2019年1月
Thermoelectric Properties and Electronic Structures of CuTi2S4 Thiospinel and Its Derivatives: Structural Design for Spinel-Related Thermoelectric Materials
INORGANIC CHEMISTRY
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- 巻
- 58
- 号
- 2
- 開始ページ
- 1425
- 終了ページ
- 1432
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acs.inorgchem.8b02955
- 出版者・発行元
- AMER CHEMICAL SOC
We report the preparations, thermoelectric and magnetic properties, and electronic structures of Cu-Ti-S systems, namely, cubic thiospinel c-Cu1-xTi2S4 (x <= 0.375), a derivative cubic and Ti-rich phase c-Cu1-xTi2.25S4 (x = 0.5, 0.625), and a rhombohedral phase r-CuTi2S4. All samples have the target compositions except for r-CuTi2S4, whose actual composition is Cu1.14Ti1.80S4. All of the phases have n-type metallic character and exhibit Pauli paramagnetism, as proven by experiments and first-principles calculations. The Cu and Ti deficiencies in c-Cu1-xTi2S4 and r-CuTi2S4, respectively, decrease the electron-carrier concentration, whereas the excess of Ti ions in c-Cu1-xTi2.25S4 largely increases it. For r-CuTi2S4, the reduced carrier concentration increases the electrical resistivity and Seebeck coefficient, leading to the highest thermoelectric power factor of 0.5 mW K-2 m(-1) at 670 K. For all of the CuTiS phases, the thermal conductivity at 670 K is 3.55 W K-1 m(-1), where the lattice part of the conductivity is as low as 1 W K-1 m(-1) at 670 K. As a result, r-CuTi2S4 shows the highest dimensionless thermoelectric figure of merit ZT of 0.2. The present systematic study on the Cu-Ti-S systems provides insights into the structural design of thermoelectric materials based on Cu-M-S (M = transition-metal elements).
- リンク情報
- ID情報
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- DOI : 10.1021/acs.inorgchem.8b02955
- ISSN : 0020-1669
- eISSN : 1520-510X
- Web of Science ID : WOS:000456633400051