Highly Pure White Light-Emitting Single-Component Perovskite Colloidal Quantum Dots

Metal halide perovskite colloidal quantum dots (QDs) show great potential application for lighting and high-definition displays because of their wide color gamut (∼140%), high photoluminescence quantum yield (PLQY), and narrow emission widths. However, they face a big challenge to obtain directly highly pure white light-emitting colloidal QDs with a single component. Here, we devise a bromide-ligand-assisted synthesis method to prepare white light-emitting Mn2+-doped perovskite colloidal QDs. The didodecyldimethylammonium bromide (DDAB) is used to trigger both anion and ligand exchanges of Mn/CsPbCl3 QDs. By regulating the exchange reactions, the balanced emission intensities of the band edge emission of the QD host and Mn2+ emission are achieved to obtain white light emission. Moreover, the Br– ions from DDAB can bond with uncoordinated Pb2+ of the QD surface, thereby reducing the surface trap density of QDs. As a result, the QDs show pure white light emission with a Commission International de l’Eclairage (CIE) coordinate value of (0.31, 0.33) and a high photoluminescence yield of 66%. This work demonstrates a novel strategy for pure white light-emitting diodes using single-component perovskites.