Tailoring microstructure and electrical transportation through tensile stress in Bi2Te3 thermoelectric fibers

Bismuth telluride (Bi 2 Te 3 ) has attracted much attention in the field of thermoelectrics since it is one kind of commercial room-temperature thermoelectric material. Herein three kinds of Bi 2 Te 3 thermoelectric fibers with internal tensile stress are fabricated utilizing an optical fiber template method. The effects of internal stress on the microstructure and the electrical transportation of Bi 2 Te 3 thermoelectric fibers are investigated. The Bi 2 Te 3 cores in the fibers are highly crystalline and possess a tensile nanosheet structure with preferential orientation as evidenced by X-ray diffraction and Raman studies. Tensile stress can enhance electrical properties of the fibers. And a paper cup generator covered with 20 pieces of optimized fibers provides a μW-level output power. It is inferred that tensile stress tuning can be an effective tool for the material optimization of thermoelectric performance.