New Ternary Arsenides for High-Temperature Thermoelectric Applications

Abstract

Two isostructural materials Mo3(Sb,Te)7 and Re3(Ge,As)7 were synthesized and characterized in our laboratories during the past decade. Both crystallize in the Ir3Ge7 type, possessing the space group $$ Im\bar{3}m $$ . They show excellent potential for thermoelectric energy conversion at high temperatures. Our recent physical properties measurements revealed a higher Seebeck coefficient for the new ternary Re3Sn0.2As6.8, as compared with Re3(Ge,As)7, while the power factors are comparable. Rietveld refinements indicate an increasing unit cell volume with increasing Sn content. It has also been found that intercalation of an additional transition-metal atom (Co, Ni) into the cubic void of Re3(Ge,As)7 can significantly alter the Seebeck coefficient.