Wang Lingrui, Wang Kai, Xiao Guanjun, Zeng Qiaoshi, Zou Bo
State Key Laboratory of Superhard Materials, Jilin University , Changchun 130012, China.
Center for High Pressure Science & Technology Advanced Research , Shanghai 201203, China.
J Phys Chem Lett. 2016 Dec 15;7(24):5273-5279. doi: 10.1021/acs.jpclett.6b02420. Epub 2016 Dec 7.
Organometal halide perovskites are promising materials for optoelectronic devices. Further development of these devices requires a deep understanding of their fundamental structure-property relationships. The effect of pressure on the structural evolution and band gap shifts of methylammonium lead chloride (MAPbCl) was investigated systematically. Synchrotron X-ray diffraction and Raman experiments provided structural information on the shrinkage, tilting distortion, and amorphization of the primitive cubic unit cell. In situ high pressure optical absorption and photoluminescence spectra manifested that the band gap of MAPbCl could be fine-tuned to the ultraviolet region by pressure. The optical changes are correlated with pressure-induced structural evolution of MAPbCl, as evidenced by band gap shifts. Comparisons between Pb-hybrid perovskites and inorganic octahedra provided insights on the effects of halogens on pressure-induced transition sequences of these compounds. Our results improve the understanding of the structural and optical properties of organometal halide perovskites.
有机金属卤化物钙钛矿是用于光电器件的有前景的材料。这些器件的进一步发展需要深入了解其基本的结构-性能关系。系统地研究了压力对甲基氯化铵铅（MAPbCl）结构演变和带隙移动的影响。同步加速器X射线衍射和拉曼实验提供了关于原始立方晶胞收缩、倾斜畸变和非晶化的结构信息。原位高压光吸收和光致发光光谱表明，通过压力可以将MAPbCl的带隙微调至紫外区域。如带隙移动所证明的，光学变化与压力诱导的MAPbCl结构演变相关。铅杂化钙钛矿与无机八面体之间的比较提供了关于卤素对这些化合物压力诱导转变序列影响的见解。我们的结果增进了对有机金属卤化物钙钛矿结构和光学性质的理解。
