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Title: High Thermoelectric Performance in Copper Telluride

Recently, Cu 2-δ S and Cu 2-δ Se were reported to have an ultralow thermal conductivity and high thermoelectric figure of merit zT. Thus, as a member of the copper chalcogenide group, Cu 2-δ Te is expected to possess superior zTs because Te is less ionic and heavy. However, the zT value is low in the Cu 2Te sintered using spark plasma sintering, which is typically used to fabricate high-density bulk samples. In addition, the extra sintering processes may change the samples’ compositions as well as their physical properties, especially for Cu 2Te, which has many stable and meta-stable phases as well as weaker ionic bonding between Cu and Te as compared with Cu 2S and Cu 2Se. In this study, high-density Cu 2Te samples were obtained using direct annealing without a sintering process. In the absence of sintering processes, the samples’ compositions could be well controlled, leading to substantially reduced carrier concentrations that are close to the optimal value. The electrical transports were optimized, and the thermal conductivity was considerably reduced. The zT values were significantly improved—to 1.1 at 1000 K—which is nearly 100% improvement. Furthermore, this method saves substantial time and cost during the sample’s growth.more » The study demonstrates that Cu 2-δ X (X=S, Se and Te) is the only existing system to show high zTs in the series of compounds composed of three sequential primary group elements.« less
 [1] ;  [2] ;  [2] ;  [3] ;  [2]
  1. Chinese Academy of Sciences (CAS), Beijing (China); Univ. of Chinese Academy of Sciences, Beijing (China)
  2. Chinese Academy of Sciences (CAS), Beijing (China)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1884-4057
Grant/Contract Number:
Accepted Manuscript
Journal Name:
NPG Asia Materials (Online)
Additional Journal Information:
Journal Name: NPG Asia Materials (Online); Journal Volume: 7; Related Information: NPG Asia Materials; Journal ID: ISSN 1884-4057
Nature Publishing Group Asia
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
Country of Publication:
United States
14 SOLAR ENERGY; 77 NANOSCIENCE AND NANOTECHNOLOGY; thermal conductivity; Cu1Te; direct annealing
OSTI Identifier: