Nanostructuring and improved performance of ternary Bi-Sb-Te thermoelectric materials

A ternary (Bi,Sb)(2)Te-3 bulk nanostructured thermoelectric compound has been prepared by a combination of hydrothermal synthesis and hot pressing. It was found that the grain sizes of the hot-pressed bulk sample vary from tens to hundreds of nanometers, which would be favorable to enhance the scattering of both carriers and phonons, resulting in a high Seebeck coefficient with a satisfactory electrical conductivity and a very low thermal conductivity. The highest figure of merit ZT of the nanostructured (Bi,Sb)(2)Te-3 bulk sample reaches 1.28 at 303 K, which is not only remarkably higher than the zone-melted one, but also higher than commercial state-of-the-art Bi2Te3-based materials.