While tin-based \(\hbox {FASnI}_3\) perovskite has emerged as a leading lead-free alternative for photovoltaic applications, its standalone implementation in perovskite solar cells (PSCs) continues to face efficiency limitations. This study addresses this challenge through an innovative dual-absorber approach, combining \(\hbox {FASnI}_3\) with the newly explored inorganic perovskite \(\hbox {AgCdF}_3\) in an inverted device architecture. Through rigorous SCAPS-1D numerical modeling, we first established a validated baseline by replicating experimental results from single-absorber \(\hbox {FASnI}_3\) PSCs (10.55% PCE). Building upon this foundation, we developed a novel bilayer configuration with \(\hbox {FASnI}_3\) (300 nm) as the primary absorber and \(\hbox {AgCdF}_3\) (900 nm) as the bottom layer. Systematic optimization of key parameters, including the selection of optimal HTL and ETL materials, layer thickness, doping concentrations, series and shunt resistances, and back contact work function tuning, yielded a record 30.73% PCE, a 2.9x improvement over single-absorber designs. The enhanced performance stems from synergistic bandgap alignment (extended photon harvesting) and reduced recombination at the \(\hbox {FASnI}_3\) / \(\hbox {AgCdF}_3\) heterojunction, and the effective charge transport enabled by the graphene oxide (GO) HTL and copper-doped strontium titanate (CSTO) ETL. This work not only highlights the potential of high-efficiency, lead-free PSCs through dual-absorber design and careful optimization but also demonstrates \(\hbox {AgCdF}_3\) ’s viability as a partner material, establishing a generalizable framework for experimentally realizing environmentally friendly, high-performance PSCs.
