Achieving zT > 2 in p-Type AgSbTe2−xSex alloys via exploring the extra light valence band and introducing dense stacking faults

Hong, Min and Chen, Zhi-Gang and Yang, Lei and Liao, Zhi-Ming and Zou, Yi-Chao and Chen, Yan-Hui and Matsumura, Syo and Zou, Jin (2018) Achieving zT > 2 in p-Type AgSbTe2−xSex alloys via exploring the extra light valence band and introducing dense stacking faults. Advanced Energy Materials, 8 (9 - Article 1702333). ISSN 1614-6832

Abstract

Through simultaneously enhancing the power factor by engineering the extra light band and enhancing phonon scatterings by introducing a high density of stacking faults, a record figure-of-merit over 2.0 is achieved in p-type AgSbTe2−xSex alloys. Density functional theory calculations confirm the presence of the light valence band with large degeneracy in AgSbTe2, and that alloying with Se decreases the energy offset between the light valence band and the valence band maximum. Therefore, a significantly enhanced power factor is realized in p-type AgSbTe2−xSex alloys. In addition, transmission electron microscopy studies indicate the appearance of stacking faults and grain boundaries, which together with grain boundaries and point defects significantly strengthen phonon scatterings, leading to an ultralow thermal conductivity. The synergetic strategy of simultaneously enhancing power factor and strengthening phonon scattering developed in this study opens up a robust pathway to tailor hermoelectric performance.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to Published version, in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - No Department
Date Deposited: 08 Feb 2019 00:29
Last Modified: 11 Feb 2019 04:35
Fields of Research : 03 Chemical Sciences > 0302 Inorganic Chemistry > 030206 Solid State Chemistry
10 Technology > 1007 Nanotechnology > 100708 Nanomaterials
02 Physical Sciences > 0204 Condensed Matter Physics > 020403 Condensed Matter Modelling and Density Functional Theory
09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Identification Number or DOI: 10.1002/aenm.201702333
URI: http://eprints.usq.edu.au/id/eprint/35471

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