CaltechAUTHORS
  A Caltech Library Service

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. http://resolver.caltech.edu/CaltechAUTHORS:20160119-133528867

[img] PDF - Published Version
See Usage Policy.

1778Kb

Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:20160119-133528867

Abstract

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
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/C5TA07612A DOIArticle
http://pubs.rsc.org/en/content/articlelanding/2015/ta/c5ta07612aPublisherArticle
ORCID:
AuthorORCID
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.
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
Scientific and Technological Research Council of Turkey (TÜBİTAK)UNSPECIFIED
Record Number:CaltechAUTHORS:20160119-133528867
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160119-133528867
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
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:19 Jan 2016 22:23
Last Modified:18 Feb 2016 22:22

Repository Staff Only: item control page