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This content will become publicly available on February 12, 2019

Title: High Thermoelectric Performance in SnTe–AgSbTe 2 Alloys from Lattice Softening, Giant Phonon–Vacancy Scattering, and Valence Band Convergence

We report on the underlying mechanism that enables the SnTe-AgSbTe 2 system to exhibit superior thermoelectric figure of merit (ZT) compared to its parent compound SnTe. We show that AgSbTe 2 alloying has a profound impact on the band structure of SnTe by converging the energies of its light and heavy valence bands, leading to significantly enhanced Seebeck coefficients. We have also unraveled a significant connection between alloying and defect stability in this system, wherein the Sn vacancy concentration increases significantly when Ag and Sb are alloyed on the Sn site. The increased Sn vacancy concentration dramatically reduces the lattice thermal conductivity through both lattice softening and phonon-vacancy scattering to ~0.4 W m -1 K -1 at 800 K. Consequently, a ZT value of 1.2 at 800 K for AgSn 5SbTe 7 can be achieved by doping I on Te sites. Lastly, this represents a 300% improvement over pristine SnTe, outperforming many reported SnTe-based thermoelectric materials.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ; ORCiD logo [4] ; ORCiD logo [5] ;  [3] ; ORCiD logo [2] ;  [2] ; ORCiD logo [2] ; ORCiD logo [6]
  1. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry
  2. Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering
  3. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Physics
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  5. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Wuhan Univ. of Technology (China). State Key Lab. of Advanced Technology for Materials Synthesis and Processing
  6. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Grant/Contract Number:
AC02-06CH11357; SC0014520
Type:
Accepted Manuscript
Journal Name:
ACS Energy Letters
Additional Journal Information:
Journal Volume: 3; Journal Issue: 3; Journal ID: ISSN 2380-8195
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1459892