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 interfaces. (c) 2007 The Electrochemical Society.