Enhancement of CIGS Solar Cell Performance Parameters Using Zn2P3 as Back Surface Field and SnS2 as Buffer Layer

Copper indium gallium selenide (CIGS) thin-film solar cells with high conversion efficiency, high light absorption coefficient, high stability, tunable forbidden bandwidth, and strong radiation immunity are the main reason for the high interest of researchers. Cadmium sulfide (CdS) is commonly used as a buffer layer in some CIGS-based solar cells. However, CdS is hazardous and can adversely affect the environment. In this work, we propose to use non-toxic tin sulfide (SnS2) as a buffer layer for CIGS cells because it has good optical transparency and electrical conductivity, which makes it an ideal buffer layer material. Secondly, we recommend inserting Zn2P3 as the back surface field (BSF) between the absorber layer and the back contact layer of the cell to enhance the cell performance. By simulating the Al-ZnO/SnS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/CIGS/Zn<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>/Mo solar cell structure utilizing SCAPS-1D software, we explored and analysed the effects of absorber layer thickness, buffer layer concentration and defect density on photovoltaic parameters. The efficiency of the optimized device structure can reach 30.45% (under AM 1.5 G illumination). This helps to improve our understanding of CIGS solar cells for better performance of solar cells.