Functionalizations of Conducting Polymers by Mesoscopically Structural Control and by Molecular Combination of Reactive Moiety

Abstract

This paper contains the following three subjects; (1) in situ fabrication of mesoscopic conducting polymer heterolayers superlattice, (2) functional molecular materials constructions by incorporation of the functional molecule to conducting polymer, (3) one-dimensional photoactive molecule linked with conducting molecular wire. (1) A novel potential programmed electropolymerization method which enables us to fabricate any microscopic depth structures in conducting polymer ultrathin films, such as heterolayers and sloped layers, has been developed. The depth profiles of the heterolayers such as thickness and polymer composition are controlled by applied electrode potential, and not only nanometer order layered structures but also sloped ones have been easily synthesized. Accordingly, this method is aimed at manipulating electric, optical and other various properties specific to the depth structure by changing structural parameters such as polymer composition or doping level of the layers, finally to realize an organic superlattice such as type I and type II heterostructures Esaki et al proposed1). Here, an organic superlattice having the structure-specific properties, including a quantum size effect was realized. (2) By the electrochemical polymerization and/or doping methods, conducting polymers incorporating functional molecules which show the specific function attributed, to the incorporated molecule were presented. (3) One-dimensional phosphorus(V)porphyrin polymers linked with the various length of oligothienyl molecular wire toward the axial direction of the porphyrin ring were synthesized from symmetrical phosphorus(V)porphyrin triads with two oligothienyl axial groups. In the polymers, the phosphorus(V)porphyrin unit which tends to be an electron acceptor acted as a photoinduced hole generator, and the oligothienyl moiety which tends to be an electron donor was able to transfer the positive hole just as molecular electric wire. The conductivity of these donor-acceptor polymers was strongly enhanced by the photoirradiation, indicating that the photoinduced carrier formation and transfer occurs efficiently along the polymeric chain.