TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The hydrazine-coordinated Cu chalcogenide complex component (A) is obtained by reacting Cu or copper selenide (Cu2Se) and a chalcogen in dimethylsulfoxide in the presence of hydrazine, and adding a poor solvent to the resulting solution or subjecting the resulting solution to concentration and filtration. The hydrazine-coordinated Sn chalcogenide complex component (B) is obtained by adding a chalcogen and at least one of Sn, SnSe and SnSe2 to hydrazine to obtain a crude product, and extracting the crude product with dimethylsulfoxide. The hydrazine-coordinated Zn chalcogenide complex component (C) is obtained by mixing Zn or ZnSe and a chalcogen in the presence of hydrazine to obtain a crude product, and extracting the crude product with dimethylsulfoxide. Preferred Components: The chalcogen is sulfur or selenium.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The poor solvent is an alcohol solvent. EXAMPLE - A metal copper (383 mg) and selenium (1903.2 mg) were stirred in dimethylsulfoxide (10 ml) at room temperature for 3 days to 1 week in the presence of hydrazine (12.05 mmol). Then, isopropylamine (IPA) (20 ml) was gradually added to the filtrate to perform recrystallization, to obtain a black hydrazine-coordinated Cu-Se chalcogenide complex. Separately tin (356 mg) and selenium (711 mg) were stirred in hydrazine (5 ml) at room temperature for 1-3 days. Then, the remaining hydrazine was removed by flowing nitrogen, to obtain a crude product. Subsequently, IPA was added and stirred to precipitate a dark-red product. Then, supernatant was removed, and the precipitate was washed with IPA and dried, to form a dark-yellow hydrazine-coordinated Sn-Se chalcogenide complex. Then zinc selenide (460 mg) and selenium (1588 mg) were stirred in dimethylsulfoxide (8 ml) at room temperature for 3 days to 1 week in the presence of hydrazine (12.07 mmol). Then, the remaining hydrazine was removed by flowing nitrogen to obtain a reaction intermediate solution. The reaction intermediate solution was extracted, and subjected to filtration, followed by concentration under reduced pressure, and filtering obtained concentrated solution to form a hydrazine-coordinated Zn precursor solution. The hydrazine-coordinated Cu-Se complex, the hydrazine-coordinated Sn-Se complex and the hydrazine-coordinated Zn-Se complex were individually dissolved in dimethylsulfoxide to obtain a hydrazine-coordinated Cu-Se complex/DMSO solution (solution A), a hydrazine-coordinated Sn-Se complex/DMSO solution (solution B) and a hydrazine-coordinated Zn-Se complex/DMSO solution (solution C), respectively. The solution A (1.904 ml), the solution B (1.255 ml) and the solution C (14.400 ml) were mixed together to prepare a copper zinc tin sulfide/dimethylsulfoxide precursor solution.