Issue 6, 2020

Mg3(Bi,Sb)2 single crystals towards high thermoelectric performance


The rapid growth of the thermoelectric cooler market makes the development of novel room temperature thermoelectric materials of great importance. Ternary n-type Mg3(Bi,Sb)2 alloys are promising alternatives to the state-of-the-art Bi2(Te,Se)3 alloys but grain boundary resistance is the most important limitation. n-type Mg3(Bi,Sb)2 single crystals with negligible grain boundaries are expected to have particularly high zT but have rarely been realized due to the demanding Mg-rich growth conditions required. Here, we report, for the first time, the thermoelectric properties of n-type Mg3(Bi,Sb)2 alloyed single crystals grown by a one-step Mg-flux method using sealed tantalum tubes. High weighted mobility ∼140 cm2 V−1 s−1 and a high zT of 0.82 at 315 K are achieved in Y-doped Mg3Bi1.25Sb0.75 single crystals. Through both experimental angle-resolved photoemission spectroscopy and theoretical calculations, we denote the origin of the high thermoelectric performance from a point of view of band widening effect and electronegativity, as well as the necessity to form high Bi/Sb ratio ternary Mg3(Bi,Sb)2 alloys. The present work paves the way for further development of Mg3(Bi,Sb)2 for near room temperature thermoelectric applications.

Graphical abstract: Mg3(Bi,Sb)2 single crystals towards high thermoelectric performance

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Article information

Article type
16 Mar 2020
04 May 2020
First published
04 May 2020
This article is Open Access
Creative Commons BY license

Energy Environ. Sci., 2020,13, 1717-1724

Mg3(Bi,Sb)2 single crystals towards high thermoelectric performance

Y. Pan, M. Yao, X. Hong, Y. Zhu, F. Fan, K. Imasato, Y. He, C. Hess, J. Fink, J. Yang, B. Büchner, C. Fu, G. J. Snyder and C. Felser, Energy Environ. Sci., 2020, 13, 1717 DOI: 10.1039/D0EE00838A

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