ELECTROCHEMICAL POLYMERIZATION OF OLIGOTHIOPHENE DERIVATIVES AND THEIR DOPING PROPERTIES

Preparation of high-quality conducting poly(trans-TTTE) and poly(trans -BTTTE) by the electrochemical polymerization of oligothiophene deriva tives such as hene-2-yl)-(2,2':5'2''-terthiophene-5-yl)ethylene, trans -TTTE, and hene-5-yl)-(2,2':5'2''-terthiophene-5-yl)ethylene, trans-BT TTE have been carried out. Evidence for electrochemical p-type doping of poly(trans-TTTE) and poly(trans-BTTTE) is obtained from in situ mea surements of the cyclic voltammetry, optical absorption spectroscopy a nd electron spin resonance. These results are tentatively explained in terms of a conformation change in the molecular structure, such as a difference in the torsion angle between neighboring thiophene rings du e to the introduction of vinylene groups and are discussed in terms of polaron and/or bipolaron model.