Weak electron–phonon coupling contributing to high thermoelectric performance in n-type PbSe
Abstract
PbSe is a surprisingly good thermoelectric material due, in part, to its low thermal conductivity that had been overestimated in earlier measurements. The thermoelectric figure of merit, zT, can exceed 1 at high temperatures in both p-type and n-type PbSe, similar to that found in PbTe. While the p-type lead chalcogenides (PbSe and PbTe) benefit from the high valley degeneracy (12 or more at high temperature) of the valence band, the n-type versions are limited to a valley degeneracy of 4 in the conduction band. Yet the n-type lead chalcogenides achieve a zT nearly as high as the p-type lead chalcogenides. This effect can be attributed to the weaker electron–phonon coupling (lower deformation potential coefficient) in the conduction band as compared with that in the valence band, which leads to higher mobility of electrons compared to that of holes. This study of PbSe illustrates the importance of the deformation potential coefficient of the charge-carrying band as one of several key parameters to consider for band structure engineering and the search for high performance thermoelectric materials.
Additional Information
© 2012 by the National Academy of Sciences. Edited by Ali Shakouri, University of California, Santa Cruz, CA, and accepted by the Editorial Board April 13, 2012 (received for review July 14, 2011). Published online before print May 21, 2012. The authors thank Xun Shi and Lidong Chen at Shanghai Institute of Ceramics–Chinese Academy of Science and Alexandra Zevalkink at Jet Propulsion Laboratory for confirming measurements, and Defense Advanced Research Planning Agency's Nano-Structured Materials for Power program and National Aeronautics and Space Administration–Jet Propulsion Laboratory for financial support. Author contributions: H.W., Y.P., and G.J.S. designed research; H.W. performed research; A.D.L. contributed new reagents/analytic tools; H.W. analyzed data; H.W., Y.P., and G.J.S. discussed results; and H.W., Y.P., and G.J.S. wrote the paper.Attached Files
Published - Wang2012p18873P_Natl_Acad_Sci_Usa.pdf
Supplemental Material - pnas.1111419109_SI.pdf
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Additional details
- PMCID
- PMC3382475
- Eprint ID
- 32670
- Resolver ID
- CaltechAUTHORS:20120724-102851626
- Defense Advanced Research Projects Agency (DARPA)
- NASA/JPL
- Created
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2012-07-26Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field