Effects of Non-Noble Metal Current-Collecting Grids on Internal Resistance for Dye-Sensitized Solar Cells

Abstract

We studied the effectiveness of various non-noble metals used as current-collecting grids on fluorine-doped (FTO) for dye-sensitized solar cells (DSCs). Non-noble metal grids were deposited by dc magnetron sputtering, and the mechanical adhesion of non-noble metals was improved by a 300 nm thick Cr interlayer between FTO and a grid. The metals were evaluated on the basis of photocurrent–voltage characteristics and impedance spectra. An analysis using an equivalent circuit model showed that such metal grids affect the internal ohmic resistance, which is inversely related to the fill factor. A thick NiCr grid affords a fill factor of 0.639, as much as that of Ag, but with a slightly lower efficiency of 6.4%, which supports the feasibility of using stable non-noble metal grids in DSCs, albeit with a 5% reduction in photovoltaic efficiency.