Approaches to conducting polymer devices with nanostructures: Photoelectrochemical function of one-dimensional and two-dimensional porphyrin polymers with oligothienyl molecular wire

The nanofabrication of molecular semiconductors for the construction of molecular photoelectronic devices is an important area of research; to this end, we have constructed porphyrin polymers possessing a tailor-made structure. In this paper, we report the photoelectronic function of the porphyrin polymers connected by oligothienyl bridges. One-dimensional porphyrin polymers with various lengths of oligothienyl bridge in the axial direction were synthesized by the electrochemical polymerization of symmetrical bis(oligothienylalkoxy) phosphorus(V)-porphyrin. The conductivity of the polymer was strongly enhanced by photoirradiation, indicating photoinduced carrier formation. The layered sandwich cell of the polymer with polybithiophene showed electric rectifying properties in the dark. Interestingly, photovoltage and photocurrent were observed on photoirradiation. On the basis of these results, a microscopic polymerjunction chip was constructed. Two-dimensional porphyrin polymers containing oligothienyl bridges in the lateral direction were prepared by similar electrochemical oxidation of meso-tetrakis (oligothienyl) porphyrin metal complexes and were fabricated as layered diodes.