Facile development of carbon nanotube (CNT)-based flexible thermoelectric materials for energy-harvesting applications

In this study, we investigate the thermoelectric properties of functionalized multi-walled carbon nanotubes (F-MWCNTs) dispersed over a flexible substrate through a facile vacuum filtration route. To improve their interfacial adhesion and dispersion, F-MWCNTs underwent hot-pressing. The heat-treatment has improved the nanotubes' connections and subsequently reduced porosity as well, which results in an increasing electrical conductivity upon increasing temperature of hot-pressing. Thermoelectric power factor (PF) value was greatly increased upon simultaneous heating and pressing of the CNTs and a highest PF value of 3.17 μW m⁻¹ K⁻² at 398 K, has been achieved, which is about 400% higher than that of the as-deposited CNTs without hot pressing. The current study presents a prototype for CNT-based flexible thermoelectric devices which opens up an avenue for the deployment of CNTs into flexible electronics.