Achieving High-Performance in Flexible CIGS Solar Cells Through Advanced Deposition Optimization

This study investigates advanced optimization strategies to enhance the performance of Cu(In,Ga)Se2 (CIGS) solar cells on flexible polyimide substrates. To ensure stable operation near the thermal limits of the polyimide, the deposition temperature was carefully optimized to balance performance improvements with substrate integrity. At low deposition temperatures, key performance drivers were identified, including precise control of the gallium gradient, the positioning of the bandgap notch, and alkali metal post-deposition treatments. These factors play a critical role and need further refinement. This paper examines how these combined parameters affect the material properties of the absorbers as well as the Voc, Jsc, and the fill factor (FF), enabling high-performance, low-temperature CIGS solar cells with efficiencies reaching 17.4% (without antireflecting layer). This progress expands their potential for lightweight and portable photovoltaic applications.