Photon-Induced Reshaping in Perovskite Material Yields of Nanocrystals with Accurate Control of Size and Morphology

Benefiting from morphology-/size-tunable optical features, nanocrystals have been considered promising candidates for display or lighting applications. To achieve selective characteristic emission, precise control in size and morphology is thus a prerequisite. Herein, we report that the nanosecond-pulsed laser irradiation induces CsPbBr₃ reshaping, yielding precise control of size and morphology. Under 532 and 355 nm laser irradiation, polydisperse CsPbBr₃ nanocrystals or raw micron powders can be reshaped into uniform sizes of 12 and 6 nm, respectively. Moreover, by tuning ligand composition, the morphology of reshaped nanocrystals can be manipulated, such as nanocubes, nanorods, or nanosheets. Results reveal that the reshaping process relies on striving for a delicate balance between energy deposition and heat dissipation under irradiation. A low dissipation rate leads to temperature rising and lattice breaking, which turn out to be the driving forces for reshaping. This feasible method provides a reliable, and scalable route toward preparation of perovskite functional nanocrystals.