Optimizing Electronic Quality Factor toward High Performance Ge1−x−yTaxSbyTe Thermoelectrics: The Role of Transition Metal Doping

Li, Meng and Sun, Qiang and Xu, Sheng-Duo and Hong, Min ORCID: https://orcid.org/0000-0002-6469-9194 and Lyu, Wan-Yu and Liu, Ji-Xing and Wang, Yuan and Dargusch, Matthew and Zou, Jin and Chen, Zhi-Gang ORCID: https://orcid.org/0000-0002-9309-7993 (2021) Optimizing Electronic Quality Factor toward High Performance Ge1−x−yTaxSbyTe Thermoelectrics: The Role of Transition Metal Doping. Advanced Materials, 33 (40):2102575. pp. 1-8. ISSN 0935-9648


Abstract

Owing to high intrinsic figure-of-merit implemented by multi-band valleytronics, GeTe-based thermoelectric materials are promising for medium-temperature applications. Transition metals are widely used as dopants for developing high-performance GeTe thermoelectric materials. Herein, relevant work is critically reviewed to establish a correlation among transition metal doping, electronic quality factor, and figure-of-merit of GeTe. From first-principle calculations, it is found that Ta, as an undiscovered dopant in GeTe, can effectively converge energy offset between light and heavy conduction band extrema to enhance effective mass at high temperature. Such manipulation is verified by the increased Seebeck coefficient of synthesized Ge1−x−yTaxSbyTe samples from 160 to 180 µV K−1 at 775 K upon doping Ta, then to 220 µV K−1 with further alloying Sb. Characterization using electron microscopy also reveals the unique herringbone structure associated with multi-scale lattice defects induced by Ta doping, which greatly hinder phonon propagation to decrease thermal conductivity. As a result, a figure-of-merit of ≈2.0 is attained in the Ge0.88Ta0.02Sb0.10Te sample, reflecting a maximum heat-to-electricity efficiency up to 17.7% under a temperature gradient of 400 K. The rationalized beneficial effects stemming from Ta doping is an important observation that will stimulate new exploration toward high-performance GeTe-based thermoelectric materials.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
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: 24 May 2022 02:54
Last Modified: 24 May 2022 22:14
Uncontrolled Keywords: figures of merit, GeTe, quality factor, thermoelectrics, transition metal doping
Fields of Research (2008): 10 Technology > 1007 Nanotechnology > 100708 Nanomaterials
09 Engineering > 0912 Materials Engineering > 091203 Compound Semiconductors
09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Fields of Research (2020): 40 ENGINEERING > 4016 Materials engineering > 401603 Compound semiconductors
40 ENGINEERING > 4016 Materials engineering > 401605 Functional materials
34 CHEMICAL SCIENCES > 3403 Macromolecular and materials chemistry > 340301 Inorganic materials (incl. nanomaterials)
40 ENGINEERING > 4018 Nanotechnology > 401807 Nanomaterials
Identification Number or DOI: https://doi.org/10.1002/adma.202102575
URI: http://eprints.usq.edu.au/id/eprint/48494

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