Water‐induced CsBr crystalline transition to CsPbBr3 and the change of luminescence properties in borophosphate glass

Abstract The application of all‐inorganic perovskite CsPbBr 3 nanocrystal glasses recently has enjoyed increasing and diverse attention due to their excellent optical properties. However, a full understanding of their formation process and mechanism still remains uncharted. In an attempt to develop and improve the properties of these glasses, it is significant to explore the formation of CsPbBr 3 nanocrystals (NCs) in it. Herein, a borophosphate‐based precursor glass with bright blue emission was prepared by melt quenching, and CsPbBr 3 NCs were precipitated in it by water induction; the glass powders’ photoluminescence gradually changed from blue to green (478–525 nm). It is proven that the blue luminescence originated from the combination of CsBr and oxygen vacancies in the glass, and the crystal transformation mechanism of CsBr to CsPbBr 3 in glass is proposed; the potential application in anti‐counterfeiting is explored based on its special properties. The findings of this study are significant to the basic research for the CsPbBr 3 NCs glasses, and also contribute new insights toward their application in different fields.