Lasing from solution-processed CsPbBr3 octahedral resonators

ABSTRACT CsPbBr3 has been recognized as one of the most important members in the family of metal halide perovskites, which could offer high optical gain for low-threshold lasing. Despite of significant advances achieved thus far, it is still in high demand to develop new material platforms to further rationally design perovskite-based resonators. Here, CsPbBr3 microcrystals in octahedral shape are developed via a simple antisolvent approach, which exhibit single-or dual-mode lasing upon excitation with picosecond laser pulses. The experimental results reveal an unusual phenomenon that the pump threshold shows a profound dropdown of nearly one order from 65.5 down to 7.4 μJ/cm2 when the microcrystal size is varying from 20 to 4 μm. The experimental results are in contrary to numerical simulations that a larger microcrystal supports eigenmodes with a higher quality factor. We propose that such a dependence is perhaps dominated with scattering losses of different-sized microcrystals. The lowest pump threshold achieved in CsPbBr3 octahedral resonators is comparable to those supported in high-quality CsPbBr3 resonators reported before. The results suggest the potential of the developed CsPbBr3 octahedral microcrystals in creating high-quality light emitters.