Issue 10, 2012

Thermoelectric properties of Sr3GaSb3 – a chain-forming Zintl compound

Abstract

Inspired by the promising thermoelectric properties in the Zintl compounds Ca3AlSb3 and Ca5Al2Sb6, we investigate here the closely related compound Sr3GaSb3. Although the crystal structure of Sr3GaSb3 contains infinite chains of corner-linked tetrahedra, in common with Ca3AlSb3 and Ca5Al2Sb6, it has twice as many atoms per unit cell (N = 56). This contributes to the exceptionally low lattice thermal conductivity (κL = 0.45 W m−1 K−1 at 1000 K) observed in Sr3GaSb3 samples synthesized for this study by ball milling followed by hot pressing. High temperature transport measurements reveal that Sr3GaSb3 is a nondegenerate semiconductor (consistent with Zintl charge-counting conventions) with relatively high p-type electronic mobility (∼30 cm2 V−1 s−1 at 300 K). Density functional calculations yield a band gap of ∼0.75 eV and predict a light valence band edge (∼0.5 me), in qualitative agreement with experiment. To rationally optimize the electronic transport properties of Sr3GaSb3 in accordance with a single band model, doping with Zn2+ on the Ga3+ site was used to increase the p-type carrier concentration. In optimally hole-doped Sr3Ga1−xZnxSb3 (x = 0.0 to 0.1), we demonstrate a maximum figure of merit of greater than 0.9 at 1000 K.

Graphical abstract: Thermoelectric properties of Sr3GaSb3 – a chain-forming Zintl compound

Article information

Article type
Paper
Submitted
29 May 2012
Accepted
15 Aug 2012
First published
11 Sep 2012

Energy Environ. Sci., 2012,5, 9121-9128

Thermoelectric properties of Sr3GaSb3 – a chain-forming Zintl compound

A. Zevalkink, W. G. Zeier, G. Pomrehn, E. Schechtel, W. Tremel and G. J. Snyder, Energy Environ. Sci., 2012, 5, 9121 DOI: 10.1039/C2EE22378C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements