Highly Stable CsPbBr Colloidal Nanocrystal Clusters as Photocatalysts in Polar Solvents.

One of the main challenges of all-inorganic cesium lead halide (CsPbX) perovskite nanocrystals (NCs) in photocatalysis is their poor stability in hostile environments such as polar solvents. Herein, we report highly stable CsPbBr colloidal nanocrystal clusters (CNCs) with uniform morphology and size prepared by using a PVP-assisted reprecipitation method. A possible formation process through a self-assembly avenue is proposed. These CsPbBr CNCs exhibit much enhanced resistance against a variety of polar solvents in comparison with CsPbBr NCs obtained from the commonly used hot-injection method. In addition, this method can be generalized to the synthesis of lead-free perovskites CNCs. The as-prepared CsPbBr CNCs display good reactivity and high durability in photocatalytic degradation of methylene blue in alcoholic systems. This work will shed some light on the stabilization of perovskite NCs in polar solvents and perovskite NC-based photocatalysts.