钙钛矿(结构)
卤化物
材料科学
拉曼光谱
衍射
相(物质)
化学物理
相变
拉曼散射
结晶学
物理
无机化学
凝聚态物理
化学
光学
量子力学
作者
Yinsheng Guo,Omer Yaffe,Daniel W. Paley,Alexander N. Beecher,Trevor D. Hull,Guilherme Szpak,Jonathan S. Owen,L. E. Brus,M. A. Pimenta
出处
期刊:Physical Review Materials
[American Physical Society]
日期:2017-09-27
卷期号:1 (4)
被引量:89
标识
DOI:10.1103/physrevmaterials.1.042401
摘要
Organic-inorganic coupling in the hybrid lead-halide perovskite is a central issue in rationalizing the outstanding photovoltaic performance of these emerging materials. Here we compare and contrast the evolution of structure and dynamics of the hybrid CH3NH3PbBr3 and the inorganic CsPbBr3 lead-halide perovskites with temperature, using Raman spectroscopy and single-crystal X-ray diffraction. Results reveal a stark contrast between their order-disorder transitions, abrupt for the hybrid whereas smooth for the inorganic perovskite. X-ray diffraction observes an intermediate incommensurate phase between the ordered and the disordered phases in CH3NH3PbBr3. Low-frequency Raman scattering captures the appearance of a sharp soft mode in the incommensurate phase, ascribed to the theoretically predicted amplitudon mode. Our work highlights the interaction between the structural dynamics of organic cation CH3NH3+ and the lead-halide framework, and unravels the competition between tendencies of the organic and inorganic moieties to minimize energy in the incommensurate phase of the hybrid perovskite structure.
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