Co9Se8 Nanosheets Electrodes: Drop‐Cast versus in situ Growth

Abstract Co 9 Se 8 nanosheets are synthesized via a solvothermal reaction. Thin films of Co 9 Se 8 nanosheets are respectively fabricated through drop‐cast and in situ growth for use as the electrocatalyst in dye‐sensitized solar cells ( DSSCs ). Comparative studies reveal that the in situ growth Co 9 Se 8 nanosheets film exhibits higher electrocatalytic activity for the electrocatalytic reduction of triiodide to iodide and better electrochemical stability than the drop‐casted film. When applied as the counter electrode in DSSCs , the in situ growth film yields higher power conversion efficiency (8.65%) than the drop‐casted film (5.87%) and even outperforms the reference Pt electrode (8.16%) under comparable conditions.