THE THERMOELECTRIC FIGURE OF MERIT OF THE PBTE - CARBON NANOPARTICLES COMPOSITE
The dependences of the specific electrical conductivity, the thermal conductivity and the thermoelectric figure of merit of the ZT of the semiconductor thermoelectric material of lead telluride on the temperature and concentration of inclusions of carbon nanoparticles were obtained on the basis of the Maxwell theory for the generalized conductivity of an isotropic medium with particle inclusions. Carbon flocculent granules, compacted carbon nanotubes, nanofractal carbon and nanotube carbon are considered as inclusions. The dependences of the specific electrical conductivity on the concentration of inclusions and on the temperature are monotonic in nature with according to calculations. The temperature dependence of the specific thermal conductivity is also monotonic. However, the dependence on the concentration of inclusions is more complex and passes through a minimum at high temperatures. The addition of all types of the considered nano-sized carbon inclusions leads to a decrease in the thermoelectric figure of merit ZT. With an increase in temperature to about 500 K the thermoelectric figure of merit increases. With a further increase in temperature the thermoelectric figure of merit decreases. The dependence of the thermoelectric figure of merit on the concentration of inclusions has a monotonous character in the all considered temperature region.