High Water Resistance of Monoclinic CsPbBr3 Nanocrystals Derived from Zero-Dimensional Cesium Lead Halide Perovskites

An all-inorganic cesium lead halide perovskite is particularly attractive as an alternative to next-generation display with high quantum yields and color purity for lasers, light-emitting diode (LED) devices, and single-photon sources. Unfortunately, the vulnerable properties induced by moisture limit the hopeful application of CsPbBr3, especially for high-performance devices. In this work, a monoclinic CsPbBr3 derived from hexagonal Cs4PbBr6 with the assistance of water was presented. Moisture-induced decomposition and phase segregation were recorded at the atomic level in detail. Moreover, the obtained monoclinic CsPbBr3 nanocrystals (NCs) are demonstrated to be decorated with hydroxyl (OH) ligands, which provide a valid approach for the resistance to further moisture attack. The highly stable CsPbBr3 NCs could preserve the photoluminescence intensity above 97% even after the sample was deposited in water for 30 days. Furthermore, a white LED constructed with the as-prepared green-emitting CsPbBr3 and a commercial N628 red phosphor demonstrate the monoclinic CsPbBr3 as a compelling material platform well suited to applications as next-generation light emitters.