Fabrication and Photocurrent Generation Properties of Insoluble Hierarchical Polythiophene Thin Films Prepared by Sequential Electrochemical Polymerization

Insoluble hierarchical polybithiophene/poly(ethylenedioxythiophene) thin films with a double-layered structure were prepared on an indium tin oxide transparent electrode by sequential electrochemical polymerization. The formation of the hierarchical structure was supported by the transmission absorption spectra and Raman scattering spectra of the double-layered polythiophene thin films. In the presence of residual oxygen as an electron acceptor, light irradiation on the polythiophene-modified electrodes generated stable cathodic photocurrents. A broad peak at approximately 440 nm corresponding to the absorption of neutral polythiophene was observed in the incident photon to current conversion efficiency profile of the polybithiophene/poly(ethylenedioxythiophene)-modified electrode. The photocurrent density of the polybithiophene/poly(ethylenedioxythiophene)-modified electrode was higher than that of the poly(ethylenedioxythiophene)-modified electrode.