High carrier mobility and high figure of merit in the CuBiSe2 alloyed GeTe
Article
Article Title | High carrier mobility and high figure of merit in the CuBiSe2 alloyed GeTe |
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ERA Journal ID | 200105 |
Article Category | Article |
Authors | Yin, Liang-Cao (Author), Liu, Wei-Di (Author), Li, Meng (Author), Sun, Qiang (Author), Gao, Han (Author), Wang, De-Zhuang (Author), Wu, Hao (Author), Wang, Yi-Feng (Author), Shi, Xiao-Lei (Author), Liu, Qingfeng (Author) and Chen, Zhi-Gang (Author) |
Journal Title | Advanced Energy Materials |
Journal Citation | 11 (45), pp. 1-8 |
Article Number | 2102913 |
Number of Pages | 8 |
Year | 2021 |
Publisher | John Wiley & Sons |
Place of Publication | Germany |
ISSN | 1614-6832 |
1614-6840 | |
Digital Object Identifier (DOI) | https://doi.org/10.1002/aenm.202102913 |
Web Address (URL) | https://onlinelibrary.wiley.com/doi/full/10.1002/aenm.202102913 |
Abstract | According to the Mott's relation, the figure-of-merit of a thermoelectric material depends on the charge carrier concentration and carrier mobility. This explains the observation that low thermoelectric properties of GeTe-based materials suffer from the degraded carrier mobility, on account of the fluctuation of electronegativity and ionicity of various elements. Here, high-performance CuBiSe2 alloyed GeTe with high carrier mobility due to the small electronegativity difference between Cu and Ge atoms and the weak ionicity of Cu-Te and Bi-Te bonds, is developed. Density functional theory calculations indicate that CuBiSe2 alloying increases the formation energy of Ge vacancies and correspondingly reduces the amount of Ge vacancies, leading to an optimized carrier concentration and a high power factor of ≈37.4 µW cm−1 K−2 at 723 K. Moreover, CuBiSe2 alloying induces dense point defects and triggers ubiquitous lattice distortions, leading to a reduced lattice thermal conductivity of 0.39 W m−1 K−1 at 723 K. These synergistic effects result in an optimization of the carrier mobility, the carrier concentration, and the lattice thermal conductivity, which favors an enhanced peak figure-of-merit of ≈2.2 at 723 K in (GeTe)0.94(CuBiSe2)0.06. This study provides guidance for the screening of GeTe-based thermoelectric materials with high carrier mobility. |
Keywords | carrier mobility; figure-of-merit; GeTe; thermoelectrics |
ANZSRC Field of Research 2020 | 401605. Functional materials |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Nanjing Tech University, China |
Centre for Future Materials | |
University of Queensland | |
Zhengzhou University, China | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q6v76/high-carrier-mobility-and-high-figure-of-merit-in-the-cubise2-alloyed-gete
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