Improvement of Photophysical Properties of CsPbBr3and Mn2+:CsPb(Br,Cl)3Perovskite Nanocrystals by Sr2+Doping for White Light-Emitting Diodes

Abstract

All-inorganic metal halide perovskite nanocrystals (NCs) having the general formula ABX3, where A is a monovalent cation, for example, Cs+, B is a divalent cation, typically Pb2+, and X is Cl-, Br-, I-, or their binary mixture, show potential in optoelectronic devices. In this work, we explore the effect of B-site doping on the optoelectronic properties of CsPbX3NCs (X = Br, Cl). First, the Pb2+ions in the pristine CsPbBr3NC are partially substituted by Mn2+ions. The alkaline earth metal strontium is then doped on both pristine and the Mn2+-substituted NCs. We found that a small percentage of Sr2+doping remarkably improves the photoluminescence quantum yield of CsPbBr3and Mn2+-state emission in Mn2+:CsPb(Br,Cl)3NCs. Perovskite NC film/poly(methyl methacrylate) composites with all four NC variants were used in a white light-emitting diode (WLED), where Sr2+doping increased the luminous efficiency of the WLED by â 4.7%. We attribute this performance enhancement to a reduced defect density and an attenuated microstrain in the local NC structure. © 2022 American Chemical Society. All rights reserved.