Electrochemical construction of ultrathin film composed of quasi two-dimensional porphyrin polymers

Construction of an ultrathin film composed of porphyrin polymer with quasi two-dimensional (2D) structure on a facet of a gold single crystal as the substrate was attempted by the electrochemical polymerization of zinc tetrakis(oligothienyl) porphyrin. In order to produce uniform thin film the polymerization was performed under the adsorption equilibrium by sweeping the potential, and the total electric charge supplied in the polymerization was controlled toward the formation of the monolayer of porphyrin polymer. We also investigated (i) change in the surface structure of the gold crystal substrate under the influence of the applied potential and (ii) morphologies of the polymers depending on the molecular structures of the monomers.