Several highly efficient catalysts for Pt-free and FTO-free counter electrodes of dye-sensitized solar cells

Three nanomaterials, namely, TiC, WO2 and VN, are introduced into dye-sensitized solar cells (DSCs) as counter electrode (CE) catalysts to replace the expensive Pt CE. Three kinds of substrates of bare glass (BG), Ti foil, and polyimide (PI) film are applied as F-doped Sn oxide (FTO)-free substrates for rigid and flexible DSCs; thus realizing FTO-free and Pt-free CEs simultaneously in the DSC system. A C layer is used as an electron collector to replace the expensive FTO conductive layer in the insulative BG and PI film. Cyclic voltammetry, electrochem. impedance spectroscopy, and Tafel polarization curves are performed to compare the catalytic activities of these CEs for the redn. of triiodide to iodide. The DSCs that use TiC, WO2, and VN as CEs on Ti foil have better photovoltaic performance than those that use CEs on traditional FTO glass. Also, the TiC, WO2, and VN on the BG substrates show excellent catalytic activities that can match the performance of the CEs on FTO glasses.