Issue 40, 2015

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

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.

Graphical abstract: Mechanochemical synthesis and high temperature thermoelectric properties of calcium-doped lanthanum telluride La3−xCaxTe4

Article information

Article type
Paper
Submitted
04 jun 2015
Accepted
22 jun 2015
First published
31 jul 2015
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2015,3, 10459-10466

Author version available

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

J. M. Ma, S. M. Clarke, W. G. Zeier, T. Vo, P. Von Allmen, G. Jeffrey Snyder, R. B. Kaner, J. Fleurial and S. K. Bux, J. Mater. Chem. C, 2015, 3, 10459 DOI: 10.1039/C5TC01648G

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