Solvothermal synthesis and thermoelectric properties of lanthanum contained Bi–Te and Bi–Se–Te alloys

Abstract Novel nano-sized lanthanum contained Bi 2 Te 3 and Bi 2 Se 0.3 Te 2.7 powders have been synthesized in ethanol at 150 °C for 24 h via solvothermal processes. It was found that alloying of lanthanum in both Bi 2 Te 3 and Bi 2 Se 0.3 Te 2.7 does not change their crystal structures. The maximal dimensionless figure of merit measured is about 0.11 for La–Bi 2 Se 0.3 Te 2.7 at 450 K. However, the very low thermal conductivity of 0.4–0.5 W (m K) −1 and the moderate Seebeck coefficient of about 170 μV K −1 indicate the potential to improve the thermoelectric properties of the material by doping optimization.