Significant enhancement in the Seebeck coefficient and power factor of thermoelectric polymers by the Soret effect of polyelectrolytes.

Autor: Guan, Xin, Cheng, Hanlin, Ouyang, Jianyong
Zdroj: Journal of Materials Chemistry A; 10/28/2018, Vol. 6 Issue 40, p19347-19352, 6p
Abstrakt: Intrinsically conductive polymers are promising as next-generation thermoelectric (TE) materials. They have high electrical conductivity but a low Seebeck coefficient. On the other hand, polyelectrolytes have a high Seebeck coefficient but very low electrical conductivity. Mixtures of conductive polymers with polyelectrolytes exhibit a low power factor. In this work, a polyelectrolyte, poly(4-styrenesulfonic acid) (PSSH) or poly(sodium 4-styrenesulfonate) (PSSNa), is coated on a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film instead of forming a mixture. The polyelectrolyte can enhance the Seebeck coefficient while not remarkably affecting the electrical conductivity of PEDOT:PSS, and thus significantly enhance the TE properties. At 100% relative humidity (RH), the PEDOT:PSS film coated with PSSH exhibits a power factor of 401 μW m−1 K−2 with a Seebeck coefficient of 43.5 μV K−1 and an electrical conductivity of 2120 S cm−1. This power factor is higher than that of PEDOT:PSS mixed with PSSH by several orders of magnitude. In addition, these samples provide a stable and continuous output voltage under a temperature gradient. The enhancement is ascribed to the energy filtering of the charge carriers of PEDOT:PSS arising from the Soret effect of the ions in the polyelectrolyte layer. [ABSTRACT FROM AUTHOR]
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