Enhancement of the efficiency of ultra-thin CIGS/Si structure for solar cell applications

This paper describes a numerical study of ultrathin CIGS solar cell using the one-dimensional simulation program. The various properties of the absorber layer such as the band gap energy, the absorption coefficient, and the reflection coefficient are investigated. In addition, the impact of adding silicon to reduce the thickness of CIGS is also examined. We have carried out a theoretical study to show the influence of the thickness and the gallium concentration of the CIGS absorber layer on the performance of the Mo/Si/CIGS/ZnS/ZnO structure. It has been demonstrated that increasing x(Ga) and d(CIGS) affect the conversion efficiency, FF, V-oc, and J(sc). Finally, we have achieved a conversion efficiency eta = 21.08% with an optimal value of gallium content equal to 20% when the thickness of the absorber layer has been reduced to 0.75 mu m. This study allowed us to improve the performance of thin film solar cell.