Effect of the electrolyte cations and anions on the photocurrent of dodecylsulphate doped polypyrrole films

Photoelectrochemical and UV-Vis spectroelectrochemical measurements were performed in a three-electrode cell containing dodecylsulphate-doped polypyrrole films as active layers in contact with different aqueous electrolytes. The effect of both cations and anions of the electrolyte on the photocurrent generation and on the absorption spectra of the system was studied. Dynamic photocurrent and absorption spectra measurements performed during the redox cycles of the films show that both cation and anion insertion and deinsertion occurs during the cycles. These results are in agreement with the previously reported redox mechanism proposed for amphiphilic anion doped polypyrrole. Reduced films show cathodic photocurrent at –0.4>E>−0.8 V vs. Ag|AgCl. Photocurrent voltammograms are reproducible after the conditioning of the films and the higher cathodic currents were observed in films with thickness of ∼0.05–0.5 μm.