Pressure-Induced Structural and Optical Properties\nof Inorganic Halide Perovskite CsPbBr₃

Abstract

Perovskite\nphotovoltaic materials are gaining sustained attention\nbecause of their excellent photovoltaic properties and extensive practical\napplicability. In this Letter, we discuss the changes in the structure\nand optical properties of CsPbBr₃ under high pressure.\nAs the pressure increased, the band gap initially began to red shift\nbefore 1.0 GPa followed by a continuous blue shift until the crystal\nwas completely amorphized. An isostructural phase transition at 1.2\nGPa was determined by high-pressure synchrotron X-ray and Raman spectroscopy.\nThe result could be attributed to bond length shrinkage and PbBr₆ octahedral distortion under high pressure. The amorphization\nof the crystal was due to the severe distortion and tilt of the PbBr₆ octahedron, leading to broken long-range order. Changes in\noptical properties are closely related to the evolution of the crystal\nstructure. Our discussion shows that high-pressure study can be used\nas an effective means to tune the structure and properties of all-inorganic\nhalide perovskites.