Fully Organic Nanocomposites with High Thermoelectric Power Factors by using a Dual‐Stabilizer Preparation
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Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The thermoelectric properties of fully organic nanocomposites were investigated, for which meso-tetra(4-carboxyphenyl) porphine (TCPP) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were used as instrinically conductive and semiconducting stabilizers, respectively. The electrical conductivity (σ) of these dual-stabilizer organic composites increased to approximately 9500 S m−1 as the concentrations of both the multiwalled carbon nanotubes (MWNTs) and PEDOT:PSS were increased. The thermopower (or Seebeck coefficient, S) and thermal conductivity, however, remained relatively unaffected by the increase in concentration (≈40 μV K−1 and ≈0.12 W m−1 K−1, respectively). Replacing MWNTs with double-walled carbon nanotubes (DWNTs) increased σ and S to approximately 96 000 S m−1 and 70 μV K−1, respectively, at 40 wt % DWNTs. This study suggests that σ and S can be simultaneously tailored by using multiple stabilizing agents to affect the transport properties of the junctions between nanotubes. Combining semiconducting and intrinsically conductive molecules as CNT-stabilizers has led to a power factor that is among the best for a completely organic, free-standing film (≈500 μW m−1 K−2). These flexible, segregated-network nanocomposites now exhibit properties that rival the more conventional inorganic semiconductors, particularly when normalized by the mass.
author list (cited authors)
Moriarty, G. P., Briggs, K., Stevens, B., Yu, C., & Grunlan, J. C.