Thermoelectric properties of p-type Pb-doped Bi85Sb15−xPbx alloys at cryogenic temperatures

In this study we have investigated the effect of the Pb on the thermoelectric propertied of Bi–Sb alloy with different Pb-content. The Pb-doped Bi85Sb15−xPbx (x = 0, 0.5, 1, 2, 3) alloys were synthesized by mechanical alloying followed by pressureless sintering. The crystal structure was characterized by X-ray diffraction. The Seebeck coefficients, electrical conductivities, and thermal conductivities were measured in the temperature range of 77–300 K. The results show that all the Pb-doped alloys are p-type thermoelectric materials in the whole measurement temperature range. A minimum thermal conductivity of 1.7 W/mK was obtained for Bi85Sb12Pb3 sample at 150 K. A maximum ZT value of 0.11, which is higher than those previous reported, was obtained for Bi85Sb14Pb1 at 210 K.

► A series of Bi85Sb15−xPbx alloys were synthesized by a relatively easy powder-based process. ► The measurement of the Seebeck coefficients showed that all the doped alloys are p-type. ► The lattice thermal conductivities were reduced by doping the element of Pb. ► A maximum ZT value of 0.11 has been obtained, which is higher than previous report.