Synthesis and Thermoelectric Properties of an Sn1-xPbxSb4Te8 Solid Solution Doped with Bismuth

The thermoelectric properties of a solid solution of Sn1 - xPbxSb4Te8 and Sn(1 - x)Pb(x)Sb(4 - y)BiyTe(8) (y = 0.4, 0.8, 1.2) are measured over a wide temperature range (100-800 K). The substitution of Sb atoms with Bi atoms leads to an increase in the thermal emf coefficient and a decrease in the lattice component of thermal conductivity in comparison with the corresponding properties of an Sn1 - xPbxSb4Te8 solid solution. The lower values of lattice thermal conductivity in alloys y = 1.2 compared to an Sn1 - xPbxSb4Te8 solid solution are related to distortions because of the difference of the atomic masses and size of Sb and Bi atoms. With an increase in the Bi content in solid solutions, the lattice thermal conductivity decreases and, accordingly, the thermoelectric efficiency increases. The thermoelectric efficiency of the Sn1 - xPbxSb4 - yBiyTe8 (y = 1.2) sample has the maximum value Z = 3.2 x 10(-3) at 300 K.