Method of manufacturing thin-film light-absorbing layer, and method of manufacturing thin-film solar cell using the same

1. A method of manufacturing a thin-film light-absorbing layer on a substrate, comprising:

preparing a mixture solution by mixing precursor solutions comprising CuCl 2 , InCl 3 and SeC(NH 2 ) 2 under a nitrogen atmosphere at room temperature;

preparing a substrate;

spraying the mixture solution comprising Cu, In and Se on the substrate and drying the mixture solution, thus forming a light-absorbing thin film; and

selenizing the light-absorbing thin film under a selenium atmosphere.

2. The method of claim 1 , wherein the preparing the mixture solution comprises adjusting a solution composition of the precursor solutions thus preparing a mixture solution represented by Cu X In Y Se Z (X=0.5˜1.4, Y=0.5˜1.4, Z=1˜6).

3. The method of claim 1 , wherein the precursor solutions further comprises GaCl 3 .

4. The method of claim 3 , wherein the mixture solution contains Ga of the GaCl 3 , the Ga replacing some of In of the InCl 3 in the mixture solution.

5. The method of claim 1 , wherein the spraying is performed in a non-vacuum.

6. The method of claim 1 , wherein the substrate is heated at 300˜500° C. for 30˜60 min.

7. The method of claim 6 , wherein the substrate is heated using a heater provided in an apparatus for manufacturing a thin-film light-absorbing layer.

8. The method of claim 7 , wherein the apparatus for manufacturing a thin-film light-absorbing layer comprises an inlet port into which the mixture solution is introduced, a spray nozzle for spraying the mixture solution, a spray gun provided between the inlet port and the spray nozzle so that the mixture solution is transferred by a carrier gas, and a rotary shaker provided under the heater.

9. The method of claim 8 , wherein the carrier gas is nitrogen, and is sprayed at 3˜50 ml/h.

10. The method of claim 8 , wherein the rotary shaker is rotated at 10˜50 rpm.

11. The method of claim 1 , wherein the drying comprises cooling to room temperature at a rate of 8˜12° C./min.

12. The method of claim 1 , wherein the selenizing is performed at 450˜610° C. for 30˜120 min.

13. A method of manufacturing a CIS-based thin-film solar cell, comprising:

forming a back contact layer on a glass substrate using sputtering;

spraying on the back contact layer a mixture solution comprising CuCl 2 , InCl 3 and SeC(NH 2 ) 2 precursor solutions mixed under a nitrogen atmosphere at room temperature, and performing selenization, thus forming a CIS-based light-absorbing layer;

forming a buffer layer on the light-absorbing layer using chemical vapor deposition;

forming a window layer on the buffer layer using sputtering; and

forming an upper electrode layer on the window layer.

14. The method of claim 13 , wherein the spraying is performed using an apparatus for manufacturing a thin-film light-absorbing layer comprising an inlet port into which the mixture solution is introduced, a spray nozzle for spraying the mixture solution, a spray gun provided between the inlet port and the spray nozzle so that the mixture solution is transferred by a carrier gas, a heater for heating the substrate, and a rotary shaker provided under the heater.

15. A method of manufacturing a CIGS-based thin-film solar cell, comprising:

forming a back contact layer on a glass substrate using sputtering;

spraying on the back contact layer a mixture solution comprising CuCl 2 , InCl 3 , GaCl 3 and SeC(NH 2 ) 2 precursor solutions mixed under a nitrogen atmosphere at room temperature, and performing selenization, thus forming a CIGS-based light-absorbing layer;

forming a buffer layer on the light-absorbing layer using chemical vapor deposition;

forming a window layer on the buffer layer using sputtering; and

forming an upper electrode layer on the window layer.