The photothermal stability study of silica-coated CsPbBr3 perovskite nanocrystals

The lead halide perovskite (LHP) semiconductor material has many outstanding advantages and was widely used light-emitting device, however their low stability severely limited the practical application and further commercialization. We proposed a two-step method for synthesizing CsPbBr3/SiO2 composites to improve the stability of CsPbBr3 perovskite nanocrystals (PNCs). The synthesized CsPbBr3/SiO2 composites can maintain photothermal stability, and also have a narrower photoluminescence (PL) bandwidth of 20.2 ​± ​0.26 ​nm, and the PL peak (518 ​nm) hardly shifted during the two-step synthesizing process. Through the temperature-dependent PL spectroscopy, we show that the CsPbBr3/SiO2 composites have a high exciton binding energy 50.0 ​meV and longitudinal optical phonon energy 80.1 ​meV, suggesting that the robust excitons exist in CsPbBr3/SiO2 composites. The improved stability of the composites is demonstrated by exposure to harsh environments such as laser irradiation, heating and water. These findings are greatly significant for further applications of CsPbBr3 PNCs in optoelectronic devices.