Auto-Desiccating Synthesis of Lead Halide Perovskite Nanocrystals via a Saponification Process

In this work, a new process is developed to synthesize lead halide perovskite nanocrystals with the goal of reducing the manufacture cost. By using a saponification reaction to create the cesium precursor solution, synthesis can be achieved at room temperature and without the use of a vacuum oven. Blue-green tunable emission is obtained by varying the synthesis temperature. The crystal phase of the nanocrystals exhibit an increasingly directionally aligned orthorhombic phase with increasing temperature. Also, the saponification process uses low-cost compounds to produce the cesium precursor. Furthermore, the moisture instability of halide perovskite nanocrystals is well managed by this process because the highly hygroscopic by-products in this process auto-desiccate the reactants. Therefore, the nanocrystals can be efficaciously synthesized in an air atmosphere without interference from local humidity. This provides an accessible and low-cost pathway for synthesizing this material outside of controlled laboratory conditions.