Ge/Sn合金化对CsPbBr_(3)钙钛矿热载流子弛豫影响的非绝热分子动力学研究  

Nonadiabatic molecular dynamics study on effect of Ge/Sn alloy on hot carrier relaxation of CsPbBr_(3) perovskite

作　　者：王斐 杨振清[1] 夏雨虹 刘畅 林春丹[1] Wang Fei;Yang Zhen-Qing;Xia Yu-Hong;Liu Chang;Lin Chun-Dan(Beijing Key Laboratory of Optical Detection Technology for Oil and Gas,Basic Research Center for Energy Interdisciplinary,College of Science,China University of Petroleum,Beijing 102249,China)

机构地区：[1]中国石油大学(北京)理学院,能源交叉学科基础研究中心,油气光学检测技术北京市重点实验室,北京102249

出　　处：《物理学报》2024年第2期310-316,共7页Acta Physica Sinica

摘　　要：铯基全无机钙钛矿CsPbBr_(3)具有良好的热稳定性,在应用中表现出优越的发光特性,是近年来光电领域的明星材料.CsPbBr_(3)界面的光生载流子过程与其光电性能密切相关.本文采用非绝热分子动力学方法结合含时密度泛函理论,对CsPbBr_(3)及其合金化结构的激发态动力学过程进行了系统研究.研究结果表明,Sn/Ge合金化能够有效缩短退相干时间,减缓电子-空穴复合.CsPb_(0.75)Ge_(0.25)Br_(3)体系的载流子寿命延长至1.6倍,而CsPb_(0.5)Ge_(0.25)Sn_(0.25)Br_(3)体系的载流子寿命延长为原始体系的4.2倍.证明了B位(钙钛矿结构ABX_(3)中的B位)金属阳离子的双原子合金化对CsPbBr_(3)的非辐射电子-空穴复合具有很强的影响.本研究提供了一种能够有效延长钙钛矿载流子寿命,合理优化太阳能电池性能的合金化方案,为未来钙钛矿太阳能电池材料的设计提供了思路.Perovskite solar cells have been a prominent focus in the field of photovoltaics in recent decades,owing to their exceptional performance:easy synthesis,and cost-effectiveness.The all-inorganic cesium-based perovskite CsPbBr_(3),known for its remarkable thermal stability,has become a star material in the field of optoelectronics due to its outstanding luminescent properties.Despite the high efficiency of lead-based perovskite solar cells,the toxicity associated with lead and the poor long-term stability of these devices remain significant barriers to their large-scale commercialization.As is well known,non-radiative electron-hole recombination significantly shortens the carrier lifetime,acting as a primary pathway for excited state charge to loss energy.This phenomenon directly affects the photovoltaic conversion efficiency and charge transfer performance of perovskite materials.Therefore,maximizing the reduction of non-radiative recombination energy loss in perovskite solar cells has become a crucial research focus.In this study,a systematic exploration is conducted by using a non-adiabatic molecular dynamics approach combined with time-dependent density functional theory to investigate the excited-state carrier dynamics of CsPbBr_(3) and its alloyed structures,CsPb_(0.75)Ge_(0.25)Br_(3) and CsPb_(0.5)Ge_(0.25)Sn_(0.25)Br_(3).The study comprehensively analyzes the non-radiative electron-hole recombination scenarios and the mechanisms for reducing charge energy loss based on crystal structure,electronic properties,and excited-state properties.The research findings reveal that alloying with Sn/Ge can reduce the bandgap,increase nonadiabatic coupling,and shorten the decoherence time.The interplay of reduced quantum decoherence,smaller bandgap,and larger non-adiabatic coupling effectively decelerates the electron-hole recombination process.Consequently,the carrier lifetime of the CsPb_(0.75)Ge_(0.25)Br_(3) system extends by 1.6 times.Moreover,under the joint influence of Sn/Ge,the carrier lifetime of the CsPb_(0.5)G

关 键 词：CsPbBr_(3) 非绝热分子动力学 合金化 非辐射电子-空穴复合 

分 类 号：TB34[一般工业技术—材料科学与工程] O561[理学—原子与分子物理]