Realizing high power factor and thermoelectric performance in band engineered AgSbTe2

Yu Zhang; Congcong Xing; Dongyang Wang; Aziz Genç; Seng Huat Lee; Cheng Chang; Zhi Li; Luyao Zheng; Khak Ho Lim; Hangtian Zhu; Rabeya Bosry Smriti; Yu Liu; Shaobo Cheng; Min Hong; Xiaolei Fan; Zhiqiang Mao; Li-Dong Zhao; Andreu Cabot; Tiejun Zhu; Bed Poudel

doi:10.1038/s41467-024-55280-0

Realizing high power factor and thermoelectric performance in band engineered AgSbTe₂

Nat Commun. 2025 Jan 2;16(1):22. doi: 10.1038/s41467-024-55280-0.

Authors

Yu Zhang^#^{1

2}, Congcong Xing^#^{3

4}, Dongyang Wang⁵, Aziz Genç⁶, Seng Huat Lee^{7

8}, Cheng Chang⁹, Zhi Li¹⁰, Luyao Zheng⁴, Khak Ho Lim¹¹, Hangtian Zhu^{4

12}, Rabeya Bosry Smriti^{4

13}, Yu Liu¹⁴, Shaobo Cheng⁵, Min Hong¹⁵, Xiaolei Fan^{3

16}, Zhiqiang Mao⁸, Li-Dong Zhao⁹, Andreu Cabot^{17

18}, Tiejun Zhu^{19

20}, Bed Poudel²¹

Affiliations

¹ Institute of Wenzhou, Zhejiang University, Wenzhou, China. [email protected].
² Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA. [email protected].
³ Institute of Wenzhou, Zhejiang University, Wenzhou, China.
⁴ Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA.
⁵ Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics, Zhengzhou University, Zhengzhou, China.
⁶ Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Cardiff, UK.
⁷ 2D Crystal Consortium, Materials Research Institute, The Pennsylvania State University, University Park, PA, USA.
⁸ Department of Physics, The Pennsylvania State University, University Park, PA, USA.
⁹ School of Materials Science and Engineering, Beihang University, Beijing, China.
¹⁰ Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA.
¹¹ Institute of Zhejiang University-Quzhou, Quzhou, China.
¹² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
¹³ Department of Mechanical Engineering, Pennsylvania State University, University Park, PA, USA.
¹⁴ Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, China.
¹⁵ Centre for Future Materials, and School of Engineering, University of Southern Queensland, Springfield Central, Queensland, Australia.
¹⁶ Department of Chemical Engineering, School of Engineering, The University of Manchester Oxford Road, Manchester, UK.
¹⁷ Catalonia Institute for Energy Research-IREC, Sant Adrià de Besòs, Barcelona, Catalonia, Spain.
¹⁸ ICREA, Pg. Lluis Companys, Barcelona, Catalonia, Spain.
¹⁹ Institute of Wenzhou, Zhejiang University, Wenzhou, China. [email protected].
²⁰ State Key Laboratory of Silicon and Advanced Semiconductor Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou, China. [email protected].
²¹ Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, USA. [email protected].

^# Contributed equally.

Abstract

AgSbTe₂ is a promising p-type thermoelectric material operating in the mid-temperature regime. To further enhance its thermoelectric performance, previous research has mainly focused on reducing lattice thermal conductivity by forming ordered nanoscale domains for instance. However, the relatively low power factor is the main limitation affecting the power density of AgSbTe₂-based thermoelectric devices. In this work, we demonstrate that hole-doped AgSbTe₂ with Sn induces the formation of a new impurity band just above the valence band maximum. This approach significantly improves the electrical transport properties, contrary to previous strategies that focused on reducing lattice thermal conductivity. As a result, we achieve a record-high power factor of 27 μWcm^-1K^-2 and a peak thermoelectric figure of merit zT of 2.5 at 673 K. This exceptional performance is attributed to an increased hole concentration resulting from the formation of the impurity band and a lower formation energy of the defect complexes ( $V_{A g}^{1 -}$ + ${S n}_{S b}^{1 -}$ ). Besides, the doped materials exhibit a significantly improved Seebeck coefficient by inhibiting bipolar conductivity and preventing the formation of n-type Ag₂Te. Additionally, the optimized AgSbTe₂ is used to fabricate a unicouple thermoelectric device that achieves energy conversion efficiencies of up to 12.1% and a high power density of 1.13 Wcm^-2. This study provides critical insights and guidance for optimizing the performance of p-type AgSbTe₂ in thermoelectric applications.

Abstract

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