High-efficiency CIGS solar cells with optimization of layers thickness and doping

The effects of layers thickness and doping on the photovoltaic cell parameters in copper-indium-gallium-diselenide (CIGS) based solar cells, with a window layer (ZnO) and a buffer layer (CdS) have been investigated using solar cell capacitance simulator (SCAPS). The optimization has been made layer by layer. Our results showed that the best structure must have a window layer (ZnO), a buffer layer (CdS) and an absorber layer (CIGS) that have thicknesses of 0.02, 0.05 and 4 μm, and doped with 1016, 1016 and 1016 cm−3, respectively. Cells with these features are found to give conversion efficiency of 25.9%. Such efficiency value is better than those previously reported in the literature for the CIGS solar cells.