In-Depth Analysis of Electron and Hole Transport Layers for Enhancing Ca₃PI₃ Solar Cell Efficiency through Advanced Numerical Simulation

This study investigates lead-free calcium-phosphorus iodide (Ca₃PI₃) perovskite solar cells with various electron transport layers (ETLs) like TiO₂ and SnS₂ and hole transport layers (HTLs) such as CuO, MoO₃, P₃HT, Sb₂S₃, CuSbS₂, and GeSe. The ideal HTL, MoO₃, was chosen, and its performance was simulated by using the SCAPS-1D tool. Two device structures were analyzed: device-I (Al/FTO/TiO₂/Ca₃PI₃/MoO₃/Ni) and device-II (Al/FTO/SnS₂/Ca₃PI₃/MoO₃/Ni). Various parameters were carefully optimized to achieve the best device performance, including donor and acceptor densities, defect density, thickness, series and shunt resistances, generation-recombination dynamics, current density (IV), quantum efficiency (QE%), and temperature. The top-performing device-I achieved a power conversion efficiency (PCE) of 29.02%, with a <i>V</i>_OC of 1.288 V, a <i>J</i>_SC of 25.235 mA/cm², and a fill factor (FF) of 89.26%. Device II showed a PCE of 26.47%, with a <i>V</i>_OC of 1.2486 V, <i>J</i>_SC of 25.233 mA/cm², and FF of 84.01%. These results emphasize the promise of device-I for high-performance Ca₃PI₃-based photovoltaic applications.