A Numerical Strategy for Achieving Efficiency Exceeding 32% with a Novel Lead‐Free Dual‐Absorber Solar Cell Using Ca₃SbI₃ and Sr₃SbI₃ Perovskites

This study presents a numerical approach to achieve high efficiency using a novel dual‐absorber perovskite solar cell (PSC) utilizing environmentally friendly inorganic perovskite materials focusing on the optimization of different parameters. Ca 3 SbI 3 and Sr 3 SbI 3 are employed as the upper and lower absorber layer, respectively, in the proposed PSC structure. The device architecture also incorporates SnS 2 as the electron transport layer (ETL) and Spiro‐OMeTAD as the hole transport layer (HTL). The further investigation explores the effect of ETL and HTL thicknesses and doping concentrations on device performance, revealing significant impact on photovoltaic parameters. Using double‐graded materials of Ca 3 SbI 3 /Sr 3 SbI 3 with ETL and HTL, the PSC in this study achieves an optimized efficiency of 32.74% with J SC of 34.17 mA cm −2 , fill factor of 83.77%, and V OC of 1.14 V having an optimized level of doping 1 × 10 17 cm −3 for Sr 3 SbI 3 and 1 × 10 16 cm −3 for Ca 3 SbI 3 perovskite materials, with a thickness of 800 and 200 nm for Sr 3 SbI 3 and Ca 3 SbI 3 , respectively, and defect density of 1 × 10 12 cm −3 for both the materials at room temperature. These findings provide a blueprint for developing highly efficient and cost‐effective PSCs, emphasizing the importance of dual‐absorber configurations in surpassing limit of efficiency of single‐junction solar cells.