Transmission electron microscopy of organic-inorganic hybrid perovskites: myths and truths

• 作者: Guanglei Zhang Jian Cao Jiangyu Li Jicai Feng Jingmin Zhang Jinjin Zhao Junlei Qi Peng Gao Shulin Chen Ying Zhang Zhou Mi
• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2020,（19）
• 页码范围: 1643-1649
• 页数: 7页
• 语种: 英文

摘要

Organic-inorganic hybrid perovskites (OIHPs) have attracted extensive research interest as a promising candidate for efficient and inexpensive solar cells.Transmission electron microscopy (TEM) characterizations that can benefit the fundamental understanding and the degradation mechanism are widely used for these materials.However,their sensitivity to the electron beam illumination and hence structural instabilities usually prevent us from obtaining the intrinsic information or even lead to significant artifacts.Here,we systematically investigate the structural degradation behaviors under different experimental factors to reveal the optimized conditions for TEM characterizations of OIHPs by using low-dose electron diffraction and imaging techniques.We find that a low temperature (-180 ℃) does not slow down the beam damage but instead induces a rapid amorphization for OIHPs.Moreover,a less severe damage is observed at a higher accelerating voltage.The beam-sensitivity is found to be facetdependent that a (1 0 0) exposed CH3NH3PbI3 (MAPbI3) surface is more stable than a (001) surface.With these guidance,we successfully acquire the atomic structure of pristine MAPbI3 and identify the characterization window that is very narrow.These findings are helpful to guide future electron microscopy characterizations of these beam-sensitive materials,which are also useful for finding strategies to improve the stability and performance of the perovskite solar cells.