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Eco-friendly SnTe based thermoelectric materials are intensively studied recently as candidates to replace PbTe; yet the thermoelectric performance of SnTe is suppressed by its intrinsically high carrier concentration and high thermal conductivity. In this work, we confirm that the Ag and La co-doping can be applied to simultaneously enhance the power factor and reduce the thermal conductivity, contributing to a final promotion of figure of merit. On one hand, the carrier concentration and band offset between valence bands are concurrently reduced, promoting the power factor to a highest value of ~2436 μW·m-1·K-2 at 873 K. On the other hand, lots of dislocations (~3.16×107 mm-2) associated with impurity precipitates are generated, resulting in the decline of thermal conductivity to a minimum value of 1.87 W·m-1·K-1 at 873 K. As a result, a substantial thermoelectric performance enhancement up to zT ≈ 1.0 at 873 K is obtained for the sample Sn0.94Ag0.09La0.05Te, which is twice that of the pristine SnTe (zT ≈ 0.49 at 873 K). This strategy of synergistic manipulation of electronic band and microstructures via introducing rare earth elements could be applied to other systems to improve thermoelectric performance.


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Substantial thermoelectric enhancement achieved by manipulating the band structure and dislocations in Ag and La co-doped SnTe

Show Author's information Wenjing XUaZhongwei ZHANGaChengyan LIUa( )Jie GAOaZhenyuan YEaChunguang CHENaYing PENGaXiaobo BAIaLei MIAOa,b( )
Guangxi Key Laboratory of Information Material, Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, School of Material Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China
Department of Materials Science and Engineering, SIT Research Laboratories, Innovative Global Program, Faculty of Engineering, Shibaura Institute of Technology, Tokyo 135-8548, Japan

† Wenjing Xu and Zhongwei Zhang contributed equally to this work.

Abstract

Eco-friendly SnTe based thermoelectric materials are intensively studied recently as candidates to replace PbTe; yet the thermoelectric performance of SnTe is suppressed by its intrinsically high carrier concentration and high thermal conductivity. In this work, we confirm that the Ag and La co-doping can be applied to simultaneously enhance the power factor and reduce the thermal conductivity, contributing to a final promotion of figure of merit. On one hand, the carrier concentration and band offset between valence bands are concurrently reduced, promoting the power factor to a highest value of ~2436 μW·m-1·K-2 at 873 K. On the other hand, lots of dislocations (~3.16×107 mm-2) associated with impurity precipitates are generated, resulting in the decline of thermal conductivity to a minimum value of 1.87 W·m-1·K-1 at 873 K. As a result, a substantial thermoelectric performance enhancement up to zT ≈ 1.0 at 873 K is obtained for the sample Sn0.94Ag0.09La0.05Te, which is twice that of the pristine SnTe (zT ≈ 0.49 at 873 K). This strategy of synergistic manipulation of electronic band and microstructures via introducing rare earth elements could be applied to other systems to improve thermoelectric performance.

Keywords:

SnTe, band convergence, dislocation, Ag and La co-doping, thermoelectric performance
Received: 24 February 2021 Revised: 17 March 2021 Accepted: 31 March 2021 Published: 05 August 2021 Issue date: August 2021
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Publication history
Copyright
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Publication history

Received: 24 February 2021
Revised: 17 March 2021
Accepted: 31 March 2021
Published: 05 August 2021
Issue date: August 2021

Copyright

© The Author(s) 2021

Acknowledgements

This work was supported by National Natural Science Foundation of China (Grant Nos. 51801040, 51961011, 51772056) and Guangxi Natural Science Foundation of China (Grant Nos. 2020GXNSFAA159111, AD20159006, 2018GXNSFAA294135, 2018JJA160257, and 2019GXNSFBA245028).

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