Charge Carrier Localization in Doped Perovskite Nanocrystals Enhances Radiative Recombination
Sascha Feldmann, Mahesh K. Gangishetty, Ivona Bravić, Timo Neumann, Bo Peng, Thomas Winkler, Richard H. Friend, Bartomeu Monserrat, Daniel N. Congreve, Felix Deschler
Abstract
Nanocrystals based on halide perovskites offer a promising material platform for highly efficient lighting. Using transient optical spectroscopy, we study excitation recombination dynamics in manganese-doped CsPb(Cl,Br)3 perovskite nanocrystals. We find an increase in the intrinsic excitonic radiative recombination rate upon doping, which is typically a challenging material property to tailor. Supported by ab initio calculations, we can attribute the enhanced emission rates to increased charge carrier localization through lattice periodicity breaking from Mn dopants, which increases the overlap of electron and hole wave functions locally and thus the oscillator strength of excitons in their vicinity. Our report of a fundamental strategy for improving luminescence efficiencies in perovskite nanocrystals will be valuable for maximizing efficiencies in light-emitting applications.