TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The copper element source is cuprous chloride, copper chloride, cuprous iodide, copper iodide, cuprous acetate, copper acetate and/or copper acetylacetone. The indium element source is indium salts of indium chloride, indium acetylacetone, indium acetate and/or indium iodide. The aluminum element source is aluminum salts of aluminum chloride, aluminum iodide, aluminum acetate and/or aluminum acetylacetone. The selenium source is tri-n-octyl phosphine selenide solution, tri-n-octyl phosphine oxide selenium solution, octadecene amine solution of selenium, and/or selenourea. The sulfur source is octadecene amine dissolved in sulfur, tri-n-octyl phosphine dissolved in sulfur, tri-n-octyl phosphine oxide dissolved in sulfur, thiourea and/or thiol.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The organic solvent is octadecene amine, tri-n-octyl phosphine, tri-n-octyl phosphine oxide, orthodichlorobenzene or anhydrous hydrazine and the alcohol is anhydrous methanol, anhydrous ethanol or anhydrous propanol. The surfactant is dodecanol, pyridine, polyethylene glycol, hexadecyl trimethyl ammonium bromide, sodium dodecyl sulfonate or nonylphenol polyoxyethylene ether. Preferred Method: In step (i), the surfactant is added when placing the copper, indium and aluminum element sources into the organic solvent, where the obtained copper (indium, aluminum) disulfide, copper (indium aluminum) diselenide or copper (indium, aluminum) disulfide diselenide photovoltaic semiconductor nanocrystal is linear or micro-spherical. The step (ii) comprises, mixing the sulfur element source and/or the selenium element source with the organic solvent, reacting at 100-120 degrees C under the protection of an inert gas, and heating at 220-250 degrees C for 10 minutes, maintaining the temperature, dissolving the sulfur element source and/or the selenium element source to obtain a solution B and under agitation, adding the solution A into the solution B, slowly cooling to 100 degrees C, and heating to 180-300 degrees C, and maintaining the temperature. The product copper (indium, aluminum) disulfide, copper (indium aluminum) diselenide or copper (indium, aluminum) disulfide diselenide photovoltaic semiconductor nanocrystal is repeatedly purified by dispersing with benzene, toluene and/or chloroform solvent.