CIGS solar cell with CdS buffer layer deposited by ammonia-free process



We have successfully fabricated high-efficiency CuInGaSe2 (CIGS) solar cells with CdS film deposited by ammonia-free process. The CdS films were formed on CIGS films by chemical bath deposition from an aqueous solution containing cadmium acetate and thioacetamide. The properties of CdS films deposited on soda lime glass were investigated by atomic force microscopy and optical transmission measurement. By optimizing the concentration of the solution used for the formation of CdS films and the thickness of i-ZnO films used for solar cell production, high-efficiency ammonia-free cells were fabricated. The properties of the ammonia-free cell fabricated by the optimized process were VOC = 0.695 V, JSC = 32.812 mA/cm2, FF = 0.755 and η = 17.22%. These values are comparable to those of the cells produced by the conventional process using ammonia. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)