Electro-optical and electrochemical properties of poly(2-ethynylthiophene)

A polyacetylene having thiophene substituent, poly(2-ethynylthiophene), was prepared by WCl6Ph4Sn catalyst system in high yield. The chemical structure of polymer was characterized by various instrumental methods to have polyacetylene backbone with 2-thienyl substituents. The 1H NMR spectrum indicated that the present polymer seems to have trans polyacetylene microstructure majorly. The photoluminescence (PL) spectra of poly(2-ethynylthiophene) showed that the photoluminescence peak is located at 456 nm, corresponding to a photon energy of 2.72 eV. The cyclic voltamograms of poly(2-ethynylthiophene) exhibited irreversible electrochemical behaviors between the doped and undoped peaks. It was found that the kinetics of the redox process of polymer is controlled by the diffusion process in this electrochemical cell system.