Bismuth telluride-based alloys have long been in the spotlight as they show promising ZT and high thermal stability near the room-temperature rigion. Although there are existing fabrication methods, but they all have problems like long processing time, lower sample thermoelectric property. Hence there exists a need to develop material of high thermoelectric properties in room temperature by simple method.

The present work consists of synthesis and characterization of Bi-Te-Sb nanocomposite. Nanocomposite in thermoelectric materials has been proven to be an effective paradigm for optimizing the high thermoelectric performance primarily by reducing the thermal conductivity. In addition, changes in thermal transport properties brought up by adding dopants,material nanostructuring and dispersed phase addition, in the Bi-Te−Sb material for this methodology are measured and discussed.

For the synthesis of p-typeBi-Te−Sb thermoelectric materials, reagent-grade raw materials (>99.99%) were used, and Bi2O3 (>99.99%), TeO2 (>99.99%), and Sb2O3 (>99.99%) powders were used. Bi-Te-Sb composites were fabricated by a high energy ball milling followed by spark plasma sintering process.

Bi-Te-Sb milled powders show agglomerated particles between 100nm and 300nm in size with almost faced or rounded shape. Reduction powders with irrelgularly facetted shape and about 500nm in size. As a field-assisted technique, spark plasma sintering (SPS) enables densification of specimens in a very short period of time compared to other sintering techniques. For high performance thermoelectric material synthesis, SPS is widely used to fabricate nanograin-structured thermoelectric materials by rapidly densifying the nanopowders suppressing grain growth. Phase of powders and bulk were analyzed by X-ray diffraction. The microstructures of powders and bulk were characterized by field emission scanning electron microscopy. Bi-Te-Sb bulk materials were analyzed electrical and thermal transport properties.

The achieved higher ZT value is attributed to the unique nanostructures which increase phonon scattering in the nanostructured materials to effectively reduce thermal conductivity..

Keyword Bi2Te3, Thermoelectric, nanostructure, SPS