Li Mingming, Fei Jiajia, Zhang Xiaojiao, Li Jialin, Tong Chuanjia, Long Mengqiu
School of Microelectronics and Physics, Hunan University of Technology and Business, Changsha 410205, People's Republic of China.
Hunan Key laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, People's Republic of China.
J Phys Condens Matter. 2024 Jul 24;36(42). doi: 10.1088/1361-648X/ad604e.
Organic-inorganic hybrid perovskites have attracted tremendous attentions owing to their excellent properties as next-generation photovoltaic devices. With soft covalent framework, organic-inorganic hybrid perovskites exhibit different phases at different temperatures. The band-edge features of perovskites are mainly contributed by inorganic framework, which means the structural differences between these phases would lead to complex carrier transport. We investigated the carrier transport of Sn-based organic-inorganic hybrid perovskite CHNHSnI(MASnI), considering acoustic deformation potential scattering, ionized impurity scattering, and polar optical phonon scattering. It is found that the electron mobility of each phase of MASnIis strongly correlated with the Sn-I-Sn bond angle and there is in-plane/out-of-plane anisotropy. The projected crystal orbital Hamilton population analysis suggested that the tilt and rotation of the [SnI]octahedron influence the Sn()-I() orbital electron coupling and the electron transport, leading to different band-edge features in multiple phases. The carrier mobility with respect to temperature was further calculated for each phase of MASnIin respective temperature intervals, showing lower carrier mobility in high temperature. Comparing the contribution of different scattering mechanisms, it was found that the dominant scattering mechanism is polar optical phonon scattering, while multiple scattering mechanisms compete in individual cases.
有机-无机杂化钙钛矿因其作为下一代光伏器件的优异性能而备受关注。具有软共价骨架的有机-无机杂化钙钛矿在不同温度下呈现不同相。钙钛矿的带边特征主要由无机骨架决定，这意味着这些相之间的结构差异会导致复杂的载流子传输。我们考虑了声学形变势散射、电离杂质散射和极性光学声子散射，研究了基于锡的有机-无机杂化钙钛矿CHNHSnI（MASnI）的载流子传输。研究发现，MASnI各相的电子迁移率与Sn-I-Sn键角密切相关，且存在面内/面外各向异性。投影晶体轨道哈密顿布居分析表明，[SnI]八面体的倾斜和旋转影响Sn（）-I（）轨道电子耦合和电子传输，导致多相中出现不同的带边特征。在各自的温度区间内，进一步计算了MASnI各相的载流子迁移率随温度的变化，结果表明高温下载流子迁移率较低。比较不同散射机制的贡献，发现主导散射机制是极性光学声子散射，而在个别情况下多种散射机制相互竞争。
