Revealing the microstructure evolution of inorganic CsPbI2Br perovskite via synchrotron radiation grazing incidence X‐ray diffraction

Abstract

Abstract Perovskite devices have been developed rapidly over the past decade and all‐inorganic perovskite devices have attracted wide interest due to their outstanding stability. The crystallization process and microstructures of inorganic perovskite play important roles on the device performance. Herein, synchrotron radiation grazing incidence X‐ray diffraction (GIXRD) was utilized to investigate the microstructure evolution of CsPbI2Br all‐inorganic perovskite film during post annealing, as well as its influence on the performance of CsPbI2Br perovskite solar cells (PSCs). It was found that high‐temperature (240°C) flash annealing accelerated the precursor solution to rapidly crystallize within a few seconds and reduced the generation of non‐perovskite phase. The centroid and full‐width at half‐maximum (FWHM) of perovskite diffraction peaks, corresponding to lattice constant and crystallite size of perovskite, respectively, changed gradually with the flash annealing time. The flash annealing time was optimized to be 10 seconds, leading to the suitable microstructure and crystallite size, as well as the best photovoltaic performance of PSCs. These results indicate that the microstructure evolution of all‐inorganic perovskite film during the post flash annealing plays a key role in the device performance.

Keywords

• flash annealing
• GIXRD
• inorganic perovskite
• solar cells