Beneficial influence of Ru on the thermoelectric properties of Mo3Sb7

Abstract

Zintl phases have recently been identified as potential thermoelectric materials typified by the discovery of a high thermoelectric figure of merit in the Yb14MnSb11 compound above 1000 K. We report on the synthesis and the thermoelectric properties measurements over a wide temperature range (300–1000 K) of other Zintl phases exhibiting a complex crystalline structure, namely, Mo3Sb7 and its related compounds Mo3−xRuxSb7. While the binary compound displays low figure of merit values due to its metallic nature, we show that the partial substitution of Mo by Ru significantly improves its value to reach 0.45 at 1000 K in Mo2.2Ru0.8Sb7.