Pressure-Induced Indirect-Direct Bandgap Transition of CsPbBr₃ Single Crystal and Its Effect on Photoluminescence Quantum Yield.

ABSTRACT: Despite extensive study, the bandgap characteristics of lead halide perovskites are not well understood. Usually, these materials are considered as direct bandgap semiconductors, while their photoluminescence quantum yield (PLQY) is very low in the solid state or single crystal (SC) state. Some researchers have noted a weak indirect bandgap below the direct bandgap transition in these perovskites. Herein, application of pressure to a CsPbBr₃ SC and first-principles calculations reveal that the nature of the bandgap becomes more direct at a relatively low pressure due to decreased dynamic Rashba splitting. This effect results in a dramatic PLQY improvement, improved more than 90 times, which overturns the traditional concept that the PLQY of lead halide perovskite SC cannot excee

SUBMITTER: Gong J 

PROVIDER: S-EPMC9561783 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature