CaltechAUTHORS
  A Caltech Library Service

Improved thermoelectric properties in Zn-doped Ca_(5)Ga_(2)Sb_6

Johnson, Samantha I. and Zevalkink, Alex and Snyder, G. Jeffrey (2013) Improved thermoelectric properties in Zn-doped Ca_(5)Ga_(2)Sb_6. Journal of Materials Chemistry A, 1 (13). pp. 4244-4249. ISSN 2050-7488. doi:10.1039/C3TA00844D. https://resolver.caltech.edu/CaltechAUTHORS:20130404-153700201

[img]
Preview
PDF - Published Version
See Usage Policy.

542kB

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20130404-153700201

Abstract

Zintl compounds with the chemical formula Ca_(5)M_(2)Sb_6 have attracted attention as candidates for use in thermoelectric applications due to their low thermal conductivity and promising high temperature performance (i.e., zT = 0.6 at 1000 K in Ca_(5)Al_(2−x)Na_(x)Sb_6). We have shown previously that, relative to Ca_(5)Al_(2)Sb_6, both Ca_(5)Ga_(2)Sb_6 and Ca_(5)In_(2)Sb_6 have reduced phonon velocities and improved carrier mobility, suggesting that improved zT can be achieved in these materials. Here we further investigate Ca_(5)Ga_(2)Sb_6, which is an intrinsic semiconductor with a small concentration of p-type carriers. By substituting Zn^2+ on the Ga^3+ site, we show that it is possible to increase and control the carrier concentration in Ca_(5)Ga_(2−x)Zn_(x)Sb_6 and thus optimize its thermoelectric behavior. A single parabolic band model was used to estimate an effective mass of m* = 1.6me, which is slightly lower than Al-based compounds. Though the reduced m* leads to a lower Seebeck coefficient, it also leads to a much higher electronic mobility. The high mobility leads to increased thermoelectric figure of merit (zT) at low and intermediate temperatures relative to Zn-doped Ca5Al2Sb6. However, due to the decreased band gap in Ca_(5)Ga_(2)Sb_6 relative to Ca5Al2Sb6, the maximum zT in optimally doped Ca_(5)Ga_(2)Sb_6 is reduced (peak zT ~ 0.35 at T = 775 K).


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/C3TA00844DDOIUNSPECIFIED
http://pubs.rsc.org/en/Content/ArticleLanding/2013/TA/c3ta00844dPublisherUNSPECIFIED
ORCID:
AuthorORCID
Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:© 2013 Royal Society of Chemistry. Received 26th October 2012; Accepted 4th February 2013. First published on the web 18 Feb 2013. We would like to thank the Jet Propulsion Laboratory and the National Science Foundation for their generous support.
Funders:
Funding AgencyGrant Number
JPLUNSPECIFIED
NSFUNSPECIFIED
Issue or Number:13
DOI:10.1039/C3TA00844D
Record Number:CaltechAUTHORS:20130404-153700201
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130404-153700201
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37770
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:05 Apr 2013 17:36
Last Modified:09 Nov 2021 23:31

Repository Staff Only: item control page