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.