High Performance α-MgAgSb Thermoelectric Materials for Low Temperature Power Generation

Bi2Te3 based alloys have long been the best and most unique thermoelectric materials for power generation below 550 K. Their substitutes with abundantly available elements are highly desirable due to the scarcity of Te element. In this work the band structure calculation of the α-MgAgSb compound shows a narrow gap characteristic. Highly pure α-MgAgSb is obtained by carefully controlled processing. The samples exhibit an intrinsically low thermal conductivity due to the unique crystal structure. A high zT of ∼1.1 at 525 K is achieved in the In doped α-MgAgSb with the optimal carrier concentration of 8–9 × 1019 cm–3, comparable to that of Bi2Te3 based alloys. Considering the abundantly available constituent elements, the present results demonstrate that α-MgAgSb is a promising candidate for low-temperature (RT–550 K) power generation.