Work

Probing the thermoelectric transport properties of n-type Bi 2 Te 3 close to the limit of constitutional undercooling

Year: 2014

Type: article

Abstract: Bulk n-type Bi 2 Te 3 single crystals with optimized chemical composition were successfully prepared by a high temperature-gradient directional solidification method. We investigate the influence of alloy microstructure, chemical composition, and growth orientation on the thermoelectric transport properties. The results show that the composition of single-crystal Bi 2 Te 3 alloy, along the c axis direction, could be slightly tuned by changing the growth rate of the crystal. At a rate of 18 mm/h, the formed Bi 2 Te 3 crystal exhibits good thermoelectric properties. At 300 K, a maximum Seebeck coefficient of −245 μV/K and an electrical conductivity of 5.6 × 10 4 S/m are acquired. The optimal power factor is obtained as 3.3 × 10 −3 W/K 2 m, with a figure of merit of 0.74. It can be attributed to the increased tellurium allocation in the Bi 2 Te 3 alloys, as verified well by the density functional theory calculations.

Source: Chinese Physics B

DOI: 10.1088/1674-1056/23/11/117202

Authors: Song-Ke Feng, Shuang-Ming Li, Heng-Zhi Fu

Institutions: Northwestern Polytechnical University, State Key Laboratory of Solidification Processing

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: bronze

Funders: Northwestern University, National Natural Science Foundation of China, Northwestern Polytechnical University, State Key Laboratory of Solidification Processing