钙钛矿(结构)
化学物理
卤化物
非谐性
极地的
材料科学
偶极子
飞秒
分子动力学
相(物质)
分子物理学
凝聚态物理
物理
化学
光学
结晶学
无机化学
计算化学
天文
量子力学
激光器
作者
Omer Yaffe,Yinsheng Guo,Liang Z. Tan,David Egger,Trevor D. Hull,Constantinos C. Stoumpos,Fan Zheng,Tony F. Heinz,Leeor Kronik,Mercouri G. Kanatzidis,Jonathan S. Owen,Andrew M. Rappe,M. A. Pimenta,L. E. Brus
标识
DOI:10.1103/physrevlett.118.136001
摘要
Hybrid lead-halide perovskites have emerged as an excellent class of photovoltaic materials. Recent reports suggest that the organic molecular cation is responsible for local polar fluctuations that inhibit carrier recombination. We combine low-frequency Raman scattering with first-principles molecular dynamics (MD) to study the fundamental nature of these local polar fluctuations. Our observations of a strong central peak in the cubic phase of both hybrid (CH_{3}NH_{3}PbBr_{3}) and all-inorganic (CsPbBr_{3}) lead-halide perovskites show that anharmonic, local polar fluctuations are intrinsic to the general lead-halide perovskite structure, and not unique to the dipolar organic cation. MD simulations indicate that head-to-head Cs motion coupled to Br face expansion, occurring on a few hundred femtosecond time scale, drives the local polar fluctuations in CsPbBr_{3}.
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