Photoelectrochemical studies on electrodes coated with polymer-bound porphyrin systems

Chemically modified thin film electrodes were prepared by the electropolymerization technique using zinc(II) 5-(4'-hydroxy)phenyl-10,15,20-triphenylporphine and anthraquinone-2-(1-pyrrole) monomers. The ground and excited state properties of the zinc porphyrin were examined by steady state absorption and emission spectroscopy in order to determine the type of interaction between the different dye molecules present in the polymeric thin films. Photoelectrochemical cells were constructed using polymer-dye-coated electrodes, and the response to light was investigated in air-equilibrated and deaerated conditions. The photopotential, photocurrent, action spectra and i-V curves were recorded. In addition, the activation energy parameters for charge migration were calculated. A mechanism is proposed for the reaction of molecular oxygen at the electrode with the photogenerated species. The migration of the photogenerated charge carriers in different modified electrodes and the role of quinone are discussed. (C) 1997 Elsevier Science S.A.