Low potential electropolymerization of anisotropic conductive polythiophene films and fabrication of electrical devices

The Complexation of thiophene with a Lewis acid with moderate acidity as a solvent, such as BF3-ethyl ether (BFEE) remarkedly lowered the electrochemi cal polymerization potential. The positively charged metal surface of elect rode in the process of electrochemical deposition enhanced the coordination interaction between pi-electrons of thiophene unit and the metal, which ma kes thiophene rings lie parallel to the surface of electrode, resulting in a highly ordered polymeric structure. Because of the large intra-chain tran sfer integrals, the transport of charge is believed to be principally along the conjugated chains, which is much greater than the inter-chain hopping. The specific electrical resistance across the polythiophene film thickness is more than 10(4) times than that along the surface plane of the film. In this paper we review the recent development of polymerization technique by low potential electrochemical method performed in our lab and several elec trical devices in which the compact polythiophene films, such as anionic an d cationic sieves, and laminate film junction of undoped polythiophene deri vatives were used.