Preparation method of large-sized perovskite structure CH3NH3PbI3 crystal

The invention discloses a preparation method of a large-sized perovskite structure CH3NH3PbI3 crystal. The method comprises the following steps: dissolving PbI2 into an HI (Hydrogen Iodide) solution, and preparing a Pb -HI solution; mixing the HI solution with a CH3NH2 solution in the molar ratio of 1:1, and reacting the mixture at the temperature of 0 DEG C for 2 hours to obtain a CH3NH2I solution; mixing the Pb -HI solution with the CH3NH2I solution, preheating at the temperature of 95 DEG C for 48-72 hours to obtain an oversaturated solution, and filtering the oversaturated solution to obtain a mother liquor for growing the CH3NH3PbI3 crystal, wherein the molar ratio of CH3NH2I to Pb is (1-2):1; and preheating the mother liquor in a water bath of 95.5-96 DEG C for 12-24 hours, placing the preheated mother liquor into a crystal growing container, performing programmed cooling to 45 DEG C, and keeping a constant temperature to obtain the CH3NH3PbI3 crystal. In a process of the method, the HI solution participates in the synthesis of raw materials, and is taken as a solvent of crystal growing, so that the method has the advantages of simple synthesizing process and small number of side reactions; and a growing device is simple, and a high-quality and large-sized crystal can be grown.