Effects of Electronic Coupling on Bright and Dark Excitons in a 2D Array of Strongly Confined CsPbBr3Quantum Dots

Xueting Tang, Daniel Rossi, Jinwoo Cheon, Dong Hee Son

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2 Citations (Scopus)


In contrast to the weakly confined quantum dots dominated by bright excitons, strongly quantum confined CsPbBr3QDs exhibit both bright and dark exciton photoluminescence (PL) at cryogenic temperatures, making them a unique source of photons and charges of two very different natures. Here, we investigate the effect of inter-QD electronic coupling on the relative energetics and dynamics of the bright and dark excitons, which dictate the PL properties of the coupled arrays of these QDs at low temperatures. For this purpose, we fabricated 2D close-packed arrays of NaBr-passivated CsPbBr3QDs with a sub-nanomter facet-to-facet distance, which was necessary to introduce electronic coupling. In addition to the redshift of the PL due to electronic coupling, the electronically coupled array of strongly confined CsPbBr3QDs exhibited narrowed bright-dark level splitting and an acceleration of the decay of both bright and dark exciton PL at cryogenic temperatures. These observations are qualitatively analogous to the effects of increasing the volume of noninteracting QDs, which can be explained by the delocalization of exciton wave function among the coupled QDs.

Original languageEnglish
Pages (from-to)7181-7189
Number of pages9
JournalChemistry of Materials
Issue number16
Publication statusPublished - 2022 Aug 23

Bibliographical note

Funding Information:
This research was supported by National Science Foundation (CHE-2003961) and X-grants from Texas A&M University. J.C. acknowledges the Institute for Basic Science (IBS-R026-D1) for the support. X.T. acknowledges Mohit Khurana, Lanyin Luo, and Lok Raj Pant for their help with the acquisition of time-resolved PL intensity and temperature-dependent PL spectra of the 4.2 nm QDs.

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry


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