Electrochemical fabrication of hierarchical thin films consisting of different polythiophenes and change in photoelectric conversion properties with film thickness

Abstract Hierarchical polybithiophene/poly(3,4-ethylenedioxythiophene) films with polybithiophene layers of various thicknesses were prepared on an indium tin oxide glass transparent electrode by sequential electrochemical polymerization. In the presence of methyl viologen as a sacrificial electron acceptor, cathodic photocurrents were generated under monochromatic light irradiation. The irradiation light wavelength dependence of the incident photon-to-electron conversion efficiency changed drastically with the thickness of the polybithiophene layer. The main reason for the change in the photoelectric conversion properties was light absorption by the polybithiophene layer.