Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄

We studied the narrow bandgap (0.55 eV) semiconductor K2.5Bi8.5Se14, as a potential thermoelectric material for power generation. Samples of polycrystalline K2.5Bi8.5Se14 prepared by spark plasma sintering exhibit exceptionally low lattice thermal conductivities (κlat) of 0.57 − 0.33 Wm−1K−1 in the...

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Main Authors: Luo, Zhong-Zhen, Cai, Songting, Hao, Shiqiang, Bailey, Trevor P., Hu, Xiaobing, Hanus, Riley, Ma, Runchu, Tan, Gangjian, Chica. Daniel G., Snyder, G. Jeffrey, Uher, Ctirad, Wolverton, Christopher, Dravid, Vinayak P., Yan, Qingyu, Kanatzidis, Mercouri G.
Other Authors: School of Materials Science and Engineering
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/159049
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Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-159049
record_format dspace
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Materials::Functional materials
Phonons
Thermal Conductivity
spellingShingle Engineering::Materials::Functional materials
Phonons
Thermal Conductivity
Luo, Zhong-Zhen
Cai, Songting
Hao, Shiqiang
Bailey, Trevor P.
Hu, Xiaobing
Hanus, Riley
Ma, Runchu
Tan, Gangjian
Chica. Daniel G.
Snyder, G. Jeffrey
Uher, Ctirad
Wolverton, Christopher
Dravid, Vinayak P.
Yan, Qingyu
Kanatzidis, Mercouri G.
Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄
description We studied the narrow bandgap (0.55 eV) semiconductor K2.5Bi8.5Se14, as a potential thermoelectric material for power generation. Samples of polycrystalline K2.5Bi8.5Se14 prepared by spark plasma sintering exhibit exceptionally low lattice thermal conductivities (κlat) of 0.57 − 0.33 Wm−1K−1 in the temperature range of 300 − 873 K. The physical origin of such low κlat in K2.5Bi8.5Se14 is related to the strong anharmonicity and low phonon velocity caused by its complex low-symmetry, large unit cell crystal structure and mixed-occupancy of Bi and K atoms in the lattice. High-resolution scanning transmission electron microscopy (HRSTEM) studies and micro-analysis indicates that the K2.5Bi8.5Se14 sample is a single phase without intergrowth of the structurally related K2Bi8Se13 phase. The undoped material exhibits n-type character and a figure of merit (ZT) value of 0.67 at 873 K. Electronic band structure calculations indicate that K2.5Bi8.5Se14 is an indirect bandgap semiconductor with multiple conduction bands close to the Fermi level. Phonon dispersion calculations suggest K2.5Bi8.5Se14 has low phonon velocities and large Grüneisen parameters that can account for the observed ultralow κlat. The degree of n-type doping can be controlled by introducing Se deficiencies in the structure providing a simple route to increase the ZT to ~1 at 873 K.
author2 School of Materials Science and Engineering
author_facet School of Materials Science and Engineering
Luo, Zhong-Zhen
Cai, Songting
Hao, Shiqiang
Bailey, Trevor P.
Hu, Xiaobing
Hanus, Riley
Ma, Runchu
Tan, Gangjian
Chica. Daniel G.
Snyder, G. Jeffrey
Uher, Ctirad
Wolverton, Christopher
Dravid, Vinayak P.
Yan, Qingyu
Kanatzidis, Mercouri G.
format Article
author Luo, Zhong-Zhen
Cai, Songting
Hao, Shiqiang
Bailey, Trevor P.
Hu, Xiaobing
Hanus, Riley
Ma, Runchu
Tan, Gangjian
Chica. Daniel G.
Snyder, G. Jeffrey
Uher, Ctirad
Wolverton, Christopher
Dravid, Vinayak P.
Yan, Qingyu
Kanatzidis, Mercouri G.
author_sort Luo, Zhong-Zhen
title Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄
title_short Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄
title_full Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄
title_fullStr Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄
title_full_unstemmed Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄
title_sort ultralow thermal conductivity and high-temperature thermoelectric performance in n-type k₂.₅bi₈.₅se₁₄
publishDate 2022
url https://hdl.handle.net/10356/159049
_version_ 1773551278884913152
spelling sg-ntu-dr.10356-1590492023-07-14T16:06:05Z Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄ Luo, Zhong-Zhen Cai, Songting Hao, Shiqiang Bailey, Trevor P. Hu, Xiaobing Hanus, Riley Ma, Runchu Tan, Gangjian Chica. Daniel G. Snyder, G. Jeffrey Uher, Ctirad Wolverton, Christopher Dravid, Vinayak P. Yan, Qingyu Kanatzidis, Mercouri G. School of Materials Science and Engineering Engineering::Materials::Functional materials Phonons Thermal Conductivity We studied the narrow bandgap (0.55 eV) semiconductor K2.5Bi8.5Se14, as a potential thermoelectric material for power generation. Samples of polycrystalline K2.5Bi8.5Se14 prepared by spark plasma sintering exhibit exceptionally low lattice thermal conductivities (κlat) of 0.57 − 0.33 Wm−1K−1 in the temperature range of 300 − 873 K. The physical origin of such low κlat in K2.5Bi8.5Se14 is related to the strong anharmonicity and low phonon velocity caused by its complex low-symmetry, large unit cell crystal structure and mixed-occupancy of Bi and K atoms in the lattice. High-resolution scanning transmission electron microscopy (HRSTEM) studies and micro-analysis indicates that the K2.5Bi8.5Se14 sample is a single phase without intergrowth of the structurally related K2Bi8Se13 phase. The undoped material exhibits n-type character and a figure of merit (ZT) value of 0.67 at 873 K. Electronic band structure calculations indicate that K2.5Bi8.5Se14 is an indirect bandgap semiconductor with multiple conduction bands close to the Fermi level. Phonon dispersion calculations suggest K2.5Bi8.5Se14 has low phonon velocities and large Grüneisen parameters that can account for the observed ultralow κlat. The degree of n-type doping can be controlled by introducing Se deficiencies in the structure providing a simple route to increase the ZT to ~1 at 873 K. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Submitted/Accepted version This work was supported by the Department of Energy, Office of Science Basic Energy Sciences under grant DE-SC0014520, DOE Office of Science (sample preparation, synthesis, XRD, TE measurements, TEM measurements, DFT calculations). Z.-Z.L. and Q.Y. gratefully acknowledge the National Natural Science Foundation of China (61728401). This work made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the MRSEC program (NSF DMR1720139) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois, through the IIN. User Facilities are supported by the Office of Science of the U.S. Department of Energy under Contract Nos. DE-AC02-06CH11357 and DEAC02-05CH11231. Access to facilities of high-performance computational resources at Northwestern University is acknowledged. The authors also acknowledge Singapore MOE AcRF Tier 2 under Grant Nos. 2018-T2-1-010 and MOE2017-T2-2-069, Singapore A*STAR Pharos Program SERC 1527200022, and the support from FACTs of Nanyang Technological University for sample analysis. 2022-05-30T03:10:28Z 2022-05-30T03:10:28Z 2019 Journal Article Luo, Z., Cai, S., Hao, S., Bailey, T. P., Hu, X., Hanus, R., Ma, R., Tan, G., Chica. Daniel G., Snyder, G. J., Uher, C., Wolverton, C., Dravid, V. P., Yan, Q. & Kanatzidis, M. G. (2019). Ultralow thermal conductivity and high-temperature thermoelectric performance in n-type K₂.₅Bi₈.₅Se₁₄. Chemistry of Materials, 31(15), 5943-5952. https://dx.doi.org/10.1021/acs.chemmater.9b02327 0897-4756 https://hdl.handle.net/10356/159049 10.1021/acs.chemmater.9b02327 15 31 5943 5952 en MOE 2018-T2-1-010 MOE 2017-T2-2-069 SERC 1527200022 Chemistry of Materials This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemistry of Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.chemmater.9b02327. application/pdf