Laser-induced controllable crystallization of organic-inorganic hybrid perovskites assisted by gold nanoislands

Organic-inorganic hybrid perovskites have attracted great interest in recent years because of their excellent luminescence properties. However, the controllable and reversible growth of such perovskites by using a simple method remains a big challenge although it is highly desirable. Here, we demonstrate the controllable and reversible crystallization of MAPbBr ₃ in a thin liquid film on top of densely-packed gold (Au) nanoislands deposited on a silica substrate. The formation of MAPbBr ₃ crystal is induced by irradiating densely-packed Au nanoislands with femtosecond laser light. MAPbBr ₃ crystals with diameters of ∼10 µm can be stably created around the focal point of the laser beam and they will disappear rapidly after switching off the laser light. The threshold laser power for creating stable MAPbBr ₃ crystal depends strongly on the morphology of Au nanoislands, which can be modified by changing the sputtering time. By increasing the concentration of the precursors in the liquid film, high-quality MAPbBr ₃ microrods can be obtained after switching off the laser light. Our findings indicate a simple but effective method to induce perovskites with a controllable manner and pave the way for developing photonic devices based on organic-inorganic perovskites.