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arXiv · 2108.02296

Superior Photo-carrier Diffusion Dynamics in Organic-inorganic Hybrid Perovskites Revealed by Spatiotemporal Conductivity Imaging

Xuejian Ma·Fei Zhang·Zhaodong Chu·Ji Hao·Xihan Chen·Jiamin Quan·Zhiyuan Huang·Xiaoming Wang·Xiaoqin Li·Yanfa Yan·Kai Zhu·Keji Lai
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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 microsecond and 10 microseconds 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 micrometers) 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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Xuejian Ma, Fei Zhang, Zhaodong Chu, Ji Hao, Xihan Chen, Jiamin Quan, Zhiyuan Huang, Xiaoming Wang, Xiaoqin Li, Yanfa Yan, Kai Zhu, Keji Lai. 2021-08-04. Superior Photo-carrier Diffusion Dynamics in Organic-inorganic Hybrid Perovskites Revealed by Spatiotemporal Conductivity Imaging. https://doi.org/10.1038/s41467-021-25311-1

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