High performance polypyrrole/SWCNTs composite film as a promising organic thermoelectric material

Abstract

Conducting polymer thermoelectric (TE) materials have received great attention due to their unique properties. In this work, polypyrrole (PPy)/single-walled carbon nanotubes (SWCNTs) composite films with improved TE performance have been prepared by chemical interfacial polymerization at the cyclohexane/water interface under a controlled temperature. Attributed to the smooth surface, higher conjugation length and more ordered molecular structure of the interfacial polymerized PPy film, the electrical conductivity can be as high as ∼500 S cm⁻¹. To further enhance the TE properties of PPy, SWCNT was added to construct a PPy/SWCNTs composite. Due to the synergistic effect between the two phases and the energy filtering effect at the interfaces between PPy and SWCNTs, the Seebeck coefficient of the composite enhanced significantly with the increase SWCNTs content. The composite shows an optimal power factor of 37.6 ± 2.3 μW mK⁻² when the content of SWCNTs is 0.8 mg. This value is one of the largest values among the reported PPy based composites fabricated by the chemical polymerization method. The results indicate that interfacial polymerization under a controlled temperature is a promising way to improve the TE performance of conducting polymer based composite materials.