Title: Thermoelectric properties and conduction mechanism of conductive polythiophenes

Authors: Yoshikazu Shinohara; Yukihiro Isoda; Kentaro Hiraishi; Akito Masuhara; Hidetoshi Oikawa

Addresses: National Institute for Materials Science, I-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan. ' National Institute for Materials Science, I-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan. ' Precision Processing Materials Laboratories, JSR Corporation, 100, Kawajiri-cho, Yokkaichi, Mie, 510-8552 Japan. ' Graduate School of Science and Engineering, Department of Organic Device Engineering, Yamagata University, Yamagata 992-8510, Japan. ' Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 Japan

Abstract: In this study, we synthesised conductive polymers of polythiophene series and evaluated their thermoelectric properties in the temperature range from 88 K to 350 K. Poly-hexylthiophenes showed a conduction mechanism of the nearest-neighbour distance hopping (NDH) in the measured temperature range, while the main conduction mechanism of polythiophenes was the variable range hopping (VRH). Only polythiophenes with low electrical conductivity (such as 0.02 S/cm) presented NDH at temperatures of below 200 K. The conduction mechanism is changed by the distance between the thiophene main chains and the kinetic energy of carriers.

Keywords: thermoelectric materials; conductive polymers; conduction mechanisms; conductive polythiophenes; low electrical conductivity.

DOI: 10.1504/IJMPT.2011.044915

International Journal of Materials and Product Technology, 2011 Vol.42 No.1/2, pp.66 - 73

Published online: 07 Mar 2015 *

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