Radiative and Nonradiative Recombination in CuInS<sub>2</sub> Nanocrystals and CuInS<sub>2</sub>-Based Core/Shell Nanocrystals

Journal article (2016)

Authors

Anne C. Berends Universiteit Utrecht
Freddy T. Rabouw Universiteit Utrecht
F.C.M. Spoor ChemE/Opto-electronic Materials - AS
Eva Bladt Universiteit Antwerpen
F.C. Grozema ChemE/Opto-electronic Materials - AS
A.J. Houtepen ChemE/Opto-electronic Materials - AS
L.D.A. Siebbeles ChemE/Opto-electronic Materials - AS
Celso de Mello Donegá Universiteit Utrecht
Research Group
ChemE/Opto-electronic Materials (AS) (TU Delft)
Copyright: © 2016 Anne C. Berends, Freddy T. Rabouw, F.C.M. Spoor, Eva Bladt, F.C. Grozema, A.J. Houtepen, L.D.A. Siebbeles, Celso De Mello Donegá
DOI
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https://doi.org/10.1021/acs.jpclett.6b01668
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Published Date

23-08-2016

Language

English

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Faculty

Applied Sciences

Department

ChemE/Chemical Engineering

Research Group

ChemE/Opto-electronic Materials

Abstract

Luminescent copper indium sulfide (CIS) nanocrystals are a potential solution to the toxicity issues associated with Cd- and Pb-based nanocrystals. However, the development of high-quality CIS nanocrystals has been complicated by insufficient knowledge of the electronic structure and of the factors that lead to luminescence quenching. Here we investigate the exciton decay pathways in CIS nanocrystals using time-resolved photoluminescence and transient absorption spectroscopy. Core-only CIS nanocrystals with low quantum yield are compared to core/shell nanocrystals (CIS/ZnS and CIS/CdS) with higher quantum yield. Our measurements support the model of photoluminescence by radiative recombination of a conduction band electron with a localized hole. Moreover, we find that photoluminescence quenching in low-quantum-yield nanocrystals involves initially uncoupled decay pathways for the electron and hole. The electron decay pathway determines whether the exciton recombines radiatively or nonradiatively. The development of high-quality CIS nanocrystals should therefore focus on the elimination of electron traps.