Effects of Pb doping on the Thermoelectric Properties of Tl8.67PbxSb1.33-xTe6 Materials

We present the effects of lead doping on the thermoelectric properties of Tellurium Telluride, prepared by solid state reactions in an evacuated sealed silica tubes. Structurally, all these compounds were found to be phase pure as confirmed by the x-rays and energy dispersive spectroscopy analysis. The Seebeck co-efficient S was measured for all these compounds which show that S increases with increasing temperature from 295 to 550 K. The Seebeck coefficient is positive for the whole temperature range, showing p-type semiconductor characteristics. Complex behavior of Seebeck coefficient for lead doped compounds has been observed that at room temperature, the values of S for these compounds have complex behavior, first S decreasing with increase in lead concentration, and then S increases with increase in lead contents up to Similarly the electrical conductivity and the power factors have also complex behavior with lead concentrations. The power factor observed for these compounds are increases with increase in the whole temperature range studied here.