diffusion-driven growth model, Ge-doping influences the nucleation rate at 650 °C and has no impact at 450 °C. These results shed further light on the origin of various thermal historical effects in Cz-Si samples with high levels of Ge doping.},
author = {Li, Zhen and Will, Johannes and Yang, Deren},
doi = {10.1063/5.0027232},
faupublication = {yes},
journal = {AIP Advances},
note = {CRIS-Team Scopus Importer:2020-11-06},
peerreviewed = {Yes},
title = {{Oxygen} precipitation in {Ge}-doped {Czochralski}-silicon at 900 °c investigated by in situ high energy x-ray diffraction},
volume = {10},
year = {2020}
}
@article{faucris.108783444,
abstract = {The c/a ratios of the nine ternary Cu-III VI2 compounds in the system Cu(Al,Ga,In)(S,Se,Te)(2) range from 1.939 for CuAlSe2 to 2.014 (CuInS2) at room temperature. The validity of. Vegard's law was presumed to determine the tetragonal deformation 1-c/(2a) for all pentanary mixed crystal compounds Cu-(III,III)-(VI-VI)(2). For six of these nine compounds it is possible to achieve zero tetragonal deformation by adjusting the correct cation and anion substitution. The calculations are performed for room temperature as well as for 500 degrees C, which is a typical temperature for the synthesis of thin films of these semiconductor compounds. (c) 2006 Elsevier B.V. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Hock R, Schorr S},
doi = {10.1016/j.solmat.2006.07.001},
faupublication = {yes},
journal = {Solar Energy Materials and Solar Cells},
keywords = {semiconductors;chalcopyrite compounds;alloys},
month = {Jan},
pages = {44-46},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Pentanary} chalcopyrite compounds without tetragonal deformation in the heptanary system {Cu}({Al},{Ga},{In})({S},{Se},{Te})(2)},
volume = {91},
year = {2007}
}
@inproceedings{faucris.108783664,
abstract = {The phase relations of the Cu-Ga-ln system were investigated in a composition range which is relevant for the production of Cu(In,Ga)Se, based thin film solar cells. The alloys CU16(In-1 -gamma Ga gamma)(9), Cu-9(Ga,In)(4) and elemental In could be identified as the equilibrium phases of a ternary subsystem in the Cu-Ga-In phase diagram. The coexisting phases are well developed until 220 degrees C. In the case of Cu9Ga4 it is remarkable that the solubility of In in Cu9Ga4 highly increases with increasing temperature. Consequences for the selenization of metallic Cu-In-Ga precursors are discussed. (C) 2006 Elsevier B.V. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Purwins M, Enderle R, Schmid M, Berwian P, Muller G, Hergert F, Jost S, Hock R},
doi = {10.1016/j.tsf.2006.12.090},
faupublication = {yes},
keywords = {CuInSe2;CuGaSe2;X-ray diffraction;DC-magnetron sputtering;phase equilibria},
pages = {5895-5898},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Phase} relations in the ternary {Cu}-{Ga}-{In} system},
volume = {515},
year = {2007}
}
@article{faucris.120577204,
abstract = {A self-organized film with titania nanotubular architecture was synthesized by anodization. The dynamic characteristics and kinetic parameters of the nanotubular film during annealing were investigated using real-time resolved, in situ X-ray diffraction (XRD). The XRD results revealed that the onset activation energy for the self-organized titania nanotubular film was 135.6 kJ/mol. The rate constant for aniline blue degradation was dependent on the nanotube length, and the best photocatalytic efficiency of the TiO2 nanotube was obtained at an optimum tube length of 430 nm. (C) 2013 Elsevier Ltd. All rights reserved.},
author = {Oh, Han-Jun and Hock, Rainer and Schurr, Roland and Hölzing, Astrid and Chi, Choong-Soo},
doi = {10.1016/j.jpcs.2013.01.008},
faupublication = {yes},
journal = {Journal of Physics and Chemistry of Solids},
keywords = {Nanostructures;Oxides;X-ray diffraction;Phase transitions},
pages = {708-715},
peerreviewed = {Yes},
title = {{Phase} transformation and photocatalytic characteristics of anodic {TiO2} nanotubular film},
volume = {74},
year = {2013}
}
@article{faucris.123736844,
abstract = {Photoinduced degradation is a critical obstacle for the real application of novel semiconductors for photovoltaic applications. In this paper, the photoinduced degradation of CHNHPbI in a vacuum and air (relative humidity 40%) is analyzed by ex situ and advanced in situ technologies. Without light illumination, CHNHPbI films slowly degrade under vacuum and air within 24 hours. However, we find that CHNHPbI converts to metallic lead (Pb) when exposed to vacuum and light illumination. Further, a series of lead salts (e.g. PbO, Pb(OH) and PbCO) are formed when CHNHPbI is degraded under environmental conditions, i.e. under the combination of light, oxygen and moisture. Photoinduced degradation is found to be determined by the environmental atmosphere as CHNHPbI films remain very stable under nitrogen conditions. The results from vacuum conditions underpin that the high volatility of the organic component (CHNHI) is in conflict with reaching excellent intrinsic stability due to its role in creating ion vacancies. The degradation in air suggests that both oxygen and water contribute to the fast photodecomposition of CHNHPbI into lead salts rather than water alone. Given these basic yet fundamental understandings, the design of hydrophobic capping layers becomes one prerequisite towards long-term stable perovskite-based devices.},
author = {Tang, Xiaofeng and Brandl, Marco and May, Benjamin and Levchuk, Ievgen and Hou, Yi and Richter, Moses and Chen, Haiwei and Chen, Shi and Kahmann, Simon and Osvet, Andres and Maier, Florian and Steinrück, Hans-Peter and Hock, Rainer and Matt, Gebhard and Brabec, Christoph},
doi = {10.1039/c6ta06497c},
faupublication = {yes},
journal = {Journal of Materials Chemistry A},
keywords = {Engineering controlled terms: Lead; Perovskite; Salts; Slow light Environmental conditions; Intrinsic stability; Light illumination; Organic components; Photo-decomposition; Photoinduced degradation; Photovoltaic applications; Real applications Engineering main heading: Photodegradation},
pages = {15896-15903},
peerreviewed = {unknown},
title = {{Photoinduced} degradation of methylammonium lead triiodide perovskite semiconductors},
volume = {4},
year = {2016}
}
@article{faucris.108591824,
abstract = {Derivatives of dimethylalkylchlorosilanes are novel substances which may be used in formulations for drug targeting. In order to design their properties it is essential to perform physicochemical characterization. For this purpose, a combination of differential scanning calorimetry (DSC), FT-Raman spectroscopy and X-ray diffraction is well suited. For the starting material dimethyloctadecylchlorosilane (DMOC), the assignment of Raman bands is discussed. The influence of sugar-containing head groups on the structures of the hydrocarbon chains of 1-O-(dimethyldodecylsilyl)-[2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside] and 1-O-(dimethyloctadecylsilyl)-[2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside] was investigated using the band position of the symmetric methylene mode. The temperature dependence of conformationally sensitive bands in the CH2-stretching region (2800-2900cm(-1)), C-C-stretching region (1000-1150cm(-1)) and CH3-rocking region (830-900cm(-1)) was studied to characterize the state of order of the alkyl chains. Using X-ray diffraction, the repeating distances of layered structures was determined. The phase transitions occurring were found to be completely reversible. The subcell of DMOC shows an orthorhombic perpendicular packing structure in the crystalline state. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.},
author = {Uhr, Michael and Wartewig, S. and Unruh, Tobias and Richter, H.},
doi = {10.1016/S0009-3084(03)00021-5},
faupublication = {no},
journal = {Chemistry and Physics of Lipids},
keywords = {dimethyloctadecylchlorosilane;FT-Raman spectroscopy;X-ray diffraction;differential scanning calorimetry},
pages = {1-13},
peerreviewed = {Yes},
title = {{Physicochemical} characterization of silicon-containing glycolipids by {DSC}, {FT}-{Raman} spectroscopy and {X}-ray diffraction},
volume = {124},
year = {2003}
}
@article{faucris.123071784,
abstract = {General significance: The measured dynamic quantities showed significant and systematic variations between the investigated species, suggesting that they are the signature of an evolutionary adaptation process stimulated by the different physiological environments of the respective protein. (C) 2014 Elsevier B.V. All rights reserved.},
author = {Stadler, Andreas M. and Garvey, Christopher J. and Embs, Jan Peter and Koza, Michael Marek and Unruh, Tobias and Artmann, Gerhard and Zaccai, Giuseppe},
doi = {10.1016/j.bbagen.2014.06.007},
faupublication = {yes},
journal = {Biochimica Et Biophysica Acta-General Subjects},
keywords = {Haemoglobin;Body temperature adaptation;Protein dynamics;Picosecond dynamics;Quasielastic neutron scattering},
pages = {2989-2999},
peerreviewed = {Yes},
title = {{Picosecond} dynamics in haemoglobin from different species: {A} quasielastic neutron scattering study},
volume = {1840},
year = {2014}
}
@article{faucris.119569604,
author = {Krutyeva, M. and Pasini, S. and Monkenbusch, M. and Allgaier, J. and Maiz, Jon and Mijangos, C. and Hartmann-Azanza, B. and Steinhart, Martin and Jalarvo, N. and Ivanova, O. and Holderer, O. and Radulescu, A. and Ohl, M. and Falus, P. and Unruh, Tobias and Richter, D.},
doi = {10.1063/1.4979809},
faupublication = {yes},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{Polymer} dynamics under cylindrical confinement featuring a locally repulsive surface: {A} quasielastic neutron scattering study (vol 146, 203306, 2017)},
volume = {146},
year = {2017}
}
@article{faucris.273198786,
abstract = {Highly efficient dye-sensitized solar cells (DSSCs) have been prepared on the basis of porphyrin dyes with significant success. Recent studies have demonstrated a correlation between the solar cell efficiency and the configuration of the adsorbed porphyrin molecules at the surface of the semiconducting support material. The preparation of dense self assembled monolayers (SAMs) of upright standing porphyrin molecules on TiO2 surfaces was achieved from toluene solutions only when using a molecular exchange reaction. Here, an exchange study of an oleic acid (OLA) SAM on a <110> TiO2 surface by porphyrin molecules is presented. The exchange reaction has been studied by ex-situ as well as in-situ X-ray reflectometry (XRR) measurements. It was found that an almost complete exchange of OLA with porphyrins can be achieved. With increasing coating times the orientation of the porphyrin molecules relative to the substrate surface changed from flat lying to upright standing.},
author = {Götz, Klaus and Stollberg, Isabella and Prihoda, Annemarie and Bertram, Florian and Metwalli, Ezzeldin and Zech, Tobias and Unruh, Tobias},
doi = {10.1016/j.susc.2022.122066},
faupublication = {yes},
journal = {Surface Science},
keywords = {DESY; functionalization; interface; porphyrin; rutile; X-ray reflectometry},
note = {CRIS-Team Scopus Importer:2022-04-15},
peerreviewed = {Yes},
title = {{Porphyrin} adsorption and ligand exchange at the (110)-{TiO2} / organic liquid interface},
volume = {721},
year = {2022}
}
@inproceedings{faucris.108784324,
abstract = {The compounds CU2ZnSnX4 and Cu2SnX3 (X = S or Se) are promising semiconductor materials for thin film photovoltaic applications. Based on a crystallographic growth model we derive the solid-state reactions for these four compounds starting from the binary sulphides and selenides of copper, zinc and tin. Exploiting these predicted solid-state reactions which are promoted by epitaxial relations between the educts will result in fast formation reactions as preferred in technical processes. The direct formation of Cu2ZnSnX4 is concurring with a two-step process in which Cu2SnX3 occurs as an intermediate product. (C) 2006 Elsevier B.V. All fights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Hock R},
doi = {10.1016/j.tsf.2006.12.096},
faupublication = {yes},
keywords = {semiconductors;crystal growth epitaxy},
pages = {5953-5956},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Predicted} formation reactions for the solid-state syntheses of the semiconductor materials {Cu2SnX3} and {Cu2ZnSnX4} ({X} = {S}, {Se}) starting from binary chalcogenides},
volume = {515},
year = {2007}
}
@article{faucris.121157344,
abstract = {We apply the concept of epitaxy, which has been proven to be essential for the formation of CuInSe2 and CuGaSe2 out of binary selenide compounds to multinary compounds. We show that the formation of quaternary chalcopyrites is possible starting either with binary or with mixed crystal chalcogenide compounds. The complete sets of chemical solid-state reactions equations are given. The solid-state reactions are expected to proceed faster, if only one sublattice needs to be rearranged. It shows out, that ternary and quaternary chalcopyrite compounds can be synthesised by fast reaction mechanisms directly from chalcogenide compounds. The fastest way to obtain chalcopyrites containing more than four elements is a stepwise process. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Jost S, Hock R, Purwins M, Palm J},
doi = {10.1002/pssa.200669561},
faupublication = {yes},
journal = {physica status solidi (a)},
pages = {2615-2623},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Predicted} reaction paths for the formation of multinary chalcopyrite compounds},
volume = {203},
year = {2006}
}
@article{faucris.124161224,
abstract = {In a recent work we have described the importance of epitaxy for the formation of CuInSe2 and CuGaSe2. In this article we identify epitaxial relations between binary selenide compounds serving as educts for the formation of the title compounds. From this we derive a set of possible chemical reaction equations for those solid-state reactions, which will preferably take place. By exploiting these reactions the chalcopyrite compounds can be synthesised smartly in short annealing processes at relatively low temperatures. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Jost S, Hock R, Purwins M},
doi = {10.1002/pssa.200669559},
faupublication = {yes},
journal = {physica status solidi (a)},
pages = {2598-2602},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Prediction} of solid-state reactions for the formation of the chalcopyrites {CuInS2}, {CuGaS2},{CuAlS2} and {CuAlSe2} starting from binary compounds},
volume = {203},
year = {2006}
}
@inproceedings{faucris.272199105,
address = {CHESTER},
author = {Poppe, Romy and Vandemeulebroucke, Daphne and Neder, Reinhard and Hadermann, Joke},
booktitle = {ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES},
faupublication = {yes},
note = {CRIS-Team WoS Importer:2022-04-01},
pages = {C374-C374},
peerreviewed = {unknown},
publisher = {INT UNION CRYSTALLOGRAPHY},
title = {{Quantitative} analysis of diffuse electron scattering in the lithium-ion battery cathode material {Li1}.{2Ni0}.{13Mn0}.{54Co0}.{13O2}},
year = {2021}
}
@article{faucris.282435491,
abstract = {In contrast to perfectly periodic crystals, materials with short-range order produce diffraction patterns that contain both Bragg reflections and diffuse scattering. To understand the influence of short-range order on material properties, current research focuses increasingly on the analysis of diffuse scattering. This article verifies the possibility to refine the short-range order parameters in submicrometre-sized crystals from diffuse scattering in single-crystal electron diffraction data. The approach was demonstrated on Li1.2Ni0.13Mn0.54Co0.13O2, which is a state-of-the-art cathode material for lithium-ion batteries. The intensity distribution of the 1D diffuse scattering in the electron diffraction patterns of Li1.2Ni0.13Mn0.54Co0.13O2 depends on the number of stacking faults and twins in the crystal. A model of the disorder in Li1.2Ni0.13Mn0.54Co0.13O2 was developed and both the stacking fault probability and the percentage of the different twins in the crystal were refined using an evolutionary algorithm in DISCUS. The approach was applied on reciprocal space sections reconstructed from 3D electron diffraction data since they exhibit less dynamical effects compared with in-zone electron diffraction patterns. A good agreement was achieved between the calculated and the experimental intensity distribution of the diffuse scattering. The short-range order parameters in submicrometre-sized crystals can thus successfully be refined from the diffuse scattering in single-crystal electron diffraction data using an evolutionary algorithm in DISCUS.},
author = {Poppe, Romy and Vandemeulebroucke, Daphne and Neder, Reinhard and Hadermann, Joke},
doi = {10.1107/S2052252522007746},
faupublication = {yes},
journal = {IUCrJ},
note = {CRIS-Team WoS Importer:2022-09-30},
pages = {695-704},
peerreviewed = {Yes},
title = {{Quantitative} analysis of diffuse electron scattering in the lithium-ion battery cathode material {Li1}.{2Ni0}.{13Mn0}.{54Co0}.{13O2}},
volume = {9},
year = {2022}
}
@article{faucris.108592484,
abstract = {The rotational motion of the methyl group in pentafluoroanisole (PFA) and in pentafluorotoluene (PFT), respectively, was investigated by quasielastic neutron scattering (QENS). For solid PFA, the rotation can be described by a model for uniaxial rotational jumps between three equidistant sites on a circle. Similar to the molecular structure of alpha-toluene, two nonequivalent methyl groups in the unit cell with two different rotational barriers were found for solid PFT. From the analysis of the quasielastic scattering, the activation energies were determined. The barrier heights could be evaluated from bands in the inelastic part of the spectra. The methyl group dynamics in the liquid state is evaluated for both substances using different scattering functions, which are discussed. An empirical model for the description of the contribution of methyl groups in liquids of small organic molecules to the QENS spectra is presented. It is demonstrated that the process of methyl group rotation in the liquid phase is nearly free of a barrier. (c) 2008 American Institute of Physics.},
author = {Smuda, Christoph and Gemmecker, Gerd and Unruh, Tobias},
doi = {10.1063/1.2894847},
faupublication = {no},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{Quasielastic} and inelastic neutron scattering study of methyl group rotation in solid and liquid pentafluoroanisole and pentafluorotoluene},
volume = {128},
year = {2008}
}
@article{faucris.106869884,
abstract = {The radial oxygen nucleation and precipitation in Czochralski-grown silicon crystals is observed in real time via the local evolution of the X-ray Bragg intensity. Using a high X-ray energy and a divergent beam setup, it becomes possible to examine the impact of the local as-grown point defect configuration on the formation of bulk micro defects in a crystal of macroscopic dimensions. As a salient feature the transition from vacancy- to interstitial-dominated regions in a 12 crystal can be identified, and its influence on the precipitation kinetics is quantified through effective oxygen diffusion constant. It appears enhanced by up to a factor of six in vacancy-rich regions as compared to crystal volumes which are identified as point-defect free where it agrees well with the literature value.},
author = {Bergmann, Christoph and Will, Johannes and Gröschel, Alexander and Weißer, Matthias and Magerl, Andreas},
doi = {10.1002/pssa.201400062},
faupublication = {yes},
journal = {physica status solidi (a)},
keywords = {oxygen precipitation;point defects;silicon;X-ray diffraction},
pages = {2450-2454},
peerreviewed = {Yes},
title = {{Radial} oxygen precipitation of a 12 '' {CZ} silicon crystal studied in-situ with high energy {X}-ray diffraction},
volume = {211},
year = {2014}
}
@article{faucris.277472013,
abstract = {Utilizing ionizing radiation for in situ studies in liquid media enables unique insights into nanostructure formation dynamics. As radiolysis interferes with observations, kinetic simulations are employed to understand and exploit beam-liquid interactions. By introducing an intuitive tool to simulate arbitrary kinetic models for radiation chemistry, it is demonstrated that these models provide a holistic understanding of reaction mechanisms. This is shown for irradiated HAuCl4 solutions allowing for quantitative prediction and tailoring of redox processes in liquid-phase transmission electron microscopy (LP-TEM). Moreover, it is demonstrated that kinetic modeling of radiation chemistry is applicable to investigations utilizing X-rays such as X-ray diffraction (XRD). This emphasizes that beam-sample interactions must be considered during XRD in liquid media and shows that reaction kinetics do not provide a threshold dose rate for gold nucleation relevant to LP-TEM and XRD. Furthermore, it is unveiled that oxidative etching of gold nanoparticles depends on both, precursor concentration, and dose rate. This dependency is exploited to probe the electron beam-induced shift in Gibbs free energy landscape by analyzing critical radii of gold nanoparticles.
= 0.5 the formation of the chalcopyrite CuIn(S,Se)(2) is similar to the crystallisation path of CuInS(2). With increasing amount of selenium (S/(S+Se) = 0.25) different ternary sulfoselenides contribute to the semiconductor formation. For small amounts of sulfur, i.e. S/(S+Se) <= 0.1, the chalcopyrite crystallisation proceeds comparable to the one observed for sulfur-free Cu-In-Se precursors. The formation of CuIn(S,Se)(2) is accelerated and proceeds mainly after the peritectic decomposition of Cu(S,Se) to Cu(2)(S,Se). The sulfur content determines the crystallisation temperature of the semiconductor because Cu(S,Se) decomposes at higher temperatures with increasing sulfur. Upon heating S Se exchange reactions take place in the Cu-S-Se and Cu-In-S-Se syste},
author = {Hölzing, Astrid and Schurr, Roland and Jost, Stefan and Palm, Jörg and Deseler, Klaus and Hock, Rainer and Wellmann, Peter},
doi = {10.1557/PROC-1165-M02-02},
faupublication = {yes},
journal = {Materials Research Society Symposium - Proceedings},
keywords = {phase transformation; mixture; thin film},
month = {Jan},
pages = {25-30},
peerreviewed = {Yes},
title = {{Real}-{Time} {Investigations} on the {Formation} of {CuIn}({S},{Se})(2) {While} {Annealing} {Precursors} {With} {Varying} {Sulfur} {Content}},
volume = {1165},
year = {2010}
}
@inproceedings{faucris.123436764,
abstract = {We report on results of time-resolved and angle-dispersive XRD experiments during annealing comparing the formation reactions in sulfurized Cu-Sn precursors prepared by different deposition techniques. (C) 2010 Elsevier B.V. All rights reserved.},
author = {Schurr, R. and Hölzing, Astrid and Hock, Rainer},
doi = {10.1016/j.tsf.2010.12.166},
faupublication = {yes},
keywords = {Cu2ZnSnS4;CZTS;Cu2SnS3;Cu-Sn-S;Thin films;Real-time XRD;Formation reaction},
pages = {7412-7415},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
title = {{Real}-time investigations on the formation reactions during annealing of sulfurized {Cu}-{Sn} precursors},
volume = {519},
year = {2011}
}
@article{faucris.233255024,
abstract = {Fullerene intercalation between the side chains of conjugated polymers has a detrimental impact on both charge separation and charge transport processes in bulk heterojunction (BHJ) organic photovoltaic cells (OPVs). In situ grazing incidence X-ray scattering experiments allow to characterize the structure formation, drying kinetics, and intercalation in blends of phenyl-c61-butyric acid methyl ester (PC60BM) and poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) named (pBTTT-C14) from their 1,2-orthodichlorobenzene (oDCB) solutions with different volume fractions of dodecanoic acid methyl ester (Me12) as a solvent additive. The structure formation process during evaporation of the solvent:additive mixture can be described by five periods, which are correlated to a multistep contraction of the lamellar stacking of the bimolecular crystals. The onset of crystallization is delayed by increasing the additive volume fraction in the coating solution leading to a promoted crystallinity. A conclusive picture of fullerene intercalation and additive-tuned structural evolution during the drying of thin films of the polymer:fullerene BHJ blends will be presented.},
author = {Kassar, Thaer and Berlinghof, Marvin and Güldal, Nusret Sena and Schmutzler, Tilo and Zontone, Federico and Brandl, Marco and Metwalli, Ezzeldin and Will, Johannes and Li, Ning and Ameri, Tayebeh and Brabec, Christoph and Unruh, Tobias},
doi = {10.1002/solr.201900508},
faupublication = {yes},
journal = {Solar RRL},
month = {Jan},
note = {CRIS-Team WoS Importer:2020-02-04},
pages = {1900508},
peerreviewed = {Yes},
title = {{Real}-{Time} {Study} on {Structure} {Formation} and the {Intercalation} {Process} of {Polymer}: {Fullerene} {Bulk} {Heterojunction} {Thin} {Films}},
volume = {4},
year = {2020}
}
@inproceedings{faucris.108498324,
abstract = {Knowledge of the solid-state reactions providing the synthesis of the absorber material Cu(IngGa)Se-2 well below its melting point is an essential prerequisite for the further optimization of the technologically relevant production processes. Therefore, powder XRD has been applied as nondestructive tool to follow chemical solide-state reactions in-situ. Subsequent Rietveld refinement provides the quantitative phase evolution time.},
author = {Hock, Rainer and et al.},
author_hint = {Hergert F, Jost S, Hock R, Purwins M},
doi = {10.1002/ppsc.200501003},
faupublication = {yes},
keywords = {phase transitions;solid-state reactions;thin-film solar cell;X-ray diffraction},
pages = {423-426},
peerreviewed = {unknown},
publisher = {WILEY-V C H VERLAG GMBH},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Real}-time {XRD} investigations during the formation of {Cu}({IngGa}){Se}-2 {Thin} films},
volume = {22},
year = {2006}
}
@article{faucris.246824215,
abstract = {Herein we introduce for the first time a reduced “grey” brookite TiO2 photocatalyst, produced by thermal hydrogenation of brookite nanoparticles, that shows a remarkable noble metal free photocatalytic H2 evolution. Its activity is substantially higher than that of other TiO2 polymorphs, i.e. anatase or rutile, comparably sized and activated by hydrogenation under optimized conditions. Along with brookite powders, an oriented brookite single crystal was investigated as a defined surface to confirm the effects of the hydrogenation treatment. By a combination of Electron paramagnetic resonance (EPR), electron and X-ray characterization techniques applied to the powders and single crystal, we find that hydrogenation forms in brookite a defective crystalline surface layer rich in Ti3+ states. Amorphization effects, i.e. forming the so called “amorphous shell” as reported in previous work for black anatase TiO2, were not detected. Overall, we provide experimental evidence that hydrogenation forms in brookite a surface strained zone with point defects that are mediators for electron transfer to H2O, leading to a significantly enhanced noble metal free photocatalytic H2 evolution in comparison to anatase.
Oxygen transport of mixed ionic-electronic conductors can be measured by a 'relaxation' technique that permits to investigate the material dynamic properties with oxygen partial pressure change. However, for materials exhibiting higher electronic conductivity than ionic, the time for conductivity change is controlled by bulk ionic transport and any surface reaction can be neglected. By fitting the experimental relaxation data of CaTi 0.7Fe0.3O3-δ composition, the oxidation and reduction kinetics was found to be independent on oxygen partial pressure (PO2) and the rate constants were derived therefrom. From a relaxation experiment at a single PO2 we therefore obtain both the electronic and ionic contributions to the total conductivity as well as the chemical diffusion coefficient.
},
author = {Mashkina, Elena and Baier, Markus and Magerl, Andreas and Göbbels, Matthias and Seifert, Friedrich},
faupublication = {yes},
journal = {Ionics},
note = {UnivIS-Import:2015-03-09:Pub.2005.nat.dgeo.IGM.LM.resist},
pages = {269-274},
peerreviewed = {Yes},
title = {{Resistivity} relaxation, a new approach to study ionic mobility in perovskite mixed conductors like {CaTi0}.{7Fe0}.{3O3}-ð},
volume = {11},
year = {2005}
}
@article{faucris.108462464,
abstract = {The size of the interlayer and the size of Mt particles are two characteristic dimensions which determine the time dependent behavior of water diffusion in Mt. MD simulations show that at very short time scales water dynamics has the characteristic features of an oscillatory motion in the cage formed by neighbors in the first coordination shell. At longer time scales, the interaction of water with the surface determines the water dynamics, and the effect of confinement on the overall water mobility within the interlayer becomes evident. At time scales corresponding to an average water displacement equivalent to the average size of Mt particles, the effects of tortuosity are observed in the meso- to macroscopic pore scale simulations. Consistent with the picture obtained in the simulations, the QENS data can be described using a (local) 3D diffusion at short observation times, whereas at sufficiently long observation times a 2D diffusive motion is clearly observed. The effects of tortuosity measured in macroscopic tracer diffusion experiments are in qualitative agreement with RW simulations. By using experimental data to calibrate molecular and mesoscopic theoretical models, a consistent description of water mobility in clay minerals from the molecular to the macroscopic scale can be achieved. In turn, simulations help in choosing optimal conditions for the experimental measurements and the data interpretation. (C) 2014 Elsevier B.V. All rights reserved.},
author = {Churakov, Sergey V. and Gimmi, Thomas and Unruh, Tobias and Van Loon, Luc R. and Juranyi, Fanni},
doi = {10.1016/j.clay.2014.04.030},
faupublication = {yes},
journal = {Applied Clay Science},
keywords = {Restricted water diffusion;QENS;Molecular dynamics;2D confinement;Montmorillonite},
pages = {36-44},
peerreviewed = {Yes},
title = {{Resolving} diffusion in clay minerals at different time scales: {Combination} of experimental and modeling approaches},
volume = {96},
year = {2014}
}
@article{faucris.271008004,
abstract = {Identification and investigation of strain at buried interfaces in halide perovskite photovoltaics are crucial for directing research on the performance and stability of perovskite solar cells. In this work, we find a gradual shift in the band gap of up to 60 meV over a perovskite layer thickness of 300 nm caused by interfacial strain. This graded band gap is desired insofar as it relates to the aspect of device engineering. However, in parallel, the increased defect density causes charge recombination at the buried interface. These two effects compensate for each other, resulting in an overall performance improvement under standard 1 sun illumination. Nevertheless, the disadvantage of enhanced defect density is clearly observed at low-light intensities, where the device performance becomes dominated by charge recombination and ion migration. Moreover, the strained interfaces are proven to induce enhanced defect densities, causing significantly accelerated device degradation under illumination as well as in the dark.},
author = {Meng, Wei and Zhang, Kaicheng and Osvet, Andres and Zhang, Jiyun and Gruber, Wolfgang and Forberich, Karen and Meyer, Bernd and Heiß, Wolfgang and Unruh, Tobias and Li, Ning and Brabec, Christoph},
doi = {10.1016/j.joule.2022.01.011},
faupublication = {yes},
journal = {Joule},
keywords = {device stability; graded band gap; interface engineering; low-light PV applications; perovskite solar cells; strain engineering},
note = {CRIS-Team Scopus Importer:2022-03-18},
pages = {458-475},
peerreviewed = {Yes},
title = {{Revealing} the strain-associated physical mechanisms impacting the performance and stability of perovskite solar cells},
volume = {6},
year = {2022}
}
@article{faucris.203400371,
abstract = {Development of high-quality organic nanoparticle inks is a significant scientific challenge for the industrial production of solution processed organic photovoltaics (OPVs) with eco-friendly processing methods. In this work, we demonstrate a novel, robot-based, high throughput procedure performing automatic poly(3-hexylthio-phene-2,5-diyl) and indene-C-60 bisadduct nanoparticle ink synthesis in nontoxic alcohols. A novel methodology to prepare particle dispersions for fully functional OPVs by manipulating the particle size and solvent system was studied in detail. The ethanol dispersion with a particle diameter of around 80-100 nm exhibits reduced degradation, yielding a power conversion efficiency of 4.52%, which is the highest performance reported so far for water/alcohol-processed OPV devices. By successfully deploying the high-throughput robot-based approach for an organic nanoparticle ink preparation, we believe that the findings demonstrated in this work will trigger more research interest and effort on eco-friendly industrial production of OPVs.},
author = {Xie, Chen and Tang, Xiaofeng and Berlinghof, Marvin and Langner, Stefan and Chen, Shi and Späth, Andreas and Li, Ning and Fink, Rainer and Unruh, Tobias and Brabec, Christoph},
doi = {10.1021/acsami.8b03621},
faupublication = {yes},
journal = {ACS Applied Materials and Interfaces},
keywords = {organic photovoltaics;eco-friendly industrial production;robot-based systems;high-throughput organic nanoparticle synthesis;stable organic nanoparticle inks;organic nanoparticle size control},
pages = {23225-23234},
peerreviewed = {Yes},
title = {{Robot}-{Based} {High}-{Throughput} {Engineering} of {Alcoholic} {Polymer}: {Fullerene} {Nanoparticle} {Inks} for an {Eco}-{Friendly} {Processing} of {Organic} {Solar} {Cells}},
volume = {10},
year = {2018}
}
@article{faucris.124169584,
abstract = {Powders of zinc oxide nanoparticles with individual particle sizes below 10 nm in diameter are readily produced in base-induced sol-gel processes from ethanolic solutions of zinc acetate dihydrate. These particles are covered with acetate molecules and without further stabilization, they grow when stored as a powder. Here, we present three organic ligands, which reproducibly stabilize individual particle sizes <5 nm within the agglomerated powders for extended periods of time, up to months. Citric acid and 1,5-diphenyl-1,3,5-pentanetrione result in average diameters of 3 nm, whereas dimethyl-L-tartrate stabilizes 2.1 nm. X-ray diffraction and pair distribution function analysis were used to investigate the structural properties of the particles. TEM data confirm the individual particle size and crystallinity and show that the particles are agglomerated without structural coherence. Besides the introduction of these novel ligands for ZnO nanoparticles, we investigated, in particular, the influence of each synthesis step onto the final nanoparticle size in the powder. Previous studies often reported the employed synthesis parameters, but did not motivate the reasoning for their choice based on detailed experimental observations. Herein, we regard separately the steps of (i) the synthesis of the colloids, (ii) their precipitation, and (iii) the drying of the resulting gel to understand the role of the ligands therein. ZnO particles only covered with acetate grow to 5 nm during the drying process, whereas particles with any of the additional ligands retain their colloidal size of 2-3 nm. This clearly shows the efficient binding and effect of the presented ligands.},
author = {Zobel, Mirijam and Chatterjee, Haimantee and Matveeva, Galina and Kolb, Ute and Neder, Reinhard},
doi = {10.1007/s11051-015-3006-5},
faupublication = {yes},
journal = {Journal of Nanoparticle Research},
keywords = {ZnO;Nanoparticle;Sol-gel synthesis;Organic ligand;Room temperature synthesis},
peerreviewed = {Yes},
title = {{Room}-temperature sol-gel synthesis of organic ligand-capped {ZnO} nanoparticles},
volume = {17},
year = {2015}
}
@article{faucris.106870104,
abstract = {As of today, highly germanium doped Czochralski silicon crystals are used in applications. However, it is not clear how a germanium content in the range of 10(18) atoms/cm(3) influences the oxygen precipitation behavior, which is highly relevant for the gettering potential of the wafer. In this context, high energy X-ray diffraction is a promising tool to monitor real-time the strain introduced by the oxygen agglomeration and growth. Nevertheless, in particular, in the dynamical limit of X-ray diffraction and at elevated temperatures, the strain originating from the precipitation process has to be clearly distinguished from the intensity contribution of thermal vibrations. In Laue geometry, dynamical effects can even lead to an increment of the integrated intensity with temperature completely unexpected in the kinematical limit, where temperature is tackled solely by a Debye-Waller factor. In the following, an approach is presented allowing us to completely correct the influence of thermal vibrations in the dynamical limit. This approach is applied to undoped and highly germanium doped silicon crystals, clearly revealing an enhanced inventory of grown-in precipitates with germanium doping and suggesting a morphological transformation towards a phase of higher strain of the grown-in precipitates in the range between room temperature and 800 degrees C. Published by AIP Publishing.},
author = {Li, Zhen and Will, Johannes and Dong, Peng and Yang, Daren},
doi = {10.1063/1.4979307},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Sample} thickness effect of thermal vibration correction within {X}-ray dynamical theory for germanium-doped silicon},
volume = {121},
year = {2017}
}
@article{faucris.117542524,
abstract = {Laser scribing of the Mo back electrode is commonly applied to define the cell structure of Cu(In,Ga)(Se,S) (CIGSSe) thin film solar cells. The patterning process was performed on laboratory samples using ns and ps pulse length laser processes. After structuring, CIGSSe absorbers were processed by rapid thermal processing (RTP) of stacked elemental layer precursors. Microscopic inhomogeneities were investigated on different sample positions. For samples structured with ns pulse, the absorber morphology in the laser line vicinity is different as compared to the morphology in the unstructured cell area. Scanning electron microscopy and energy-dispersive X-ray spectroscopy show significant changes in the absorber grain size and chemical composition. Close to the laser line, the typically observed Ga accumulation on the back contact is less pronounced and more Ga is incorporated closer to the surface leading to a smaller grain size. The observed changes are attributed to partial damaging of a diffusion barrier between glass and Mo induced by the ns laser process, which allows diffusion of sodium from the glass substrate into the absorber during RTP. The enhanced Ga incorporation closer to the surface is an indication for the influence of sodium on the local phase development during RTP. The damages of the diffusion barrier can be effectively prevented by the application of a ps laser scribing process. CIGSSe absorbers processed on samples structured with ps pulse length do not show the described microscopic inhomogeneities around the laser line. © 2013 Elsevier B.V.},
author = {Künecke, Ulrike and Hölzing, Astrid and Jost, Stefan and Lechner, Robert and Vogt, Helmut and Heiss, Andreas and Palm, Jörg and Hock, Rainer and Wellmann, Peter},
doi = {10.1016/j.tsf.2012.11.069},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {Cu(In,Ga)(Se,S)2; Chalcopyrite; Solar cells; Laser patterning; Sodium; SEM; Mo back contact; SEL-RTP},
pages = {97-101},
peerreviewed = {Yes},
title = {{Scanning} electron microscopical examination of the impact of laser patterning on microscopic inhomogeneities of {Cu}({In},{Ga})({Se},{S})2 absorbers produced by rapid thermal processing},
volume = {535},
year = {2013}
}
@article{faucris.225769755,
abstract = {Self- and inter-diffusion coefficients in liquid Ge and dilute Ge-based Ge-Si, Ge-Au, Ge-In, Ge-Ce and Ge-Gd alloys-containing 2 at% additions, respectively, are measured using a comprehensive approach of measuring techniques: quasi-elastic neutron scattering, in situ long-capillary experiments combined with x-ray radiography, and a long-capillary experiment under microgravity conditions. Resulting inter-and Ge self-diffusion coefficients are equal within error bars for each investigated alloy. The interdiffusion coefficients are smaller for the alloys containing Ce and Gd, However, no dependence of the atomic mass of the minor additions, that varies by about a factor of seven between Si and Au, on the diffusion coefficients could be observed. This demonstrates that in a loosely-packed metallic liquid with fast diffusive dynamics the diffusion mechanism is highly collective in nature.},
author = {Weis, H. and Kargl, F. and Kolbe, M. and Koza, M. M. and Unruh, Tobias and Meyer, A.},
doi = {10.1088/1361-648X/ab354e},
faupublication = {yes},
journal = {Journal of Physics: Condensed Matter},
note = {CRIS-Team WoS Importer:2019-09-06},
pages = {455101},
peerreviewed = {Yes},
title = {{Self}- and interdiffusion in dilute liquid germanium-based alloys},
volume = {31},
year = {2019}
}
@article{faucris.119387444,
abstract = {The use of functional oligomers of pi-conjugated oligofluorenes led to a region-selective assembly of amorphous monolayers which exhibit robust lateral charge transport pathways in self-assembled monolayer field-effect transistors over long distances and even in mixed monolayers of semiconducting and insulating molecules. This oligomer concept might stimulate a new molecular design of self-assembling semiconducting materials.},
author = {Gothe, Bastian and de Roo, Tjaard and Will, Johannes and Unruh, Tobias and Mecking, Stefan and Halik, Marcus},
doi = {10.1039/c7nr06090d},
faupublication = {yes},
journal = {Nanoscale},
pages = {18584-18589},
peerreviewed = {Yes},
title = {{Self}-{Assembled} {Monolayer} {Field}-{Effect} {Transistors} based on {Oligo}-9,9’-dioctylfluorene {Phosphonic} {Acids}},
volume = {9},
year = {2017}
}
@article{faucris.107816104,
abstract = {The interparticle interactions in aqueous monoacid triglyceride nanosuspensions prepared by melt homogenization are strongly influenced by the thickness distribution of the platelet-shaped particles. Small-angle X-ray scattering and transmission electron microscopy investigations on the native, undiluted tripalmitin dispersions stabilized with phospholipids and sodium glycocholate indicate that the dispersed nanocrystals can form aggregates of particles which are oriented in the same direction (stacked lamellae) with interparticle distances around 20 nm. The relative concentration of the particles in the stacks increases with the total triglyceride concentration in a dispersion. The stacked lamellae almost disappear after dilution with the aqueous phase or by increasing the temperature just below the onset of melting of the tripalmitin nanocrystals. This observation indicates that the energy gained by the formation of a stack is of the order of k(B)T. The tendency to form stacked lamellae is reduced for trimyristin and even more for trilaurin suspensions, despite the fact that they also contain platelet-shaped nanocrystals.},
author = {Unruh, Tobias and Westesen, Kirsten and Boesecke, Peter and Lindner, Peter and Koch, Michel},
doi = {10.1021/la0110601},
faupublication = {no},
journal = {Langmuir},
pages = {1796-1800},
peerreviewed = {Yes},
title = {{Self}-assembly of triglyceride nanocrystals in suspension},
volume = {18},
year = {2002}
}
@article{faucris.123364164,
abstract = {A systematic time-of-flight quasielastic neutron scattering (TOF-QENS) study on diffusion of n-alkanes in a melt is presented for the first time. As another example of a medium-chain molecule, coenzyme Q(10) is investigated in the same way. The data were evaluated both in the frequency and in the time domain. TOF-QENS data can be satisfactorily described by different models, and it turned out that the determined diffusion coefficients are largely independent of the applied model. The derived diffusion coefficients are compared with values measured by pulsed-field gradient nuclear magnetic resonance (PFG-NMR). With increasing chain length, an increasing difference between the TOF-QENS diffusion coefficient and the PFG-NMR diffusion coefficient is observed. This discrepancy in the diffusion coefficients is most likely due to a change of the diffusion mechanism on a nanometer length scale for molecules of medium-chain length. (C) 2008 American Institute of Physics.},
author = {Smuda, Christoph and Busch, Sebastian and Gemmecker, Gerd and Unruh, Tobias},
doi = {10.1063/1.2943673},
faupublication = {no},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{Self}-diffusion in molecular liquids: {Medium}-chain n-alkanes and coenzyme {Q}(10) studied by quasielastic neutron scattering},
volume = {129},
year = {2008}
}
@article{faucris.108592704,
abstract = {Self-diffusion coefficients of titanium and cobalt in a silicon melt with 10 at.% metal content were measured in a temperature range between 180K above and below the liquidus temperature, respectively, with quasielastic neutron scattering. The chemical reactive melts were processed container-less by electromagnetic levitation. Whereas, in crystalline silicon self diffusion coefficients of Ti and Co impurities differ by more than 3 orders of magnitude close to the melting point, in the liquid state values of self-diffusion coefficients of Ti and Co, are equal within error bars and are of the order of 10(-8) m(2)/s. This is in line with a liquid-like, collective transport mechanism that is dominated by the mobility of the surrounding Si atoms.},
author = {Pommrich, Ines and Unruh, Tobias and Meyer, Andreas},
faupublication = {yes},
journal = {High Temperatures-High Pressures},
keywords = {Liquid silicon;liquid silicon based alloys;self-diffusion;quasielastic neutron scattering},
month = {Jan},
pages = {49-55},
peerreviewed = {Yes},
title = {{Self}-diffusion of 3d transition metals in liquid silicon alloys},
volume = {42},
year = {2013}
}
@article{faucris.263257553,
abstract = {Self-healing of defects imposed by external stimuli such as high energy radiation is a possibility to sustain the operational lifetime of electronic devices such as radiation detectors. Cs3Bi2Br3I6 polycrystalline wafers are introduced here as novel X-ray detector material, which not only guarantees a high X-ray stopping power due to its composition with elements with high atomic numbers, but also outperforms other Bi-based semiconductors in respect to detector parameters such as detection limit, transient behavior, or dark current. The polycrystalline wafers represent a size scalable technology suitable for future integration in imager devices for medical applications. Most astonishingly, aging of these wafer-based devices results in an overall improvement of the detector performance—dark currents are reduced, photocurrents are increased, and one of the most problematic properties of X-ray detectors, the base line drift is reduced by orders of magnitude. These aging induced improvements indicate self-healing effects which are shown to result from recrystallization. Optimized synthetic conditions also improve the as prepared X-ray detectors; however, the aged device outperforms all others. Thus, self-healing acts in Cs3Bi2Br3I6 as an optimization tool, which is certainly not restricted to this single compound, it is expected to be beneficial also for many further polycrystalline ionic semiconductors.},
author = {Daum, Manuel and Deumel, Sarah and Sytnyk, Mykhailo and Afify, Hany A. and Hock, Rainer and Eigen, Andreas and Zhao, Baolin and Halik, Marcus and These, Albert and Matt, Gebhard and Brabec, Christoph and Tedde, Sandro F. and Heiß, Wolfgang},
doi = {10.1002/adfm.202102713},
faupublication = {yes},
journal = {Advanced Functional Materials},
keywords = {bismuth halides; lead-free perovskites; photoconductors; self-healing; X-ray detection},
note = {CRIS-Team Scopus Importer:2021-08-27},
peerreviewed = {Yes},
title = {{Self}-{Healing} {Cs3Bi2Br3I6} {Perovskite} {Wafers} for {X}-{Ray} {Detection}},
year = {2021}
}
@article{faucris.234136212,
abstract = {Here the fabrication of an inorganic metal-halide perovskite CsPbBr3 based X-ray detector is reported utilizing a simple, scalable, and cost-sensitive melt processing directly on substrate of any size. X-ray diffraction analysis on the several 100 mm thick melt processed films confirms crystalline domains in the cm(2) range. The CsPbBr3 film features a resistance of 8.5 G omega cm and a hole mobility of 18 cm(2) V-1 s(-1). An X-ray to current conversion rate of 1450 mC Gy(air)(-1) cm(-2) at an electric field of 1.2 x 10(4) V cm(-1) and a detection limit in the sub mu Gy(air) s(-1) regime is demonstrated. The high crystallinity and chemical purity of the melt processed CsPbBr3 films are suggested to be responsible for a performance which is on par to current state-of-the-art Cd(Zn)Te based X-ray detector technology.},
author = {Matt, Gebhard and Levchuk, Ievgen and Knüttel, Judith and Dallmann, Johannes and Osvet, Andres and Sytnyk, Mykhailo and Tang, Xiaofeng and Elia, Jack and Hock, Rainer and Heiß, Wolfgang and Brabec, Christoph},
doi = {10.1002/admi.201901575},
faupublication = {yes},
journal = {Advanced Materials Interfaces},
keywords = {X-ray detection; metal-halide perovskites; photophysics},
month = {Jan},
peerreviewed = {Yes},
title = {{Sensitive} {Direct} {Converting} {X}-{Ray} {Detectors} {Utilizing} {Crystalline} {CsPbBr3} {Perovskite} {Films} {Fabricated} via {Scalable} {Melt} {Processing}},
volume = {7},
year = {2020}
}
@article{faucris.264042098,
abstract = {A customized portable SAXS instrument has recently been constructed, installed, and tested at the D22 SANS instrument at ILL. Technical characteristics of this newly established plug-and-play SAXS system have recently been reported (J. Appl. Cryst. 2020, 53, 722). An optimized lead shielding arrangement on the SAXS system and a double energy threshold X-ray detector have been further implemented to substantially suppress the unavoidable high-energy gamma radiation background on the X-ray detector. The performance of the upgraded SAXS instrument has been examined systematically by determining background suppression factors (SFs) at various experimental conditions, including different neutron beam collimation lengths and X-ray sample-to-detector distances (SDDX-ray). Improved signal-to-noise ratio SAXS data enables combined SAXS and SANS measurements for all possible experimental conditions at the D22 instrument. Both SAXS and SANS data from the same sample volume can be fitted simultaneously using a common structural model, allowing unambiguous interpretation of the scattering data. Importantly, advanced in situ/real time investigations are possible, where both the SAXS and the SANS data can reveal time-resolved complementary nanoscale structural information.
3 on freshly cleaved NaCl single-crystal substrates. Only two of the four main types of CsPbBr3 crystallization observed are epitaxial. The microscopic observation of composition gradients at the interface of CsPbBr3 grains and substrates reveals a promising opportunity to manipulate the lattice constant at the interface by simply controlling the temperature and concentration.},
author = {Elia, Jack and Levchuk, Ievgen and Hou, Yi and Matt, Gebhard and These, Albert and Zhao, Yicheng and Zhang, Jiyun and Forberich, Karen and Osvet, Andres and Götz, Klaus and Prihoda, Annemarie and Wu, Mingjian and Harreiß, Christina and Rechberger, Stefanie and Will, Johannes and Unruh, Tobias and Spiecker, Erdmann and Zorenko, Yuriy and Batentschuk, Miroslaw and Brabec, Christoph},
doi = {10.1021/acs.jpcc.3c06162},
faupublication = {yes},
journal = {Journal of Physical Chemistry C},
note = {CRIS-Team Scopus Importer:2023-12-08},
peerreviewed = {Yes},
title = {{Solution}-{Growth} {Liquid}-{Phase} {Epitaxy} of {CsPbBr3} on {NaCl} by {Optimizing} the {Substrate} {Dissolution}},
year = {2023}
}
@article{faucris.108796864,
abstract = {Poly(triazine imide) with incorporated lithium chloride has recently attracted substantial attention due to its photocatalytic activity for water splitting. However, an apparent H/Li disorder prevents the delineation of structure-property relationships, for example, with respect to bandgap tuning. Herein, we show that through a combination of one-and two-dimensional, multinuclear solid-state NMR spectroscopy, chemical modelling, automated electron diffraction tomography, and an analysis based on X-ray pair distribution functions, it is finally possible to resolve the H/Li substructure. In each cavity, one hydrogen atom is bound to a bridging nitrogen atom, while a second one protonates a triazine ring. The two lithium ions within each cavity are positioned between two nitrogen atoms of neighbouring triazine rings. The thereby induced local dipole moments cause slight buckling of the framework and lateral displacements of the Cl- ions at a coherence length below 2 nm. Nevertheless, the average structure conforms to space group P2(1)2(1)2(1). In this way, we demonstrate that, in particular, the above-mentioned techniques allow for smart interplay in delineating the real structure of PTI/LiCl.},
author = {Mesch, Maria B. and Baerwinkel, Kilian and Krysiak, Yasar and Martineau, Charlotte and Taulelle, Francis and Neder, Reinhard and Kolb, Ute and Senker, Juergen},
doi = {10.1002/chem.201603726},
faupublication = {yes},
journal = {Chemistry - A European Journal},
keywords = {electron diffraction;NMR crystallography;NMR spectroscopy;poly(triazine imide);structure elucidation},
pages = {16876-16888},
peerreviewed = {Yes},
title = {{Solving} the {Hydrogen} and {Lithium} {Substructure} of {Poly}(triazine imide)/{LiCl} {Using} {NMR} {Crystallography}},
volume = {22},
year = {2016}
}
@article{faucris.110335764,
abstract = {Random unimodular lattice triangulations have been recently used as an embedded random graph model, which exhibit a crossover behavior between an ordered, large-world and a disordered, small-world behavior. Using the ergodic Pachner flips that transform such triangulations into another and an energy functional that corresponds to the degree distribution variance, Markov chain Monte Carlo simulations can be applied to study these graphs. Here, we consider the spectra of the adjacency and the Laplacian matrix as well as the algebraic connectivity and the spectral radius. Power law dependencies on the system size can clearly be identified and compared to analytical solutions for periodic ground states. For random triangulations we find a qualitative agreement of the spectral properties with well-known random graph models. In the microcanonical ensemble analytical approximations agree with numerical simulations. In the canonical ensemble a crossover behavior can be found for the algebraic connectivity and the spectral radius, thus combining large-world and small-world behavior in one model. The considered spectral properties can be applied to transport problems on triangulation graphs and the crossover behavior allows a tuning of important transport quantities.},
author = {Krüger, Benedikt and Schmidt, Ella and Mecke, Klaus},
doi = {10.1007/s10955-016-1493-0},
faupublication = {yes},
journal = {Journal of Statistical Physics},
keywords = {Triangulations;Random graphs;Networks;Spectral graph theory},
pages = {514-543},
peerreviewed = {Yes},
title = {{Spectral} {Properties} of {Unimodular} {Lattice} {Triangulations}},
volume = {163},
year = {2016}
}
@incollection{faucris.221420059,
author = {Neder, Reinhard},
booktitle = {Structures on Different Time Scales},
doi = {10.1515/9783110433920-002},
editor = {Theo Woike, Dominik Schaniel},
faupublication = {yes},
month = {Jan},
note = {CRIS-Team WoS Importer:2019-06-28},
pages = {13-66},
peerreviewed = {unknown},
title = {{Static} structural analysis of condensed matter: from single-crystal to amorphous},
year = {2018}
}
@article{faucris.109030944,
abstract = {The temporal structure and high brilliance of the X-ray beams produced by third-generation synchrotrons open up new possibilities in time-dependent diffraction and spectroscopy, where timescales down to the sub-nanosecond regime can now be accessed. These beam properties are such that one can envisage the development of the X-ray equivalent of optical components, such as photon delay lines and resonators, that have proved indispensable in a wide range of experiments-for example, pump-probe and multiple-interaction experiments-and (through shaping the temporal structure and repetition rate of the beams) time-dependent measurements in crystallography, physics, biology and chemistry(1-3). Optical resonators, such as those used in lasers, are available at wavelengths from the visible to soft X-rays(4,5). Equivalent components for hard X-rays have been discussed for more than thirty years(4,6,7), but have yet to be realized. Here we report the storage of hard X-ray photons (energy 15.817 keV) in a crystal resonator formed by two plates of crystalline silicon. The photons are stored for as many as 14 back-and-forth cycles within the resonator, each cycle separated by one nanosecond.},
author = {Hock, Rainer and et al.},
author_hint = {Liss KD, Hock R, Gomm M, Waibel B, Magerl A, Krisch M, Tucoulou R},
faupublication = {yes},
journal = {Nature},
pages = {371-373},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Storage} of {X}-ray photons in a crystal resonator},
volume = {404},
year = {2000}
}
@article{faucris.110543004,
abstract = {Oxygen precipitation in highly boron-doped Czochralski silicon (5m Omega cm resistivity) was studied, and a strain-relieving mechanism involving the emission of silicon interstitial atoms (I-Si) was identified. Strain-sensitive X-ray diffraction was employed, and through a comparison with complementary electron microscopy measurements a linear misfit strain epsilon=0. 01 was determined. Different behavior concerning strain relaxation was measured for wafer-type samples (760 mu m thickness) and thick samples (2mm thickness), which was explained with out-diffusion of ISi in the thinner samples. Based on the experimental findings, a model was developed which invokes an increase in the solubility of interstitial silicon atoms upon boron doping. The model successfully accounts for different effects of boron doping on oxygen precipitation in silicon, which were reported on in literature such as preferential octahedral morphology of precipitates, enhanced nucleation, and relaxed accommodation of the precipitates with respect to the silicon lattice. (C) 2015 AIP Publishing LLC.},
author = {Bergmann, Christoph and Gröschel, Alexander and Will, Johannes and Magerl, Andreas},
doi = {10.1063/1.4926429},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Strain} relief via silicon self-interstitial emission in highly boron-doped silicon: {A} diffuse {X}-ray scattering study of oxygen precipitation},
volume = {118},
year = {2015}
}
@article{faucris.108370064,
abstract = {The structure of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-stabilized colloidal tetracosane emulsions was investigated by photon correlation spectroscopy and small-angle X-ray and neutron scattering, using emulsions with different neutron scattering contrasts. Special emphasis was placed on the structure of the DMPC stabilizer layer covering the emulsion droplets. A monolayer, structurally similar to a half DMPC bilayer, with a thickness of 16 å is found. Thereby, the phosphocholine headgroups arrange flat at the oil-water interface. A deep penetration of the tetracosane oil into the stabilizer layer can be ruled ou},
author = {Schmiele, Martin and Busch, Sebastian and Morhenn, H. and Schindler, Torben and Schmutzler, Tilo and Schweins, R. and Lindner, P. and Boesecke, P. and Westermann, M. and Steiniger, F. and Funari, Sergio S. and Unruh, Tobias},
doi = {10.1021/acs.jpcb.6b02519},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {5505-5512},
peerreviewed = {unknown},
title = {{Structural} {Characterization} of {Lecithin}-{Stabilized} {Tetracosane} {Lipid} {Nanoparticles}. {Part} {I}: {Emulsions}},
volume = {120},
year = {2016}
}
@article{faucris.122543124,
abstract = {Using photon correlation spectroscopy, transmission electron microscopy, microcalorimetry, wide-angle X-ray scattering (WAXS), and small-angle X-ray and neutron scattering (SAXS, SANS), the structure of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-stabilized colloidal tetracosane suspensions was studied from the molecular level to the microscopic scale as a function of the temperature. The platelike nanocrystals exhibit for tetracosane an unusual orthorhombic low-temperature crystal structure. The corresponding WAXS pattern can be reproduced with a predicted orthorhombic unit cell (space group Pca2), which usually occurs only for much longer even-numbered n-alkanes. Special emphasis was placed on the structure of the DMPC stabilizer layer covering the nanocrystals. Their structure was investigated by SAXS and SANS, using suspensions with different neutron scattering contrasts. As for the emulsions in Part I, the crystallized nanoparticles are covered by a DMPC monolayer. Their significant smaller thickness of 10.5 å (for the emulsions in Part I: 16 å) could be related to a more tilted orientation of the DMPC molecules to cover the expanded surface of the crystallized nanoparticle},
author = {Schmiele, Martin and Busch, Sebastian and Morhenn, H. and Schindler, Torben and Schmutzler, Tilo and Schweins, R. and Lindner, P. and Boesecke, P. and Westermann, M. and Steiniger, F. and Funari, Sergio S. and Unruh, Tobias},
doi = {10.1021/acs.jpcb.6b02520},
faupublication = {yes},
journal = {Journal of Physical Chemistry B},
pages = {5513-5526},
peerreviewed = {Yes},
title = {{Structural} {Characterization} of {Lecithin}-{Stabilized} {Tetracosane} {Lipid} {Nanoparticles}. {Part} {II}: {Suspensions}},
volume = {120},
year = {2016}
}
@article{faucris.108370284,
abstract = {Dispersions of crystalline nanoparticles with at least one sufficiently large unit cell dimension can give rise to Bragg reflections in the small-angle scattering range. If the nanocrystals possess only a small number of unit cells along these particular crystallographic directions, the corresponding Bragg reflections will be broadened. In a previous study of phospholipid stabilized dispersions of β-tripalmitin platelets, the x-ray powder pattern simulation analysis (XPPSA) was developed. The XPPSA method facilitates the interpretation of the rather complicated small-angle x-ray scattering (SAXS) curves of such dispersions of nanocrystals. The XPPSA method yields the distribution function of the platelet thicknesses and facilitates a structural characterization of the phospholipid stabilizer layer at the solid-liquid interface between the nanocrystals and the dispersion medium from the shape of the broadened 001 Bragg reflection. In this contribution an improved and extended version of the XPPSA method is presented. The SAXS and small-angle neutron scattering patterns of dilute phospholipid stabilized tripalmitin dispersions can be reproduced on the basis of a consistent simulation model for the particles and their phospholipid stabilizer layer on an absolute scale. The results indicate a surprisingly flat arrangement of the phospholipid molecules in the stabilizer layer with a total thickness of only 12 Å. The stabilizer layer can be modeled by an inner shell for the fatty acid chains and an outer shell including the head groups and additional water. The experiments support a dense packing of the phospholipid molecules on the nanocrystal surfaces rather than isolated phospholipid domains. © 2013 American Physical Society.},
author = {Schmiele, Martin and Schindler, Torben and Unruh, Tobias and Busch, Sebastian and Morhenn, Humphrey and Westermann, Martin and Steiniger, Frank and Radulescu, Aurel and Lindner, Peter and Schweins, Ralf and Boesecke, Peter},
doi = {10.1103/PhysRevE.87.062316},
faupublication = {yes},
journal = {Physical Review E},
peerreviewed = {Yes},
title = {{Structural} characterization of the phospholipid stabilizer layer at the solid-liquid interface of dispersed triglyceride nanocrystals with small-angle x-ray and neutron scattering},
volume = {87},
year = {2013}
}
@article{faucris.117611604,
abstract = {High energy x-ray diffraction (up to 300 keV) has been used to analyse structural defects in an as grown SiC boule with a diameter of 55 nun, a thickness of 20 mm and in a 2 inch wafer. The crystals are 6H SiC grown by PVT method. In the wafer numerous grains can be identified and localised with a mosaicity in the order of 0.05degrees, whereas the whole wafer shows a mosaic spread of around 0.1degrees. The bulk crystal shows a pronounced domain structure and a bending in the lattice plane orientation. The local reflection broadening is between 0.2degrees and 2degrees, while the tilts of the lattice planes over the entire wafer are between 2 and 6degrees (2theta-values},
author = {Weißer, Matthias and Seitz, Christoph and Wellmann, Peter and Hock, Rainer and Magerl, Andreas},
doi = {10.4028/www.scientific.net/MSF.457-460.339},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {Domain Structure; High Energy Diffraction; Structural Defects; X-Ray Diffraction (XRD)},
month = {Jan},
pages = {339-342},
peerreviewed = {Yes},
title = {{Structural} defects in {SiC} crystals investigated by high energy x-ray diffraction},
volume = {457-460},
year = {2004}
}
@inproceedings{faucris.119596224,
abstract = {A defocused Laue diffractometer setup operating with the white beam of a high energy X-ray tube has been used for a topographic visualization of structural defects in semiconductor wafers. The laboratory white beam X-ray topograph of a Czochralski Si wafer with oxygen precipitates grown in an annealing process is compared to a mu PCD image. Further, the dislocation network in a VGF GaAs wafer is studied under thermal annealing up to 1140 degrees C and the in-situ capability of the setup is demonstrated.},
author = {Gröschel, Alexander and Will, Johannes and Bergmann, Christoph and Grillenberger, Hannes and Eichler, Stefan and Scheffer-Czygan, M. and Magerl, Andreas},
doi = {10.4028/www.scientific.net/SSP.178-179.360},
faupublication = {yes},
keywords = {X-ray diffraction;topography;silicon;oxygen precipitates;GaAs;dislocations;annealing;in-situ},
month = {Jan},
pages = {360-+},
peerreviewed = {unknown},
title = {{Structural} {Defect} {Studies} of {Semiconductor} {Crystals} with {Laue} {Topography}},
volume = {178-179},
year = {2011}
}
@article{faucris.107717984,
abstract = {Self-assembled monolayers (SAMs) have been established as crucial interlayers and electronically active layers in organic electronic devices, such as organic light emitting diodes (OLEDs), organic photovoltaics (OPVs), organic thin film transistors (OTFTs), and nonvolatile memories (NVMs). The use of self-assembling functionalized organic molecules is beneficial due to mainly three advantages compared with common thin film deposition approaches. (1) Molecular self-assembly occurs with surface selectivity, determined by the interaction between the functional anchor group of the organic molecules and the target surface. (2) The film thickness of the resulting layers is perfectly controllable on the angstrom scale, due to the self-terminating film formation to only a single molecular layer. And finally, (3) the wide variability in the chemical structure of such molecules enables different SAM functionalities for devices, ranging from electrical insulation to charge storage to charge transport. The SAM approach can be further expanded by employing several functionalized molecules to create mixed SAMs with consequently mixed properties. The function of SAMs in devices depends not only on the chemical structure of the molecules but also on their final arrangement and orientation on the surface. A reliable and nondestructive in-depth characterization of SAMs on nonconductive oxide surfaces is still challenging because of the very small thickness and the impracticality of methods such as scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In this Account, we illustrate how X-ray reflectivity (XRR) provides analytical access to major questions of SAM composition, morphology, and even formation by means of investigations of pure and mixed SAMs based on phosphonic acids (PAs) of various chain structures on flat alumina (AlOx) surfaces. XRR is an analytical method that provides access to spatially averaged structural depth profiles over a relatively large area of several square micrometers. The key outcome of XRR, the surface-normal electron density profile of the SAMs, leads to precise information on the SAM thickness with subangstrom resolution and allows for the determination of molecular tilt angles and packing densities. We have systematically increased the chemical complexity of PA molecules and the resulting SAMs, utilizing XRR to provide insight into the SAM structures. In SAMs composed of functionalized molecules or complex chain structures, the distribution of electron rich and electron poor signatures is detected and thus the molecular order within the SAM is determined. In mixed SAMs of two different molecular species, electron density profiles reveal the morphology and how the surface-normal structure changes if one component of the mixed SAM is altered. Furthermore, XRR was applied to investigate in situ the self-assembly of functionalized PA molecules from solution by tracking the monolayer growth over time. Even though the results provided by XRR on in-plane molecular arrangement are limited, it presents excellent information on the molecular scale along the surface normal and in addition allows for drawing conclusions on the intermolecular interactions within the SAM.},
author = {Khassanov, Artöm and Steinrück, Hans-Georg and Schmaltz, Thomas and Magerl, Andreas and Halik, Marcus},
doi = {10.1021/acs.accounts.5b00022},
faupublication = {yes},
journal = {Accounts of Chemical Research},
pages = {1901–1908},
peerreviewed = {unknown},
title = {{Structural} {Investigations} of {Self}-{Assembled} {Monolayers} for {Organic} {Electronics}: {Results} from {X}-ray {Reflectivity}},
url = {http://pubs.acs.org/doi/abs/10.1021/acs.accounts.5b00022},
volume = {48},
year = {2015}
}
@article{faucris.108643964,
abstract = {In the spin-crossover compound [Fe(ptz)(6)](BF4)(2) (where ptz=1-n-propyltetrazole) six different phases are observed. When a single crystal is slowly cooled from high temperatures to those below 125 K, the reflections broaden into diffuse maxima and split into two maxima along the c* direction [Kusz, Gutlich & Spiering (2004). Top. Curr. Chem. 234, 129-153]. As both maxima are broad along the c* direction, the short-range order exists only along the c direction and in the ab plane the structure remains long-range ordered. In this disordered phase additional satellite reflections appear. Upon heating above 135 K, the diffuse maxima return to their previous shape and this process is completely reversible. Rapidly cooled samples, on the other hand, do not show such splitting and the symmetry remains R (3) over bar, despite a jump in lattice parameters. We use a special technique to analyse the disorder model of the slowly cooled samples, which consists of layered domains shifted in the hexagonal ab plane. The low-spin disordered phase was solved in a novel approach to accommodate the very unusual twinning and refined in the non-standard space group C (1) over bar. In contrast to the ordered low-spin phase, the Fe ion is in a non-centrosymmetric coordination polyhedron and two of the six propyl groups change their conformation.},
author = {Kusz, Joachim and Zubko, Maciej and Neder, Reinhard and Guetlich, Phillipp},
doi = {10.1107/S0108768111053298},
faupublication = {yes},
journal = {Acta Crystallographica Section B: Structural Science},
pages = {40-56},
peerreviewed = {Yes},
title = {{Structural} phase transition to disorder low-temperature phase in [{Fe}(ptz)(6)]({BF4})(2) spin-crossover compounds},
volume = {68},
year = {2012}
}
@article{faucris.108593364,
abstract = {In bulk glass forming Zr46.8Ti8.2Cu7.5Ni10Be27.5 (Vit4) the mean Ni, Ti, and Cu self-diffusion coefficient at the liquidus is about 10(-10) m(2) s(-1). Compared with these values, diffusion coefficients derived from various reported viscosity data by rescaling them via the Stokes-Einstein relation exhibit different temperature dependence and absolute values are a factor of 5-10 smaller. This raises the question of whether a slow Zr subsystem exists in the melt at temperatures well above the liquidus temperature. Here, we address this question by studying microscopic dynamics employing quasielastic neutron scattering. We utilized containerless sample processing in a novel electrostatic levitation apparatus. This excludes reactions between samples and crucible materials and gives access to a wide momentum transfer range of about 0.2-2.6 angstrom(-1). We studied the dynamics governed by the Ni, Ti, and Cu diffusive motion as well as by collective Zr motion. At 1255 K, both correlation functions decay to zero on a timescale of about 20 ps. This shows that there is neither a decoupling between the atomic dynamics of the various components nor a slow Zr subsystem in the equilibrium melt.},
author = {Yang, Fan and Kordel, Tobias and Holland-Moritz, Dirk and Unruh, Tobias and Meyer, Andreas},
doi = {10.1088/0953-8984/23/25/254207},
faupublication = {yes},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{Structural} relaxation as seen by quasielastic neutron scattering on viscous {Zr}-{Ti}-{Cu}-{Ni}-{Be} droplets},
volume = {23},
year = {2011}
}
@article{faucris.108594244,
abstract = {We report on investigations on the atomic dynamics and the static structure factors of binary Ni36Zr64 alloy melts. In order to undercool the melts deeply below the melting temperature and to avoid reactions with crucible materials, the liquids are containerlessly processed by the application of the electromagnetic levitation technique. This technique is combined with quasielastic neutron scattering at the time-of-flight spectrometer TOFTOF of the Munich research reactor (FRM II) and neutron diffraction at the diffractometer D20 of the Institut Laue-Langevin. Partial static structure factors of liquid Ni36Zr64 have been derived via isotopic substitution. The quasielastic neutron-scattering experiments indicate a large activation energy for Ni self-diffusion in liquid Ni36Zr64 of 0.64 eV. This may result from a peculiar short-range order of the Ni-Zr melts that differs from the icosahedral short-range order that was previously found to prevail in most melts of pure metals and of metallic alloys with a small difference of the atomic radii of the components and that is characterized by a high nearest-neighbor coordination number of < Z >approximate to 13.9, as found by elastic neutron scattering.},
author = {Holland-Moritz, Dirk and Stüber, Sebastian and Hartmann, Helena and Unruh, Tobias and Hansen, Thomas and Meyer, Andreas},
doi = {10.1103/PhysRevB.79.064204},
faupublication = {no},
journal = {Physical Review B},
keywords = {liquid alloys;liquid structure;melting point;neutron diffraction;nickel alloys;self-diffusion;short-range order;time of flight spectra;zirconium alloys},
peerreviewed = {Yes},
title = {{Structure} and dynamics of liquid {Ni36Zr64} studied by neutron scattering},
volume = {79},
year = {2009}
}
@article{faucris.108797524,
abstract = {Transparent mesoporous silica monoliths of well-controlled porosity and a narrow pore size distribution around 6 nm have been used to prepare sodium nitroprusside (SNP) nanocomposites. The obtained nanomaterials could be characterised using X-ray total scattering coupled to atomic pair distribution function analysis (PDF) and solid-state NMR spectroscopy. The PDF analysis allows for a structural description of the confined species, as well as for the identification of the various coexisting phases: SNP isolated molecules and SNP crystalline nanoparticles. The model obtained suggests that the nanocrystals have the same molecular structure as the bulk crystalline material and measure about 6 nm in diameter. This result is quite exceptional because the space available inside the pores is only about ten times the size of the molecules. The multi-nuclei solid state NMR investigation confirms the structural model proposed by the PDF analysis and assigns the isolated molecules to the dynamic disorder of a solvated phase. The latter approach additionally provides quantitative information on the relative ratio between the dynamic molecules and the rigid nanocrystals. This result is exploited to study the evolution of the two confined SNP phases with respect to solvating water molecules. We show that the confined SNP nanocrystals can be easily dissolved when storing the nanocomposites at increasing atmospheric relative humidity.},
author = {Bendeif, E. -E. and Gansmuller, A. and Hsieh, K. -Y. and Pillet, S. and Woike, Th. and Zobel, Mirijam and Neder, Reinhard and Bouazaoui, M. and El Hamzaoui, H. and Schaniel, Dominik},
doi = {10.1039/c4ra11470a},
faupublication = {yes},
journal = {RSC Advances},
month = {Jan},
pages = {8895-8902},
peerreviewed = {unknown},
title = {{Structure} determination of molecular nanocomposites by combining pair distribution function analysis and solid-state {NMR}},
volume = {5},
year = {2015}
}
@article{faucris.106870764,
abstract = {The structure of n-alkyltrichlorosilane self-assembled monolayers (SAMs) of alkyl chain lengths n = 12, 14, 18, and 22 formed on the amorphous native oxide of silicon (100) has been investigated via angstrom-resolution surface X-ray scattering techniques, with particular focus on the proliferation of lateral order along the molecules' long axis. Grazing incidence diffraction shows that the monolayer is composed of hexagonally packed crystalline-like domains for n = 14, 18, and 22 with a lateral size of about 60 A. However, Bragg rod analysis shows that similar to 12 of the CH, units are not included in the crystalline-like domains. We assign this, and the limited lateral crystallites' size, to strain induced by the size mismatch between the optimal chain-chain and headgroup-headgroup spacings. Analysis of X-ray reflectivity profiles for n = 12, 14, and 22 shows that the density profile used to successfully model n = 18 provides an excellent fit where the analysis-derived parameters provide complementary structural information to the grazing incidence results.},
author = {Steinrück, Hans-Georg and Will, Johannes and Magerl, Andreas and Ocko, B.},
doi = {10.1021/acs.langmuir.5b03091},
faupublication = {yes},
journal = {Langmuir},
pages = {11774-11780},
peerreviewed = {Yes},
title = {{Structure} of n-{Alkyltrichlorosilane} {Mono} layers on {Si}(100)/{SiO2}},
volume = {31},
year = {2015}
}
@article{faucris.120877724,
abstract = {We performed quasielastic neutron scattering experiments and atomistic molecular dynamics simulations on a poly(ethylene oxide) (PEO) homopolymer system above the melting point. The excellent agreement found between both sets of data, together with a successful comparison with literature diffraction results, validates the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field used to produce our dynamic runs and gives support to their further analysis. This provided direct information on magnitudes which are not accessible from experiments such as the radial probability distribution functions of specific atoms at different times and their moments. The results of our simulations on the H-motions and different experiments indicate that in the high-temperature range investigated the dynamics is Rouse-like for Q-values below approximate to 0.6 A(-1). We then addressed the single chain dynamic structure factor with the simulations. A mode analysis, not possible directly experimentally, reveals the limits of applicability of the Rouse model to PEO. We discuss the possible origins for the observed deviations.},
author = {Brodeck, Martin and Alvarez, F. and Arbe, Arantxa and Juranyi, Fanni and Unruh, Tobias and Holderer, Olav and Colmenero, Juan and Richter, Dieter},
doi = {10.1063/1.3077858},
faupublication = {no},
journal = {Journal of Chemical Physics},
keywords = {molecular dynamics method;neutron diffraction;polymer melts},
peerreviewed = {Yes},
title = {{Study} of the dynamics of poly(ethylene oxide) by combining molecular dynamic simulations and neutron scattering experiments},
volume = {130},
year = {2009}
}
@article{faucris.311729363,
abstract = {Porous materials are widely used in applications such as adsorption, catalysis and separation. The use of expander molecules is a versatile route to enlarge the mesopore size in micellar templated mesoporous silica materials. Typical expanders used for this purpose are fossil-based organic molecules such as trimethylbenzene (TMB). In the course of making such syntheses greener and more sustainable, it is highly desirable to substitute such fossil-based chemicals with renewable ones. Here, we show that bio-based limonene can be used as an alternative expander molecule for the synthesis of large-pore templated silica. On the basis of electron microscopy, nitrogen physisorption and small angle X-ray scattering we show that the substitution of TMB by limonene leads to very similar material characteristics, reaching mean mesopore diameters of 17-19 nm. A comparative life-cycle assessment demonstrates the reduced environmental impact of limonene production from citrus peel waste compared to TMB production, supporting the call for more applications of renewable chemicals, ideally from waste-streams, also for the production of porous materials.},
author = {Sultan, Umair and Städtke, Katrin and Göpfert, Andreas and Lemmen, Daniel and Metwali, Ezzeldin and Maiti, Santanu and Schlumberger, Carola and Yokosawa, Tadahiro and Apeleo Zubiri, Benjamin and Spiecker, Erdmann and Vogel, Nicolas and Unruh, Tobias and Thommes, Matthias and Inayat, Alexandra},
doi = {10.1039/d3su00068k},
faupublication = {yes},
journal = {RSC Sustainability},
note = {CRIS-Team Scopus Importer:2023-10-06},
pages = {1449-1461},
peerreviewed = {Yes},
title = {{Substituting} fossil-based with bio-based chemicals: the case of limonene as a greener pore expander for micellar templated silica},
volume = {1},
year = {2023}
}
@article{faucris.123226224,
abstract = {The affinity of the metals Cu and In is higher to sulfur. A crystallisation of mixed sulfo-selenides of Cu, In and Cu-In due to exchange reactions between S and Se is observed. Within the Cu-Se-S subsystem a wider solid solution range of S and Se is apparent as compared to the In-Se-S system. The reactions during the chalcopyrite crystallisation for chalcogen ratio [S]:[Se]=1:1 are similar to those of the pure sulfur system at least within the In-Se-S subsystem. (C) 2008 Elsevier B.V. All rights reserved.},
author = {Hölzing, Astrid and Schurr, R. and Schäfer, Horst and Jaeger, A. and Jost, S. and Palm, J. and Deseler, Klaus and Wellmann, Peter and Hock, Rainer},
doi = {10.1016/j.tsf.2008.10.089},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {CuIn(S,Se)2; Chalcopyrite; Thin films; Real-time X-ray diffraction},
pages = {2213-2217},
peerreviewed = {Yes},
title = {{Sulfo}-selenization of metallic thin films of {Cu}, {In} and {Cu}-{In}},
volume = {517},
year = {2009}
}
@inproceedings{faucris.230326354,
author = {Taccardi, Nicola and Grabau, Mathias and Debuschewltz, Jonas and Distaso, Monica and Brandl, Marco and Hock, Rainer and Maier, Florian and Papp, Christian and Erhard, Jannis and Neiß, Christian and Peukert, Wolfgang and Görling, Andreas and Wolf, Moritz and Haumann, Marco and Steinrück, Hans-Peter and Wasserscheid, Peter},
booktitle = {12th Natural Gas Conversion Symposium 2019},
date = {2019-06-02/2019-06-06},
faupublication = {yes},
isbn = {9781510888883},
note = {CRIS-Team Scopus Importer:2019-12-10},
pages = {353-354},
peerreviewed = {unknown},
publisher = {AIChE},
title = {{Supported} liquid metals - {A} new class of robust dehydrogenation catalysts},
venue = {San Antonio, TX},
year = {2019}
}
@article{faucris.122286604,
abstract = {Two new solid MO(OH)(2) (M = Zr, Hf) oxyhydroxides have been synthesised by an ion-exchange reaction from Li2MO3 (M = Zr, Hf) precursors obtained by a citrate combustion technique. The crystal structure of the oxyhydroxides has been solved by direct methods and refined using Rietveld full profile fitting based on X-ray powder diffraction data. Both oxyhydroxides crystallize in a P2(1)/c monoclinic unit cell and have a structure resembling that of the related salts. Detailed characterisation of the fine-structure features and chemical bonding in precursors and oxyhydroxide powders has been performed using vibrational spectroscopy, nuclear magnetic resonance spectroscopy, scanning electron microscopy, pair distribution function analysis and quantum-chemical modelling.},
author = {Baklanova, Yana V. and Denisova, Tatyana A. and Maksimova, Lidiya G. and Tyutyunnik, Alexander P. and Baklanova, Inna V. and Shein, Igor R. and Neder, Reinhard and Tarakina, Nadezda V.},
doi = {10.1039/c3dt52929k},
faupublication = {yes},
journal = {Dalton Transactions},
month = {Jan},
pages = {2755-2763},
peerreviewed = {Yes},
title = {{Synthesis} and characterisation of new {MO}({OH})(2) ({M} = {Zr}, {Hf}) oxyhydroxides and related {Li2MO3} salts},
volume = {43},
year = {2014}
}
@article{faucris.113468564,
abstract = {The formation of multilamellar MFI-type zeolite has been studied systematically by investigating the crystallization kinetics and the influence of different synthesis parameters under static conditions. Depending on the template amount and alkalinity, multilamellar MFI-type zeolites with different degrees of purity were obtained. In accordance with X-ray diffraction, SAXS and SEM results, highly crystalline multilamellar MFI-type zeolites were obtained within 4 days of crystallization time. Depending on the Si/Al ratio of the synthesis gel, different crystallization rates, textural properties and product morphologies were observed. (C) 2014 Elsevier Inc. All rights reserved.},
author = {Machoke, Albert and Knoke, I. Y. and Lopez-Orozco, S. and Schmiele, Martin and Selvam, Thangaraj and Marthala, V. R. R. and Spiecker, E. and Unruh, Tobias and Hartmann, Martin and Schwieger, Wilhelm and Hartmann, Martin and Spiecker, Erdmann},
doi = {10.1016/j.micromeso.2014.02.026},
faupublication = {yes},
journal = {Microporous and Mesoporous Materials},
keywords = {Nanosheets of MFI;Multilamellar MFI;Hierarchical zeolites;ZSM-5;Static conditions},
pages = {324-333},
peerreviewed = {Yes},
title = {{Synthesis} of multilamellar {MFI}-type zeolites under static conditions: {The} role of gel composition on their properties},
volume = {190},
year = {2014}
}
@article{faucris.287559319,
abstract = {The formation of multilamellar MFI-type zeolite has been studied systematically by investigating the crystallization kinetics and the influence of different synthesis parameters under static conditions. Depending on the template amount and alkalinity, multilamellar MFI-type zeolites with different degrees of purity were obtained. In accordance with X-ray diffraction, SAXS and SEM results, highly crystalline multilamellar MFI-type zeolites were obtained within 4 days of crystallization time. Depending on the Si/Al ratio of the synthesis gel, different crystallization rates, textural properties and product morphologies were observed.
tv structure of illite could be solved based on a single dataset of a 50 nm illite fiber. Illites that were altered with synthetic Gerolstein brine showed one-dimensional diffuse scattering, indicating a disorder in the stacking of the illite layers. The degree of disorder is dependent on the potassium content of the fluid, since the K+ ions of the interlayer can be released via the (010) facet. This causes a stability reduction of the structure, resulting in a high fragmentation and detachment of individual illite layers. Fluids interacting with the sandstone can then transport such mobile layer fragments, leading to entangling and interweaving of illite fibers. These new insights into the structure of illite fibers show a significant dependence of the arrangement of the fibers in the pores on the potassium content of the fluid. The increased migration and interweaving of illite fibers associated with a low potassium content can lead to severe clogging of the pores and thus to a reduction in fluid permeability. Altered sandstones with illitic pore filling are therefore less suitable for long-term geothermal projects.},
author = {Götz, Emilia and Neder, Reinhard and Kolb, Ute and Kleebe, Hans Joachim},
doi = {10.1016/j.clay.2023.107082},
faupublication = {yes},
journal = {Applied Clay Science},
keywords = {Fibrous illite; Hydrothermal alteration; Order-disorder; Reservoir sandstone; Structure solution; Three-dimensional electron diffraction},
note = {CRIS-Team Scopus Importer:2023-08-11},
peerreviewed = {Yes},
title = {{The} alteration of illite by {Bad} {Nauheim} and {Gerolstein} brine; {Implications} on fluid permeability in geothermal systems},
volume = {243},
year = {2023}
}
@inproceedings{faucris.108806764,
abstract = {The build-up of strain fields caused by the precipitation of oxygen in Czochralski-silicon during annealing up to 1200 degrees C and for process times up to 70 hours has been observed in real time by high energy x-ray diffraction. Five different processes are distinguished in the temperature evolution of the intensity and of the rocking width of the silicon 220-reflection. These features are attributed to different precipitation mechanisms. A fit to part of the data with a diffusion limited precipitation model leads to an activation energy for oxygen diffusion in silicon of 2.2 eV in the temperature range from 700 degrees C to 950 degrees C.},
author = {Hock, Rainer and et al.},
author_hint = {Stockmeier M, Weisser M, Hock R, Magerl A},
faupublication = {yes},
keywords = {Czochralski Si;internal gettering;high energy x-ray diffraction},
month = {Jan},
pages = {631-636},
peerreviewed = {unknown},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{The} build-up of strain fields in {Czochralski}-{Si} observed in real time by high energy x-ray diffraction},
volume = {108-109},
year = {2005}
}
@inproceedings{faucris.118540004,
abstract = {The best CZTS solar cell so far was produced by co-sputtering continued with vapour phase sulfurization method. Efficiencies of up to 5.74% were reached by Katagiri et al. The one step electrochemical deposition of copper, zinc, tin and subsequent sulfurization is an alternative fabrication technique for the production of Cu2ZnSnS4 based thin film solar cells. A kesterite based solar cell (size 0.5 cm(2)) with a conversion efficiency of 3.4% (AM1.5) was produced by vapour phase sulfurization of co-electroplated Cu-Zn-Sn films. We report on results of in-situ X-ray diffraction (XRD) experiments during crystallisation of kesterite thin films from electrochemically co-deposited metal films. The kesterite crystallisation is completed by the solid state reaction of Cu2SnS3 and ZnS. The measurements show two different reaction paths depending on the metal ratios in the as deposited films. In copper-rich metal films Cu3Sn and CuZn were found after electrodeposition. In copper-poor or near stoichiometric precursors additional Cu6Sn5 and Sn phases were detected. The formation mechanism of Cu2SnS3 involves the binary sulphicles Cu2 -xS and SnS2 in the absence of the binary precursor phase Cu6Sn5. The presence of Cu6Sn5 leads to a preferred formation of Cu2SnS3 Via the reaction educts Cu2-xS and SnS2 in the presence of a SnS2(Cu4SnS6) melt. The melt phase may be advantageous in crystallising the kesterite, leading to enhanced grain growth in the presence of a liquid phase. (C) 2008 Elsevier B.V. All rights reserved.},
author = {Schurr, R. and Hölzing, Astrid and Jost, Stefan Georg and Hock, Rainer and Voss, T. and Schulze, J. and Kirbs, A. and Ennaoui, Ahmed, Prof. Dr. and Lux-Steiner, M. and Weber, A. and Koetschau, I. and Schock, H. -W.},
doi = {10.1016/j.tsf.2008.11.019},
faupublication = {yes},
keywords = {Cu2ZnSnS4;CZTS;Kesterite;Thin films;Real-time XRD},
pages = {2465-2468},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
title = {{The} crystallisation of {Cu2ZnSnS4} thin film solar cell absorbers from co-electroplated {Cu}-{Zn}-{Sn} precursors},
volume = {517},
year = {2009}
}
@article{faucris.108597104,
abstract = {The dynamics of the ammonium ion in ammonium persulfate is studied by inelastic neutron scattering at energy transfers between 0.7 mu eV and about 100 meV. NH4+ librational modes are clearly split into four energetically different bands, in agreement with the absence of symmetry at the ammonium site. One strong, one medium and two weak hydrogen bonds from the NH4 ion to neighboring oxygens lead to this unusual potential shape with one dominating overlap matrix elements hi. Therefore the ammonium dynamics seen by neutron tunneling spectroscopy looks like a rotation about a single axis, that of the strongest hydrogen bond. Quasi-elastic scattering up to T = 100 K is dominated by jumps about this specific axis, too. Jumps about the second weak axis modify the quasi-elastic scattering at higher temperature. Results of a previous nuclear magnetic resonance (NMR) quadrupole resonance experiment are consistently interpreted to show the dynamics around the remaining two strong axes. The reduced isotope effect of the lowest librational band is due to a special shape of the potential and not to changes of the hydrogen bond with deuteration.},
author = {Prager, Michael and Grimm, H. and Natkaniec, I. and Nowak, D. and Unruh, Tobias},
doi = {10.1088/0953-8984/20/12/125218},
faupublication = {no},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{The} dimensionality of ammonium reorientation in ({NH4})(2){S2O8}: the view from neutron spectroscopy},
volume = {20},
year = {2008}
}
@article{faucris.124169364,
abstract = {Recent total scattering experiments have opened up the possibility to study nanoparticle formation in situ and to observe the structural transformation from precursor clusters to adult particles. Organic ligand molecules interact with precursors of metal oxide nanoparticles, yet their influence onto the evolution of crystallinity during particle formation has not been addressed in detail; nor have in situ total scattering experiments ventured into the field of low-concentration, room-temperature syntheses in organic solvents to date. In this report, we follow the crystallization of ZnO nanoparticles in ethanol in the presence of different organic ligands. Low coordinated zinc precursor clusters rapidly polymerize upon base addition to particles of ca. 1 nm in diameter. In situ SAXS experiments reveal that the overall particle size increases to 2 to 4 nm with advancing reaction time. Complementary in situ PDF experiments show smaller crystalline domain sizes, which are only one third to half as large as the particle diameter. The ZnO particles thus feature a crystalline core surrounded by a disordered shell. Both, the core and the shell diameter are influenced by the different surface-bound organic ligands, which prevent an immediate relaxation to fully crystalline particles. A slow crystallization takes place in solution. We assume a dynamic equilibrium of the ligand and solvent molecules at the particle surface, which enables gradual bond restructuring. With suitably adjusted synthesis conditions, in our case by a continuous base addition, we show how to bypass the disordered intermediates, allowing the spontaneous nucleation of fully crystalline nanoparticles.},
author = {Zobel, Mirijam and Windmueller, Anna and Schmidt, Ella and Götz, Klaus and Milek, Theodor and Zahn, Dirk and Kimber, Simon A. J. and Hudspeth, Jessica M. and Neder, Reinhard},
doi = {10.1039/c5ce02099a},
faupublication = {yes},
journal = {Crystengcomm},
month = {Jan},
pages = {2163-2172},
peerreviewed = {Yes},
title = {{The} evolution of crystalline ordering for ligand-ornamented zinc oxide nanoparticles},
volume = {18},
year = {2016}
}
@inproceedings{faucris.108528244,
abstract = {Secondary phase formation in a Cu2ZnSn(S,Se)(4) based p-type layer for photovoltaic applications is one of the major problems which must be overcome to improve solar cell efficiency. To better understand the crystallization mechanism of secondary phases in the material system Cu-Zn-Sn-Se, we investigated the selenization of binary metallic layers as a function of temperature. The sputtered thin film precursors comprise Cu-Zn, Cu-Sn, and Zn-Sn with different sequence. A total six precursors were studied by time-resolved X-ray diffraction while temperature increased from 30 degrees C to 550 degrees C. Selenium had been always deposited on top of the metallic precursors in a separate thermal evaporation step. The observed reaction sequences were shown different results depending on the metals which are in first contact with selenium. From these experimental results, the mutual affinities of metals are determined, and a way of reducing the ZnSe crystallization is presented. Preferable precursor composed of ternary metallic layers with Se is also suggested in conclusion with respect to a stacking order of the metals. (C) 2014 Elsevier B.V. All rights reserved.},
author = {Yoo, Hye Sun and Wibowo, Rachmat Adhi and Manoharan, G. and Lechner, R. and Jost, S. and Verger, A. and Palm, J. and Hock, Rainer},
doi = {10.1016/j.tsf.2014.08.048},
faupublication = {yes},
keywords = {Secondary phase;Binding affinity;CZTSe;Stacking order;Sequence;Layer;Formation},
pages = {245-248},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
title = {{The} formation mechanism of secondary phases in {Cu2ZnSnSe4} absorber layer},
volume = {582},
year = {2015}
}
@article{faucris.107826444,
abstract = {We report on microsecond-resolved in-situ SAXS experiments of the early nucleation and growth behavior of both cadmium sulfide (CdS) quantum dots in aqueous solution including the temperature dependence and of gold (Au) nanoparticles. A novel free-jet setup was developped to access reaction times as early as 20 μs. As the signal in particular in the beginning of the reaction is weak the containment-free nature of this sample environment prooved crucial. The SAXS data reveal a two-step pathway with a surprising stability of a structurally relaxed cluster with a diameter of about 2 nm. While these develop rapidly by ionic assembly, a further slower growth is attributed to cluster attachment. WAXS diffraction confirms, that the particles at this early stage are not yet crystalline. This growth mode is confirmed for a temperature range from 25°C to 45°C. An energy barrier for the diffusion of primary clusters in water of 0.60 eV was experimentally observed in agreement with molecular simulations. To access reaction times beyond 100 ms, a stopped-drop setup -again contaiment- free is introduced. SAXS experiments on the growth of Au nanoparticles on an extended time scale provide a much slower growth with one population only. Further, the influence of ionizing X-ray radiation on the Au particle fromation and growth is discussed.},
author = {Schiener, Andreas and Schmidt, Ella and Bergmann, Christoph and Seifert, Soenke and Zahn, Dirk and Krach, Alexander and Weihrich, Richard and Magerl, Andreas},
doi = {10.1515/zkri-2016-1978},
faupublication = {yes},
journal = {Zeitschrift fur Kristallographie - Crystalline Materials},
keywords = {Au nanoparticles; CdS quantum dots; Containment-free; In-situ SAXS; Nucleation and growth},
pages = {39-46},
peerreviewed = {unknown},
title = {{The} formation of {CdS} quantum dots and {Au} nanoparticles},
volume = {232},
year = {2017}
}
@article{faucris.122629584,
abstract = {The formation of the compound semiconductor CuInSe2 by laser annealing of electroplated precursor films in inert gas atmosphere represents an entire non-vacuum production process of thin-film solar cell absorbers. Besides this technological aspect, the impact of extreme annealing rates on structural properties of the resulting semiconductor is interesting from a fundamental research point of view. For this reason, we compared absorbers processed by laser annealing with absorbers annealed with moderate heating rates in the range of 1 K/s by means of X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). All absorbers processed with laser or furnace annealing consist of crystalline CuInSe2 in the chalcopyrite crystal structure with a high degree of cation disorder. We show that laser annealing does not lead to unintentional selenium loss during the semiconductor formation process. (c) 2007 Elsevier B.V. All rights reserved.},
author = {Jost, Stefan Georg and Schurr, R. and Hergert, Frank and Hock, Rainer and Schulze, J. and Kirbs, A. and Voss, T. and Purwins, Michael and Palm, J. and Mys, I.},
doi = {10.1016/j.solmat.2007.10.002},
faupublication = {yes},
journal = {Solar Energy Materials and Solar Cells},
keywords = {CuInSe2;thin films;laser annealing;electrodeposition;non-vacuum processing},
pages = {410-417},
peerreviewed = {Yes},
title = {{The} formation of {CuInSe2} thin-film solar cell absorbers by laser annealing of electrodeposited precursors},
volume = {92},
year = {2008}
}
@article{faucris.124161664,
abstract = {We present results from real-time X-ray diffraction experiments on the formation of CuInSe2 solar cell absorbers by annealing precursors, produced by simultaneous electrodeposition of copper, indium and selenium. The investigations reveal, that a reduced amount of electrochemically deposited selenium is the decisive parameter in order to realise a chalcopyrite formation behaviour as observed for sputtered stacked elemental layer (SEL) precursors. A simultaneous electrodeposition of the elements copper, indium and selenium in the molar ratio 1: 1:2 of the chalcopyrite CuInSe2 leads to the formation of binary copper and indium selenides during the electrodeposition process. The existence of binary selenides besides the intermetallic phase Cu11In9 as initial phases leads to an unfavourable absorber morphology. This can be explained by the observed semiconductor formation mechanism. A reduction of the deposited amount of selenium favours the formation of the intermetallic compound Cu11In9 and reduces the amount of binary selenides. These precursors show a formation behaviour and resulting absorber morphology as known for sputtered SEL precursors. (C) 2007 Elsevier B.V. All rights reserved.},
author = {Hock, Rainer and et al.},
author_hint = {Jost S, Hergert F, Hock R, Schulze J, Kirbs A, Voss T, Purwins M},
doi = {10.1016/j.solmat.2007.05.016},
faupublication = {yes},
journal = {Solar Energy Materials and Solar Cells},
keywords = {CuInSe2;chalcopyrites;thin films;real-time x-ray diffraction;electrodeposition},
pages = {1669-1675},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{The} formation of {CuInSe2} thin film solar cell absorbers from electroplated precursors with varying selenium content},
volume = {91},
year = {2007}
}
@inproceedings{faucris.124145164,
abstract = {We present results of in-situ X-ray diffraction experiments on the formation of CuInS2 thin film solar cell absorbers. The experiments have been performed while annealing Cu-In-S stacked elemental layer precursors produced by sputtering and thermal evaporation to investigate the crystallisation process of the chalcopyrite CuInS2. Rietveld refinement has been performed to obtain the quantitative phase evolution of crystalline phases while annealing. The annealing process is characterised by a rapid sulfurisation of the initially present intermetallic alloy Cu11In9 forming the sulfide phases CuS, Dg-Cu2-xS, InS and/or CuIn5S8. The chalcopyrite CuInS2 crystallises at elevated sample temperatures by the consumption of these sulfide phases as educts. Three different chalcopyrite formation reactions have been identified by an analysis of the quantitative phase evolution. A comparison to earlier investigations on the formation of CuInSe2 from Cu-In-Se precursors is presented to show similarities and differences of sulfurisation and selenisation processes. The chalcopyrite forms from chalcogenide educts in both cases. However, distinct differences concerning the chalcogenisation kinetics of sulfur and selenium containing Cu-In precursors have been revealed. The chalcogenisation of the intermetallic alloy phase Culling proceeds extremely fast for Cu-In-S precursors as compared to Cu-In-Se samples. (C) 2008 Elsevier B.V. All lights reserved.},
author = {Jost, S. and Schurr, R. and Hölzing, Astrid and Hergert, Frank and Hock, Rainer and Purwins, Michael and Palm, J.},
doi = {10.1016/j.tsf.2008.10.076},
faupublication = {yes},
keywords = {CuInS2;Chalcopyrite;Thin films;Real-time X-ray diffraction},
pages = {2136-2139},
peerreviewed = {unknown},
publisher = {ELSEVIER SCIENCE SA},
title = {{The} formation of the thin-film solar cell absorber {CuInS2} by annealing of {Cu}-{In}-{S} stacked elemental layer precursors - {A} comparison of selenisation and sulfurisation},
volume = {517},
year = {2009}
}
@article{faucris.108598424,
abstract = {The TOFTOF spectrometer is a multi-disc chopper time-of-flight spectrometer for cold neutrons at the research neutron source Heinz Maier-Leibnitz (FRM II). After five reactor cycles of routine operation the characteristics of the instrument are reported in this article. The spectrometer features an excellent signal to background ratio due to its remote position in the neutron guide hall, an elaborated shielding concept and an s-shaped curved primary neutron guide which acts i.a. as a neutron velocity filter. The spectrometer is fed with neutrons from the undermoderated cold neutron source of the FRM II leading to a total neutron flux of similar to 10(10)n/cm(2)/s in the continuous white beam at the sample position distributed over a continuous and particularly broad wavelength spectrum. A high energy resolution is achieved by the use of high speed chopper discs made of carbon-fiber-reinforced plastic. In the combination of intensity, resolution and signal to background ratio the spectrometer offers new scientific prospects in the fields of inelastic and quasielastic neutron scattering. (C) 2007 Elsevier B.V. All rights reserved.},
author = {Unruh, Tobias and Neuhaus, Jürgen and Petry, Winfried},
doi = {10.1016/j.nima.2007.07.015},
faupublication = {no},
journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
keywords = {neutron scattering;time-of-flight spectrometer;QENS;INS},
pages = {1414-1422},
peerreviewed = {Yes},
title = {{The} high-resolution time-of-flight spectrometer {TOFTOF}},
volume = {580},
year = {2007}
}
@article{faucris.123365264,
abstract = {Pressure is a ubiquitous physical parameter in life and is commonly used in the life sciences to study new protein folding pathways or association-dissociation phenomena. In this paper, an investigation of the influence of pressure on hemoglobin, a multimeric protein, at the picosecond time scale is presented using time-of-flight neutron scattering. The aim is to observe the influence of pressure on the translational diffusion and internal motions of hemoglobin in a concentrated solution and a possible dissociation of the subunits as suggested by Pin et al. (Biochemistry 29:9194, 1990) using fluorescence spectroscopy. A new flat 2 kbar pressure cell made of an aluminum alloy has been used, which allowed the effect of pressure to be studied with minimum background contribution. Within this range of pressure, the effect of this physical parameter on global diffusion can be explained in terms of the change in the water buffer viscosity and an oligomerization of hemoglobin subunits, whereas the internal motions were less affected.},
author = {Appavou, Marie-Sousai and Busch, Sebastian and Doster, Wolfgang and Gaspar, A. M. and Unruh, Tobias},
doi = {10.1007/s00249-011-0678-3},
faupublication = {yes},
journal = {European Biophysics Journal},
keywords = {Pressure;Protein;Hemoglobin;Dynamics;Quasielastic neutron scattering},
pages = {705-714},
peerreviewed = {Yes},
title = {{The} influence of 2 kbar pressure on the global and internal dynamics of human hemoglobin observed by quasielastic neutron scattering},
volume = {40},
year = {2011}
}
@article{faucris.108600184,
abstract = {The influence of additives on the molecular dynamics of the phospholipid dimyristoylphosphatidylcholine (DMPC) in its fully hydrated liquid crystalline phase was studied. Quasielastic neutron scattering (QENS) was used to detect motions with dimensions of some Angstroms on two different time scales, namely 60 ps and 900 Ps. The effects of myristic acid, farnesol, cholesterol, and sodium glycocholate could consistently be explained on the basis of collective, flow-like motions of the phospholipid molecules. The influence of the additives on these motions was explained by packing effects, corresponding to the reduction of free volume. Cholesterol was found to decrease the mobility of DMPC seen on the 900 ps time scale with increasing cholesterol content. In contrast, all other studied additives have no significant effect on the mobility. (C) 2010 Elsevier B.V. All rights reserved.},
author = {Busch, Sebastian and Unruh, Tobias},
doi = {10.1016/j.bbamem.2010.10.012},
faupublication = {no},
journal = {Biochimica Et Biophysica Acta-Biomembranes},
keywords = {DMPC;Dynamics;QENS;Myristic acid;Farnesol;Cholesterol;Sodium Glycocholate;Dynamic Heterogeneity},
month = {Jan},
pages = {199-208},
peerreviewed = {Yes},
title = {{The} influence of additives on the nanoscopic dynamics of the phospholipid dimyristoylphosphatidylcholine},
volume = {1808},
year = {2011}
}
@article{faucris.123219844,
abstract = {Chalcopyrite based photovoltaic materials Cu(InxGa1-x)(SySe1-y)(2) (CIGSSe) are substituted in the cation and anion lattice to adopt the semiconductor bandgap to the terrestrial solar spectrum. In-situ X-ray diffraction (XRD) investigations on the crystallisation of thin film absorber materials Cu(In,Ga)(S,Se)(2) while annealing stacked elemental layers (SEL) show phase transitions proceeding during the chalcopyrite synthesis. Thin layers of metals with elemental ratio Cu:In:Ga = 3:2:1 are deposited onto Mo-coated polyimide foil by DC-magnetron sputtering. The metal precursor is covered with S and subsequently Se by thermal evaporation of the elements in chalcogen excess (S + Se)/(Cu + In + Ga) = 23. Investigated chalcogen ratios reach from pure Se to pure S. Crystalline phases formed during the annealing of SEL are qualitatively determined. The results are compared to conclusions drawn from previous experiments on Ga-free CuIn(S,Se)(2) absorbers. The presence of Ga and S influences significantly the time-scale and the temperatures of phase transitions, i.e. the sulfoselenisation of precursor phases Cu-16(In,Ga)(9) and Cu-9(Ga,In)(4) proceeds faster with increasing S and is shifted to higher temperatures as compared to Ga-free Cu11In9/Cu16In9. (C) 2011 Elsevier BM. All rights reserved.},
author = {Hölzing, Astrid and Schurr, R. and Jost, S. and Palm, J. and Deseler, Klaus and Wellmann, Peter and Hock, Rainer},
doi = {10.1016/j.tsf.2010.12.138},
faupublication = {yes},
journal = {Thin Solid Films},
keywords = {Cu(In,Ga)(S,Se)2; Chalcopyrite; Chalcogenisation; Sulfoselenisation; Formation reaction; in-situ XRD},
pages = {7197-7200},
peerreviewed = {Yes},
title = {{The} influence of gallium on phase transitions during the crystallisation of thin film absorber materials {Cu}({In},{Ga})({S},{Se})(2) investigated by in-situ {X}-ray diffraction},
volume = {519},
year = {2011}
}
@article{faucris.107684324,
abstract = {The effect of the addition of n-hexanol as co-surfactant on the structure of cetyltrimethylammonium bromide (CTAB) micelles has been studied using small-angle X-ray and neutron scattering (SAXS, SANS). Contrast variation neutron scattering experiments were performed to determine the structure of both pure CTAB and n-hexanol modified CTAB micelles. The incorporation of n-hexanol leads to an elongation of the ellipsoidal CTAB micelles. The scattering length density of the micellar shell linearly depends on the degree of deuteration of the dispersion medium water and revealed the existence of substantial amounts of water in the micellar shell. The water content in the shell increased from 20 vol-% observed for pure CTAB micelles to 44 vol-% found for n-hexanol modified CTAB micelles. The amount of n-hexanol in the micellar shell was determined by varying the amount of fully deuterated and protonated n-hexanol. These experiments revealed a volume fraction of 26 vol-% of n-hexanol molecules in the micellar core which equals a molar fraction of 50% n-hexanol within the CTAB micelles. The total composition of micellar core and shell was estimated. The packing density of headgroups, water molecules and bromide ions turned out to drastically increase in n-hexanol modified CTAB micelles. These findings contribute to a fundamental understanding of the stabilization mechanism of micelles by alcoholic co-surfactants and the resulting alteration of the morphology and interface composition. These results will facilitate the optimization of processes where CTAB and other comparable surfactants are used as phase transfer catalysts, structure directing agents or stabilizers in colloidal dispersions or emulsions.},
author = {Schmutzler, Tilo and Schindler, Torben and Schmiele, Martin and Appavou, Marie-Sousai and Lages, Sebastian and Kriele, Armin and Gilles, Ralph and Unruh, Tobias},
doi = {10.1016/j.colsurfa.2017.12.039},
faupublication = {yes},
journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects},
keywords = {CTAB micelles;Surfactants;Co-surfactants;SANS;SAXS},
pages = {56-63},
peerreviewed = {Yes},
title = {{The} influence of n-hexanol on the morphology and composition of {CTAB} micelles},
volume = {543},
year = {2018}
}
@article{faucris.123365704,
abstract = {We measured dynamic structure factors using quasielastic neutron scattering for two liquid germanium samples, one in natural isotope abundance, and a second one with a Ge-nat/73 isotope mixture which exhibits an order of magnitude larger ratio of incoherent to coherent neutron scattering cross section. In an intermediate q range corresponding spectra exhibit similar quasielastic broadening. We show that the measured quasielastic line originates from incoherent scattering. Coherent contributions appear as an almost energy independent background. From the incoherent quasielastic neutron scattering signal self-diffusion coefficients can therefore accurately be derived.},
author = {Weiss, Henning and Unruh, Tobias and Meyer, Andreas},
faupublication = {yes},
journal = {High Temperatures-High Pressures},
keywords = {Liquid germanium;atomic self diffusion;thermal diffusion;phonon dispersion;neutron scattering;X-ray scattering;coherent and incoherent scattering;Rayleigh line;Brillouin lines},
month = {Jan},
pages = {39-47},
peerreviewed = {Yes},
title = {{The} measurement of self-diffusion coefficients in liquid germanium using quasielastic neutron scattering},
volume = {42},
year = {2013}
}
@article{faucris.108644624,
abstract = {Interpretation of elastic scattering from nanocrystals is critical to building and testing models of the short and medium range atomic arrangements in environmentally relevant nanoparticles. Along with information about atomic arrangements, the diffraction pattern arising from a collection of nanoparticles contains information on the grain size, shape and defect structure and cannot simply be treated as a broadened collection of Bragg peaks. The Debye equation, a sum over all pairs of atoms in the particle, calculates the scattering at each value of Q rather than at discrete values of hkl. Especially when atomic arrangements are well known, modeling using the Debye equation allows the refinement of particle shape, allowing the investigation of dominant growth axes. We show the example of 6-line ferrihydrite, fitting the diffraction pattern using a disc of 2.3(1) nm in the ab plane and 6(2) nm along the c axis. A powerful and intuitive way to help examine the diffraction pattern is to take the Fourier transform of the normalized total scattering (Bragg and diffuse), giving the pair distribution function (PDF). The PDF represents a bond length distribution of the material weighted by the respective scattering powers of the contributing atoms. Using examples from the literature, we show that by analyzing the medium range correlations (similar to 5-15 angstrom), the structure of a nanoparticle can be distinguished using PDFs generated from model structures. (c) 2011 Elsevier B.V. All rights reserved.},
author = {Harrington, Richard and Neder, Reinhard and Parise, John B.},
doi = {10.1016/j.chemgeo.2011.06.010},
faupublication = {yes},
journal = {Chemical Geology},
keywords = {X-ray diffraction;Debye equation;Nanoparticles;Pair distribution function;PDF;Ferrihydrite},
pages = {3-9},
peerreviewed = {Yes},
title = {{The} nature of x-ray scattering from geo-nanoparticles: {Practical} considerations of the use of the {Debye} equation and the pair distribution function for structure analysis},
volume = {329},
year = {2012}
}
@article{faucris.108600404,
abstract = {The dynamics of the fully hydrated phospholipid dimyristoylphosphatidylcholine (DMPC) were studied on a time scale of about 60 picoseconds with quasielastic neutron scattering. Three types of samples were employed: multibilayers without solid support, single bilayers in vesicles, and monolayers in emulsions of perdeuterated hexadecane. The vesicles and emulsion droplets had diameters of about 130 nanometres; some of the emulsions also contained sodium glycocholate to enhance the stability. It could be shown that the mobility of the phospholipid molecules in the observed time regime increases from multibilayers over single bilayers to monolayers. Additionally, the high quality of the data of the multibilayer samples allows an evaluation of the molecular mechanism of the motions: while the interpretation in the frame of flow-like motions fits well at temperatures shortly above the main phase transition, the model of diffusive motions fits better at high temperatures of up to 80 degrees C.},
author = {Busch, Sebastian and Pardo, Luis Carlos and Smuda, Christoph and Unruh, Tobias},
doi = {10.1039/c2sm07380c},
faupublication = {yes},
journal = {Soft Matter},
month = {Jan},
pages = {3576-3585},
peerreviewed = {Yes},
title = {{The} picosecond dynamics of the phospholipid dimyristoylphosphatidylcholine in mono- and bilayers},
volume = {8},
year = {2012}
}
@article{faucris.110198704,
abstract = {The thermal expansion of 6H Silicon Carbide with different dopant concentrations of aluminum and nitrogen was determined by lattice parameter measurements at temperatures from 300 K to 1575 K. All samples have a volume of at least 6 x 6 x 6 mm(3) to ensure that bulk properties are measured. The measurements were performed with a triple axis diffractometer with high energy x-rays with a photon energy of 60 keV. The values for the thermal expansion coefficients along the a- and c-direction, alpha(11) and alpha(33), are in the range of 3.10(-6) K(-1) for 300 K and 6.10(-6) K(-1) for 1550 K. At high temperatures the coefficients for aluminum doped samples are approximately 0.5.10(-6) K(-1) lower than for the nitrogen doped crystal. alpha(11) and alpha(33) appear to be isotropi},
author = {Stockmeier, Matthias and Sakwe, Aloysius and Hens, Philip and Wellmann, Peter and Hock, Rainer and Magerl, Andreas},
doi = {10.4028/www.scientific.net/MSF.600-603.517},
faupublication = {yes},
journal = {Materials Science Forum},
keywords = {Bulk Characterization; High Energy X-Ray Diffraction; Thermal Expansion},
month = {Jan},
pages = {517-520},
peerreviewed = {Yes},
title = {{Thermal} {Expansion} {Coefficients} of {6H} {Silicon} {Carbide}},
volume = {600-603},
year = {2009}
}
@article{faucris.108457184,
abstract = {The oxygen (O) precipitate growth kinetics from moderate and high germanium (Ge) doped Czochralskigrowth silicon (Cz-Si) are in-situ investigated at 1000 degrees C utilizing high-energy X-ray diffraction and analyzed with respect to precipitate density within a diffusion-driven growth model. Distinct different precipitation kinetics are observed for high Ge doped specimens. From the comparison of three thermal treatments, it was found that even for a high Ge concentration the nucleation rate at 800 degrees C is not influenced, however it facilitates larger grown-in precipitates of smaller amount as compared to the precipitates in undoped and moderately Ge doped samples. However, those grown-in O precipitates can be erased either by a direct annealing at 1200 degrees C or 1000 degrees C, but on the other hand stabilized by an annealing step at 800 degrees C, which in this manner as a drift step of grown-in precipitates for the high Ge-doped samples. In comparison additional nuclei are formed at 800 degrees C in the moderate and undoped cases. (C) 2017 Elsevier B.V. All rights reserved.},
author = {Li, Zhen and Will, Johannes and Dong, Peng and Yang, Deren},
doi = {10.1016/j.jcrysgro.2017.09.023},
faupublication = {yes},
journal = {Journal of Crystal Growth},
keywords = {Doping;X-ray diffraction;Defects;Impurity;Czochralski method;Semiconducting silicon},
pages = {46-51},
peerreviewed = {Yes},
title = {{Thermal} history effect on the nucleation of oxygen precipitates in germanium doped {Cz}-silicon studied by high-energy {X}-ray diffraction},
volume = {479},
year = {2017}
}
@article{faucris.265525289,
abstract = {Adding to the versatile class of ionic liquids (ILs), an entirely new series of imidazolinium-based ionic liquids is reported herein, offering chirality and important thermal characteristics, such as polymorphism, glass transition, and plastic crystalline behavior. An efficient and general procedure for the preparation of long N,N′-alkyl chain-substituted compounds with either saturated (s) or chiral (c) cyclohexyl (cyC6)-substituted imidazolium (Im) backbones, namely, [C12C12RsIm][A] (A = Br-, [BF4]-, [ClO4]-, [PF6]- R = H, Me, iPr) and [C12C12cIm-cyC6][A] (A = Br-, I-, [I3]-, [BF4]-, [ClO4]-, [PF6]-, [SbF6]-, [BPh4]-), was developed, and the novel compounds were studied by thermochemical methods (DSC, TGA), X-ray diffraction in the small angle regime (SAXS), single-crystal X-ray diffraction (SC-XRD), and specific rotation analysis.},
author = {Seidl, Vera and Sternberg, Michelle and Heinemann, Frank Wilhelm and Schmiele, Martin and Unruh, Tobias and Wasserscheid, Peter and Meyer, Karsten},
doi = {10.1021/acs.cgd.1c00734},
faupublication = {yes},
journal = {Crystal Growth and Design},
note = {CRIS-Team Scopus Importer:2021-10-29},
peerreviewed = {Yes},
title = {{Thermochemical} and {Structural} {Studies} of {New} {Chiral} and {Achiral} {Long} {Alkyl} {Chain} {Functionalized} {Imidazolinium} {Ionic} {Liquids}},
year = {2021}
}
@article{faucris.235826903,
author = {Liu, Shungang and Su, Wenyan and Zou, Xianshao and Du, Xiaoyan and Cao, Jiamin and Wang, Nong and Shen, Xingxing and Geng, Xinjian and Tang, Zilong and Yartsev, Arkady and Zhang, Maojie and Gruber, Wolfgang and Unruh, Tobias and Li, Ning and Yu, Donghong and Brabec, Christoph and Wang, Ergang},
doi = {10.1039/D0TA00520G},
faupublication = {yes},
journal = {Journal of Materials Chemistry A},
pages = {5995-6003},
peerreviewed = {Yes},
title = {{The} role of connectivity in significant bandgap narrowing for fused-pyrene based non-fullerene acceptors toward high-efficiency organic solar cells},
volume = {8},
year = {2020}
}
@article{faucris.108601064,
abstract = {Quasi-elastic neutron scattering is a powerful tool for the study of non-periodic motions in condensed matter, as a detailed line shape analysis can give information about the geometry and rate of the scatterers' displacements. Unfortunately, there are also a number of artefacts which can masquerade as signatures of motions and can therefore lead to erroneous results. Their influence on the evaluation of the motions of the phospholipid dimyristoylphosphatidylcholine (DMPC) is discussed. On a 60 ps timescale, the long-range motion of the molecules has a flow-like character with similar velocities above and below the main phase transition. It is proposed that the concepts of dynamical heterogeneities and 'floppy modes' developed in glass physics provide a framework for explaining the observed behaviour.},
author = {Busch, Sebastian and Unruh, Tobias},
doi = {10.1088/0953-8984/23/25/254205},
faupublication = {yes},
journal = {Journal of Physics: Condensed Matter},
peerreviewed = {Yes},
title = {{The} slow short-time motions of phospholipid molecules with a focus on the influence of multiple scattering and fitting artefacts},
volume = {23},
year = {2011}
}
@article{faucris.108644844,
abstract = {A novel setup for containment-free time-resolved experiments at a free-hanging drop is reported. Within a dead-time of 100 ms a drop of mixed reactant solutions is formed and the time evolution of a reaction can be followed from thereon by various techniques. As an example, a small-angle X-ray scattering study on the formation mechanism of EDTA-stabilized CdS both at a synchrotron and a laboratory X-ray source is presented here. While the volution can be followed with one drop only at a synchrotron source, a stroboscopic mode with many drops is preferable for the laboratory source.},
author = {Magerl, Andreas and Schiener, Andreas and Seifert, Soenke},
doi = {10.1107/S1600577515023826},
faupublication = {yes},
journal = {Journal of Synchrotron Radiation},
keywords = {containment-free; in situ; millisecond time-resolved; sample environment; SAXS},
pages = {545-550},
peerreviewed = {unknown},
title = {{The} stopped-drop method: {A} novel setup for containment-free and time-resolved measurements},
volume = {23},
year = {2016}
}
@article{faucris.108601504,
abstract = {X-ray diffraction studies show that molecules of the 1,2,3,5-tetramethoxybenzene (TMOB)(2)center dot 1,2,4,5-tetracyanobenzene complex form center dot center dot center dot CCDCCDCC center dot center dot center dot columns with the short distances between molecular planes of C and D molecules equal to 3.186 angstrom. The vibrational spectra recorded by using the inelastic neutron scattering, Raman, IR, and quasielastic neutron scattering (QENS) techniques aided by density functional theory calculations for the isolated molecules and the crystalline state enabled all four inequivalent librational modes, ascribed to the methoxy groups, to be analyzed. A rather good consistency was found between the experimental frequencies and those calculated for the crystal. The consistency was also achieved between the experimental structure of molecules and the theoretically reproduced one. A close similarity of the structures of the TMOB molecule isolated and in the complex is taken as a sign of dominating intramolecular interaction. The QENS spectra contain three Lorentzians of relative intensities of 1:1:2. Thus the two most strongly hindered of the four inequivalent methoxy groups in the crystalline lattice are characterized by rather similar barrier heights in good agreement with the packing analysis. (c) 2008 American Institute of Physics. [DOI: 10.1063/1.2990650]},
author = {Pawlukojć, Andrzej and Prager, Michael and Dobrowolska, Wanda Sawka and Bator, Grażyna and Sobczyk, Lucjan and Ivanov, Alexander and Rols, Stephane and Grech, Eugeniusz and Nowicka-Scheibe, Joanna and Unruh, Tobias},
doi = {10.1063/1.2990650},
faupublication = {no},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{The} structure, methyl rotation reflected in inelastic and quasielastic neutron scattering and vibrational spectra of 1,2,3,5-tetramethoxybenzene and its 2:1 complex with 1,2,4,5-tetracyanobenzene},
volume = {129},
year = {2008}
}
@article{faucris.108601724,
abstract = {Diaminodurene crystallizes in the orthorhombic space group Pbca, with eight molecules in the unit cell. Four inequivalent methyl groups with different environments exist in a molecule. The amino groups are also different, which is well reflected in infrared spectra. Two tunneling modes are resolved at 23.7 and 7.0 mu eV at 4.5 K. Their intensities are consistent with the presence of two further unresolved tunneling modes. Quasielastic spectra are composed of three Lorentzians of equal intensities. The two low activation energies and tunnel modes are modeled into consistent rotational potentials. The third activation energy and a librational band are used to guess the strength of the two stronger rotational potentials. The internal modes related to the torsional/librational vibrations mix with ring torsions in the range of 70-220 cm(-1). This way the tunnel modes couple to ring torsions whose energy determines the broadening of both tunnel bands. The calculations for free molecules yield mode frequencies a little bit lower than the experimental inelastic neutron scattering (INS) values. Application of theoretical methods elaborated for the crystalline state leads to a satisfactory consistency. It is also valid for bending modes of NH(2) groups, which in the solid state show much higher frequencies than in the gas phase, as expected. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3125629]},
author = {Sobczyk, Lucjan and Prager, Michael and Sawka-Dobrowolska, Wanda and Bator, Grażyna and Pawlukojć, Andrzej and Grech, Eugeniusz and van Eijck, Lambert and Ivanov, Alexander and Rols, Stephane and Wuttke, Joachim and Unruh, Tobias},
doi = {10.1063/1.3125629},
faupublication = {no},
journal = {Journal of Chemical Physics},
peerreviewed = {Yes},
title = {{The} structure of diaminodurene and the dynamics of the methyl groups},
volume = {130},
year = {2009}
}
@article{faucris.106871424,
abstract = {The thickness dependence of the integrated Bragg intensities for Czochralski-grown silicon was measured with the characteristic tungsten K(alpha 1)-line at 59.3 keV. In contrast to previous experiments the sample is wedge shaped, which allows to take data over a wide range of Pendellosung fringes in one exposure only and without any mechanical movement of the sample. The period length, the oscillation amplitude, and the mean value of the Bragg intensity can be explored to identify the presence of point defects, and the temperature dependence of the period length allows to quantify the thermal Debye-coefficient with high precision. (c) 2011 American Institute of Physics. [doi:10.1063/1.3531761]},
author = {Will, Johannes and Gröschel, Alexander and Weißer, Matthias and Magerl, Andreas},
doi = {10.1063/1.3531761},
faupublication = {yes},
journal = {Applied Physics Letters},
month = {Jan},
peerreviewed = {Yes},
title = {{Thickness} dependence of the integrated {Bragg} intensity for statistically disturbed silicon crystals},
volume = {98},
year = {2011}
}
@article{faucris.106894524,
author = {Steinwachs, Julian and Metzner, Claus and Skodzek, Kai and Lang, Nadine and Thievessen, Ingo and Mark, Christoph and Münster, Stefan and Aifantis, Katerina E. and Fabry, Ben},
doi = {10.1038/nmeth.3685},
faupublication = {yes},
journal = {Nature Methods},
pages = {171-6},
peerreviewed = {Yes},
title = {{Three}-dimensional force microscopy of cells in biopolymer networks},
volume = {13},
year = {2016}
}
@article{faucris.108768044,
abstract = {A rod of single crystalline silicon has been subjected to high-power nanosecond laser pulses inducing ultrasonic and shock waves traveling into the bulk of the material. Stroboscopic time-resolved high-energy x-ray diffraction measurements were carried out in situ to probe for strain states in the bulk of the sample. First, a supersonic shock front is observed which moves faster than the longitudinal acoustic phonons. Following the shock front, a much slower bunch of waves travels along the crystal. The x-ray diffraction records obtained in different configurations reflect a strong dependence of the wave propagation on the sample geometry. These results offer an experimental approach for the investigation of coherent phonons, structural phase transformations, plastic deformations induced during shock peening, and for the development of x-ray free-electron-laser optics. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3204968]},
author = {Liss, K. -D. and D'Almeida, T. and Kaiser, M. and Hock, Rainer and Magerl, Andreas and Eloy, J. F.},
doi = {10.1063/1.3204968},
faupublication = {yes},
journal = {Journal of Applied Physics},
peerreviewed = {Yes},
title = {{Time}-resolved x-ray diffraction study of laser-induced shock and acoustic waves in single crystalline silicon},
volume = {106},
year = {2009}
}
@article{faucris.224989207,
abstract = {The pair distribution function (PDF) is a versatile tool to describe the structure of disordered and amorphous materials. Electron PDF (ePDF) uses the advantage of strong scattering of electrons, thus allowing small volumes to be probed and providing unique information on structure variations at the nano-scale. The spectrum of ePDF applications is rather broad: from ceramic to metallic glasses and mineralogical to organic samples. The quantitative interpretation of ePDF relies on knowledge of how structural and instrumental effects contribute to the experimental data. Here, a broad overview is given on the development of ePDF as a structure analysis method and its applications to diverse materials. Then the physical meaning of the PDF is explained and its use is demonstrated with several examples. Special features of electron scattering regarding the PDF calculations are discussed. A quantitative approach to ePDF data treatment is demonstrated using different refinement software programs for a nanocrystalline anatase sample. Finally, a list of available software packages for ePDF calculation is provided.},
author = {Gorelik, Tatiana E. and Neder, Reinhard and Terban, Maxwell W. and Lee, Zhongbo and Mu, Xiaoke and Jung, Christoph and Jacob, Timo and Kaiser, Ute},
doi = {10.1107/S205252061900670X},
faupublication = {yes},
journal = {Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials},
keywords = {disordered material; electron crystallography; electron diffraction; PDF},
note = {CRIS-Team Scopus Importer:2019-08-23},
pages = {532-549},
peerreviewed = {Yes},
title = {{Towards} quantitative treatment of electron pair distribution function},
volume = {75},
year = {2019}
}
@article{faucris.108602824,
abstract = {The water diffusion in four different, highly compacted clays [montmorillonite in the Na- and Ca-forms, illite in the Na- and Ca-forms, kaolinite, and pyrophyllite (bulk dry density rho(b)=1.85 +/- 0.05 g/cm(3))] was studied at the atomic level by means of quasielastic neutron scattering. The experiments were performed on two time-of-flight spectrometers and at three different energy resolutions [FOCUS at SINQ, PSI (3.65 and 5.75 A), and TOFTOF at FRM II (10 A)] for reliable data analysis and at temperatures between 27 and 95 degrees C. Two different jump diffusion models were used to describe the translational motion. Both models describe the data equally well and give the following ranking of diffusion coefficients: Na-montmorillonite <= Ca-montmorillonite < Ca-illite < Na-illite < water <= pyrophyllite <= kaolinite. Uncharged clays had slightly larger diffusion coefficients than that of bulk water due to their hydrophobic surfaces. The time between jumps, tau(t), follows the sequence: Ca-montmorillonite >= Na-montmorillonite>Ca-illite>Na-illite >= kaolinite>pyrophyllite >= water, in both jump diffusion models. For clays with a permanent layer charge (montmorillonite and illite) a reduction in the water content by a factor of 2 resulted in a decrease in the self-diffusion coefficients and an increase in the time between jumps as compared to the full saturation. The uncharged clay kaolinite exhibited no change in the water mobility between the two hydration states. The rotational relaxation time of water was affected by the charged clay surfaces, especially in the case of montmorillonite; the uncharged clays presented a waterlike behavior. The activation energies for translational diffusion were calculated from the Arrhenius law, which adequately describes the systems in the studied temperature range. Na- and Ca-montmorillonite (similar to 11-12 kJ/mol), Na-illite (similar to 13 kJ/mol), kaolinite and pyrophyllite (similar to 14 kJ/mol), and Ca-illite (similar to 15 kJ/mol) all had lower activation energies than bulk water (similar to 17 kJ/mol in this study). This may originate from the reduced number and strength of the H-bonds between water and the clay surfaces, or ions, as compared to those in bulk water. Our comparative study suggests that the compensating cations in swelling clays have only a minor effect on the water diffusion rates at these high densities, whereas these cations influence the water motion in non-swelling clays.},
author = {González Sánchez, Fátima and Juranyi, Fanni and Gimmi, Thomas and Van Loon, Luc R. and Unruh, Tobias and Diamond, Larryn W.},
doi = {10.1063/1.3000638},
faupublication = {no},
journal = {Journal of Chemical Physics},
keywords = {clay;hydrogen bonds;neutron diffraction;self-diffusion;swelling;water},
peerreviewed = {Yes},
title = {{Translational} diffusion of water and its dependence on temperature in charged and uncharged clays: {A} neutron scattering study},
volume = {129},
year = {2008}
}
@article{faucris.123386824,
abstract = {Nuclear incoherent neutron scattering contributions present a challenge in the structural characterization of many classes of materials. This article introduces methods for the correction of nanoparticle, bulk crystalline and amorphous powder neutron scattering data with significant incoherent contributions from hydrogen, and describes the effects the corrections have on the resulting atomic pair distribution function data sets. The approach is presented in the context of the PDFgetN data-reduction program [Peterson, Gutmann, Proffen & Billinge (2000). J. Appl. Cryst. 33, 1192].},
author = {Page, Katharine and White, Claire E. and Estell, Eben G. and Neder, Reinhard and Llobet, Anna and Proffen, Thomas},
doi = {10.1107/S0021889811001609},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
pages = {532-539},
peerreviewed = {Yes},
title = {{Treatment} of hydrogen background in bulk and nanocrystalline neutron total scattering experiments},
volume = {44},
year = {2011}
}
@article{faucris.122819004,
abstract = {The control of order in organic semiconductor systems is crucial to achieve desired properties in electronic devices. We have studied the order in fullerene functionalized self-assembled monolayers by mixing the active molecules with supporting alkyl phosphonic acids of different chain length. By adjusting the length of the molecules, structural modifications of the alignment of the C60 head groups within the SAM can be tuned in a controlled way. These changes on the sub-nanometre scale were analysed by grazing incidence X-ray diffraction and X-ray reflectivity. To study the electron transport properties across these layers, self-assembled monolayer field-effect transistors (SAMFETs) were fabricated containing only the single fullerene monolayer as semiconductor. Electrical measurements revealed that a high 2D crystalline order is not the only important aspect. If the fullerene head groups are too confined by the supporting alkyl phosphonic acid molecules, defects in the crystalline C60 film, such as grain boundaries, start to strongly limit the charge transport properties. By close interpretation of the results of structural investigations and correlating them to the results of electrical characterization, an optimum chain length of the supporting alkyl phosphonic acids in the range of C10 was determined. With this study we show that minor changes in the order on the sub-nanometre scale, can strongly influence electronic properties of functional self-assembled monolayers.},
author = {Schmaltz, Thomas and Khassanov, Artöm and Steinrück, Hans-Peter and Magerl, Andreas and Hirsch, Andreas and Halik, Marcus},
doi = {10.1039/C4NR03557G},
faupublication = {yes},
journal = {Nanoscale},
pages = {13022 - 13027},
peerreviewed = {Yes},
title = {{Tuning} the molecular order of {C60}-based self-assembled monolayers in field-effect transistors},
url = {http://pubs.rsc.org/en/content/articlelanding/2014/nr/c4nr03557g#!divAbstract},
volume = {6},
year = {2014}
}
@article{faucris.277798669,
abstract = {Solvent vapor annealing (SVA) has been shown to significantly improve the device performance of organic bulk-heterojunction solar cells, yet the mechanisms linking nanomorphology, crystallinity of the active layer, and performance are still largely missing. Here, the mechanisms are tackled by correlating the evolution of nanomorphology, crystallinity, and performance with advanced transmission electron microscopy methods systematically. Model system of DRCN5T:PC71BM blends are SVA treated with four solvents differing in their donor and acceptor solubilities. The choice of solvent drastically influences the rate at which the maximum device efficiency establishes, though similar values can be achieved for all solvents. The donor solubility is identified as a key parameter that controls the kinetics of diffusion and crystallization of the blend molecules, resulting in an inverse relationship between optimal annealing time and donor solubility. For the highest efficiency, optimum domain size and single-crystalline nature of DRCN5T fibers are found to be crucial. Moreover, the π–π stacking orientation of the crystallites is directly revealed and related to the nanomorphology, providing insight into the charge carrier transport pathways. Finally, a qualitative model relating morphology, crystallinity, and device efficiency evolution during SVA is presented, which may be transferred to other light-harvesting blends.},
author = {Harreiß, Christina and Langner, Stefan and Wu, Mingjian and Berlinghof, Marvin and Rechberger, Stefanie and Will, Johannes and Conroy, Michele and Bangert, Ursel and Unruh, Tobias and Brabec, Christoph and Spiecker, Erdmann},
doi = {10.1002/solr.202200127},
faupublication = {yes},
journal = {Solar RRL},
keywords = {crystallinity; EF-ED; EFTEM; nanomorphology; organic BHJ solar cells; small molecules; SVA},
note = {Created from Fastlane, Scopus look-up},
peerreviewed = {Yes},
title = {{Understanding} and {Controlling} the {Evolution} of {Nanomorphology} and {Crystallinity} of {Organic} {Bulk}-{Heterojunction} {Blends} with {Solvent} {Vapor} {Annealing}},
year = {2022}
}
@article{faucris.108603044,
abstract = {Our recent neutron scattering measurements of phonons and other quasi-particle excitations in solid deuterium (sD(2)) and the extraction of the density of states for phonons and rotational transitions in sD(2) have led us to a new understanding of the production of ultra-cold neutrons (UCN) in sD(2)(.) The UCN production rate reaches a maximum at an equivalent neutron temperature of T(n) = 40K for a neutron flux with Maxwellian energy distribution. The cross-section for UCN production in sD(2) has been determined by using the density of states G(1)(E) in combination with the incoherent approximation as well as by a direct calibration of our measured neutron cross-sections with the known cross-section of the J = 1 -> 0 rotational transition in deuterium. Using this cross-section we deduced the production rate of UCN in sD(2) which agrees quite well with direct measurements of this energy averaged UCN production cross-section. Copyright (C) EPLA, 2010},
author = {Frei, Andreas and Gutsmiedl, Erwin and Morkel, Christoph and Müller, A. R. and Paul, Stephan and Rols, Stephane and Schober, Helmut and Unruh, Tobias},
doi = {10.1209/0295-5075/92/62001},
faupublication = {no},
journal = {EPL - Europhysics Letters},
peerreviewed = {Yes},
title = {{Understanding} of ultra-cold-neutron production in solid deuterium},
volume = {92},
year = {2010}
}
@article{faucris.121420464,
abstract = {The dynamics of solid deuterium [H. Nielsen, et all., Phys. Rev. B 7 (1973) 1626] (sD(2)) is studied by means of inelastic thermal neutron scattering (coherent and incoherent scattering) at different temperatures and para-ortho ratios. In this paper, the results for the generalized density of states (GDOS) are presented and discussed. The measurements were performed at the thermal time-of-flight (TOF) instrument IN4 at the ILL Grenoble, and at the cold neutron TOF instrument TofTof at the FIRM II. The GDOS contains beside the hcp phonon excitations of the sD(2) the rotational transition J = 0 -> 1 and 1 -> 2. The measured and expected intensities of these rotational excitations are strongly depended on the ortho concentration in the sD(2). Above E = 10meV there are still strong excitations, which are very likely smeared out higher energy optic phonons and multiphonon contributions. An empirical method of separation of the one- and multiphonon contributions to the GDOS will be presented and discussed. The impact of these measurements on the UCN production in sD(2) will be shown in detail. (C) 2009 Elsevier B.V. All rights reserved.},
author = {Gutsmiedl, Erwin and Frei, Andreas and Müller, A. R. and Paul, Stephan and Urban, M. and Schober, Helmut and Morkel, Christoph and Unruh, Tobias},
doi = {10.1016/j.nima.2009.07.082},
faupublication = {no},
journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
keywords = {Neutron;Phonons;Ultra-cold neutrons (UCN);UCN production},
pages = {256-258},
peerreviewed = {Yes},
title = {{Understanding} {UCN} production in solid {D}-2: {The} generalized density of states measured via inelastic neutron scattering},
volume = {611},
year = {2009}
}
@article{faucris.110344124,
abstract = {Real-world networks, e.g., the social relations or world-wide-web graphs, exhibit both small-world and scale-free behaviour. We interpret lattice triangulations as planar graphs by identifying triangulation vertices with graph nodes and one-dimensional simplices with edges. Since these triangulations are ergodic with respect to a certain Pachner flip, applying different Monte Carlo simulations enables us to calculate average properties of random triangulations, as well as canonical ensemble averages, using an energy functional that is approximately the variance of the degree distribution. All considered triangulations have clustering coefficients comparable with real-world graphs; for the canonical ensemble there are inverse temperatures with small shortest path length independent of system size. Tuning the inverse temperature to a quasi-critical value leads to an indication of scale-free behaviour for degrees k >= 5. Using triangulations as a random graph model can improve the understanding of real-world networks, especially if the actual distance of the embedded nodes becomes important.},
author = {Mecke, Klaus and Krüger, Benedikt and Schmidt, Ella},
doi = {10.1088/1367-2630/17/2/023013},
faupublication = {yes},
journal = {New Journal of Physics},
keywords = {unimodular lattice triangulations;networks;maximal planar graphs},
peerreviewed = {Yes},
title = {{Unimodular} lattice triangulations as small-world and scale-free random graphs},
volume = {17},
year = {2015}
}
@article{faucris.122010944,
abstract = {Colloidal nanoparticles, used for applications from catalysis and energy applications to cosmetics, are typically embedded in matrixes or dispersed in solutions. The entire particle surface, which is where reactions are expected to occur, is thus exposed. Here, we show with x-ray pair distribution function analysis that polar and nonpolar solvents universally restructure around nanoparticles. Layers of enhanced order exist with a thickness influenced by the molecule size and up to 2 nanometers beyond the nanoparticle surface. These results show that the enhanced reactivity of solvated nanoparticles includes a contribution from a solvation shell of the size of the particle itself.},
author = {Zobel, Mirijam and Neder, Reinhard and Kimber, Simon A. J.},
doi = {10.1126/science.1261412},
faupublication = {yes},
journal = {Science},
month = {Jan},
pages = {292-294},
peerreviewed = {Yes},
title = {{Universal} solvent restructuring induced by colloidal nanoparticles},
volume = {347},
year = {2015}
}
@article{faucris.242411194,
abstract = {In this work, a widely applicable routine to characterize the core, surface, stability, and optical properties of CdSe/CdS/ZnS core–shell–shell nanorods after multiple growth steps is established. First, size, shape, and shell thickness of the nanorods are characterized by transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), and small angle X-ray/neutron scattering (SAXS/SANS). In the next step, Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), and SANS measurements are applied to determine the surface species of nanorods. Then, the colloidal stability of the nanorods is investigated by UV–vis spectroscopy and dynamic light scattering (DLS) after different washing cycles. Finally, photoluminescence quantum yield (PLQY) of the nanorods during washing and sample storage is determined. With this highly complementary routine for particle characterization, the core, surface, stability, and optical properties of nanorods after multiple growth steps are resolved. The results demonstrate the importance of the developed toolbox to characterize such highly complex, anisotropic nanorods for a technical environment. This is of major importance for the handling of colloidal quantum materials and their quality control in industrial applications.},
author = {Lin, Wei and Greve, Christoph and Härtner, Sebastian and Götz, Klaus and Walter, Johannes and Wu, Mingjian and Rechberger, Stefanie and Spiecker, Erdmann and Busch, Sebastian and Schmutzler, Tilo and Avadhut, Yamini and Hartmann, Martin and Unruh, Tobias and Peukert, Wolfgang and Segets, Doris},
doi = {10.1002/ppsc.202000145},
faupublication = {yes},
journal = {Particle & Particle Systems Characterization},
keywords = {anisotropic; characterization; core multishell; nanoparticles},
note = {CRIS-Team Scopus Importer:2020-09-11},
peerreviewed = {Yes},
title = {{Unraveling} {Complexity}: {A} {Strategy} for the {Characterization} of {Anisotropic} {Core} {Multishell} {Nanoparticles}},
year = {2020}
}
@article{faucris.235582576,
abstract = {As the power conversion efficiency (PCE) of organic solar cells (OSCs) has surpassed the 17% baseline, the long-term stability of highly efficient OSCs is essential for the practical application of this photovoltaic technology. Here, the photostability and possible degradation mechanisms of three state-of-the-art polymer donors with a commonly used nonfullerene acceptor (NFA), IT-4F, are investigated. The active-layer materials show excellent intrinsic photostability. The initial morphology, in particular the mixed region, causes degradation predominantly in the fill factor (FF) under illumination. Electron traps are formed due to the reorganization of polymers and diffusion-limited aggregation of NFAs to assemble small isolated acceptor domains under illumination. These electron traps lead to losses mainly in FF, which is in contradistinction to the degradation mechanisms observed for fullerene-based OSCs. Control of the composition of NFAs close to the thermodynamic equilibrium limit while keeping adequate electron percolation and improving the initial polymer and NFA ordering are of the essence to stabilize the FF in NFA-based solar cells, which may be the key tactics to develop next-generation OSCs with high efficiency as well as excellent stability.},
author = {Du, Xiaoyan and Heumüller, Thomas and Gruber, Wolfgang and Almora, Osbel and Classen, Andrej and Qu, Jianfei and He, Feng and Unruh, Tobias and Li, Ning and Brabec, Christoph},
doi = {10.1002/adma.201908305},
faupublication = {yes},
journal = {Advanced Materials},
keywords = {bulk-heterojunction microstructure; morphology stability; nonfullerene acceptors; organic solar cells; photostability},
note = {CRIS-Team Scopus Importer:2020-03-10},
peerreviewed = {Yes},
title = {{Unraveling} the {Microstructure}-{Related} {Device} {Stability} for {Polymer} {Solar} {Cells} {Based} on {Nonfullerene} {Small}-{Molecular} {Acceptors}},
year = {2020}
}
@article{faucris.206104673,
abstract = {The growth of silver shells on gold nanorods is investigated by in situ
liquid cell transmission electron microscopy using an advanced liquid
cell architecture. The design is based on microwells in which the liquid
is confined between a thin Si3N4 membrane on one
side and a few-layer graphene cap on the other side. A well-defined
specimen thickness and an ultraflat cell top allow for the application
of high-resolution TEM and the application of analytical TEM techniques
on the same sample. The combination of high-resolution data with
chemical information is validated by radically new insights into the
growth of silver shells on cetrimonium bromide stabilized gold nanorods.
It is shown that silver bromide particles already formed in the stock
solution play an important role in the exchange of silver ions. The Ag
shell growth can be directly correlated with the layer-by-layer
dissolution of AgBr nanocrystals, which can be controlled by the
electron flux density via distinctly generated chemical species in the
solvent. The derived model framework is confirmed by in situ UV–vis
absorption spectroscopy evaluating the blue shift in the longitudinal
surface plasmon resonance of anisotropic NRs in a complementary batch
experimen},
author = {Hutzler, Andreas and Schmutzler, Tilo and Jank, Michael P. M. and Branscheid, Robert and Unruh, Tobias and Spiecker, Erdmann and Frey, Lothar},
doi = {10.1021/acs.nanolett.8b03388},
faupublication = {yes},
journal = {Nano Letters},
keywords = {Liquid cell TEM; Ag@Au; core−shell; electron beam-induced growth; plasmonic structures; graphene},
pages = {7222 - 7229},
peerreviewed = {Yes},
title = {{Unravelling} the {Mechanisms} of {Gold}−{Silver} {Core}−{Shell} {Nanostructure} {Formation} by in {Situ} {TEM} {Using} an {Advanced} {Liquid} {Cell} {Design}},
url = {https://pubs.acs.org/doi/10.1021/acs.nanolett.8b03388},
volume = {18},
year = {2018}
}
@article{faucris.108603924,
abstract = {The effect of a nanometer confinement on the vibrational and molecular dynamics of a liquid crystals E7 was studied by dielectric spectroscopy (DS) and neutron scattering (NS). E7 undergoes a glass transition phenomenon besides the nematic to isotropic phase transition. As confining host a molecular sieve of the MCM-41 type is used having cylindrical pores with a radius of 1.25 nm. The results obtained by both methods are compared in detail.},
author = {Schönhals, Andreas and Frunza, Stefan and Frunza, Ligia and Unruh, Tobias and Frick, Bernhard and Zorn, Rainer},
doi = {10.1140/epjst/e2010-01329-5},
faupublication = {no},
journal = {European Physical Journal - Special Topics},
pages = {251-255},
peerreviewed = {Yes},
title = {{Vibrational} and molecular dynamics of a nanoconfined liquid crystal},
volume = {189},
year = {2010}
}
@article{faucris.108604144,
abstract = {Vitreous GeO2, one of the main prototypes of strong glasses, was densified at several pressures up to 6 GPa, achieving more than 20% of densification. The density dependence of the vibrational density of states and of the low temperature properties of these glasses was investigated by means of inelastic neutron scattering and calorimetric measurements. With increasing density, both the boson peak and the bump in c(p)/T-3 versus T plot exhibit variations which are stronger than the elastic medium expectation. If one reduces the measured spectra to a common master curve, one finds that this is only possible for the densified samples; the first densification step has an additional effect, similar to other cases in the literature. Nevertheless, the existence of a master curve for the three densified samples proves that the total number of excess modes remains constant on further densification. The experimental data are discussed in the framework of different theoretical models.},
author = {Orsingher, Laura and Fontana, Aldo and Gilioli, Edmondo and Carini Jr., G. and Carini, G. and Tripodo, G. and Unruh, Tobias and Buchenau, Ulrich},
doi = {10.1063/1.3360039},
faupublication = {no},
journal = {Journal of Chemical Physics},
keywords = {boson systems;densification;density;germanate glasses;high-pressure effects;neutron diffraction;specific heat;vibrational modes;vitreous state},
peerreviewed = {Yes},
title = {{Vibrational} dynamics of permanently densified {GeO2} glasses: {Densification}-induced changes in the boson peak},
volume = {132},
year = {2010}
}
@article{faucris.242002119,
abstract = {AlN slices from bulk crystals grown under low thermomechanical stress conditions via the physical vapor transport (PVT) method were analyzed by X-ray methods to study the influence of the growth mode on the crystal quality. Defect types and densities were analyzed along axial [000 (1) over bar] as well as lateral growth directions. X-ray diffraction (0 (1) over bar 10) rocking-curve mappings of representative wafer cuts reveal a low mean FWHM of 13.4 arcsec, indicating the generally high crystal quality. The total dislocation density of 2 x 10(3) cm(-2) as determined by X-ray topography is low and dislocations are largely threading edge dislocations of b = 1/3 < 11 (2) over bar0 > type. The absence of basal plane dislocations in homogeneous crystal regions void of macroscopic defects can be linked to the low-stress growth conditions. Under the investigated growth conditions this high crystal quality can be maintained both along the axial [000 (1) over bar] direction and within lateral growth directions. Exceptions to this are some locally confined, misoriented grains and defect clusters, most of which are directly inherited from the seed or are formed due to the employed seed fixation technique on the outer periphery of the crystals. Seed-shaping experiments indicate no apparent kinetic limitations for an enhanced lateral expansion rate and the resulting crystal quality, specifically with regard to the growth mode on a-face facets.},
author = {Wicht, Thomas and Mueller, Stephan and Weingaertner, Roland and Epelbaum, Boris and Besendoerfer, Sven and Blaess, Ulrich and Weißer, Matthias and Unruh, Tobias and Meißner, Elke},
doi = {10.1107/S1600576720008961},
faupublication = {yes},
journal = {Journal of Applied Crystallography},
note = {CRIS-Team WoS Importer:2020-08-28},
pages = {1080-1086},
peerreviewed = {Yes},
title = {{X}-ray characterization of physical-vapor-transport-grown bulk {AlN} single crystals},
volume = {53},
year = {2020}
}