Revealing Trap States in Lead Sulphide Colloidal Quantum Dots by Photoinduced Absorption Spectroscopy

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Kahmann S, Sytnyk M, Schrenker N, Matt G, Spiecker E, Heiß W, Brabec C, Loi MA
Zeitschrift: Advanced Electronic Materials
Verlag: Blackwell Publishing Ltd
Jahr der Veröffentlichung: 2017
ISSN: 2199-160X
Sprache: Englisch


Abstract


Due to their large surface to volume ratio, colloidal quantum dots (CQDs)

are often considered to exhibit a significant amount of surface defects. Such

defects are one possible source for the formation of in-gap states (IGS), which

can enhance the recombination of excited carriers, i.e., work as electrical traps.

These traps are investigated for lead sulphide CQDs of different size, covered

with different ligands using a mid-infrared photoinduced absorption (PIA)

technique. The obtained PIA spectra reveal two distinct absorption bands,

whose position depends on the particle size, i.e., the electronic confinement

in the CQDs. Smaller particles exhibit deeper traps. The chemical nature of

the capping ligand does not affect the resulting position other than due to its

change in confinement, but better passivating species lead to smaller signals.

Furthermore, ligand specific narrow lines observed are superimposed on the

broad electronic background of the PIA spectra, which is attributed to Fano

resonances caused by the interplay of the narrow molecular vibrations and the

continuum of trap states. Mid-infrared photoinduced absorption represents a

valuable tool to unravel distributions of IGS in CQDs and allows for an assessment

of the quality of ligand exchanged films. These findings have implications

for understanding the performances of CQD-based (opto-) electronic

devices, such as solar cells, transistors, or quantum dot light emitting diodes,

which are limited by frequent carrier trapping events.



FAU-Autoren / FAU-Herausgeber

Brabec, Christoph Prof. Dr.
Heiß, Wolfgang Prof. Dr.
Lehrstuhl für Werkstoffwissenschaften (Materialien der Elektronik und der Energietechnologie)
Professur für Werkstoffwissenschaften (lösungsprozessierte Halbleitermaterialien)
Matt, Gebhard Dr.
Lehrstuhl für Werkstoffwissenschaften (Materialien der Elektronik und der Energietechnologie)
Schrenker, Nadine
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)
Spiecker, Erdmann Prof. Dr.
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)
Sytnyk, Mykhailo
Lehrstuhl für Werkstoffwissenschaften (Materialien der Elektronik und der Energietechnologie)


Zusätzliche Organisationseinheit(en)
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)
Graduiertenkolleg 1896/2 In situ Mikroskopie mit Elektronen, Röntgenstrahlen und Rastersonden
Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)


Autor(en) der externen Einrichtung(en)
University of Groningen / Rijksuniversiteit Groningen


Zitierweisen

APA:
Kahmann, S., Sytnyk, M., Schrenker, N., Matt, G., Spiecker, E., Heiß, W.,... Loi, M.A. (2017). Revealing Trap States in Lead Sulphide Colloidal Quantum Dots by Photoinduced Absorption Spectroscopy. Advanced Electronic Materials. https://dx.doi.org/10.1002/aelm.201700348

MLA:
Kahmann, Simon, et al. "Revealing Trap States in Lead Sulphide Colloidal Quantum Dots by Photoinduced Absorption Spectroscopy." Advanced Electronic Materials (2017).

BibTeX: 

Zuletzt aktualisiert 2019-29-05 um 08:37