Md Faruk Hossain, Humayun Ahmed Himel, Jehan Y Al-Humaidi, Nacer Badi, Faoz H Al-Atawi, Ahmad Irfan, Md Ferdous Rahman
This work presents a comprehensive numerical analysis of high-performance thin-film solar cells utilizing AgCdF3 and Cu2GeSiS4 as absorber materials through SCAPS-1D simulations. To evaluate their photovoltaic potential, four device configurations were examined: FTO/SnS2/AgCdF3/Au, FTO/SnS2/Cu2GeSiS4/Au, the dual-absorber structure FTO/SnS2/AgCdF3/Cu2GeSiS4/Au, and FTO/SnS2/AgCdF3/Cu2GeSiS4/SnSe/Au. A systematic optimization of critical device parameters, together with absorber thickness, acceptor concentration, and bulk defect density, was performed to maximize solar-cell performance. The optimal absorber thicknesses were found to be 800 nm for AgCdF3 and 1100 nm for Cu2GeSiS4, while the corresponding acceptor concentrations and defect densities were determined to be 8.36 × 107 cm-3 and 1 × 1013 cm-3 for AgCdF3, and 1 × 1019 cm-3 and 1 × 1014 cm-3 for Cu2GeSiS4. These optimized conditions significantly suppressed Shockley-Read-Hall recombination, improved carrier mobility, and enhanced charge-collection efficiency. Among all investigated architectures, the dual-absorber device with SnSe HTL exhibited the most outstanding photovoltaic characteristics, delivering a short-circuit current density (J SC) of 43.836 mA cm-2, an open-circuit voltage (V OC) of 0.819 V, a fill factor (FF) of 86.18%, and a maximum power conversion efficiency (PCE) of 30.94%. The remarkable enhancement originates from the synergistic combination of broad-spectrum light harvesting, favorable energy-band alignment, efficient charge separation, and reduced interfacial recombination losses. These findings demonstrate that integrating AgCdF3 and Cu2GeSiS4 in a dual-absorber configuration offers a promising way toward next-generation, high-performance, and cost-effective thin-film photovoltaic technologies.