Issue 8, 2019

Correlation of near-unity quantum yields with photogenerated excitons in X-type ligand passivated CsPbBr3 perovskite quantum dots

Abstract

We investigated the exciton decay dynamics of CsPbBr3 perovskite quantum dots (PQDs) through an X-type ligand passivation process. 1-Dodecanethiol (DDT), as an X-type ligand, covers Br vacancies of PQDs and then the photoluminescence quantum yield (PLQY) sharply improved from 76.1% to 99.8%. Impressively, after passivation, the photoluminescence (PL) lifetime of PQDs decreased from 3.16 ns to 2.42 ns, contrary to the PLQY increase. To clarify this phenomenon, we observed exciton decay dynamics by varying the temperature. Thereby, we found that shallow traps from Br vacancies not only reduce the PLQY but also induce a longer lifetime related to the nonradiative exciton decay leading to an increase in the lifetime. Our results are novel and important in a way that we provide a systematic understanding of the exciton decay dynamics by combining two key concepts together: (1) near unity PLQY via ligand engineering and (2) temperature-dependent photogenerated excitons.

Graphical abstract: Correlation of near-unity quantum yields with photogenerated excitons in X-type ligand passivated CsPbBr3 perovskite quantum dots

Supplementary files

Article information

Article type
Communication
Submitted
10 Maijs 2019
Accepted
10 Maijs 2019
First published
13 Maijs 2019
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2019,1, 2828-2834

Correlation of near-unity quantum yields with photogenerated excitons in X-type ligand passivated CsPbBr3 perovskite quantum dots

S. Park, H. Cho, W. Choi, H. Zou and D. Y. Jeon, Nanoscale Adv., 2019, 1, 2828 DOI: 10.1039/C9NA00292H

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