阴极发光
辐照
辐射损伤
电子
透射电子显微镜
材料科学
电子束处理
表征(材料科学)
辐射
原子物理学
分子物理学
化学
纳米技术
物理
光学
光电子学
核物理学
发光
作者
Zenghua Cai,Yu‐Ning Wu,Shiyou Chen
摘要
Radiation damage mechanism of organic–inorganic hybrid perovskites under electron beam irradiation is currently under controversy. First-principles calculations of threshold energies show that the knock-on atomic displacement damage in CH3NH3PbI3 is significant and highly energy-dependent, i.e., for the incident energy below 2.3 keV, knock-on damage is negligible; when the incident energy increases to 2.3, 26.4, 70.4, and 249.4 keV, H, C, N, and I displacements start, respectively; however, Pb does not displace even for 1 MeV incident energy. This finding explains the observation that 5 keV or higher-energy irradiation causes obvious changes in cathodoluminescence spectra while 2 keV causes only small changes. For the 300 keV high energy irradiation used in recent experiments, our results show that the H, C, N, and I knock-on displacements can cause the loss of CH3NH3 and I simultaneously, so the knock-on damage should play an important role in these experiments. The electron diffraction characterization cannot distinguish the CH3NH3 and I loss, so it might give confusing conclusions about damage processes. These results change our fundamental understandings on the radiation-damage mechanisms of CH3NH3PbI3-related perovskites, laying the foundation for the transmission-electron-microscopy characterization of their microscopic structures.
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