Photoelectrochemical Polymerization of Pyrrole on TiO2 and Its Application to Conducting Pattern Generation

Abstract

Polymerization of pyrrole occurred on an irradiated surface of semiconductor electrode in aqueous solutions of pyrrole, when the electrode potential was set between −0.6 and +1.5V vs. SCE. The conductivity of deposited polypyrrole film (as grown, in the doped state) was ca. 1S cm−1. Electrochemical undoping of the film gave conductivity of . The deposition rate for the photoelectrochemical polymerization, 0.6 μm per 100 mC cm−2, was three times that for electrochemical polymerization, 0.2 μm per 100 mC cm−2. From the relationship between the charge passed through the circuit and the absorbance of the film, it was revealed that the current efficiency for the photoelectrochemical polymerization and that for the electrochemical polymerization are almost the same. It was concluded that coarseness and the relatively low doping level of the film were the reasons for the relatively low conductivity of the photoelectrochemically deposited films. Conducting polypyrrole patterns with a line width of 45 μm were formed on the electrode surface by area selective irradiation of the electrode.