Achieving zT > 2 in p‐Type AgSbTe2−xSex Alloys via Exploring the Extra Light Valence Band and Introducing Dense Stacking Faults |
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| Authors: | Min Hong Zhi‐Gang Chen Lei Yang Zhi‐Ming Liao Yi‐Chao Zou Yan‐Hui Chen Syo Matsumura Jin Zou |
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| Institution: | 1. Materials Engineering, The University of Queensland, Brisbane, Queensland, Australia;2. Centre of Future Materials, The University of Southern Queensland, Springfield, Queensland, Australia;3. Beijing Key Lab of Microstructure and Property of Advanced Materials, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing, China;4. Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Nishi‐ku, Fukuoka, Japan;5. Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, Australia |
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| 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 thermoelectric performance. |
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| Keywords: | AgSbTe2− xSex alloys engineering light valence band stacking fault phonon scattering thermoelectric |
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