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Issue 5, 2016
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Enhanced thermoelectric properties of the Zintl phase BaGa2Sb2via doping with Na or K

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Abstract

Na- or K-doped samples of Ba1−x(Na, K)xGa2Sb2 were prepared by ball-milling followed by hot-pressing. The topological analysis of the electron density of BaGa2Sb2 implies a polar covalent nature of the Sb–Ga bonds in which the Sb atoms receive the electrons transferred from Ba rather than the Ga atoms. Successful doping of BaGa2Sb2 with Na or K was confirmed with combined microprobe and X-ray diffraction analysis. Alkali metal doping of BaGa2Sb2 increased the p-type charge carrier concentration to almost the predicted optimum values (∼1020 h+ cm−3) needed to achieve high thermoelectric performance. With increasing alkali metal concentration, electronic transport was shifted from non-degenerate semiconducting behaviour observed for BaGa2Sb2 to degenerate one for Na- or K-doped compounds. Overall, the thermoelectric figure of merit, zT, values reached up to ∼0.65 at 750 K, considerably higher than the undoped sample (zT ∼ 0.1 at 600 K), and a slight improvement relative to previously reported Zn-doped samples (∼0.6 at 800 K).

Graphical abstract: Enhanced thermoelectric properties of the Zintl phase BaGa2Sb2via doping with Na or K

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Publication details

The article was received on 22 Sep 2015, accepted on 25 Dec 2015 and first published on 29 Dec 2015


Article type: Paper
DOI: 10.1039/C5TA07612A
Author version available: Download Author version (PDF)
Citation: J. Mater. Chem. A, 2016,4, 1867-1875
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    Enhanced thermoelectric properties of the Zintl phase BaGa2Sb2via doping with Na or K

    U. Aydemir, A. Zevalkink, A. Ormeci, S. Bux and G. J. Snyder, J. Mater. Chem. A, 2016, 4, 1867
    DOI: 10.1039/C5TA07612A

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