Issue 1, 2018

Band engineering in Mg3Sb2 by alloying with Mg3Bi2 for enhanced thermoelectric performance

Abstract

Mg3Sb2–Mg3Bi2 alloys show excellent thermoelectric properties. The benefit of alloying has been attributed to the reduction in lattice thermal conductivity. However, Mg3Bi2-alloying may also be expected to significantly change the electronic structure. By comparatively modeling the transport properties of n- and p-type Mg3Sb2–Mg3Bi2 and also Mg3Bi2-alloyed and non-alloyed samples, we elucidate the origin of the highest zT composition where electronic properties account for about 50% of the improvement. We find that Mg3Bi2 alloying increases the weighted mobility while reducing the band gap. The reduced band gap is found not to compromise the thermoelectric performance for a small amount of Mg3Bi2 because the peak zT in unalloyed Mg3Sb2 is at a temperature higher than the stable range for the material. By quantifying the electronic influence of Mg3Bi2 alloying, we model the optimum Mg3Bi2 content for thermoelectrics to be in the range of 20–30%, consistent with the most commonly reported composition Mg3Sb1.5Bi0.5.

Graphical abstract: Band engineering in Mg3Sb2 by alloying with Mg3Bi2 for enhanced thermoelectric performance

Supplementary files

Article information

Article type
Communication
Submitted
20 Nhl 2017
Accepted
20 Huk 2017
First published
20 Huk 2017

Mater. Horiz., 2018,5, 59-64

Band engineering in Mg3Sb2 by alloying with Mg3Bi2 for enhanced thermoelectric performance

K. Imasato, S. D. Kang, S. Ohno and G. J. Snyder, Mater. Horiz., 2018, 5, 59 DOI: 10.1039/C7MH00865A

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