Emitting State of Bulk CsPbBr3 Perovskite Nanocrystals Reveals a Quantum-Confined Excitonic Structure

摘要

Metal halide perovskites have emerged as promising materials for light-emitting and photovoltaic applications over recent years. However, unlike quantum dots (QDs) where emission occurs from a quantum-confined exciton state, the nature of emitting states within these bulk nanocrystals remains ambiguous. Herein, we present time-resolved photo-luminescence (t-PL) measurements on bulk CsPbBr3 nanocrystals (NCs). These data reveal that these bulk NCs exhibit a spectrum to the average photoluminescence lifetime, as is seen in CdSe. Notably, there is an absence of physical confinement within these perovskites due to their large size giving them bulk character. The presence of a lifetime spectrum suggests the existence of an excitonic structure. The presence of an excitonic structure suggests the possibility of quantum confinement. Unlike conventional QDs that have quantum confinement due to physical boundaries, perovskite nanocrystals (PNCs) may possess polaronic confinement.