Hydrothermally synthesized and hot-pressed Bi 2(Te,Se) 3 thermoelectric alloys

Abstract

Bi 2(Te,Se) 3 nanopowders have been synthesized by an aqueous chemical route in an open beaker at 70 °C for 72 h. The powders were hot-pressed under a pressure of 50 MPa at 250 °C for 15 min. X-ray diffraction and energy-dispersive analysis of X-rays show that both the powders and the hot-pressed samples are mainly composed of Bi 2(Te,Se) 3 and Te. Scanning electron microscopy observation shows that the crystallite size is smaller than 100 nm in the powders and the width of the polygonal prismatic rods is about 100 nm in the hot-pressed sample. The alloys were doped with SbI 3 before hot pressing. The SbI 3-doped sample shows a higher electrical conductivity and a lower Seebeck coefficient, indicating that SbI 3 is electrically actively incorporated into the alloys.