Ultrastable lasing from perovskite colloidal nanocrystals.

Lead halide perovskites have emerged as promising candidates for a variety of optoelectronic devices, including lasing applications. However, the intrinsic stability issue of halide perovskites, especially under strong excitation conditions required for lasing, remains to be solved. Previous development of perovskite lasing has been largely limited to proof-of-concept devices with short operation time. Here, we report remarkably stable green lasing from colloidal CsPbBr perovskite nanocrystals dispersed in liquids placed in a Fabry-Pérot cavity under excitation by nanosecond pulses. The output intensity of this laser is stable for more than 10 days of continuous operation. Transient absorption measurements reveal that the optical power efficiency of the laser is limited by the relatively short gain lifetime of NCs (160 ps), which nevertheless can be enhanced to 4.2% by implementing a double-pulse excitation scheme. Deep-red liquid lasing from CsPbI nanocrystals has also been achieved, suggesting the feasibility to develop perovskite liquid lasers that are seamlessly tunable across the whole visible spectrum.