NOVELTY - A copper (Cu)-indium (In)-selenium (Se) photoelectric thin film is produced by successive ion layer absorption and reaction comprising mixing solutions of copper chloride dihydrate (CuCl2.2H2O), deionized water and triethanolamine (TEA), and indium chloride tetrahydrate (InCl3.4H2O), deionized water and citric acid to obtain mixed cation precursor solution; dissolving sodium seleno sulfite (Na2SeSO3) into deionized water to obtain anion precursor solution; and respectively immersing clean substrate into mixed cation and anion precursor solutions.    USE - Method for production of Cu-In-Se photoelectric thin film (claimed) for photovoltaic battery and light absorbing layer of solar batteries.    ADVANTAGE - The thin film has good shape.    DETAILED DESCRIPTION - Production of Cu-In-Se photoelectric thin film using successive ion layer absorption and reaction comprises:    (A) dissolving CuCl2.2H2O into deionized water and dissolving TEA (10 times mol ratio) into CuCl2 solution (0.015-0.045 mol) to obtain first solution;    (B) dissolving InCl3.4H2O into deionized water and dissolving citric acid (1 mol ratio) into InCl3.4H2O solution to obtain second solution;    (C) leaving two solutions for 2 hours until stable and mixing two solutions to obtain mixed cation precursor solution with pH 8-8.2;    (D) dissolving Na2SeSO3 into deionized water to obtain anion precursor solution with pH 8.5;    (E) immersing clean substrate into mixed cation precursor solution;    (F) washing substrate with deionized water to remove antiparticles;    (G) immersing into anion precursor solution to react ions Cu2+, In3+ and Se2- and generate deposition compound;    (H) washing substrate with deionized water to remove antiparticles and excess non-reacted ions; and    (I) fully drying deposited samples for thermal processing at 400 degrees C for 1 hour with argon.    The CuCl2 and indium chloride (InCl3) are present at 0.75-3 mol ratio. The Na2SeSO3 has mol amount equal to sum of CuCl2 and InCl3 in precursor solution. The leaving, depositing and washing steps are controlled at 10-40 s. A thin film having desired thickness is produced by repeating immersing and absorption steps.