E.S.R. studies of poly(thiophene) doped with AsF5 and iodine are reported. At high AsF5 concentration (∼ 24 mole % AsF5), we find a temperature-independent Pauli spin susceptibility indicative of a metallic density of states. Measurements on iodine-doped samples in the intermediate regime (below 10 mole % I3-) indicate Curie spin concentration independent of the doping level, but significantly larger than in pristine poly(thiophene). The relaxation of these Curie spins is relatively fast (faster by several orders of magnitude with respect to that of pure poly(thiophene)) and temperature dependent. These features are discussed in terms of charge storage in polarons and bipolarons, and the possibility of formation of a finite density of electronic states in the gap.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry