Highly efficient lead-free solar cell using perovskite and chalcogenide materials

This study achieves a high-performance, non-toxic solar cell based on a new perovskite/chalcogenide hybrid dual absorber configuration using MASnBr₃ and AgInSe₂. The proposed structure, FTO/TiO₂/AgInSe₂/MASnBr₃/Gra-phene/CNTS, leverages the complementary bandgaps of AgInSe₂ (1.19 eV), a chalcogenide thin-film absorber, and MASnBr₃ (1.3 eV), a lead-free perovskite, to enhance spectral absorption across the visible to near-IR spectrum. A total of 56 ETL/HTL combinations were evaluated, with TiO${}_2$ and CNTS identified as optimal based on both device performance metrics and energy band alignment analysis using band edge alignment parameters. Incorporating a graphene interfacial layer between MASnBr₃ and CNTS reduced interfacial recombination and improved carrier transport dynamics. Furthermore, layer thicknesses, doping and defect densities were systematically optimized, followed by analysis of temperature and resistive losses for practical viability. The proposed optimized device architecture gained a PCE of 37.78%, with $V_{OC}$ of 1.15 V, $J_{SC}$ of 39.07 mA/cm², and FF of 84.31%. Quantum efficiency analysis revealed that the AgInSe₂ absorber extends the spectral response up to 1100 nm, maintaining QE above 90% across a broad range. This indicates efficient carrier collection, low recombination, and enhanced photocurrent generation. The optimized dual-absorber architecture demonstrates excellent potential for next-generation, high efficiency, environmentally friendly, lead-free perovskite solar cells.