Size-dependent dark exciton properties in cesium lead halide perovskite quantum dots

Daniel Rossi, Tian Qiao, Xiaohan Liu, Mohit Khurana, Alexey V. Akimov, Jinwoo Cheon, Dong Hee Son

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17 Citations (Scopus)


The fine structure of the band edge exciton and the dark exciton photoluminescence (PL) are topics of significant interest in the research of semiconducting metal halide perovskite nanocrystals, with several conflicting reports on the level ordering of the bright and dark states and the accessibility of the emitting dark states. Recently, we observed the intense dark exciton PL in strongly confined CsPbBr3 nanocrystals at cryogenic temperatures, in contrast to weakly confined nanocrystals lacking dark exciton PL, which was explained by the confinement enhanced bright-dark exciton splitting. In this work, we investigated the size-dependence of the dark exciton photoluminescence properties in CsPbBr3 and CsPbI3 quantum dots in the strongly confined regime, showing the clear role of confinement in determining the bright-dark energy splitting (ΔEBD) and the dark exciton lifetime (τD). We observe the increase in both ΔEBD and τD with increasing quantum confinement in CsPbBr3 and CsPbI3 QDs, consistent with the earlier predictions on the size-dependence of ΔEBD and τD. Our results show that quantum confinement plays a crucial role in determining the accessibility to the dark exciton PL and its characteristics in metal halide perovskite nanocrystals.

Original languageEnglish
Article number27972
JournalJournal of Chemical Physics
Issue number18
Publication statusPublished - 2020 Nov 14

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation (Grant No. CHE-1836538) and X-Grants from Texas A&M University and Institute for Basic Science (Grant No. IBS-R026-D1).

Publisher Copyright:
© 2020 Author(s).

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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