Thermoelectric Properties of Scandium Sesquitelluride

Rare-earth (RE) tellurides have been studied extensively for use in high-temperature thermoelectric applications. Specifically, lanthanum and praseodymium-based compounds with the Th₃P₄ structure type have demonstrated dimensionless thermoelectric figures of merit (zT) up to 1.7 at 1200 K. Scandium, while not part of the lanthanide series, is considered a RE element due to its chemical similarity. However, little is known about the thermoelectric properties of the tellurides of scandium. Here, we synthesized scandium sesquitelluride (Sc₂Te₃) using a mechanochemical approach and formed sintered compacts through spark plasma sintering (SPS). Temperature-dependent thermoelectric properties were measured from 300⁻1100 K. Sc₂Te₃ exhibited a peak zT = 0.3 over the broad range of 500⁻750 K due to an appreciable power factor and low-lattice thermal conductivity in the mid-temperature range.