Synthesis of CoS@NiS core/shell nanoarrays as efficient counter electrode for dye-sensitized solar cells

Co3O4@NiO core/shell nanowire arrays were prepared on FTO substrate by a solution-based method and then the Co3O4/NiO were converted to CoS/NiS core/shell structure via an ion-exchange reaction. The dye-sensitized solar cell (DSSC) using CoS/NiS nanowire arrays as the counter electrode (CE) achieves a power conversion efficiency of 6.64%, which is higher than that of samples using individual CoS CE (5.75%) and individual NiS CE (0.64%). This result indicates the unique core/shell structure possesses better catalytic properties. The low cost and high conversion efficiency make the CoS@NiS core/shell nanoarrays competitive as counter electrodes in DSSCs.