High Thermoelectric Performance in PbSe–NaSbSe2 Alloys from Valence Band Convergence and Low Thermal Conductivity

Tyler J. Slade, Trevor P. Bailey, Jann A. Grovogui, Xia Hua, Xiaomi Zhang, Jimmy Jiahong Kuo, Ido Hadar, G. Jeffrey Snyder, Chris Wolverton, Vinayak P. Dravid, Ctirad Uher, Mercouri G. Kanatzidis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


PbSe is an attractive thermoelectric material due to its favorable electronic structure, high melting point, and lower cost compared to PbTe. Herein, the hitherto unexplored alloys of PbSe with NaSbSe2 (NaPbmSbSem+2) are described and the most promising p-type PbSe-based thermoelectrics are found among them. Surprisingly, it is observed that below 500 K, NaPbmSbSem+2 exhibits unorthodox semiconducting-like electrical conductivity, despite possessing degenerate carrier densities of ≈1020 cm−3. It is shown that the peculiar behavior derives from carrier scattering by the grain boundaries. It is further demonstrated that the high solubility of NaSbSe2 in PbSe augments both the thermoelectric properties while maintaining a rock salt structure. Namely, density functional theory calculations and photoemission spectroscopy demonstrate that introduction of NaSbSe2 lowers the energy separation between the L- and Σ-valence bands and enhances the power factors under 700 K. The crystallographic disorder of Na+, Pb2+, and Sb3+ moreover provides exceptionally strong point defect phonon scattering yielding low lattice thermal conductivities of 1–0.55 W m-1 K-1 between 400 and 873 K without nanostructures. As a consequence, NaPb10SbSe12 achieves maximum ZT ≈1.4 near 900 K when optimally doped. More importantly, NaPb10SbSe12 maintains high ZT across a broad temperature range, giving an estimated record ZTavg of ≈0.64 between 400 and 873 K, a significant improvement over existing p-type PbSe thermoelectrics.

Original languageAmerican English
Article number1901377
JournalAdvanced Energy Materials
Issue number30
StatePublished - Aug 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • PbSe alloying
  • band structure engineering
  • grain boundary charge transport
  • low thermal conductivity
  • thermoelectric materials


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