Abstract
The electrochemical, optical and magnetic properties of poly(3-hexylthiophene) (PAT-6) in comparison with those of polythiophene (PT) during electrochemical p- and n-type doping have been investigated by cyclic voltammetry, optical absorption spectroscopy and electron spin resonance measurements. The results are discussed in terms of polaron and/or bipolaron models and lead to a better understanding of the electronic levels. Specifically, as the top of the valence band of PAT-6 is located at a higher energy state than that of PT by about 0.3 eV, the p-type dopant in PAT-6 is relatively stable compared with that in PT. However, because the bottom of the conduction band of PAT-6 was evaluated to be located at a higher energy state by about 0.3 eV than that of PT, the n-type doping in PAT-6 is more difficult than in PT.