Photoelectrochemical Synthesis of Polypyrrole on Anodic Ta2O5 Films

Polypyrrole film was photoelectrochemically grown on insulating Ta2O5 anodic film in acetonitrile solution. A characterization by photocurrent spectroscopy PCS of metal/oxide/polypyrrole interface was carried out. The PCS results suggest that a metallic-like PPy is formed under illumination at constant anodic potential. By polarizing the polypyrrole at cathodic potentials a photocurrent spectrum typical of p-type semiconducting film was recorded. A scanning electron microscopy study of PPy surfaces solution side and oxide side allowed us to obtain information on the morphology of the polymer as well as a rough estimate of the film thickness and of the diameter of PPy globules at the two int…