Crystallization of Methylammonium Lead Halide Perovskites by Optical Trapping

Vasudevan BIJU, Ken-ichi Yuyama, Md Jahidul Islam, Kiyonori Takahashi, Takayoshi Nakamura

Single crystals of organo‐lead halide perovskites attract much attention to electrooptical and photovoltaic applications. They are usually prepared in precursor solutions incubated at controlled temperatures or under optimized vapor atmosphere conditions, nucleating multiple perovskite crystals all over the solution. Multiple nucleation of crystals prevents efficient use of precursors in the preferential growth of large single crystals, Here, we show an innovative approach for spatio‐temporally controlled, selective nucleation and growth of single crystals of lead halide perovskites by optical trapping with a focused laser beam. Upon such a trapping in unsaturated precursor solutions, nucleation of MAPbX3 (MA = CH3NH3+, X = Cl‐, Br‐, or I‐) is induced at the focal spot through increase in the concentration of perovskite precursors in the focal volume. The rate at which the nucleated crystal grows depends upon whether the perovskite absorbs the trapping laser or not. These findings suggest that optical trapping would be useful to prepare various perovskite single crystals and modify their optical and electronic properties, offering new methodologies to engineer perovskite crystals.

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