Ultrahigh photo-stable all-inorganic perovskite nanocrystals and their robust random lasing.

Photo-instability has prevented further commercialization of all-inorganic perovskite nanocrystals (NCs) in the field of high-power optoelectronics. Here, an accelerated transformation process from non-luminescent CsPbBr to CsPbBr NCs with bright green emission is explored with irradiation at 365 nm during water-triggered structural transformation. The photoelectric field provided by the photon energy of 365 nm promotes the rapid stripping of CsBr and atomic reconstruction, contributing to the production of ultrahigh photo-stable defect-free CsPbBr NCs. The robust emission output of the as-obtained CsPbBr NCs is well preserved even when recorded after 160 min. Moreover, a long-term stable random lasing could be achieved when excited using an ∼800 nm femtosecond laser for at least 8.6 × 10 laser shots. Our results not only elucidate the photo-induced accelerated phase transformation process of the all-inorganic perovskites, but also open up opportunities to synthesize highly stable CsPbBr NCs for their practical application in photovoltaics and optoelectronics.