文献类型：期刊文献

英文题名：Phase Transition Kinetics of MAPbI3 for Tetragonal-to-Orthorhombic Evolution

作者：Wu, Jiawei[1,2];Chen, Jianfu[1,2];Wang, Haifeng[1,2]

机构：[1]East China Univ Sci & Technol, Ctr Computat Chem, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Res Inst Ind Catalysis, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China

年份：2023

卷号：3

期号：4

起止页码：1205

外文期刊名：JACS AU

收录：WOS:【ESCI(收录号:WOS:000959465500001)】；

基金：This project was supported by the National Key R&D Program of China (2021YFA1500700, 2018YFA0208602), NSFC (92045303, 21703067, 22202069, 21873028), and the Fundamental Research Funds for the Central Universities. J.W.W. thanks the China Scholarship Council for sponsorship.

语种：英文

外文关键词：hybrid organic-inorganic perovskite; phase transition kinetics; photovoltaic efficiency; molecular reorientation; molecular switch

摘要：Despite the commonly observed phase-instability-induced photovoltaic degradation of MAPbI(3), the phase transition kinetics at the atomic level remains elusive. Herein, by developing a stepwise NEB method, we clarify a nonsynergistic minimum-energy pathway for the tetragonal-to-orthorhombic phase transition. It is kinetically driven by the tilting of PbI64- that induces a spontaneous small rotation of adjoining MA(+) and ends with stepwise similar to 110 degrees reorientations of two nonadjacent MA(+) enabled by the cavity expansion. Compared to the common concerted mechanism, this process gives a low barrier of 0.08 eV/unit, demonstrating the easiness of the transition at extremely low temperatures and the importance of rotational entropies in regulating transition at elevated temperatures. With an explicit phase transition mechanism, we explore the structure-induced property response and reveal that introducing even low content of large-sized organic cations could help maintain the quasi-stable low-temperature performance of MAPbI(3) solar cells.