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Title: Superior thermoelectric performance in PbTe-PbS pseudo-binary. Extremely low thermal conductivity and modulated carrier concentration

Lead chalcogenides have exhibited their irreplaceable role as thermoelectric materials at the medium temperature range, owing to highly degenerate electronic bands and intrinsically low thermal conductivities. PbTe-PbS pseudo-binary has been paid extensive attentions due to the even lower thermal conductivity which originates largely from the coexistence of both alloying and phase-separated precipitations. To investigate the competition between alloying and phase separation and its pronounced effect on the thermoelectric performance in PbTe-PbS, we systematically studied Spark Plasma Sintered (SPSed), 3 at% Na- doped (PbTe) 1-x(PbS)x samples with x=10%, 15%, 20%, 25%, 30% and 35% by means of transmission electron microscopy (TEM) observations and theoretical calculations. Corresponding to the lowest lattice thermal conductivity as a result of the balance between point defect- and precipitates- scattering, the highest figure of merit ZT~2.3 was obtained at 923 K when PbS phase fraction x is at 20%. The consistently lower lattice thermal conductivities in SPSed samples compared with corresponding ingots, resulting from the powdering and follow-up consolidation processes, also contribute to the observed superior ZT. Notably, the onset of carrier concentration modulation ~600 K due to excessive Na’s diffusion and re-dissolution leads to the observed saturations of electrical transport properties, which is believed equally crucialmore » to the outstanding thermoelectric performance of SPSed PbTe-PbS samples.« less
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [4] ;  [5] ;  [1] ;  [4] ;  [3] ;  [2] ;  [1]
  1. South Univ. of Science and Technology of China, Shenshen (China)
  2. Northwestern Univ., Evanston, IL (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Tsinghua Univ., Beijing (China)
  5. Beihang Univ., Beijing (China)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1754-5692; R&D Project: MA015MACA; KC0201010
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Energy & Environmental Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 7; Journal ID: ISSN 1754-5692
Royal Society of Chemistry
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States