Superior photo-carrier diffusion dynamics in organic-inorganic hybrid perovskites revealed by spatiotemporal conductivity imaging

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Date

2021-08-18

Authors

Ma, Xuejian
Zhang, Fei
Chu, Zhaodong
Hao, Ji
Chen, Xihan
Quan, Jiamin
Huang, Zhiyuan
Wang, Xiaoming
Li, Xiaoqin
Yan, Yanfa

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Springer Nature Limited

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 map- ping 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.

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Ma, X., Zhang, F., Chu, Z. et al. Superior photo-carrier diffusion dynamics in organic-inorganic hybrid perovskites revealed by spatiotemporal conductivity imaging. Nat Commun 12, 5009 (2021). https://doi.org/10.1038/s41467-021-25311-1