The model of sub-bandgap light induced all-optical luminescence switching of lead-halide perovskite microcrystals

The phenomenon of sub-bandgap light induced luminescence switching for lead tribromide perovskite microcrystals with excess lead was recently discovered by Wan et al., Adv. Mater. 35, 2209851 (2023). It was found that the photoluminescence caused by the high energy excitation light is suppressed by the control light, the photon energy of which is less than the bandgap of the crystal, and is restored after switching off the control light. We propose an original model of this phenomenon, taking into account the spatially distributed kinetics of charge carrier recombination and the creation/annihilation of trap states induced by both light sources. The model successfully reproduces the main features of light induced luminescence switching.