Modulating carrier transport for the enhanced thermoelectric performance of carbon nanotubes/polyaniline composites

The typical inverse proportion of electrical conductivity and Seebeck coefficient is a great challenge to optimize power factor of thermoelectric (TE) materials. Based on single wall carbon nanotubes (SWCNT)/polyaniline (PANI) composite film, a facile and convenient partial dedoping process is proposed to modulating charge carrier transport and optimizing TE parameters by ammonium hydroxide treatment, in which the Seebeck coefficient is improved without significantly sacrificing electrical conductivity. This is attributed to the existence of CNT interconnected network that facilitates effective charge transport within the composites even though the carrier channels in PANI are deteriorated after base treatment as PANI chains structure transfers from benzenoid rings to quinoid. With properly modulating the charge transport by modifying dedoping process, SWCNT/PANI composite films exhibit enhanced power factor of 345 μW m−1 K−2 from 234 μW m−1 K−2 of pristine composites, super to most of CNT/PANI composites ever reported. Furthermore, a flexible TE generator composed of this material was fabricated, which generates high output power of 1.11 μW. With the advantages of low cost and facile processing, this strategy shows potential application to improve TE performance of organic composites.