Isotropic CsPbBr₃ Perovskite Nanocrystals\nbeyond Nanocubes: Growth and Optical Properties

Abstract

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