Alkali‐Metal–Assisted Green‐Solvent Synthesis for In Situ Growth of Perovskite Nanocrystals in Porous Materials

Abstract Inorganic metal halide perovskite CsPbX 3 (X = I, Br, and Cl) nanocrystals (NCs) are rapidly developed due to their excellent photophysical properties and potential applications in lighting, lasers, and scintillators. However, the materials for growing perovskite NCs are insoluble or hydrolyzed in most green solvents, limiting their further development. Based on rational chemical analysis, an alkali‐metal–assisted green‐solvent synthesis method for in situ growth of CsPbBr 3 NCs within SAPO‐34 zeolite with bright luminescence is developed. Water is the only solvent used in the whole process. Surprisingly, by the synergistic effect of the channel structure of SAPO‐34 and alkali‐metal ions crystallization regulation, the CsPbBr 3 NCs embedded in SAPO‐34 assisted by Na + emit bright blue light under ultraviolet illumination, with a 30 nm blue shift comparing to the CsPbBr 3 NCs assisted by K + . Moreover, CsPbBr 3 NCs can also be grown in mesoporous SiO 2 SBA‐15 and zeolites including ZSM‐5, AlPO‐5, and SOD, indicating that the method is universal for in situ growth of luminescent perovskite NCs in porous materials. This alkali‐metal–assisted green‐solvent synthesis provides a new strategy for developing high‐quantum–yield, tunable‐emission, and stable perovskite luminescent materials.