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  • Thermoelectric (TE) energy conversion with nontraditional organic materials is promising in wearable electronics and roll-to-roll manufacturing because of mechanical flexibility, lightweight, and easy processing. Although typical organic materials have a benefit of low thermal conductivity that creates a large temperature gradient, relatively small thermopower (or Seebeck coefficient) often requires copious number of TE legs to fabricate practical TE devices. Here, we show that hybrids of poly(3,4-ethylenedioxythiophene)-tosylate (PEDOT-Tos) and carbon nanotubes (CNTs) can produce extremely large thermopower, 14 mV/K at room temperature by a chemical reduction. With decent electrical conductivity, an extraordinary power factor of 1200 W/m K2 at room temperature was observed. The large power factor could be attributed to prominent dual electronic and ionic conduction, which islikely to be promoted by embedding the CNTs in PEDOT due tothe improvementin thecarrier mobility, in comparison with the inferior and widely varyingTE properties of PEDOT-only samplesin the literature. While a higher CNT concentration gave a larger electronic contribution, a longer reduction or a lower CNT concentration provided a larger ionic contribution. Meanwhile, well-separated CNTs created CNT junctions intervened by PEDOT-Tos, suppressing the thermal transport. Further research utilizing the high TE responses could greatly help to develop practical wearable and/or mass-producible thermal energy harvesting and storage devices.

published proceedings

  • ACS Appl Mater Interfaces

author list (cited authors)

  • Choi, K., Kim, S. L., Yi, S., Hsu, J., & Yu, C.

publication date

  • January 1, 2018 11:11 AM