Enhancing thermoelectric performance of SrFBiS2−Se via band engineering and structural texturing
| Autor: | Jianxin Zhang, Jun Luo, Juanjuan Xing, Hai Huang, Chen Lin, Jiong Yang, Wanyu Lyu, Ying Jiang, Kai Guo, Jiye Zhang, Shijing Li |
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| Rok vydání: | 2022 |
| Předmět: |
Materials science
Annealing (metallurgy) Band gap business.industry Metals and Alloys Sintering Layered compound Texturing Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystal Grain growth Effective mass (solid-state physics) Semiconductor Energy band engineering Thermoelectric effect TA401-492 Optoelectronics Carrier mobility business SrFBiS2 Materials of engineering and construction. Mechanics of materials |
| Zdroj: | Journal of Materiomics, Vol 8, Iss 2, Pp 302-310 (2022) |
| ISSN: | 2352-8478 |
| Popis: | SrFBiS2 is a quaternary n-type semiconductor with rock-salt-type BiS2 and fluorite-type SrF layers alternately stacked along the c axis. The tunability of the crystal and electronic structures as well as the intrinsically low thermal conductivity make this compound a promising parent material for thermoelectric applications. In the current work, we show that alloying of Se and S in SrFBiS2 reduces the optical band gap with the second conduction band serving as an electron-transport medium, simultaneously increasing the electron concentration and effective mass. In addition, the raw material Bi2Se3 is shown to act as liquid adjuvant during the annealing process, favoring preferred-orientation grain growth and forming strengthen microstructural texturing in bulk samples after hot-pressed sintering. Highly ordered lamellar grains are stacked perpendicular to the pressure direction, leading to enhanced mobility along this direction. The synthetic effect results in a maximum power factor of 5.58 μW cm-1 K-2 at 523 K for SrFBiSSe and a peak zT = 0.34 at 773 K, enhancements of 180% compared with those of pristine SrFBiS2. |
| Databáze: | OpenAIRE |
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