Dye sensitized solar cell (DSC) is an emerging unique photovoltaic system featuring both low-cost and attractive efficiency. However, the counter electrode used in most literatures is a nanoparticular Pt film coated FTO (fluorine doped tin oxide) glass, which is expensive and brittle. Here we demonstrated, for the first time, a flexible, seamlessly connected, 3-dimensional vertically-aligned carbon nanotubes (VACNTs)/graphene on Ni foil can act as the counter electrodes for DSCs, achieving better photovoltaic performance than standard brittle Pt/FTO combination. The covalently bonded graphene and SWCNTs ensure the excellent electron transport on the electrode, and the large electroactive surface area of hybrid carbon materials rivals the catalytic capability of Pt analog. DSCs utilizing flexible VACNTs/graphene counter electrode over performed the Pt based cells in both rigid (8.2% vs. 6.4%) and flexible (3.9% vs. 3.4%) assemblies. Electrochemical impedance spectroscopy (EIS) results indicate that electrons transfer a magnitude faster at the counter electrode/electrolyte interface for VACNTs/graphene samples than Pt electrodes. To the best of our knowledge, this is also the lowest value of charge transfer resistance ever reported for the TCO and Pt-free systems. Thus, the VACNTs/graphene on Ni foil provides a novel inexpensive, better-performed, flexible counter electrode for DSC. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/240nm/uploads/35590_figure_1.jpg' alt='' />

Oxide-free, flexible, seamlessly connected carbon nanotubes/graphene counter electrode for efficient dye-sensitized solar cells

247th National Meeting (2014)

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