Low Barrier for Exciton Self-Trapping Enables High Photoluminescence Quantum Yield in Cs3Cu2I5

Young Kwang Jung, Sunghyun Kim, Yong Churl Kim, Aron Walsh

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


The metal halide Cs3Cu2I5 displays anomalous optical properties: an optical absorption onset in the ultraviolet region (∼330 nm) with highly efficient luminescence in the blue region (∼445 nm). Although self-trapped exciton formation has been proposed as the origin of giant Stokes shift, its connection to the photoluminescence quantum yield exceeding 90% remains unknown. Here, we explore the photochemistry of Cs3Cu2I5 from first-principles and reveal a low energy barrier for exciton self-trapping associated with Cu-Cu dimerization. Kinetic analysis shows that the quantum yield of blue emission in Cs3Cu2I5 is sensitive to the excited carrier density due to the competition between exciton self-trapping and band-to-band radiative recombination.

Original languageEnglish
Pages (from-to)8447-8452
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number34
Publication statusPublished - 2021 Sept 2

Bibliographical note

Funding Information:
This research was supported by Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (2018M3D1A1058536). Computational resources have been provided by the KISTI Supercomputing Center (KSC-2018-CRE-0108). We are grateful to the UK Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1).

Publisher Copyright:
© 2021 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physical and Theoretical Chemistry


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