High-Performance n-Type Bi2Te3 Thermoelectric Fibers with Oriented Crystal Nanosheets

High-performance thermoelectric fibers with n-type bismuth telluride (Bi2Te3) core were prepared by thermal drawing. The nanosheet microstructures of the Bi2Te3 core were tailored by the whole annealing and Bridgman annealing processes, respectively. The influence of the annealing processes on the microstructure and thermoelectric performance was investigated. As a result of the enhanced crystalline orientation of Bi2Te3 core caused by the above two kinds of annealing processes, both the electrical conductivity and thermal conductivity could be improved. Hence, the thermoelectric performance was enhanced, that is, the optimized dimensionless figure of merit (ZT) after the Bridgman annealing processes increased from 0.48 to about 1 at room temperature.