Stable CsPbX₃ (X = Cl, Br, I) Nanocrystal‐in‐Glass Composite (NGC) for Solid‐State Laser‐Driven White Light Generation

Abstract Perovskite CsPbX₃ (X = Cl, Br, I) nanocrystals with advantages of high quantum yield, narrow emission peaks, and tunable fluorescence are considered as the next generation of light‐emitting sources. However, fluorescence degradation due to the poor stability of perovskite nanocrystals in moisture, high temperature, and illumination remains one of the greatest challenges in their further development. In this work, a fully dense coating strategy is proposed to improve the overall stability of perovskite nanocrystals, especially under high‐density laser irradiation. A mesoporous silica SiO₂ layer is introduced to construct a stable coating for isolating the perovskite from external environment. To eliminate the pores of the CsPbX₃@SiO₂, an inorganic glass is also employed via solution‐combustion technique to generate a fully compact encapsulation for further stability promotion. The as‐prepared nanocrystal‐in‐glass composite exhibits efficient and stable fluorescence performance in luminous efficiency, chromaticity, and long‐term reliability in the conditions of thermal shock, humidity, and blue laser irradiation. With the integration of red/green/blue emitting nanocrystals, the color gamut of the white laser lighting source covers 134% of the National Television Standards Committee standard, providing exciting opportunity for high performance laser‐driven white light generation.