High ZT 2D Thermoelectrics by Design: Strong Interlayer Vibration and Complete Band-Extrema Alignment

Xiwen Zhang; Chenhan Liu; Yi Tao; Yunhai Li; Yilv Guo; Yunfei Chen; Xiao Cheng Zeng; Jinlan Wang

doi:10.1002/adfm.202001200

High ZT 2D Thermoelectrics by Design: Strong Interlayer Vibration and Complete Band-Extrema Alignment

Xiwen Zhang, Chenhan Liu, Yi Tao, Yunhai Li, Yilv Guo, Yunfei Chen, Xiao Cheng Zeng, Jinlan Wang

Chemistry

Research output: Contribution to journal › Article › peer-review

34 Scopus citations

Abstract

The discovery of a record high figure of merit (ZT) of ≈2.6 associated with bulk SnSe has stimulated considerable enthusiasm in searching for 2D systems with similar high ZT. However, previously reported 2D thermoelectric (TE) materials generally possess very low ZT due to the high lattice thermal conductivity (κ_L) and/or small power factor (PF). Herein, a very high ZT (≈2.08) value associated with atomically thin 2D KAgSe nanosheet is reported, which also exhibits an unprecedented low intrinsic κ_L (≈0.03 Wm⁻¹ K⁻¹ at 700 K for trilayer) and fairly large PF. The low κ_L mainly stems from the high lattice anharmonicity induced by both the “interfacial shear slip” vibrations and the asymmetric “Ag-Se pair” vibrations from distorted AgSe₄ tetrahedrons. Meanwhile, the complete band-extrema alignment and coexistence of heavy and light bands result in an optimal Seebeck coefficient and electrical conductivity, thereby a large PF. This work suggests not only an alternative way to acquiring high lattice anharmonicity but also a highly competitive 2D TE candidate for wide applications.

Original language	English (US)
Article number	2001200
Journal	Advanced Functional Materials
Volume	30
Issue number	22
DOIs	https://doi.org/10.1002/adfm.202001200
State	Published - May 1 2020

Keywords

2D thermoelectrics
band-extrema alignment
figure of merit
interlayer-related vibration

ASJC Scopus subject areas

Chemistry(all)
Materials Science(all)
Condensed Matter Physics

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title = "High ZT 2D Thermoelectrics by Design: Strong Interlayer Vibration and Complete Band-Extrema Alignment",

abstract = "The discovery of a record high figure of merit (ZT) of ≈2.6 associated with bulk SnSe has stimulated considerable enthusiasm in searching for 2D systems with similar high ZT. However, previously reported 2D thermoelectric (TE) materials generally possess very low ZT due to the high lattice thermal conductivity (κL) and/or small power factor (PF). Herein, a very high ZT (≈2.08) value associated with atomically thin 2D KAgSe nanosheet is reported, which also exhibits an unprecedented low intrinsic κL (≈0.03 Wm−1 K−1 at 700 K for trilayer) and fairly large PF. The low κL mainly stems from the high lattice anharmonicity induced by both the “interfacial shear slip” vibrations and the asymmetric “Ag-Se pair” vibrations from distorted AgSe4 tetrahedrons. Meanwhile, the complete band-extrema alignment and coexistence of heavy and light bands result in an optimal Seebeck coefficient and electrical conductivity, thereby a large PF. This work suggests not only an alternative way to acquiring high lattice anharmonicity but also a highly competitive 2D TE candidate for wide applications.",

keywords = "2D thermoelectrics, band-extrema alignment, figure of merit, interlayer-related vibration",

author = "Xiwen Zhang and Chenhan Liu and Yi Tao and Yunhai Li and Yilv Guo and Yunfei Chen and Zeng, {Xiao Cheng} and Jinlan Wang",

note = "Funding Information: X.W.Z. and C.H.L. contributed equally to this work. J.W. was supported by the National Key Research and Development Program of China (2017YFA0204800), Natural Science Foundation of China (21525311, 51435003). J.W. thanks the computational resources from the Big Data Center of Southeast University and National Supercomputing Center in Tianjin. Funding Information: X.W.Z. and C.H.L. contributed equally to this work. J.W. was supported by the National Key Research and Development Program of China (2017YFA0204800), Natural Science Foundation of China (21525311, 51435003). J.W. thanks the computational resources from the Big Data Center of Southeast University and National Supercomputing Center in Tianjin. Publisher Copyright: {\textcopyright} 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim",

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month = may,

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doi = "10.1002/adfm.202001200",

language = "English (US)",

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T1 - High ZT 2D Thermoelectrics by Design

T2 - Strong Interlayer Vibration and Complete Band-Extrema Alignment

AU - Zhang, Xiwen

AU - Liu, Chenhan

AU - Tao, Yi

AU - Li, Yunhai

AU - Guo, Yilv

AU - Chen, Yunfei

AU - Zeng, Xiao Cheng

AU - Wang, Jinlan

N1 - Funding Information: X.W.Z. and C.H.L. contributed equally to this work. J.W. was supported by the National Key Research and Development Program of China (2017YFA0204800), Natural Science Foundation of China (21525311, 51435003). J.W. thanks the computational resources from the Big Data Center of Southeast University and National Supercomputing Center in Tianjin. Funding Information: X.W.Z. and C.H.L. contributed equally to this work. J.W. was supported by the National Key Research and Development Program of China (2017YFA0204800), Natural Science Foundation of China (21525311, 51435003). J.W. thanks the computational resources from the Big Data Center of Southeast University and National Supercomputing Center in Tianjin. Publisher Copyright: © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

PY - 2020/5/1

Y1 - 2020/5/1

N2 - The discovery of a record high figure of merit (ZT) of ≈2.6 associated with bulk SnSe has stimulated considerable enthusiasm in searching for 2D systems with similar high ZT. However, previously reported 2D thermoelectric (TE) materials generally possess very low ZT due to the high lattice thermal conductivity (κL) and/or small power factor (PF). Herein, a very high ZT (≈2.08) value associated with atomically thin 2D KAgSe nanosheet is reported, which also exhibits an unprecedented low intrinsic κL (≈0.03 Wm−1 K−1 at 700 K for trilayer) and fairly large PF. The low κL mainly stems from the high lattice anharmonicity induced by both the “interfacial shear slip” vibrations and the asymmetric “Ag-Se pair” vibrations from distorted AgSe4 tetrahedrons. Meanwhile, the complete band-extrema alignment and coexistence of heavy and light bands result in an optimal Seebeck coefficient and electrical conductivity, thereby a large PF. This work suggests not only an alternative way to acquiring high lattice anharmonicity but also a highly competitive 2D TE candidate for wide applications.

AB - The discovery of a record high figure of merit (ZT) of ≈2.6 associated with bulk SnSe has stimulated considerable enthusiasm in searching for 2D systems with similar high ZT. However, previously reported 2D thermoelectric (TE) materials generally possess very low ZT due to the high lattice thermal conductivity (κL) and/or small power factor (PF). Herein, a very high ZT (≈2.08) value associated with atomically thin 2D KAgSe nanosheet is reported, which also exhibits an unprecedented low intrinsic κL (≈0.03 Wm−1 K−1 at 700 K for trilayer) and fairly large PF. The low κL mainly stems from the high lattice anharmonicity induced by both the “interfacial shear slip” vibrations and the asymmetric “Ag-Se pair” vibrations from distorted AgSe4 tetrahedrons. Meanwhile, the complete band-extrema alignment and coexistence of heavy and light bands result in an optimal Seebeck coefficient and electrical conductivity, thereby a large PF. This work suggests not only an alternative way to acquiring high lattice anharmonicity but also a highly competitive 2D TE candidate for wide applications.

KW - 2D thermoelectrics

KW - band-extrema alignment

KW - figure of merit

KW - interlayer-related vibration

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ER -

High ZT 2D Thermoelectrics by Design: Strong Interlayer Vibration and Complete Band-Extrema Alignment

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Keywords

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