Electrical and Optical Properties of Substituted Heterocyclic Conducting Polymers

치환 복소환 도전성 고분자의 전기.광학적 성질

Electrical conductivity of poly (3-alkylthiophene) derivatives with substituted long alkyl chain such as poly (3-butylthiophene), poly (3-hexylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), and poly (3-docosylthiophene) increases with increasing temperature. However, after attaining a maxiumum value, it decreases with further temperature increase. Hysteresis is also observed in the temperature dependence of conductivity and absorption spectra. The absorption spectra also changes rapidly at the phase transition. These phenomena are discussed in terms of the increase of the energy band gap in the liquid states due to the decrease of co-planarity of thiophene rings accompanied by remarkable conformation changes.