Poly(3,4-ethylenedioxythiophene)-tosylate (PEDOT-Tos) can be synthesized through an in situ polymerization and doping process with iron(III) p-toluenesulfonate hexahydrate as an oxidant. Both the Seebeck coefficient and the electrical conductivity were modified by varying the concentration of the oxidant. We investigated the effects of varying the concentration of the oxidant on the particle sizes and doping (oxidation) levels of PEDOT-Tos for thermoelectric applications. We demonstrated that an increase in the oxidant enabled an expansion of the particle sizes and the doping levels of the PEDOT-Tos. The modification of the doping levels by the concentration of the oxidant can provide another approach for having an optimal power factor for thermoelectric applications. De-doping of PEDOTs by reduction agents has been generally investigated for changing its oxidation levels. In this study, we investigated the effect of the concentration of the oxidant of PEDOT-Tos on the oxidation levels, the electrical conductivities and the Seebeck coefficients. As loading the oxidant of PEDOT-Tos, the Seebeck coefficient was compromised, while the electrical conductivity increased.
Keywords: conjugated polymer; doping concentration; seebeck effect.