Influence of Tail Groups during Functionalization of ZnO Nanoparticles on Binding Enthalpies and Photoluminescence

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Segets D, Lin W, Schmidt J, Peukert W, Mahler M, Schindler T, Unruh T, Meyer B
Zeitschrift: Langmuir
Verlag: American Chemical Society
Jahr der Veröffentlichung: 2017
Band: 33
Heftnummer: 47
Seitenbereich: 13581-13589
ISSN: 0743-7463
eISSN: 1520-5827
Sprache: Englisch


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
H) 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 basis.


FAU-Autoren / FAU-Herausgeber

Lin, Wei
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Mahler, Michael
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Meyer, Bernd Prof. Dr.
Professur für Computational Chemistry
Peukert, Wolfgang Prof. Dr.-Ing.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Schindler, Torben
Lehrstuhl für Kristallographie und Strukturphysik
Schmidt, Jochen Dr.
Sonderforschungsbereich 814 Additive Fertigung
Segets, Doris Dr.-Ing.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Unruh, Tobias Prof. Dr.
Professur für Nanomaterialcharakterisierung (Streumethoden)


Zitierweisen

APA:
Segets, D., Lin, W., Schmidt, J., Peukert, W., Mahler, M., Schindler, T.,... Meyer, B. (2017). Influence of Tail Groups during Functionalization of ZnO Nanoparticles on Binding Enthalpies and Photoluminescence. Langmuir, 33(47), 13581-13589. https://dx.doi.org/10.1021/acs.langmuir.7b03079

MLA:
Segets, Doris, et al. "Influence of Tail Groups during Functionalization of ZnO Nanoparticles on Binding Enthalpies and Photoluminescence." Langmuir 33.47 (2017): 13581-13589.

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Zuletzt aktualisiert 2018-18-10 um 05:00