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

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 parameters are primarily studied here. It is observed that the increasing defects in the CI(G)Se TFSCs could impact negatively the device's performance by recombining the generated charge carriers. Better results were found for CI(G)Se TFSCs at a lower work temperature (by reducing the saturation current, and at a smaller series resistance value as well as a larger shunt resistance value (by reducing the alternative paths for generated charge carriers). Therefore, understanding these results could provide complete information on the optimization process that can serve as a guide to achieve highly efficient electronic devices experimentally.