Integrative characterization of the thermoelectric performance of an individual multiwalled carbon nanotube

Carbon nanotube-based organic composites and carbon nanotube networks are important flexible and lightweight thermoelectric materials. Characterization of the thermoelectric performance of individual carbon nanotubes is of vital importance for exploring the coupling mechanism between carbon nanotubes and organic composites, and proposing further improvement measures. The thermoelectric performance of an individual multiwalled carbon nanotube with a diameter of 66 nm has been comprehensively studied by applying our T-type method from 260 K to 420 K, using the same measurement configuration. The figure of merit increases from 4.84 × 10^-8 to 1.32 × 10^-6 on increasing the temperature, which is smaller than previous experimental results on carbon nanotube samples. The thermal conductivity increases from 706 W m^-1 K^-1 at 260 K to 769.3 W m^-1 K^-1 at 320 K, and then stays nearly constant until 420 K. The phonons dominate the thermal transport. The electrical conductivity exhibits thermally activated carrier generation and transport with an energy barrier of 194.5 meV. The Seebeck coefficient is in the range of 29.4-41.0 μV K^-1 and tends to decrease with temperature.