Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process

Minority carrier blocking through heterointerface barriers has been theoretically proposed to enhance the thermoelectric figure of merit (ZT) of bismuth telluride based nanocomposites at elevated temperatures recently (Phys. Rev. B2016, 93, 165209). Here, to experimentally realize the minority carri...

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Main Authors: Zhang, Chaohua, Ng, Hongkuan, Li, Zhong, Khor, Khiam Aik, Xiong, Qihua
Other Authors: School of Mechanical and Aerospace Engineering
Format: Article
Language:English
Published: 2020
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Online Access:https://hdl.handle.net/10356/140362
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1403622023-02-28T19:24:53Z Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process Zhang, Chaohua Ng, Hongkuan Li, Zhong Khor, Khiam Aik Xiong, Qihua School of Mechanical and Aerospace Engineering School of Physical and Mathematical Sciences Science::Physics Minority Carrier Blocking Liquid-phase Sintering Minority carrier blocking through heterointerface barriers has been theoretically proposed to enhance the thermoelectric figure of merit (ZT) of bismuth telluride based nanocomposites at elevated temperatures recently (Phys. Rev. B2016, 93, 165209). Here, to experimentally realize the minority carrier blocking, a liquid-phase sintering process enabled by excess Te is applied to the solution-processed BixSb2–xTe3 nanocomposites to introduce interfacial energy barriers. The controlling parameters in the liquid-phase sintering process such as the amount of excess Te, sintering temperature and holding time, and the Bi composition (x) are systemically tuned and investigated to fully understand the minority carrier blocking mechanism. These interface-engineering parameters are optimized for introducing maximum lattice imperfections and band-bending interfaces that are responsible for blocking the minority carrier and wide-range scattering of the phonons toward enhanced thermoelectric performance. High ZT > 1.4 at 375 K is realized in the Bi0.5Sb1.5Te3 sample, which is much higher than those of the state-of-the-art commercial ingots (ZT ∼ 1) and other solution-processed nanocomposites. The enhanced ZT at elevated temperatures is mostly due to the suppression of bipolar thermal conductivity by minority carrier blocking as well as the reduction of lattice thermal conductivity. Adapting this solution synthesis process to design favorable heterointerfaces for minority carrier blocking in the liquid-phase sintering process holds promise to further enhance the ZT values. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version 2020-05-28T05:22:05Z 2020-05-28T05:22:05Z 2017 Journal Article Zhang, C., Ng, H., Li, Z., Khor, K. A., & Xiong, Q. (2017). Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process. ACS Applied Materials & Interfaces, 9(14), 12501-12510. doi:10.1021/acsami.7b01473 1944-8244 https://hdl.handle.net/10356/140362 10.1021/acsami.7b01473 28318220 2-s2.0-85017461968 14 9 12501 12510 en ACS Applied Materials & Interfaces This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, 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/acsami.7b01473 application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Physics
Minority Carrier Blocking
Liquid-phase Sintering
spellingShingle Science::Physics
Minority Carrier Blocking
Liquid-phase Sintering
Zhang, Chaohua
Ng, Hongkuan
Li, Zhong
Khor, Khiam Aik
Xiong, Qihua
Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process
description Minority carrier blocking through heterointerface barriers has been theoretically proposed to enhance the thermoelectric figure of merit (ZT) of bismuth telluride based nanocomposites at elevated temperatures recently (Phys. Rev. B2016, 93, 165209). Here, to experimentally realize the minority carrier blocking, a liquid-phase sintering process enabled by excess Te is applied to the solution-processed BixSb2–xTe3 nanocomposites to introduce interfacial energy barriers. The controlling parameters in the liquid-phase sintering process such as the amount of excess Te, sintering temperature and holding time, and the Bi composition (x) are systemically tuned and investigated to fully understand the minority carrier blocking mechanism. These interface-engineering parameters are optimized for introducing maximum lattice imperfections and band-bending interfaces that are responsible for blocking the minority carrier and wide-range scattering of the phonons toward enhanced thermoelectric performance. High ZT > 1.4 at 375 K is realized in the Bi0.5Sb1.5Te3 sample, which is much higher than those of the state-of-the-art commercial ingots (ZT ∼ 1) and other solution-processed nanocomposites. The enhanced ZT at elevated temperatures is mostly due to the suppression of bipolar thermal conductivity by minority carrier blocking as well as the reduction of lattice thermal conductivity. Adapting this solution synthesis process to design favorable heterointerfaces for minority carrier blocking in the liquid-phase sintering process holds promise to further enhance the ZT values.
author2 School of Mechanical and Aerospace Engineering
author_facet School of Mechanical and Aerospace Engineering
Zhang, Chaohua
Ng, Hongkuan
Li, Zhong
Khor, Khiam Aik
Xiong, Qihua
format Article
author Zhang, Chaohua
Ng, Hongkuan
Li, Zhong
Khor, Khiam Aik
Xiong, Qihua
author_sort Zhang, Chaohua
title Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process
title_short Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process
title_full Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process
title_fullStr Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process
title_full_unstemmed Minority carrier blocking to enhance the thermoelectric performance of solution-processed BixSb2 – xTe3 nanocomposites via a liquid-phase sintering process
title_sort minority carrier blocking to enhance the thermoelectric performance of solution-processed bixsb2 – xte3 nanocomposites via a liquid-phase sintering process
publishDate 2020
url https://hdl.handle.net/10356/140362
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