Excitonic optical properties and lasing mode shifts in square CsPbBr3 nanoplate cavities.

Cesium lead bromide (CsPbBr 3) perovskite micro/nanostructures have potential applications in miniaturized integrated light sources due to their confined modal volume and high luminous efficiency. In this work, we synthesized CsPbBr 3 nanoplates with regular square shapes and smooth surface by the chemical vapor deposition method. The temperature-dependent and excitation power-dependent photoluminescence spectra reveal the excitonic photoluminescence properties. The whispering gallery mode (WGM)-like lasing in CsPbBr 3 nanoplates was observed at room temperature. We systematically investigated the pump fluence-dependent multi-mode and single-mode lasing actions in square microcavities. The blueshift of individual lasing modes can be attributed to the variation of refractive index resulting from the formation of the electron-hole plasma (EHP) state under highly injected carrier density. The results reveal the dependence of emission properties on excitation intensity, providing further understanding of the carrier-induced mode shift mechanism in the WGM-like lead halide perovskite microcavities. • The excitons in CsPbBr 3 nanoplates undergo a detrapping process with increasing temperature. • The electron-hole plasma lasing mechanism in square CsPbBr 3 nanoplates was revealed. • The refractive index-dependent lasing mode shift behavior was demonstrated by simulation results. [ABSTRACT FROM AUTHOR]