Effect of Carbon Nanotubes on Thermoelectric Properties in Zn0.98Al0.02O

Thermoelectric oxides can provide the advantage of high-temperature stability in oxygen-containing atmospheres. It is known that the incorporation of multiwalled carbon nanotubes (mw-CNT) can change the thermoelectric as well as the structural properties of oxides. Here, we report the influence of mw-CNT on the thermoelectric properties of Al-doped ZnO (AZO). The preparation of the mw-CNT-added AZO was done using an ultrasonic mixing of the starting materials followed by a spark plasma sintering process under vacuum. The Seebeck coefficient S, thermal conductivity k and electrical conductivity sigma were determined in the temperature range between 300 K and 900 K. It was observed that the thermal conductivity is significantly reduced by the incorporation of the mw-CNT. At the same time, the electrical conductivity is increased by a factor of 21 from 8700 S/m to 190,000 S/m. The Power factor PF = S-2 sigma indicates that the addition of mw-CNT improves the thermoelectric properties of Al doped ZnO in comparison to the reference sample prepared with same process but without mw-CNT.