The Investigation of the Seebeck Effect of the Poly(3,4-Ethylenedioxythiophene)-Tosylate with the Various Concentrations of an Oxidant

Abstract

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.

Functionalization Strategies of PEDOT and PEDOT:PSS Films for Organic Bioelectronics Applications

“…This intimal electrical connection On the other hand, the influence of the oxidant concentration and the solvent employed for the polymerization on the final features of the polymer film have also been studied. For instance, a lower oxidant concentration was shown to produce smoother films, while the thickness increases with decreasing boiling point of alcoholic solvents (while conductivity remains constant) [28,33].…”

Poly(3,4 ethylenedioxythiophene)‐tosylate—Its synthesis, properties and various applications

“…The areal ratio of S(2p) tosylate /S(2p) thiophene gives a measure of the oxidation level of PEDOT‐Tos 11,32b,35 . Further, the spectral shape of C(1s), O(1s) and S(2p) was modified by the oxidization level of PEDOT‐Tos when exposed into the different pH solution, 38 concentration of oxidant, 39 reducing agent, 11 washing solvents 32b and different solution treatment 35,40 which in turn enhances various properties of the polymer.…”

“…Again addition of copolymer like PEO‐b‐PPO‐b‐PEO BCP, polyurethane (PU) and polyethylene glycol (PEG) to the oxidation polymerization reaction is another modification which was reported recently 32b,48,49 . Even to control the oxidation level in PEDOT‐Tos so as to enhance its structural and electrical properties, two different approaches were adopted, for example, the variation of the concentrations of iron(III) p‐toluenesulfonate solution 39 and the use of reducing agents like tetrakis(dimethylamino) ethylene(TDAE) 11 and L‐ascorbic acid (vitamin C) 40 …”

“…It has been observed that the control of the oxidation level of PEDOT‐Tos using tetrakis(dimethylamino) ethylene (TDAE), 11 aqueous vitamin C solution 40 or variation in concentrations of iron(III) p‐toluenesulfonate hexahydrate with respect to n‐butanol 39 greatly influence the electrical conductivity and thermoelectric power which in turn affect the ZT.…”

“…It was observed that the power factor has a high value at around 20% of oxidation level which again decreases with the increase in the oxidation level. But it again increases and reaches to the maximum value at 80% of oxidation level which is probably due to the increase in the electrical conductivity with oxidation level 11,39 . Treating the PEDOT‐Tos thin films synthesized by both VPP and chemical process by acids and bases is another way to influence the thermoelectric properties.…”