Photophysical properties of micron -sized CH 3 NH 3 PbBr 3 single crystals

Perovskite crystals have shown potential applications in lasers, solar cells and functional electronics. Micron-sized CH3NH3PbBr3 single crystals were fabricated with antisolvent method in this work. The photoluminescence dynamics of perovskite microcrystals were investigated in the temperature range from 77 K to 300 K. The fluorescence intensity of perovskite microcrystals decreases as the temperature increases. At the same time, the full width at half maximum of fluorescence peak is broadened, accompanied by the red shift of the peak position. These are attributed to the phase transition and enhanced scattering effect between exciton and phonon. The fluorescence lifetime of perovskite microcrystals decreases as the excitation intensity increases, indicating that exciton-exciton annihilation dominates the recombination process. Spatially and temporally fluorescence measurements show the different recombination processes in single perovskite microcrystal owing to the different density of defect states at the surface and the bulk regions. © 2020 Elsevier B.V.