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Metavalent Bonding in Cubic SnSe Alloys Improves Thermoelectric Properties over a Broad Temperature Range.

Authors :
Lin, Nan
Han, Shuai
Ghosh, Tanmoy
Schön, Carl‐Friedrich
Kim, Dasol
Frank, Jonathan
Hoff, Felix
Schmidt, Thomas
Ying, Pingjun
Zhu, Yuke
Häser, Maria
Shen, Minghao
Liu, Ming
Sui, Jiehe
Cojocaru‐Mirédin, Oana
Zhou, Chongjian
He, Ran
Wuttig, Matthias
Yu, Yuan
Source :
Advanced Functional Materials. 7/24/2024, Vol. 34 Issue 30, p1-13. 13p.
Publication Year :
2024

Abstract

Monocrystalline SnSe is one of the most promising thermoelectric materials with outstanding performance and a high abundance of constituting elements. However, polycrystalline SnSe, which is more robust for applications, only shows large figure‐of‐merit (zT) values in its high‐symmetry phase. Stabilizing the high‐symmetry phase at low temperatures can thus enhance the average zT value over a broad temperature range. In this work, the high‐symmetry rock‐salt SnSe phase is successfully obtained by alloying SnSe with AgVVI2 compounds (V = Sb, Bi; VI = Se, Te). These cubic SnSe phases show a unique portfolio of properties including a high optical dielectric constant, a large maximum of optical absorption, a large Born effective charge, and abnormal bond‐breaking behavior in laser‐assisted atom probe tomography. All of these characteristics are indicative of metavalent bonding. In contrast, the Pnma phase of SnSe employs covalent bonding. The enhanced symmetry at low temperatures is realized by tailoring chemical bonding. Concomitantly, zT near room temperature is increased by a factor of more than 10 from the pristine Pnma SnSe to Fm3¯${{\bar{3}}}$m SnSe alloys. This provides insights into the enhancement of the thermoelectric performance of SnSe and other chalcogenides over a broad temperature range by manipulating the chemical bonds. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
1616301X
Volume :
34
Issue :
30
Database :
Academic Search Index
Journal :
Advanced Functional Materials
Publication Type :
Academic Journal
Accession number :
178592365
Full Text :
https://doi.org/10.1002/adfm.202315652