Investigation of organic thermoelectric materials using potential‐step chronocoulometry: Effect of polymerization methods on thermoelectric properties of poly(3‐hexylthiophene)

Abstract

To establish the correlation between the thermoelectric properties of conducting polymers and their doping levels, we have utilized the potential-step chronocoulometry for the quantitative estimation of the doping levels. In this paper, three types of poly(3-hexylthiophene)s synthesized by different polymerization methods were investigated. The electrical conductivities and the Seebeck coefficients of poly(3-hexylthiophene)s with various doping levels were measured and plotted against the doping level. It was found that the electrical conductivity linearly increased with increasing the doping level in the range of 1-10%, and then saturated. On the other hand, the relationship between the Seebeck coefficient and the doping level showed a good linearity in all the polymers.

Thermoelectric Properties of Conductive Freestanding Films Prepared from PEDOT:PSS Aqueous Dispersion and Ionic Liquids

“…To analyze the above-mentioned change in detail, the number of positive charges introduced into the film was quantified by potential-step chronocoulometry. − In this method, the polymer film was electrochemically reduced to a neutral state by applying a sufficiently negative potential to the PEDOT film, which was originally present in the oxidized state. The number of electrons injected from the electrode into the polymer film was monitored as an electrical quantity by a coulometer, and the number of positive charges per unit volume in the film was accurately determined.…”

Recent progress of poly(3-hexylthiophene)-based materials for thermoelectric applications

“…Interestingly, the measured conductivity values show no obviously close link to the channel length of the 4-line electrodes and are independent of the film thickness of the deposited P3HT film. Imae et al 139 utilized the potential-step chronocoulometry for the quantitative estimation of the doping levels of P3HT with tetraethylammonium perchlorate (TEAP). Their results indicate that the electrical conductivity shows a linearly increasing trend with the increase in doping level in the range of 1–10%.…”

Reduction of Graphene Oxide Using an Environmentally Friendly Method and Its Application to Energy-Related Materials

“…Organic thermoelectric materials using conducting polymers (polythiophene and polyaniline) and nanocarbon compounds (carbon nanotubes and graphene) have been attracting attention for their application to the recovery of unused heat. We have also been working on the development of thermoelectric materials based on polythiophenes with various molecular structures [25][26][27][28][29][30][31] and their composites with carbon nanotubes [32]. As part of these studies, we also investigated the thermoelectric properties of the erGO/PAn composite film prepared by the method shown above.…”