Traversing the metal-insulator transition in a zintl phase: Rational enhancement of thermoelectric efficiency in Yb14Mn 1-xAlxSb11

Eric S. Toberer, Catherine A. Cox, Shawna R. Brown, Teruyuki Ikeda, Andrew F. May, Susan M. Kauzlarich, G. Jeffrey Snyder

Research output: Contribution to journalArticle

208 Scopus citations

Abstract

For high temperature thermoelectric applications, Yb14MnSb 11 has a maximum thermoelectric figure of merit (zT) of ∼1,0 at 1273 K. Such a high zT is found despite a carrier concentration that is higher than typical thermoelectric materials. Here, we reduce the carrier concentration with the discovery of a continuous transition between metallic Yb 14MnSb11 and semiconducting Yb14AlSb 11. Yb14Mn1-xAlxSb11 forms a solid solution where the free carrier concentration gradually changes as expected from the Zintl valence formalism. Throughout this transition the electronic properties are found to obey a rigid band model with a band gap of 0.5 eV and an effective mass of 3 me. As the carrier concentration decreases, an increase in the Seebeck coefficient is observed at the expense of an increased electrical resistivity. At the optimum carrier concentration, a maximum zT of 1.3 at 1223 K is obtained, which is more than twice that of the state-of-the-art Si0.8Ge0.2 flown by NASA.

Original languageEnglish (US)
Pages (from-to)2795-2800
Number of pages6
JournalAdvanced Functional Materials
Volume18
Issue number18
DOIs
StatePublished - Sep 23 2008

ASJC Scopus subject areas

  • Biomaterials
  • Electrochemistry
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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