Simulation-Based Optimization of Alkaline Earth Metal Sulfide Buffer Layers for High-Efficiency CdTe Solar Cells

Cadmium telluride (CdTe) is one of the most recognized thin film solar cell materials. The present study explores and investigates the integrability of alkaline earth metal sulfides (AeMS) as potential buffer layer for CdTe solar cells. A theoretical simulation study is conducted through Solar cell Capacitance Simulator-1D (SCAPS-1D) software. The study focuses on the use of AeMS: CaS, MgS, SrS, and BaS as buffer layers in CdTe-based solar cells. The simulation approach is aimed to enhance PV parameters, developing the FTO/AZO/AeMS/CdTe/V₂O₅/Au heterojunction solar cell. The thickness and carrier density are tuned for each layer with all the buffer materials. The impact of the variation on the fundamental PV parameters is examined to optimize the cell. The temperature effect on the final cell is evaluated after optimization of each layer. The study indicates that the thickness and carrier density of the absorber layer have a huge impact on the cell parameters. The optimized parameters achieved are efficiency of 31.7%, 31.14%, 31.31%, and 31.73% for MgS, CaS, SrS, and BaS buffer layers at 303 K temperatures, respectively. The open circuit voltage ranges between 1.25 and 1.26 V for all buffer layers. Among all buffer layers, the MgS and BaS attain the highest short circuit current density of ~ 27.94 mA/cm². Each buffer layer configuration exhibits a fill factor that exceeds 89%. The findings underscore the utility of simulation-driven approaches in formulating experimental strategies for the development of AeMS-buffered CdTe solar cells with enhanced conversion efficiency.