Single-junction perovskite solar cells, part of the emerging third-generation photovoltaic technologies, face intrinsic limitations such as poor charge separation, instability, and elevated recombination losses. To overcome these challenges and address the environmental concerns associated with lead-based perovskites, a novel, lead-free next-generation, tin-based dual absorber perovskite solar cell (TDAPSC) featuring the device architecture Au/FTO/ \(\textrm{SnS}_{2}\) / \(\textrm{BaSnS}_{3}\) / \(\textrm{Rb}_{2}\textrm{SnI}_{6}\) /PEDOT/Ni is proposed here. Through the integration of two complementary tin-based absorbers, \(\textrm{Rb}_{2}\textrm{SnI}_{6}\) (a halide perovskite variant) and \(\textrm{BaSnS}_{3}\) (a sulfide perovskite) this architecture eliminates lead-related toxicity while leveraging broad spectral absorption, superior carrier mobility, and high quantum efficiency. Detailed SCAPS-1D simulations to optimize key performance parameters including recombination pathways, absorber thicknesses, defect densities, charge carrier distributions, and energy level alignment across interfaces are conducted. As a result, the optimized TDAPSC achieved an open-circuit voltage ( \(V_{\textrm{oc}}\) ) of 1.20 V, a short-circuit current density ( \(J_{\textrm{sc}}\) ) of 35.83 mA/cm2, and a fill factor (FF) of 89.33%, leading to a remarkable power conversion efficiency (PCE) of 38.44%. This enhanced performance stems from suppressed recombination and efficient charge extraction facilitated by energy-level alignment between \(\textrm{BaSnS}_{3}\) and \(\textrm{Rb}_{2}\textrm{SnI}_{6}\) . Moreover, the fully inorganic composition ensures excellent chemical and thermal stability, while also offering scalable fabrication potential. Altogether, this TDAPSC design presents a highly promising pathway toward next-generation photovoltaic technologies that prioritize environmental safety, performance, and long-term durability.
