Defect‐Engineered SnS ₂ @Nitrogen‐Doped Carbon Spheres as High‐Efficiency Pt‐Free Counter Electrodes for Dye‐Sensitized Solar Cells

This study presents the development of nitrogen‐doped carbon sphere/SnS ₂ nanocomposites (SnS ₂ @NCS) as efficient platinum‐free counter electrodes for dye‐sensitized solar cells (DSSCs). Nitrogen doping introduces topological defects into the carbon matrix, facilitating the epitaxial growth of ultrathin SnS ₂ nanosheets into hierarchical architectures. The optimized SnS ₂ @NCS electrode exhibits significantly enhanced catalytic activity, demonstrated by a low charge–transfer resistance of 1.070 Ω cm ⁻² (representing a 74.6% reduction compared to the undoped SnS ₂ @CS) and achieves a power conversion efficiency of 8.18%, rivaling that of platinum‐based counterparts. The improved performance is attributed to synergistic effects arising from CN bonds and SnS ₂ nanosheets, which collectively enhance interfacial charge transport and electrolyte infiltration. This work demonstrates a cost‐effective strategy for fabricating high‐performance DSSCs.