Realizing zT of 2.3 in Ge1−x−ySbxInyTe via Reducing the Phase-Transition Temperature and Introducing Resonant Energy Doping
Article
Article Title | Realizing zT of 2.3 in Ge1−x−ySbxInyTe via Reducing the Phase-Transition Temperature and Introducing Resonant Energy Doping |
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ERA Journal ID | 4865 |
Article Category | Article |
Authors | Hong, Min (Author), Chen, Zhi-Gang (Author), Yang, Lei (Author), Zou, Yi-Chao (Author), Dargusch, Matthew (Author), Wang, Hao (Author) and Zou, Jin (Author) |
Journal Title | Advanced Materials |
Journal Citation | 30 (11), pp. 1-8 |
Article Number | 1705942 |
Number of Pages | 8 |
Year | 2018 |
Publisher | John Wiley & Sons |
Place of Publication | Germany |
ISSN | 0935-9648 |
1521-4095 | |
Digital Object Identifier (DOI) | https://doi.org/10.1002/adma.201705942 |
Web Address (URL) | https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201705942 |
Abstract | GeTe with rhombohedral-to-cubic phase transition is a promising lead-free thermoelectric candidate. Herein, theoretical studies reveal that cubic GeTe has superior thermoelectric behavior, which is linked to (1) the two valence bands to enhance the electronic transport coefficients and (2) stronger enharmonic phonon–phonon interactions to ensure a lower intrinsic thermal conductivity. Experimentally, based on Ge1−xSbxTe with optimized carrier concentration, a record-high figure-of-merit of 2.3 is achieved via further doping with In, which induces the distortion of the density of states near the Fermi level. Moreover, Sb and In codoping reduces the phase-transition temperature to extend the better thermoelectric behavior of cubic GeTe to low temperature. Additionally, electronic microscopy characterization demonstrates grain boundaries, a high-density of stacking faults, and nanoscale precipitates, which together with the inevitable point defects result in a dramatically decreased thermal conductivity. The fundamental investigation and experimental demonstration provide an important direction for the development of high-performance Pb-free thermoelectric materials. |
Keywords | density-functional-theory calculations, GeTe alloys, phase transition, phonon dynamics, thermoelectrics |
ANZSRC Field of Research 2020 | 340210. Solid state chemistry |
401807. Nanomaterials | |
401605. Functional materials | |
510403. Condensed matter modelling and density functional theory | |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Byline Affiliations | Centre for Future Materials |
University of Queensland | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q504z/realizing-zt-of-2-3-in-ge1-x-ysbxinyte-via-reducing-the-phase-transition-temperature-and-introducing-resonant-energy-doping
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