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Author
Myint, May Thu Zar Graduate School of Natural Science and Technology, Okayama University
Nishikawa, Takeshi Graduate School of Natural Science and Technology, Okayama University Kaken ID publons researchmap
Omoto, Kazuki Graduate School of Natural Science and Technology, Okayama University
Inoue, Hirotaka Graduate School of Natural Science and Technology, Okayama University
Yamashita, Yoshifumi Graduate School of Natural Science and Technology, Okayama University Kaken ID publons researchmap
Kyaw, Aung Ko Ko Department of Electrical and Electronic Engineering, Southern University of Science and Technology
Hayashi, Yasuhiko Graduate School of Natural Science and Technology, Okayama University ORCID Kaken ID researchmap
Abstract
Flexible, light-weight and robust thermoelectric (TE) materials have attracted much attention to convert waste heat from low-grade heat sources, such as human body, to electricity. Carbon nanotube (CNT) yarn is one of the potential TE materials owing to its narrow band-gap energy, high charge carrier mobility, and excellent mechanical property, which is conducive for flexible and wearable devices. Herein, we propose a way to improve the power factor of CNT yarns fabricated from few-walled carbon nanotubes (FWCNTs) by two-step method; Joule-annealing in the vacuum followed by doping with p-type dopants, 2,3,5,6-tetrafluo-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). Numerical calculations and experimental results explain that Joule-annealing and doping modulate the electronic states (Fermi energy level) of FWCNTs, resulting in extremely large thermoelectric power factor of 2250 mu Wm(-1) K-2 at a measurement temperature of 423K. Joule-annealing removes amorphous carbon on the surface of the CNT yarn, which facilitates doping in the subsequent step, and leads to higher Seebeck coefficient due to the transformation from (semi) metallic to semiconductor behavior. Doping also significantly increases the electrical conductivity due to the effective charge transfers between CNT yarn and F4TCNQ upon the removal of amorphous carbon after Joule-annealing.
Keywords
Materials science
Nanoscience and technology
Published Date
2020-04-29
Publication Title
Scientific Reports
Volume
volume10
Issue
issue1
Publisher
Nature
Start Page
7307
ISSN
2045-2322
Content Type
Journal Article
language
英語
OAI-PMH Set
岡山大学
Copyright Holders
© The Author(s) 2020
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publisher
PubMed ID
DOI
Web of Science KeyUT
Related Url
isVersionOf https://doi.org/10.1038/s41598-020-64435-0
License
http://creativecommons.org/licenses/by/4.0/
Funder Name
Japan Society for the Promotion of Science
助成番号
17K20065
18H01708