材料科学
钙钛矿(结构)
晶界
阴极发光
微晶
能量转换效率
光致发光
相(物质)
钙钛矿太阳能电池
光电子学
聚焦离子束
磁滞
离子束
化学物理
化学工程
离子
分析化学(期刊)
微观结构
发光
凝聚态物理
复合材料
化学
有机化学
冶金
色谱法
工程类
物理
作者
Wei Li,Mathias Uller Rothmann,Amelia C. Y. Liu,Ziyu Wang,Yupeng Zhang,Alexander R. Pascoe,Jianfeng Lu,Liangcong Jiang,Yu Chen,Fuzhi Huang,Yong Peng,Qiaoliang Bao,Joanne Etheridge,Udo Bach,Yi‐Bing Cheng
标识
DOI:10.1002/aenm.201700946
摘要
Organic–inorganic hybrid perovskite solar cells with mixed cations and mixed halides have achieved impressive power conversion efficiency of up to 22.1%. Phase segregation due to the mixed compositions has attracted wide concerns, and their nature and origin are still unclear. Some very useful analytical techniques are controversial in microstructural and chemical analyses due to electron beam-induced damage to the “soft” hybrid perovskite materials. In this study photoluminescence, cathodoluminescence, and transmission electron microscopy are used to study charge carrier recombination and retrieve crystallographic and compositional information for all-inorganic CsPbIBr2 films on the nanoscale. It is found that under light and electron beam illumination, “iodide-rich” CsPbI(1+x)Br(2−x) phases form at grain boundaries as well as segregate as clusters inside the film. Phase segregation generates a high density of mobile ions moving along grain boundaries as ion migration “highways.” Finally, these mobile ions can pile up at the perovskite/TiO2 interface resulting in formation of larger injection barriers, hampering electron extraction and leading to strong current density–voltage hysteresis in the polycrystalline perovskite solar cells. This explains why the planar CsPbIBr2 solar cells exhibit significant hysteresis in efficiency measurements, showing an efficiency of up to 8.02% in the reverse scan and a reduced efficiency of 4.02% in the forward scan, and giving a stabilized efficiency of 6.07%.
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