Optimization of the thermopower of the antimonide Mo3Sb7 by a partial Sb/Te substitution

The binary antimonide Mo3Sb7 is metallic with poor thermoelectric properties. Since band structure calculations indicated a possible change to semiconducting behavior by adding two more valence-electrons, the substitutional series Mo3Sb7 − δTeδ has been investigated. Te atoms can replace up to 2.3 Sb atoms in Mo3Sb7 without noticeable structural changes. This substitution leads to a dramatic enhancement in the thermopower, indicating that in fact semiconducting properties have been achieved with the synthesis of Mo3Sb5Te2.