We investigated the initial photooxidation mechanism leading to reactive radical formation of polythiophene derivatives by focusing on the differences in the photochemical behaviors of photounstable poly(3-hexylthiophene) (P3HT) and photostable poly(3-octyloxythiophene) (P3OOT). Electron spin resonance measurements revealed that the [P3HT]+· (formed by oxygen doping) decayed, whereas no change was observed in the photostable [P3OOT]+· after light irradiation. Furthermore, the absorption decrease of the [P3HT]+· was suppressed by superoxide dismutase. Therefore, the oxygen dopant is superoxide, which might also initiate the oxidation of P3HT.
- Yoshinori Aoyama
- Toshihiro Yamanari
- Yuji Yoshida
