Constructions of NiCo₂S₄@rGO composite for use as a low-cost counter electrode material in dye-sensitised solar cells

Hydrothermal reduction was used to synthesise NiCo₂S₄ nanoparticles anchored on reduced graphene oxide (NiCo₂S₄@RGO), which were then employed as the counter electrode (CE) in dye-sensitised solar cells (DSSC), as detailed in this paper. Graphene nanosheets have a highly scattered distribution of NiCo₂S₄ nanoparticles, as seen by scanning electron microscopy and transmission electron microscopy. The iodide/triiodide redox reaction shows great promise when this novel nanostructure is used to enhance electrocatalytic performance via a synergistic impact. Researchers found that the electrocatalytic activity of NiCo₂S₄ nanostructures was enhanced by the synergistic interaction of nickel and cobalt ions with the highly electrically conductive RGO networks. The enhanced conductivity of rGO and the increased number of octahedral catalytic active sites of Co³⁺ in NiCo₂S₄ inverse spinel crystal structure are likely the causes of their synergistic action. A dye-sensitised solar cell utilising a NiCo₂S₄@RGO composite counter electrode achieves a conversion efficiency of 8.5% when exposed to AM 1.5 simulated solar light (100 mWcm⁻²), an efficiency that is on par with that of a cell based on a Pt electrode (7.1%) and significantly higher than devices utilising NiCo₂S₄ (7.3%) and RGO (3.1%). The recently created NiCo₂S₄ counter electrodes are formidable competitors for potential dye-sensitised solar cell uses due to their novel production method, reasonable price, and outstanding electrocatalytic properties.