Issue 2, 2016

Quasi-type II CuInS2/CdS core/shell quantum dots

Abstract

Ternary chalcopyrite CuInS2 quantum dots (QDs) have been extensively studied in recent years as an alternative to conventional QDs for solar energy conversion applications. However, compared with the well-established photophysics in prototypical CdSe QDs, much less is known about the excited properties of CuInS2 QDs. In this work, using ultrafast spectroscopy, we showed that both conduction band (CB) edge electrons and copper vacancy (VCu) localized holes were susceptible to surface trappings in CuInS2 QDs. These trap states could be effectively passivated by forming quasi-type II CuInS2/CdS core/shell QDs, leading to a single-exciton (with electrons delocalized among CuInS2/CdS CB and holes localized in VCu) half lifetime of as long as 450 ns. Because of reduced electron–hole overlap in quasi-type II QDs, Auger recombination of multiple excitons was also suppressed and the bi-exciton lifetime was prolonged to 42 ps in CuInS2/CdS QDs from 10 ps in CuInS2 QDs. These demonstrated advantages, including passivated trap states, long single and multiple exciton lifetimes, suggest that quasi-type II CuInS2/CdS QDs are promising materials for photovoltaic and photocatalytic applications.

Graphical abstract: Quasi-type II CuInS2/CdS core/shell quantum dots

Supplementary files

Article information

Article type
Edge Article
Submitted
30 sep. 2015
Accepted
12 nov. 2015
First published
12 nov. 2015
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2016,7, 1238-1244

Quasi-type II CuInS2/CdS core/shell quantum dots

K. Wu, G. Liang, D. Kong, J. Chen, Z. Chen, X. Shan, J. R. McBride and T. Lian, Chem. Sci., 2016, 7, 1238 DOI: 10.1039/C5SC03715H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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