CHARGE STORAGE IN A SOLUBLE CONDUCTING POLYMER

ESR measurements and spectroscopic studies have been carried out on fi lms of a soluble conducting polymer, poly (3-hexylthiophene) [P3HT], p -doped electrochemically. The nature of the lowest energy charge stora ge configurations, determined by these studies, arc found to be spinle ss bipolarons for both doping methods. The results, when contrasted wi th similar studies performed on P3HT (in solution) and on polythiophen e, suggest that the long alkyl substituents on the thiophene unit of t he P3HT are responsible for some kind of localization phenomenon preva iling in the beta-substituted systems. At temperatures below about 150 K, spins become localized.