Unraveling the Microstructure of Inorganic Halide Perovskites during Thermally Driven Phase Transition and Degradation

X Luo and RX Hao and H Wang and WB Zhai and ZY Wang and ZJ Ning and Y Yu, JOURNAL OF PHYSICAL CHEMISTRY C, 127, 11632-11640 (2023).

DOI: 10.1021/acs.jpcc.3c02319

The microstructure of halide perovskites during thermallydrivenphase transition and degradation is difficult to probe because oftheir radiation-sensitive nature. Taking advantage of low dose insitu high- resolution transmission electron microscopy imaging, wedirectly observed the nucleation and growth process of the phase transitionfrom orthorhombic gamma-CsPbBr3 to cubic alpha-CsPbBr3 in nanoplates during heating. The normalization of (PbBr6)(4-) octahedra was observed, and phase transitionpathways (edge-to-center growth and island growth) were summarized.Phase fluctuation/recovery occurs during the phase transition process.In addition, the thermal degradation caused by high temperature wasinvestigated. Degradation occurs from the outer edge to the centerregion. This work provides a microscopic basis for the understandingof phase transition and its application in devices.

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