Enhanced Efficiency of Cu(In,Ga)Se2 Solar Cells with a Thin CdS Buffer Layer Via a Zn0.8Mg0.2O Second Buffer Layer

Cu(In, Ga)Se-2 (CIGS) polycrystalline thin-film solar cells with an area of 0.25 cm(2) were prepared by a three-stage co-evaporation method. By applying Zn0.8Mg0.2O secondary buffer layer, we obtained CIGS solar cells with an efficiency of 13.97% with only 20 nm CdS first buffer layer. The thickness of CdS buffer layer was greatly reduced by applying Zn0.8Mg0.2O secondary buffer layer. The Zn0.8Mg0.2O buffer layer reduced the optical loss and interface recombination, leasing to the enhanced performance of CIGS solar cells.