Excess Cesium Iodide Induces Spinodal Decomposition of CsPbI 2 Br Perovskite Films

We report an exploratory study on the crystal formation behavior of CsPbI Br perovskite films by adding excess cesium iodide (CsI). Surprisingly, facile co-crystallization of CsI and CsPbI Br in the form of spinodal decomposition is observed. Significantly, the two phases spontaneously form morphing...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2019-01, Vol.10 (2), p.194-199
Main Authors: Meng, Xiangyue, Wang, Zheng, Qian, Wei, Zhu, Zonglong, Zhang, Teng, Bai, Yang, Hu, Chen, Xiao, Shuang, Yang, Yinglong, Yang, Shihe
Format: Article
Language:English
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Summary:We report an exploratory study on the crystal formation behavior of CsPbI Br perovskite films by adding excess cesium iodide (CsI). Surprisingly, facile co-crystallization of CsI and CsPbI Br in the form of spinodal decomposition is observed. Significantly, the two phases spontaneously form morphing into a remarkably uniform bicontinuous nanoscale blend with high orientational correlation through the well-matched (110) plane of CsI and the (200) plane of CsPbI Br. The CsPbI Br films produced by the spinodal decomposition method not only enjoy a compact surface, low defect concentration, and long carrier lifetimes, they also retain their excellent charge transport property. By employing such a CsPbI Br film for carbon-based perovskite solar cells, power conversion efficiency exceeding 10% is achieved with remarkable thermal stability. Our results provide valuable insight into the role of CsI in perovskite crystallization and a promising approach for designing inorganic halide perovskite-based devices.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.8b03742