Enhanced thermoelectric properties of nanostructured n-type Bi2Te3 by suppressing Te vacancy through non-equilibrium fast reaction

Wang, Yuan and Liu, Wei-Di and Shi, XIao-Lei ORCID: https://orcid.org/0000-0003-0905-2547 and Hong, Min and Wang, Li-Jun and Li, Meng and Wang, Hao and Zou, Jin and Chen, Zhi-Gang (2019) Enhanced thermoelectric properties of nanostructured n-type Bi2Te3 by suppressing Te vacancy through non-equilibrium fast reaction. Chemical Engineering Journal. ISSN 1385-8947


Abstract

As one promising low-temperature thermoelectric material, Bi2Te3 suffers from high carrier concentrations beyond the optimal value contributed by excess Te vacancies. In this study, Te vacancies can be effectively suppressed in the n-type nanostructured Bi2Te3 via a non-equilibrium reaction induced by spark plasma sintering. The electron concentration has been greatly reduced from pristinely ~1 × 1020 to ~7 × 1019 cm−3, generating a decent power factor of 12.84 µW cm−1 K−2 at 320 K. Meanwhile, the decreased electronic thermal conductivity due to deteriorated electrical conductivity enables a very low thermal conductivity of 0.48 W m−1 K−1, which ultimately secures a promising peak figure of merit zT of ~1.1 at 420 K and an outstanding average zT of ~1 from 320 to 470 K. Such a high performance is one of the cutting-edge values reported in binary n-type Bi2Te3 so far. Our study provides a new insight into manipulating intrinsic point defects in nanostructured Bi2Te3 thermoelectric materials for achieving higher zT.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published online: 14 November 2019. Permanent restricted access to ArticleFirst version, in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Date Deposited: 03 Mar 2020 23:44
Last Modified: 13 Mar 2020 06:25
Uncontrolled Keywords: thermoelectrics, bismuth telluride, Te vacancy, nanostructure
Fields of Research : 09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Identification Number or DOI: 10.1016/j.cej.2019.123513
URI: http://eprints.usq.edu.au/id/eprint/37906

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