Fabrication of graphitic carbon nitride-decorated MoSe₂ hybrid nanocomposite as an efficient counter electrode for Pt-free dye-sensitized solar cells

Here, g-C₃N₄ incorporated MoSe₂ is synthesized as novel counter electrode material for dye-sensitized solar cells (DSSCs) through a combination of ultrasonic and a straightforward hydrothermal process. The synthesized pristine MoSe₂, g-C₃N₄ and MoSe₂-gC₃N₄ hybrid composite were characterized by various physical and electrochemical analyses. Powder X-ray diffraction results reveal that MoSe₂ nanoparticles with hexagonal structure and the results are matched well with the standard value JCPDS no. 29–0914. The transmission electron microscopy analysis highlights a hierarchical structure observed in the synthesized MoSe₂/g-C₃N₄ composite samples, showcasing the secure anchoring of MoSe₂ nanosheets onto the g-C₃N₄ substrate. The hybrid displayed an increased surface area of 28.37 m²/g, estimated through BET analysis, compared to the pristine MoSe₂, which exhibited only 22.42 m²/g. The newly developed MoSe₂-gC₃N₄, serving as an innovative counter electrode (CE) for Pt-free dye-sensitized solar cells, has exhibited a notable power conversion efficiency of 8.26%. Electrochemical impedance spectroscopy studies revealed that 20% g-C₃N₄-mixed MoSe₂ hybrid electrodes displayed lower R_CT values compared to other materials, while Tafel polarization measurements demonstrated that the hybrid exhibited the highest limiting current value. The results suggested that g-C₃N₄-mixed MoSe₂ could function as an affordable alternative to pricey Pt as a CE in DSSCs and other electrochemical clean energy systems.