Fabrication of Discontinuous Dendritic CH₃NH₃PbBr₃ Perovskite Microdisk Arrays for Microlasers

Abstract Methylammonium (CH₃NH₂, MA) lead halide single crystals have attracted attention due to their excellent properties, such as tunable bandgap, high absorption efficiency, long carrier diffusion length, low non‐radiative recombination rate, high gain efficiency, and ultra‐low trap state density. However, excellent methylammonium lead bromine (MAPbBr₃) microdisk laser arrays reported at present mainly rely on nanoimprint or inkjet printing technology, which highly depends on the equipment. Herein, an approach to prepare high‐quality MAPbBr₃ microdisk arrays is developed in which well‐aligned microdisk arrays grow via partial dissolution and recrystallization of dendrites induced by Marangoni flow in a solution self‐assembly growth process. On the same dendrite, the growth direction of the microdisk crystals is highly consistent, and the crystal size distribution is uniform. Besides, the MAPbBr₃ microdisks show excellent laser performance with a low threshold of 43.3 µJ cm⁻² and a high Q factor (Q = 2072). The small volume and high‐quality square MAPbBr₃ perovskite microdisks have great potential in the application of integrated photoelectric lasers.