A computational study for understanding the effect of various parameters on the performance of three different CI(G)Se-based thin film solar cells

•In this research work, three different types of CIGSe-based thin film solar cells (TFSCs) such as CISe, CIGSe, and CIGSe bilayer TFSCs are simulated through SCAPS software.•Comparative study on the solar cell parameters of these CI(G)Se TFSCs and finding the best conditions for achieving high device performance are the novel approaches of this research work.•The device’s performance is optimized to get maximum efficiency by analyzing the material properties, such as thickness and carrier concentrations of CI(G)Se, CdS, ZnO, and ZnO:Al materials used in CIGSe-based thin film solar cells.•The experimentally obtained parameters of CIGSe thin films deposited by the hybrid deposition method and CdS thin films deposited by the chemical bath deposition method are also analyzed through this simulation and obtained more than 20% efficiency, showing potential to get high device performance.•Finally, the influence of defects (present in the absorber layer, buffer layer, and their interface), work temperatures, and parasitic resistances on the solar cell parameters are investigated.•Understanding the results obtained from the theoretical modeling can help in designing the experimental work, saving material resources and research time. The copper indium selenium/copper indium gallium selenium (CI(G)Se)-based thin film solar cells (TFSCs) have been fascinating in the photovoltaic market due to their potential to attain high efficiency of solar cells and modules at relatively little cost. This research work introduces the simulation of the CI(G)Se TFSCs through SCAPS software. Some parameters like thickness, bandgap, and carrier concentration of semiconducting materials used in the CI(G)Se TFSCs were optimized to get the solar cell efficiency as high as possible. The optimized efficiencies for CISe, CIGSe, and CIGSe bilayer TFSCs were 22.81, 27.32, and 27.99%, respectively. It is seen from the results that the device’s performance using two absorber layers in CI(G)Se TFSCs was comparatively higher than using a single absorber layer. This outcome is mainly due to the better absorption of photons in CI(G)Se TFSCs containing two absorber layers. The SCAPS software also analyzed the experimentally obtained parameters of CI(G)Se and CdS thin films and noticed more than 20% efficiency, showing potential parameters to use in commercial applications. The effect of defects found in the CI(G)Se absorber layer, CdS buffer layer, and CdS/CI(G)Se interface on the solar cell paramete