Isotropic CsPbBr₃ Perovskite Nanocrystals beyond Nanocubes: Growth and Optical Properties

Abstract

Bright emitting lead halide perovskite nanocrystals reported to date are mostly obtained in a six-faceted perfect cube shape. While extensive research has been carried out for intensifying and stabilizing the bright emission of these nanocrystals, little attention has been paid to obtaining isotropic (sphere-like) nanocrystals in other shapes. Using a nanocrystal-to-nanocrystal dissolution–formation protocol and under limited ligands and insufficient halides in reaction medium, herein, dimension-variable faceted isotropic orthorhombic phase CsPbBr3 nanocrystals beyond the cubic shape are reported, and their optical properties are studied. The size and facets of these nanocrystals were also tuned as a function of injection temperature. However, unlike cube-shaped samples, because these nanocrystals were prepared under ligand- and halide-deficient conditions, they showed poor emission efficiency. Because these were colloidally stable, beyond light-emitting devices, these might be useful as a potential material in other applications where suppression of charge carrier recombination is essential.