Spherical Fe₇S₈@rGO nanoflowers as electrodes with high electrocatalytic performance in dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) can directly convert solar energy into electricity, and have aroused great research interest from researchers. Here, the spherical Fe₇S₈@rGO nanocomposites were expediently fabricated by facile methods, and applied in DSSCs as counter electrodes (CEs). The morphological features show the porous structure of Fe₇S₈@rGO, and it is beneficial to enhance the permeability of ions. Reduced graphene oxide (rGO) has a large specific surface area and good electrical conductivity, shortening the electron transfer path. The presence of rGO promotes the catalytic reduction of I₃^- ions to I^- ions and reduces the charge transfer resistance (R_ct). The experimental findings show that the power conversion efficiency (PCE) of Fe₇S₈@rGO as CEs for DSSCs can reach 8.40% (20 wt% for rGO), significantly higher than Fe₇S₈ (7.60%) and Pt (7.69%). Therefore, Fe₇S₈@rGO nanocomposite is expected to be an efficient and cost-effective CE material for DSSCs.