Thermoelectric Properties of p-type (Bi2Te3)0.2(Sb2Te3)0.8 Thermoelectric Material Doped with PbTe

We have investigated thermoelectric properties of p-type Bi-Te thermoelectric material doped with PbTe. The samples (Bi2Te3)0.2(Sb2Te3)0.8+xmass%PbTe(x=0, 0.05, 0.1, 0.3, 0.5) were fabricated by mechanical alloying and spark plasma sintering(SPS) method. The Seebeck coefficient(α), the electric conductivity(σ) and the thermal conductivity(κ) were measured in the temperature range 323-523 K. The α decreased and the σ increased with increasing PbTe content. The dimensionless figure of merit(ZT) were calculated. The maximum point of the ZT shifted toward higher temperature with increasing PbTe content. The maximum ZT of 1.12 was obtained for x=0.3 sample at 373 K.