Tong Chuan-Jia, Cai Xiaoyi, Zhu An-Yu, Liu Li-Min, Prezhdo Oleg V
Hunan Key Laboratory of Nanophotonics and Devices, Hunan Key Laboratory of Super-Microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China.
School of Physics, Beihang University, Beijing 100191, China.
J Am Chem Soc. 2022 Apr 13;144(14):6604-6612. doi: 10.1021/jacs.2c02148. Epub 2022 Apr 1.
Ion migration, hole trapping, and electron-hole recombination are common processes in metal halide perovskites. We demonstrate using ab initio non-adiabatic molecular dynamics and time-domain density functional theory that they are intricately related and strongly influence each other. The hole injection accelerates ion migration by decreasing the diffusion barrier and shortening the migration length. The injected hole also promotes the nonradiative charge recombination by strengthening electron-phonon interactions in the low-frequency region and prolonging the quantum coherence time. The synergy stems from the soft perovskite lattice and response of the valence band maximum to the Pb-I lattice distortion induced by the hole. This work provides important insights into the influence of ion mobility and hole injection on the performance of perovskite solar cells and suggests that high concentration of holes should be avoided.
离子迁移、空穴俘获和电子 - 空穴复合是金属卤化物钙钛矿中的常见过程。我们使用从头算非绝热分子动力学和时域密度泛函理论证明，它们之间存在复杂的关联且相互强烈影响。空穴注入通过降低扩散势垒和缩短迁移长度来加速离子迁移。注入的空穴还通过增强低频区域的电子 - 声子相互作用和延长量子相干时间来促进非辐射电荷复合。这种协同作用源于钙钛矿软晶格以及价带最大值对空穴诱导的Pb - I晶格畸变的响应。这项工作为离子迁移率和空穴注入对钙钛矿太阳能电池性能的影响提供了重要见解，并表明应避免高浓度空穴。
