Electrochemical Behavior and Characterization of Polypyrrole-CopperPhthalocyanine Tetrasulfonate Thin Film: Cyclic Voltammetry and In situ Raman Spectroscopic Investigation

摘要

Cyclic voltammetry has shown that polypyrrole thin films doped with copperphthalocyanine tetrasulfonate are electrochemically conducting in the negative potential range where polypyrrole (PPy) in the PPy-CuPcTs film exists as a neutral form. In situ Raman spectroscopy showed that ion transport in the PPy-CuPcTs film was carried out by small cations from the supporting electrolytes during the redox reaction of the PPy. Majority of the CuPcTs of the original doping level still remains in the film after the reduction of the PPy. Large cations, such as tetrabutylammonium and methyl viologen, showed strong effects on shifting the redox potential of the PPy thin film electrodes. A very strong resonance Raman band, which is due to the symmetric stretching of the C=C bond in the neutral form of PPy, disappeared when a PPy thin film electrode was oxidized. Redox potentials of several PPy thin films formed with different anions were calculated by monitoring the intensity change of the Raman band when the electrode potential was changed. The redox potentials obtained by this method are very close to those by cyclic voltammetry.