Mixed monomolecular and bimolecular-like recombination processes in CsPbBr3 perovskite film revealed by time-resolved photoluminescence spectroscopy

Very recently, the newly emerging all inorganic perovskite have attracted a tremendous world-wide attention due to their unique optical properties. Particularly, CsPbBr3 is a very promising material for many optoelectronic devices. Hence, the understanding of the physics underlying these excellent photo-physical properties is highly required. Herein, we investigated the recombination mechanism in CsPbBr3 thin film using mainly the power-dependent time-resolved photoluminescence (PLRT) measurements. The photoluminescence (PL) emission in CsPbBr3 perovskite was suggested to arise from the recombination of free carriers and localized trap states. We have found that the PL is decaying faster at a high excitation power density, from 11.2 to 2.1 ns for the excitation densities between 3.58 and 11.94 W/cm(2). We used a dynamic recombination model to fit the unusual power-dependence transient PL results, from which numerous trap and recombination parameters can be extracted such as the trap density, which was evaluated, ranging from 3.10(15) to 10.10(15) cm(-3) for the excitation densities between 3.58 and 11.94 W/cm(2). Our analysis provides a clear identification of competing monomolecular-like and bimolecular-like recombination processes, These findings shed some light on the interesting luminescence mechanism of CsPbBr3 perovskite.