Enhancement of thermoelectric properties in CuI-doped Bi2Te2.7Se0.3 by hot-deformation

• Published in: Journal of alloys and compounds 2018-01, Vol.731, p.531-536
• Main Authors: Cho, Hyunyong, Kim, Jin Hee, Back, Song Yi, Ahn, Kyunghan, Rhyee, Jong-Soo, Park, Su-Dong
• Format: Article
• Language: English
• Subjects: Bi2Te3; CuI doping; High ZT; Hot deformation; n-type; Thermoelectric
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.10.016

We investigated the thermoelectric properties of CuI-doped Bi2Te2.7Se0.3 compounds, fabricated by a repetitive hot-deformation process. The degree of texture of the materials was enhanced by the number of hot-deformation processings, and experimentally verified by X-ray diffraction measurements. Very interestingly, the enhanced texture induced by the hot-deformation produced a moderate reduction in electrical resistivity by improving electron mobility, while the Seebeck coefficient remained almost unchanged. The corresponding power factor at room temperature was significantly improved, from 3.1 mW m−1 K−2 to 4.1 mW m−1 K−2 after two successive hot-deformation processings, and consequently a high value of ZT of 1.07 was achieved at 423 K. This demonstrates that tuning the texture of Bi2Te3 based materials by multiple hot-deformation processing steps can be an effective approach for increasing ZT. [Display omitted] •We investigated thermoelectric properties the CuI-doped Bi2Te2.7Se0.3 by hot-deformation.•Anisotropic texture is enhanced by hot deformation process.•CuI doping and enhanced texture improves electron mobility.•CuI doping is effective to increase power factor by increasing carrier density.•It achieved high power factor and high ZT 1.07 at 423 K in n-type materials.