High temperature thermoelectric properties of Mo₃Sb_7-xTe_x for x = 1.6 and 1.5

We have prepared and measured the electrical resistivity, Seebeck coefficient and thermal conductivity of the titled compounds in the 300-1050 K temperature range. The results show that both members of the solid solution are heavily doped semiconductor with a figure of merit zT reaching 0.80 at 1050 K for x = 1.6. Higher values of x resulted in multi phase samples. The heavily doped semiconducting nature of the materials is consistent with theoretical predictions based on valence-electron count (VEC). The flexible nature of the crystalline structure, range of VEC attainable, and existence of intercalation sites are discussed as a way to enhance the thermoelectric properties of materials of this particular structure type.