化学
晶体缺陷
放松(心理学)
钙钛矿(结构)
光伏系统
电子
化学物理
卤化物
电子冷却
分子动力学
带隙
凝聚态物理
分子物理学
计算化学
结晶学
无机化学
离子
物理
生物
社会心理学
量子力学
有机化学
生态学
心理学
作者
Zhaobo Zhou,Junjie He,Thomas Frauenheim,Oleg V. Prezhdo,Jinlan Wang
摘要
Hot carriers (HCs) in lead halide perovskites are prone to rapidly relax at the band edge and waste plentiful photon energy, severely limiting their conversion efficiency as HC photovoltaic devices. Here, the HC cooling dynamics of MAPbI3 perovskite with common vacancy point defects (e.g., MAv+ and Iv-) and an interstitial point defect (e.g., Ii-) is elucidated, and the underlying physics is explicated using ab initio nonadiabatic molecular dynamics. Contrary to vacancy point defects, the interstitial point defect reduces the band degeneracy, decreases the HC -phonon interaction, weakens the nonadiabatic coupling, and ultimately slows down hot electron cooling by a factor of 1.5-2. Furthermore, the band-by-band relaxation pathway and direct relaxation pathway are uncovered for hot electron cooling and hot hole cooling, respectively, explaining why hot electrons can store more energy than hot holes during the cooling process. Besides, oxygen molecules interacting with Ii- sharply accelerate the hot electron cooling, making it even faster than that of the pristine system and revealing the detrimental effect of oxygen on HC cooling. This work provides significant insights into the defect-dependent HC cooling dynamics and suggests a new strategy to design high-efficiency HC photovoltaic devices.
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