The application of camphorsulfonic acid doped polyaniline films prepared on TCO-free glass for counter electrode of bifacial dye-sensitized solar cells

In this paper, we assembled a low-cost and bifacial dye-sensitized solar cell with an optically transparent TCO (transparent conducting oxide)-free counter electrode using camphorsulfonic acid-doped polyaniline coated on normal glass. This polymer counter electrode was fabricated by spin coating on a TCO-free glass substrate followed by optimizing process of film thickness and thermal treatment. Because the camphorsulfonic acid doped polyaniline film had the high conductivity and the superior electrocatalytic activity, it could successfully act as a counter electrode that performs a dual role, transporting electrons from the electrode to an external circuit and reducing the redox couple in electrolyte. The superior photovoltaic performances with camphorsulfonic acid-doped polyaniline film, 84% from front illumination and 93% from rear illumination of conventional dye-sensitized solar cell using Pt and TCO glass, was exhibited. Because the complementary absorption properties with dye and electrochromic properties of PANI/CSA film had the advantage of light absorption from rear side illumination, this optically transparent polymer film was particularly used as an effective Pt and TCO-free counter electrode for bifacial dye-sensitized solar cell.