Thermoelectric power generation using doped MWCNTs

In this paper, the performance of thermoelectric (TE) devices constructed with the TE elements packed with randomly oriented multiwalled carbon nanotubes (MWCNTs) has been presented. B-doped and N-doped MWCNTs were produced using different doping methods and their thermal and thermoelectric properties have been reported. The carrier type and carrier densities of the doped nanotubes were determined using Mott-Schottky analysis. Doping of the MWCNTs resulted in a simultaneous increase in the Seebeck coefficient and a decrease in the thermal conductivity leading to a significant improvement (up to 1900%) of the figure of merit (ZT) of the TE device. The effects of changing packing density, diameter, and length of the MWCNT–TE elements on the performance of the device were investigated. It was observed that the power generated by the TE device depended directly on the ZT of the device. A TE module was constructed by connecting several TE cells in series with alternating p-type and n-type MWCNT–TE elements and the scale-up of power generation as the number of TE cells was increased was examined. This study is expected to help researchers to evaluate and improve the performance of CNT-based TE devices over conventional devices.