Se-alloying reducing lattice thermal conductivity of Ge0.95Bi0.05Te

Wang, De-Zhuang and Liu, Wei-Di and Shi, Xiao-Lei ORCID: https://orcid.org/0000-0003-0905-2547 and Gao, Han and Wu, Hao and Yin, Liang-Cao and Zhang, Yuewen and Wang, Yifeng and Wu, Xueping and Liu, Qingfeng and Chen, Zhi-Gang ORCID: https://orcid.org/0000-0002-9309-7993 (2021) Se-alloying reducing lattice thermal conductivity of Ge0.95Bi0.05Te. Journal of Materials Science and Technology. ISSN 1005-0302


Abstract

High lattice thermal conductivity of intrinsic GeTe limits the wide applicaion of GeTe-based thermoelectrics. Recently, the optimization of GeTe-based thermoelectric materials has been focusing on reducing lattice thermal conductivity via strengthening phonon scattering. In this study, we systematically studied thermoelectric properties of Se-alloyed Ge0.95Bi0.05Te via theoretical calculations, structural characterizations, and performance evaluations. Our results indicate that Se-alloying can induce dense point defects with mass/radius fluctuations and correspondingly enhance point defect phonon scatteirng of the Ge0.95Bi0.05Te matrix. Se-alloying might also change chemical bonding strength to introduce resonant states in the base frequency of Ge0.95Bi0.05Te matrix, which can strengthen Umklapp phonon scattering. Finally, a decreased lattice thermal conductivity from ∼1.02 W m−1 K−1 to ∼0.65 W m−1 K−1 at 723 K is obtained in Ge0.95Bi0.05Te1-xSex pellets with increasing the Se content from 0 to 0.3. A peak figure of merit value of ∼1.6 at 723 K is achieved in Ge0.95Bi0.05Te0.7Se0.3 pellet, which is ∼77% higher than that of pristine GeTe. This study extends the understanding on the thermoelectric performance of GeTe.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published online: 6 October 2021. Permanent restricted access to Publisher's Accepted 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: 08 Oct 2021 01:15
Last Modified: 17 Nov 2021 04:17
Uncontrolled Keywords: thermoelectric; GeTe; Se-alloying; lattice thermal conductivity
Fields of Research (2008): 09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Fields of Research (2020): 40 ENGINEERING > 4016 Materials engineering > 401605 Functional materials
Identification Number or DOI: https://doi.org/10.1016/j.jmst.2021.08.020
URI: http://eprints.usq.edu.au/id/eprint/43758

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