Preparation and thermoelectric properties of Bi2SexTe3−x bulk materials.

Bi 2 Te 3 and Bi 2 Se 3 nanoplates were synthesized by a microwave-assisted wet chemical method, and Bi 2 Se x Te 3−x (x=1, 2, 3) bulk nanocomposites were then prepared by hot pressing the Bi 2 Te 3 and Bi 2 Se 3 nanoplates at 80 MPa and 723 K in vacuum. The phase composition and microstructures of the bulk samples were characterized by powder X-ray diffraction and field-emission scanning electron microscopy, respectively. The electrical conductivity of the Bi 2 Se x Te 3−x bulk nanocomposites increases with increasing Se content, and the Seebeck coefficient value is negative, showing n-type conduction. The absolute Seebeck coefficient value decreases with increasing Se content. A highest power factor, 24.5 µWcm −1 K −2 , is achieved from the sample of x=1 at 369 K among the studied samples. [ABSTRACT FROM AUTHOR]