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Enhanced thermoelectric properties of the Zintl phase BaGa_2Sb_2 via doping with Na or K

Aydemir, Umut and Zevalkink, Alex and Ormeci, Alim and Bux, Sabah and Snyder, G. Jeffrey (2016) Enhanced thermoelectric properties of the Zintl phase BaGa_2Sb_2 via doping with Na or K. Journal of Materials Chemistry A, 4 (5). pp. 1867-1875. ISSN 2050-7488. doi:10.1039/C5TA07612A.

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Na- or K-doped samples of Ba_(1−x)(Na, K)xGa_2Sb_2 were prepared by ball-milling followed by hot-pressing. The topological analysis of the electron density of BaGa_2Sb_2 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 BaGa_2Sb_2 with Na or K was confirmed with combined microprobe and X-ray diffraction analysis. Alkali metal doping of BaGa_2Sb_2 increased the p-type charge carrier concentration to almost the predicted optimum values (∼10^(20) 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 BaGa_2Sb_2 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).

Item Type:Article
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URLURL TypeDescription DOIArticle
Aydemir, Umut0000-0003-1164-1973
Bux, Sabah0000-0002-5372-354X
Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:© 2015 The Royal Society of Chemistry. Received 22 Sep 2015, Accepted 25 Dec 2015. First published online 29 Dec 2015. U. A. acknowledges the financial assistance of The Scientific and Technological Research Council of Turkey. This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration and was supported by the NASA Science Missions Directorate's Radioisotope Power Systems Technology Advancement Program. We would like to acknowledge the Molecular Materials Research Center (MMRC) at Caltech for allowing use of their instruments for the optical measurements obtained in this work. A. O. thanks Ulrike Nitzsche from IFW Dresden, Germany for technical help in computational work.
Funding AgencyGrant Number
Scientific and Technological Research Council of Turkey (TÜBİTAK)UNSPECIFIED
Issue or Number:5
Record Number:CaltechAUTHORS:20160119-133528867
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Official Citation:Enhanced thermoelectric properties of the Zintl phase BaGa2Sb2 via doping with Na or K Umut Aydemir, Alex Zevalkink, Alim Ormeci, Sabah Bux and G. Jeffrey Snyder J. Mater. Chem. A, 2016,4, 1867-1875 DOI: 10.1039/C5TA07612A, Paper First published online : 29 Dec 2015
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63766
Deposited By: Ruth Sustaita
Deposited On:19 Jan 2016 22:23
Last Modified:10 Nov 2021 23:21

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