Experimental study of thermoelectric properties of randomly distributed SWCNTs and SiC nanoparticles

In this experimental study we have investigated the thermoelectric (TE) properties of Single wall carbon nanotubes (SWCNTs) and Silicon carbide (SiC) nanoparticles. The nanoparticles were randomly distributed on a nonconductive glass substrate and hot and cold junctions were created using silver epoxy and Alumel (Ni-Al) wire. The carbon nanotubes used were approximately 60% semiconducting and 40% metallic. Voltage (mV), current (μA) and resistance (Ω) were measured across the distributed nanoparticles within 200 °C temperature difference. The Seebeck coefficient for SWCNTs was 0.12 mV/°C whereas SiC nanoparticles showed no TE effect. However, when SWCNTs (at 10, 25 and 50 wt%) were infused into SiC, substantial TE effect was present. Even though the Seebeck coefficient was in a similar range with different SWCNT concentrations, current, resistance and Power factor (P.F.) changed with wt% of nanotubes. Current and P.F. increased with the increased concentration of SWCNTs in the samples. However, resistance slightly decreased with the increase in temperature. Finally, the structures created were analyzed in a SEM (scanning electron microscope). It was revealed that fiber like SWCNTs created randomly distributed network with Nano junctions (NJ) inside the SiC matrix and infused the thermoelectric properties in the combined SiC+SWCNTs material system.