Preparation of CH₃NH₃PbBr₃ Perovskites Encapsulated in ZIF-8 with Improved Stability and Their Application in Fluorimetry and Information Encryption

Metal halide perovskites (MHPs) have been promising functional materials for developing solar cells, lasers, photodetectors, and sensors due to their outstanding optical and electrical characteristics. However, they suffer from very poor stability for their high sensitivity to some environmental factors such as temperature, UV irradiation, pH, and polar solvent, which limits their extensive practical applications. Herein, a derived metal organic framework material, Pb-ZIF-8, was prepared as a precursor via a doping protocol. Then, CH 3 NH 3 PbBr 3 perovskites encapsulated in ZIF-8 (CH 3 NH 3 PbBr 3 @ZIF-8) with green fluorescent (FL) emission were synthesized via a facile in situ protocol by using the derived metal organic frameworks material as a source of Pb element. With the protection of encapsulated ZIF-8, the perovskites material shows good FL properties under various harsh environmental conditions, which facilitates facile application in various fields. To verify the practical application potential of CH 3 NH 3 PbBr 3 @ZIF-8, we utilized them as FL probes to establish a highly sensitive method for detecting glutathione. Furthermore, the rapid conversion process from non-FL Pb-ZIF-8 to FL CH 3 NH 3 PbBr 3 @ZIF-8 was utilized to realize encryption and decryption of confidential information. This work opens an avenue to the development of perovskites-based devices with greatly improved stability in harsh external environments.