Superior Photo-Carrier Diffusion Dynamics in Organic-Inorganic Hybrid Perovskites Revealed by Spatiotemporal Conductivity Imaging

Xuejian Ma, Fei Zhang, Zhaodong Chu, Ji Hao, Zihan Chen, Jiamin Quan, Zhiyuan Huang, Xiaoming Wang, Xiaoqin Li, Yanfa Yan, Kai Zhu, Keji Lai

Research output: Contribution to journalArticlepeer-review

11 Scopus Citations

Abstract

The outstanding performance of organic-inorganic metal trihalide solar cells benefits from the exceptional photo-physical properties of both electrons and holes in the material. Here, we directly probe the free-carrier dynamics in Cs-doped FAPbI3 thin films by spatiotemporal photoconductivity imaging. Using charge transport layers to selectively quench one type of carriers, we show that the two relaxation times on the order of 1 μs and 10 μs correspond to the lifetimes of electrons and holes in FACsPbI3, respectively. Strikingly, the diffusion mapping indicates that the difference in electron/hole lifetimes is largely compensated by their disparate mobility. Consequently, the long diffusion lengths (3~5 μm) of both carriers are comparable to each other, a feature closely related to the unique charge trapping and de-trapping processes in hybrid trihalide perovskites. Our results unveil the origin of superior diffusion dynamics in this material, crucially important for solar-cell applications.

Original languageAmerican English
Article numberArticle No. 5009
Number of pages7
JournalNature Communications
Volume12
Issue number1
DOIs
StatePublished - 1 Dec 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).

NREL Publication Number

  • NREL/JA-5900-80240

Keywords

  • imaging
  • perovskite
  • transport
  • trapping

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