Design and Numerical Optimization of Dual Interface Layers for MASnI₃ Perovskite Solar Cells Based on SCAPS-1D Simulation

Lead-based perovskite solar cells (PSCs) have achieved a power conversion efficiency (PCE) of 27%, demonstrating excellent photovoltaic performance. However, lead toxicity remains a significant barrier to large-scale commercialization. Tin-based perovskites, with lower toxicity and suitable bandgaps, are considered promising lead-free alternatives. Their implementation remains challenged by poor stability and pronounced interfacial recombination. Interface engineering, an important approach to enhance device performance, has been extensively studied in lead-based PSCs, while systematic research on tin-based PSCs remains limited. In this work, we propose a dual-interface structure combining 3C-SiC and CBz-PAI, optimized through SCAPS-1D simulations. This structure effectively suppresses carrier back-diffusion and minimizes recombination at critical interfaces. Compared to the initial structure, the dual-interface design improves the fill factor (FF) and PCE by 10.82% and 3.09%. After optimization and resistance adjustments, the device achieves an open-circuit voltage (<i>V</i>_oc) of 1.1418 V, a short-circuit current density (<i>J</i>_sc) of 29.54 mA/cm², a FF of 84.53%, and a PCE of 28.52% at 250 K. Additionally, the device maintains stable operation over a wide temperature range from 240 to 360 K. These findings provide theoretical insight into the design of high-performance lead-free PSCs and offer a pathway toward environmentally sustainable solar technologies.