Mechanochemical synthesis and high temperature thermoelectric properties of calcium-doped lanthanum telluride La3-xCaxTe4

James M. Ma, Samantha M. Clarke, Wolfgang G. Zeier, Trinh Vo, Paul Von Allmen, G. Jeffrey Snyder, Richard B. Kaner, Jean Pierre Fleurial, Sabah K. Bux*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

The thermoelectric properties from 300-1275 K of calcium-doped La3-xTe4 are reported. La3-xTe4 is a high temperature n-type thermoelectric material with a previously reported zTmax ∼ 1.1 at 1273 K and x = 0.23. Computational modeling suggests the La atoms define the density of states of the conduction band for La3-xTe4. Doping with Ca2+ on the La3+ site is explored as a means of modifying the density of states to improve the power factor and to achieve a finer control over the carrier concentration. High purity, oxide-free samples are produced by ball milling of the elements and consolidation by spark plasma sintering. Calcium substitution upon the lanthanum site was confirmed by a combination of Rietveld refinements of powder X-ray diffraction data and wave dispersive spectroscopy. A zTmax ∼ 1.2 is reached at 1273 K for the composition La2.2Ca0.78Te4 and the relative increase compared to La3-xTe4 is attributed to the finer carrier concentration.

Original languageEnglish (US)
Pages (from-to)10459-10466
Number of pages8
JournalJournal of Materials Chemistry C
Volume3
Issue number40
DOIs
StatePublished - 2015

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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