The dye-sensitized solar cells based on the interconnected ternary cobalt diindium sulfide nanosheet array counter electrode

The ternary cobalt diindium sulfide (CoIn 2 S 4 ) counter electrode (CE) with interconnected nanosheet array structure is fabricated on the fluorine-doped tin oxide (FTO) substrate by in situ ethanol solvothermal synthesis. The ethanol solvent and In 2.77 S 4 intermediate play important roles on the formation of the interconnected nanosheet array structure. The dye-sensitized solar cell (DSSC) with the optimized ternary CoIn 2 S 4 CE gives an energy conversion efficiency of 8.83%, which is much higher than that of DSSCs based on the binary CoS 2 (6.47%), and In 2.77 S 4 (0.46%) CEs and can be comparable with that of Pt CE (8.19%) under full sunlight illumination (100 mW cm −2 , AM 1.5 G). Except for the intrinsically electrocatalytic activity from the CoIn 2 S 4 , the higher conversion efficiency of CoIn 2 S 4 based DSSC can be attributed to that the interconnected nanosheet array structure provides plentiful catalytic active sites, abundant electron transport channels, and fast electrolyte diffusion.