Ultra‐Rapid Synthesis of Perovskite Micro/Nanocubes Induced by Nanoporous Surface for Micro/Nanolasers

Abstract Perovskite micro/nanostructure with regular compact structure and high optical gain has provided a viable route toward the miniaturization of micro/nanolaser without an external cavity. Herein, a new process for the ultra‐rapid room‐temperature synthesis of perovskite micro/nanocubes with controllable size by combining surface‐induced crystallization with the perovskite solution route is described. At first, the perovskite precursors PbBr 2 are encapsulated into the nanoporous glass monolith and then react with CsBr solution on a glass surface, where nanoscopic pores facilitate heterogeneous nucleation significantly. The whole synthesis process of micro/nanocubes is ultra‐rapid and complete within 20 s. Based on the synthetic perovskite micro/nanocubes, low‐threshold upconversion lasing is successfully realized with a high‐quality factor of 2845, which further confirms the high quality and excellent optical performance of perovskite micro/nanocubes. This powerful solution route provides an ultra‐rapid and facile method for the synthesis of perovskite micro/nanostructure toward miniaturized optoelectronic devices.