Hot-pressing for improving performance of CNT/conjugated polymer thermoelectric films and power generators

This study demonstrates a post-treatment method for enhancing the thermoelectric power factor of carbon nanotube (CNT)/conjugated polymer nanocomposite films. For the fabrication of the nanocomposite films a mixture of P3HT (50 wt%) and few-walled CNT (50 wt%) in o-dichlorobenzene (oDCB), or a mixture of PEDOT:PSS (50 wt%) and few-walled CNT (50 wt%) in distilled deionized (DDI) water was used. The uniaxial hot-pressing treatment of the as-prepared nanocomposite films resulted in their densification and increased the electrical conductivity and power factor. It was found that the thermoelectric power factor of the CNT/P3HT and CNT/PEDOT:PSS nanocomposite films increased from 150 ± 9 to 217 ± 30 μW m−1K−2, and from 371 ± 44 to 572 ± 92 μW m−1K−2, respectively, after hot-pressing. We fabricated organic thermoelectric generators using the hot-pressed CNT/conjugated polymer nanocomposites and evaluated their capabilities of electrical power generation. The maximum power outputs of the hot-pressed CNT/P3HT and CNT/PEDOT:PSS OTEGs were 46.0 and 36.3 nW, respectively, under a temperature difference of 10 K.