Maximizing the solar output power using hybrid (CdS/ZnSe) buffer for CIGS thin film solar cell

In this work, a hybrid buffer layer (CdS & ZnSe) is placed between the absorber and the window layer in a CIGS (Copper Indium Gallium Selenide) solar cell replacing the commonly used single-layer CdS. The buffer layer plays a crucial role in interface electricity to enhance the performance of the solar cell. Although, CdS is used as a buffer layer in CIGS solar cells, the toxic nature and parasitic absorption due to the narrowband gap (2.4 eV) become issues during its application in devices. To reduce Cd concentration and ameliorate the bandgap issue, the hybrid buffer layer (CdS & ZnSe) is a perfect supplant. In this study, numerical simulation is performed on CIGS-based solar cells comprised of a hybrid buffer layer to enhance the performance by optimizing the physical parameters (thickness, carrier concentration, and defect density) of both absorber and buffer layer using SCAPS-1D software. In the process of optimizing physical parameters, the effect of the mentioned parameters is observed on the solar cell performance. Later, the impact of working temperature is shown in the solar cell performance. Finally, with all those optimized parameters, a comparison has been done between the reference and the proposed structure. The comparison asserts that the proposed structure with a conversion efficiency of 24.55% is outdistancing the reference structure as well as some relative structures from the recent study. The simulation results in this study can be a didactic one in the fabrication of high-efficiency CIGS solar cells