High Color Purity CsPbBr₃ Nanocrystals Prepared by a Heterogeneous Reaction System

Abstract

All inorganic perovskite CsPbX3 (X = Cl, Br, and I) nanocrystals (NCs) have emerged as new semiconductor materials for light-emitting applications due to their high light absorption coefficient, tunable spectrum, and high photoluminescence quantum yields (PLQYs). However, owing to their burst nucleation and growth, the size distribution of CsPbX3 NCs prepared by the conventional homogeneous reaction system is wide, which affects their high color purity. Here, a heterogeneous reaction system was designed to prepare CsPbBr3 NCs with a narrow size distribution by controlling the nucleation and growth kinetics of CsPbBr3 NCs and eliminating the undesired Ostwald ripening effect. The synthesized CsPbBr3 NCs exhibit nearly a unit PLQY and a narrow size distribution. Benefiting from the tight ligands on the surface of NCs that can both stabilize the inorganic nuclei of CsPbBr3 NCs and passivate the Br vacancy defects of the NC surface, the obtained CsPbBr3 NCs have excellent optical stability. In particular, the PLQY of the CsPbBr3 NC colloidal dispersion can be as high as 86% even after 13 cycles of purification with methyl acetate