Photo-induced structural and optical changes of CsPbBr3 perovskite nanocrystals in glasses

Abstract

Cesium lead halide perovskite nanocrystals have particular optoelectronic properties and important applications in various fields. Embedding cesium lead halide perovskite nanocrystals into glass matrices have improved their thermal and chemical stabilities. However, these cesium lead halide perovskite nanocrystals in glasses are still sensitive to intense light irradiation, limiting their wide applications. In this work, fs laser irradiation on the structural and optical properties of cesium lead bromide (CsPbBr3) perovskite nanocrystals (PNCs) is investigated. It turns out that fs laser irradiation does not change the structural skeletons and band gap energies of CsPbBr3 PNCs in glasses, but induces surface Br vacancies. In-situ transient absorption spectral analysis reveals one <10 ps trapping process of photo-generated carriers after fs laser irradiation, and confirms that Br vacancies are induced by Br migration driven by photo-generated carriers. In addition, CsPbBr3 PNCs with high PL QY in glasses through Br passivation can be more easily damaged by fs laser, making it difficult to achieve stable stimulated emission towards laser application. These results shine light on the effect of halogen contents on the photo-stability of cesium lead halide PNCs and the regulation of cesium lead halide PNCs embedded glasses for photo-electronic applications.