Aqueous Precursor Induced Morphological Change and Improved Water Stability of CsPbBr₃ Nanocrystals

In the literature, lead halide perovskites are very notable for their degradation in the presence of polar solvents, such as water. In contrast, in this research, it is observed that adding a minor amount of water into the precursor solution can improve the stability and photoluminescence quantum yield of CsPbBr₃ nanocrystals through a ligand-assisted reprecipitation (LARP) method. In this way, the shape and phase transformation from CsPbBr₃ nanoplates to CsPbBr₃ /Cs₄ PbBr₆ nanorods and Cs₄ PbBr₆ nanowires can be controlled with increasing water content in the precursor solution. Upon adding water up to an ideal amount, CsPbBr₃ maintains its phase and nanoplate morphology. The key role of water amount for tuning the crystallinity, stability, morphology, optical properties, and phase transformation of cesium lead halide perovskite nanocrystals will be beneficial in the future commercialization of optoelectronics.