Optimizing Electronic Quality Factor toward High-Performance Ge1- x - y Tax Sby Te Thermoelectrics : The Role of Transition Metal Doping
© 2021 Wiley-VCH GmbH.
| Veröffentlicht in: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 33(2021), 40 vom: 16. Okt., Seite e2102575 |
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| Weitere Verfasser: | , , , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2021
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| Zugriff auf das übergeordnete Werk: | Advanced materials (Deerfield Beach, Fla.) |
| Schlagworte: | Journal Article GeTe figures of merit quality factor thermoelectrics transition metal doping |
| Zusammenfassung: | © 2021 Wiley-VCH GmbH. 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 - y Tax Sby Te 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 Ge0.88 Ta0.02 Sb0.10 Te 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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| Beschreibung: | Date Revised 06.10.2021 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.202102575 |