Thermoelectric Properties of Carbon Nanotubes

We have investigated the thermoelectric properties of both Singlewall Carbon Nanotubes (SCWNTs) and Multiwall Carbon Nanotubes (MCWNTs). These nanotubes consisted of approximately 60% semiconducting and 40% metallic tubes. Nanotubes were randomly dispersed on a nonconductive glass substrate and thermoelectric properties were tested by creating a temperature difference. Voltage (mV), current (µA) and resistance (Ω) were taken with respect to temperature difference (°C). Seeback coefficient and power factors were also calculated. The seeback coefficient of SWNTs was approximately 0.124±0.008 (mV/ºC). On the other hand, for the MWCNTs that was about 0.06±0.007 (mV/ºC). Moreover, as temperature difference increased resistance decreased for both SWCNTs and MWCNTs; however, SWCNTs showed lower resistance than MWCNTs. The experiment results validated that SWNTs displays better thermoelectric properties than MWNTs.