Flexible and free-standing thermoelectric devices prepared from poly(vinylidene fluoride-co-hexafluoropropylene)/graphite nanoplatelet/single-walled carbon nanotube composite films

Abstract In this study, poly(vinylidene fluoride-co-hexafluoropropylene)/carbon composite films with enhanced thermoelectric performance are prepared. A hybrid filler of graphite nanoplatelets (GNPs) and single-walled carbon nanotubes (SWNTs) increase the electrical conductivity as a bridge between neighboring GNPs in the carbon hybrid films. The improved electrical conductivity is due to the purification process performed in an acid solution, which effectively removes the amorphous carbon, additives, and impurities in the carbon fillers. The Seebeck coefficient of the composite films is similarly maintained at approximately 40 μV/K owing to the intrinsic properties of the material. The calculated power factor is considerably increased to approximately 14 μW/mK 2 owing to purification of the SWNTs, which is twice the value of the highest value reported value for freestanding-type thermoelectric materials based on polymer/carbon composites.