Electrochemical synthesis and electronic properties of poly(3,4-dibutyl-α-terthiophene)

Abstract

Electrochemically prepared poly(3,4-dibutyl-α-terthiophene) has been investigated and the relationship between the electronic properties, the chemical structure of the monomer and the electrolyte used during the electropolymerization was studied. Doping studies were carried out with various electrolytes. We have electrochemically oxidized (p-doping) and reduced (n-doping) thin films of this polymer on platinum electrode under the same electrochemical conditions. We find that the films show a reversible oxidation wave yielding an electrically conducting polymer and a reversible reduction wave which is sensitive to the nature of the electrolyte. A value for the band gap derived electrochemically compares well with that obtained by optical absorption measurements and X-ray photoelectron spectroscopy. The electrical conductivity varies by 10 12 S cm −1 between the doped and undoped states of the polymer. The temperature-independent magnetic susceptibility above 100 K is consistent with the conducting properties of this polymer. The electrochemically prepared material is compared with the chemically prepared one using the same monomer.