Superradiance and Exciton Delocalization in Perovskite Quantum Dot Superlattices

Achieving superradiance in solids is challenging due to fast dephasing processes from inherent disorder and thermal fluctuations. Perovskite quantum dots (QDs) are an exciting class of exciton emitters with large oscillator strength and high quantum efficiency, making them promising for solid-state...

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Bibliographic Details
Published in:Nano letters 2022-10, Vol.22 (19), p.7811-7818
Main Authors: Blach, Daria D., Lumsargis, Victoria A., Clark, Daniel E., Chuang, Chern, Wang, Kang, Dou, Letian, Schaller, Richard D., Cao, Jianshu, Li, Christina W., Huang, Libai
Format: Article
Language:English
Subjects:
exciton coherence
NANOSCIENCE AND NANOTECHNOLOGY
perovskite
quantum dot solids
superradiance
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Summary:Achieving superradiance in solids is challenging due to fast dephasing processes from inherent disorder and thermal fluctuations. Perovskite quantum dots (QDs) are an exciting class of exciton emitters with large oscillator strength and high quantum efficiency, making them promising for solid-state superradiance. However, a thorough understanding of the competition between coherence and dephasing from phonon scattering and energetic disorder is currently unavailable. Here, we present an investigation of exciton coherence in perovskite QD solids using temperature-dependent photoluminescence line width and lifetime measurements. Our results demonstrate that excitons are coherently delocalized over 3 QDs at 11 K in superlattices leading to superradiant emission. Scattering from optical phonons leads to the loss of coherence and exciton localization to a single QD at temperatures above 100 K. At low temperatures, static disorder and defects limit exciton coherence. These results highlight the promise and challenge in achieving coherence in perovskite QD solids.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.2c02427