Electropolymerization and application of polyoxometalate-doped polypyrrole film electrodes in dye-sensitized solar cells

A polyoxometalate (H 3 PW 12 O 40 , PW 12 )-doped polypyrrole (PW 12 -PPy) hybrid film was successfully prepared by electropolymerization. The PW 12 -PPy composite film was used as an efficient Pt-free counter electrode in a dye-sensitized solar cell (DSSC). The surface appearance, chemical composition and internal phase structure of the samples were investigated by scanning electron microscopy, infrared spectroscopy and X-ray diffraction. Electrochemical impedance spectroscopy and cyclic voltammetry measurements recorded using the prepared electrodes indicate that the PW 12 -PPy electrode has a higher reduction peak current density and a smaller series resistance than the Pt electrode, suggesting that the electrocatalytic activity of the PW 12 -PPy electrode for I 3 − reduction is better than that of the Pt electrode. Under simulated solar irradiation (AM 1.5) with an intensity of 100 mW⋅cm −2 , the DSSC based on the PW 12 -PPy counter electrode produces an average power conversion efficiency (PCE) of 6.19%; this efficiency value is on a par with that of similar devices using Pt as the cathode (6.25%).