Enhanced photovoltaic performance of dye sensitized solar cells using synergistically Co-doped FeCu@MoS2 counter electrodes

• Introduces Fe and Cu co-doped MoS₂ as an advanced photoanode for DSSCs. • First study on synergistic effects of Fe and Cu co-doping in MoS₂. • Co-doping enhances charge generation, transport, and reduces recombination. • The FeCu@MoS₂ photoanode achieved an impressive PCE of 12.86%. • Offers a new strategy for designing high-efficiency DSSCs with co-doped materials. The development of cost-effective and electrocatalytically active counter electrodes (CEs) is crucial for advancing dye-sensitized solar cells (DSSCs). While molybdenum disulfide (MoS₂) is a promising alternative to scarce platinum, its performance is limited by low conductivity and insufficient active sites. This work introduces a novel bimetallic doping strategy to engineer a high-performance CE for DSSCs. We successfully synthesized an iron (Fe) and copper (Cu) co-doped MoS₂ nanocomposite (FeCu@MoS₂) via a facile hydrothermal method. The material was comprehensively characterized to understand its structural, optical, and morphological properties and evaluated as a CE through detailed electrochemical analysis. The Fe-Cu co-doping induces significant lattice strain, reduces the crystallite size to 3.3 nm, and narrows the bandgap to 1.40 eV. The resulting material exhibits a highly porous 2D hierarchical morphology with a substantially increased surface area (137 m²/g) and demonstrates superior electrocatalytic activity for the I₃⁻/I⁻ redox reaction, evidenced by a low charge transfer resistance (60 Ω). When deployed in a DSSC, the FeCu@MoS₂ CE achieves remarkable power conversion efficiency (PCE) of 12.86%, significantly outperforming devices with pristine MoS₂ (5.39%), Fe@MoS₂ (8.12%), and Cu@MoS₂ (9.43%) CEs. It also shows exceptional operational stability, retaining over 90% of its initial PCE after 20 days. This study underscores the profound synergistic effect of Fe-Cu co-doping in enhancing the catalytic and electronic properties of MoS₂, establishing FeCu@MoS₂ as a highly efficient, durable, and cost-effective platinum-free CE for next-generation photovoltaic devices. Schematic illustration for the synthesis of FeCu@MoS 2 composite