Metal-organic framework-derived cobalt diselenide as an efficient electrocatalyst for dye-sensitized solar cells

In this paper, cobalt-based metal-organic framework (Co-MOF) precursor is synthesized on fluorine-doped tin oxide (FTO) glass through an electrodeposition and solvothermal process. Then, cobalt diselenide (CoSe2-D) film is directly obtained through a selenization process. Meanwhile, Co-MOF film is also fabricated by spraying Co-MOF solution onto FTO glass, and selenized to form CoSe2(CoSe2-S) film. It is found that CoSe2-S film is composed of particles with porous structure, which is beneficial to increase electrocatalytic active sites and provide more diffusion channels for the I-/I(3)(-)redox couples. As a result, CoSe2-S counter-electrode (CE) displays a higher electrocatalytic performance than those of platinum (Pt) and CoSe2-D CEs. The photoelectric conversion efficiency of the dye-sensitized solar cell (DSC) based on CoSe2-S CE is up to 6.86%, which is larger than that of the DSC based on Pt CE (6.36%). The results indicate the potential of using CoSe(2)as low-cost and facile CE for DSCs.