Method for recovering valuable material from perovskite solar cell

A method for recovering a valuable material from a perovskite solar cell, comprising:

• (a) immersing a perovskite solar cell device in an organic solvent to separate an absorbing layer containing at least one monovalent metal cation, at least one divalent metal cation, and at least two halogen anions, an electron transport layer, and a transparent conductive layer from the perovskite solar cell device, and to dissolve the at least one monovalent metal cation, the at least one divalent metal cation, and the at least two halogen anions of the absorbing layer in the organic solvent;
• (b) adding an oxidizing agent to the organic solvent to obtain a mixture containing a halogen molecule formed by oxidation of one of the two halogen anions;
• (c) heating the mixture until dry to form a first solid phase residue containing the at least one monovalent metal cation, the at least one divalent metal cation, and the other one of the two halogen anions, and to sublime and recover the halogen molecule;
• (d) dissolving the recovered halogen molecule in step (c) in deionized water to form a recovered halogen solution;
• (e) rinsing the first solid phase residue in step (c) with deionized water to obtain a second solid phase residue containing a hydroxide of the divalent metal and a liquid phase containing the at least one monovalent metal cation, the at least one divalent metal cation, and the other one of the two halogen anions;
• (f) calcining the second solid phase residue containing the hydroxide of the divalent metal in step (e) into a metal oxide, or dissolving the second solid phase residue containing the hydroxide of the divalent metal in step (e) in an aqueous solution, followed by mixing with the recovered halogen solution in step (d), so as to obtain a first metal halide;
• (g) subjecting the liquid phase containing the at least one monovalent metal cation, the at least one divalent metal cation, and the other one of the two halogen anions in step (e) to an extraction treatment with an extractant diluted with an oil, so as to form an oil phase layer containing the at least one monovalent metal cation, and a water phase layer containing the at least one divalent metal cation and the other one of the two halogen anions,
• wherein the extractant is 4-tert-butyl-2-(α-methylbenzyl) phenol;
• (h) subjecting the oil phase layer containing the at least one monovalent metal cation in step (g) to a back-extraction treatment with an ammonium hydroxide solution, so as to obtain an aqueous phase solution containing the at least one monovalent metal cation;
• and
• (i) adding the recovered halogen solution in step (d) to the aqueous phase solution containing the at least one monovalent metal cation in step (h), followed by conducting a vacuum concentration treatment, so as to obtain a second metal halide.