The New Semiconductor Cs4Cu3Bi9S17
- Chinese Academy of Sciences (CAS), Beijing (China); Northwestern Univ., Evanston, IL (United States)
- Northwestern Univ., Evanston, IL (United States)
- Chinese Academy of Sciences (CAS), Beijing (China)
In this work, new quaternary chalcogenide Cs4Cu3Bi9S17 has been synthesized by solid state reaction in a vacuum-sealed silica tube. Cs4Cu3Bi9S17 adopts monoclinic space group P21/m, with the following dimensions: a = 20.006(4) Å, b = 4.0556(8) Å, c = 22.279(5) Å, and β = 96.921°. The crystal structure of Cs4Cu3Bi9S17 features a unique three-dimensional framework consisting of interconnected Bi2Te3- and CdI2-type fragments forming three different-sized tunnels running parallel to the b-axis. The tunnels are filled with different numbers (1, 2, or 4) of Cs atoms. Cs4Cu3Bi9S17 is stable in air at room temperature, and differential thermal analysis showed that it decomposes at elevated temperatures. Cs4Cu3Bi9S17 is a semiconductor with a direct optical band gap of 0.9 eV, which is in agreement with density functional theory calculations. Electrical conductivity and Seebeck coefficient measurements show n-type semiconductor behavior. The electrical conductivity is 10–4 S/cm at 300 K and increases to 0.9 S/cm at 773 K. Cs4Cu3Bi9S17 possesses a very low thermal conductivity of 0.71 W m–1 K–1 at room temperature that decreases linearly with an increase in temperature to 0.46 W m–1 K–1 at 773 K. The low thermal conductivity shows the promise of Cs4Cu3Bi9S17 as a new thermoelectric material with appropriate doping.
- Research Organization:
- Northwestern Univ., Evanston, IL (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES); State of Illinois
- Grant/Contract Number:
- SC0014520; DMR-1410169; DMR-1121262; EEC-0118025/003
- OSTI ID:
- 1534455
- Journal Information:
- Chemistry of Materials, Vol. 29, Issue 4; ISSN 0897-4756
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Odyssey of thermoelectric materials: foundation of the complex structure
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journal | June 2018 |
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