Temperature dependent geometry in perovskite microcrystals for whispering gallery and Fabry-Perot mode lasing

Lead halide perovskite-based lasers have attracted much research attention due to their tunable emission colors, high gain coefficient and low threshold. Here, we demonstrated a facile solution method via temperature modulation to synthesize CH3NH3PbBr3 perovskite crystals with sub-circular and quasi-cubic shapes for whispering gallery resonant mode and Fabry-Perot mode lasing emission, respectively. A low lasing threshold of 6.4 J cm(-2) and a full width at half maximum of 0.7 nm in an individual sub-circular cavity can be achieved at room temperature. In the quasi-cubic cavities, the Fabry-Perot lasing oscillation modes not only exist in the horizontal directions, but also in the vertical directions according to the adjustment of the optical pumping method. The lasing thresholds and linewidths are in the range of 14-25 J cm(-2) and 0.18-0.51 nm, respectively. This work may create possibilities for cavity design and fabrication of perovskite lasers in future potential applications.