Enhanced performance of a dye-sensitized solar cell with a modified poly(3,4-ethylenedioxythiophene)/TiO2/FTO counter electrode

ClO4−-poly(3,4-ethylenedioxythiophene)/TiO2/FTO (ClO4−-PEDOT/TiO2/FTO) counter electrode (CE) in dye-sensitized solar cells (DSSCs) is fabricated by using an electrochemical deposition method. Comparing with the DSSCs with ClO4−-PEDOT/FTO counter electrode, the photocurrent–voltage (I–V) measurement reveals that the photocurrent conversion efficiency (η), fill factor (FF) and short-circuit current density (JSC) of DSSCs with a ClO4−-PEDOT/TiO2/FTO CE increase. The enhanced performances of the DSSCs are attributed to the higher JSC arising from the increase of active surface area of ClO4−-PEDOT/TiO2/FTO CE. Electrochemical impedance spectra (EIS) also indicate that the charge-transfer resistance on the ClO4−-PEDOT/electrolyte interface decreases. Cyclic voltammetry results indicate that the ClO4−-PEDOT/TiO2/FTO electrode shows higher activity towards I3−/I− redox reaction than that of ClO4−-PEDOT/FTO electrode.