Simulation-Optimized CIGS Solar Cells with BaSi₂ BSF for Improved Performance

Copper indium gallium diselenide (CIGS) photovoltaic cells typically provide considerably more efficiency comparing other thin-film cells like cadmium telluride (CdTe). However, due to the high cost and scarcity of materials, this study explores the use of less expensive materials to enhance the affordability and efficiency of the device. The traditional Al/ZnO/CdS/CIGS/Mo structure is replaced by an Al/ZnSe/ZnS/CIGS/BaSi<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/Mo configuration in the SCAPS-1D simulator. BaSi<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> is introduced as the back surface field (BSF) layer, reducing the absorber layer thickness from 3 μm to 0.8 μm, which improves the absorption coefficient, conversion efficiency, and lowers manufacturing costs. ZnSe is used as the window layer because of its excellent optical transparency and chemical stability, while ZnS replaces CdS which is the buffer layer for its lower toxicity, wider bandgap, and environmental friendliness. The conversion efficiency (η), open circuit voltage (Voc), short circuit current density (Jsc), and fill factor (FF) were analyzed. Our findings show an efficiency 29.22%, open circuit voltage 0.8550 V, short circuit current density 42.15 mA/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, and also fill factor 81.08%. The experimental outcomes represent a significant improvement over typical CIGS solar cells, with efficiency increasing from 20.65% to 29.22%.