Weak Electron–Phonon Coupling and Enhanced Thermoelectric Performance in n-type PbTe–Cu2Se via Dynamic Phase Conversion

Ming Wu; Hong Hua Cui; Songting Cai; Shiqiang Hao; Yukun Liu; Trevor P. Bailey; Yinying Zhang; Zixuan Chen; Yubo Luo; Ctirad Uher; Christopher Wolverton; Vinayak P. Dravid; Yan Yu; Zhong Zhen Luo; Zhigang Zou; Qingyu Yan; Mercouri G. Kanatzidis

doi:10.1002/aenm.202203325

Weak Electron–Phonon Coupling and Enhanced Thermoelectric Performance in n-type PbTe–Cu₂Se via Dynamic Phase Conversion

Ming Wu, Hong Hua Cui, Songting Cai, Shiqiang Hao, Yukun Liu, Trevor P. Bailey, Yinying Zhang, Zixuan Chen, Yubo Luo, Ctirad Uher, Christopher Wolverton, Vinayak P. Dravid, Yan Yu, Zhong Zhen Luo^*, Zhigang Zou, Qingyu Yan^*, Mercouri G. Kanatzidis^*

^*Corresponding author for this work

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

35 Scopus citations

Abstract

This study investigates Ga-doped n-type PbTe thermoelectric materials and the dynamic phase conversion process of the second phases via Cu₂Se alloying. Introducing Cu₂Se enhances its electrical transport properties while reducing its lattice thermal conductivity (κ_lat) via weak electron–phonon coupling. Cu₂Te and CuGa(Te/Se)₂ (tetragonal phase) nanocrystals precipitate during the alloying process, resulting in Te vacancies and interstitial Cu in the PbTe matrix. At room temperature, Te vacancies and interstitial Cu atoms serve as n-type dopants, increasing the carrier concentration and electrical conductivity from ≈1.18 × 10¹⁹ cm⁻³ and ≈1870 S cm⁻¹ to ≈2.26 × 10¹⁹ cm⁻³ and ≈3029 S cm⁻¹, respectively. With increasing temperature, the sample exhibits a dynamic change in Cu₂Te content and the generation of a new phase of CuGa(Te/Se)₂ (cubic phase), strengthening the phonon scattering and obtaining an ultralow κ_lat. Pb_0.975Ga_0.025Te-3%CuSe exhibits a maximum figure of merit of ≈1.63 at 823 K, making it promising for intermediate-temperature device applications.

Original language	English (US)
Article number	2203325
Journal	Advanced Energy Materials
Volume	13
Issue number	1
DOIs	https://doi.org/10.1002/aenm.202203325
State	Published - Jan 6 2023

Keywords

Cu Se alloying
dynamic phase conversion
electron–phonon coupling
n-type PbTe
thermoelectrics

ASJC Scopus subject areas

Renewable Energy, Sustainability and the Environment
General Materials Science

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1002/aenm.202203325

Cite this

Wu, M., Cui, H. H., Cai, S., Hao, S., Liu, Y., Bailey, T. P., Zhang, Y., Chen, Z., Luo, Y., Uher, C., Wolverton, C., Dravid, V. P., Yu, Y., Luo, Z. Z., Zou, Z., Yan, Q., & Kanatzidis, M. G. (2023). Weak Electron–Phonon Coupling and Enhanced Thermoelectric Performance in n-type PbTe–Cu₂Se via Dynamic Phase Conversion. Advanced Energy Materials, 13(1), Article 2203325. https://doi.org/10.1002/aenm.202203325

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title = "Weak Electron–Phonon Coupling and Enhanced Thermoelectric Performance in n-type PbTe–Cu2Se via Dynamic Phase Conversion",

abstract = "This study investigates Ga-doped n-type PbTe thermoelectric materials and the dynamic phase conversion process of the second phases via Cu2Se alloying. Introducing Cu2Se enhances its electrical transport properties while reducing its lattice thermal conductivity (κlat) via weak electron–phonon coupling. Cu2Te and CuGa(Te/Se)2 (tetragonal phase) nanocrystals precipitate during the alloying process, resulting in Te vacancies and interstitial Cu in the PbTe matrix. At room temperature, Te vacancies and interstitial Cu atoms serve as n-type dopants, increasing the carrier concentration and electrical conductivity from ≈1.18 × 1019 cm−3 and ≈1870 S cm−1 to ≈2.26 × 1019 cm−3 and ≈3029 S cm−1, respectively. With increasing temperature, the sample exhibits a dynamic change in Cu2Te content and the generation of a new phase of CuGa(Te/Se)2 (cubic phase), strengthening the phonon scattering and obtaining an ultralow κlat. Pb0.975Ga0.025Te-3%CuSe exhibits a maximum figure of merit of ≈1.63 at 823 K, making it promising for intermediate-temperature device applications.",

keywords = "Cu Se alloying, dynamic phase conversion, electron–phonon coupling, n-type PbTe, thermoelectrics",

author = "Ming Wu and Cui, {Hong Hua} and Songting Cai and Shiqiang Hao and Yukun Liu and Bailey, {Trevor P.} and Yinying Zhang and Zixuan Chen and Yubo Luo and Ctirad Uher and Christopher Wolverton and Dravid, {Vinayak P.} and Yan Yu and Luo, {Zhong Zhen} and Zhigang Zou and Qingyu Yan and Kanatzidis, {Mercouri G.}",

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year = "2023",

month = jan,

day = "6",

doi = "10.1002/aenm.202203325",

language = "English (US)",

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Wu, M, Cui, HH, Cai, S, Hao, S, Liu, Y, Bailey, TP, Zhang, Y, Chen, Z, Luo, Y, Uher, C, Wolverton, C , Dravid, VP, Yu, Y, Luo, ZZ, Zou, Z, Yan, Q & Kanatzidis, MG 2023, 'Weak Electron–Phonon Coupling and Enhanced Thermoelectric Performance in n-type PbTe–Cu₂Se via Dynamic Phase Conversion', Advanced Energy Materials, vol. 13, no. 1, 2203325. https://doi.org/10.1002/aenm.202203325

TY - JOUR

T1 - Weak Electron–Phonon Coupling and Enhanced Thermoelectric Performance in n-type PbTe–Cu2Se via Dynamic Phase Conversion

AU - Wu, Ming

AU - Cui, Hong Hua

AU - Cai, Songting

AU - Hao, Shiqiang

AU - Liu, Yukun

AU - Bailey, Trevor P.

AU - Zhang, Yinying

AU - Chen, Zixuan

AU - Luo, Yubo

AU - Uher, Ctirad

AU - Wolverton, Christopher

AU - Dravid, Vinayak P.

AU - Yu, Yan

AU - Luo, Zhong Zhen

AU - Zou, Zhigang

AU - Yan, Qingyu

AU - Kanatzidis, Mercouri G.

PY - 2023/1/6

Y1 - 2023/1/6

N2 - This study investigates Ga-doped n-type PbTe thermoelectric materials and the dynamic phase conversion process of the second phases via Cu2Se alloying. Introducing Cu2Se enhances its electrical transport properties while reducing its lattice thermal conductivity (κlat) via weak electron–phonon coupling. Cu2Te and CuGa(Te/Se)2 (tetragonal phase) nanocrystals precipitate during the alloying process, resulting in Te vacancies and interstitial Cu in the PbTe matrix. At room temperature, Te vacancies and interstitial Cu atoms serve as n-type dopants, increasing the carrier concentration and electrical conductivity from ≈1.18 × 1019 cm−3 and ≈1870 S cm−1 to ≈2.26 × 1019 cm−3 and ≈3029 S cm−1, respectively. With increasing temperature, the sample exhibits a dynamic change in Cu2Te content and the generation of a new phase of CuGa(Te/Se)2 (cubic phase), strengthening the phonon scattering and obtaining an ultralow κlat. Pb0.975Ga0.025Te-3%CuSe exhibits a maximum figure of merit of ≈1.63 at 823 K, making it promising for intermediate-temperature device applications.

AB - This study investigates Ga-doped n-type PbTe thermoelectric materials and the dynamic phase conversion process of the second phases via Cu2Se alloying. Introducing Cu2Se enhances its electrical transport properties while reducing its lattice thermal conductivity (κlat) via weak electron–phonon coupling. Cu2Te and CuGa(Te/Se)2 (tetragonal phase) nanocrystals precipitate during the alloying process, resulting in Te vacancies and interstitial Cu in the PbTe matrix. At room temperature, Te vacancies and interstitial Cu atoms serve as n-type dopants, increasing the carrier concentration and electrical conductivity from ≈1.18 × 1019 cm−3 and ≈1870 S cm−1 to ≈2.26 × 1019 cm−3 and ≈3029 S cm−1, respectively. With increasing temperature, the sample exhibits a dynamic change in Cu2Te content and the generation of a new phase of CuGa(Te/Se)2 (cubic phase), strengthening the phonon scattering and obtaining an ultralow κlat. Pb0.975Ga0.025Te-3%CuSe exhibits a maximum figure of merit of ≈1.63 at 823 K, making it promising for intermediate-temperature device applications.

KW - Cu Se alloying

KW - dynamic phase conversion

KW - electron–phonon coupling

KW - n-type PbTe

KW - thermoelectrics

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