Sonochemical synthesis of nanocrystalline Bi 2Te 3 thermoelectric compounds

Abstract

Nanocrystalline Bi 2Te 3 thermoelectric compounds have been synthesized by sonochemical methods at 70 °C using Te and BiCl 3 as the reactants, NaBH 4 as the reductant and NaOH as the pH-value controller. The samples were characterized by X-ray diffraction and transmission electron microscopy. It is found that the addition of EDTA chelator can suppress the formation of the Bi 2Te 3 phase. The prepared powders consist of granular and flake nano-particles. The size of the particles are very fine arising from ultrasound effect, about 10∼20 nm. The possible formation mechanism of Bi 2Te 3 is proposed.