Improving the thermoelectric power factor of CNT/PEDOT:PSS nanocomposite films by ethylene glycol treatment

Abstract

This study investigates a post treatment method for improving the thermoelectric properties of carbon nanotube (CNT)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) nanocomposite films. Ethylene glycol (EG) treatment is performed by immersing the as-prepared CNT/PEDOT:PSS nanocomposite films in EG for 1 h followed by annealing at 140 °C for 10 min. Non-complexed PSS chains could be effectively removed using the EG treatment, resulting in a decrease in inter-bundle distances in the nanocomposite films. This drastically increases the electrical conductivity of the PEDOT:PSS matrix. EG-treated nanocomposite films with 20 wt% CNTs exhibited the highest power factor of 151 ± 34 μW m⁻¹ K⁻² among all the prepared samples. Our results indicate that the EG treatment is a promising method for fabricating cost-effective, high-performance thermoelectric CNT/PEDOT:PSS nanocomposite films. We fabricated an organic thermoelectric generator using EG-treated CNT/PEDOT:PSS nanocomposite patterns and evaluated its electric power generation capabilities.