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Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena

Temperature dependence of electrical conductivity/resistivity of CNT networks (dry or impregnated), which is characterised by a temperature coefficient of resistance (TCR), is experimentally observed to be negative, especially for the case of aligned CNT (A-CNT). The paper investigates the role of t...

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Autores principales: Lomov, Stepan V., Akmanov, Iskander S., Liu, Qiang, Wu, Qi, Abaimov, Sergey G.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9921551/
https://www.ncbi.nlm.nih.gov/pubmed/36771980
http://dx.doi.org/10.3390/polym15030678
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author Lomov, Stepan V.
Akmanov, Iskander S.
Liu, Qiang
Wu, Qi
Abaimov, Sergey G.
author_facet Lomov, Stepan V.
Akmanov, Iskander S.
Liu, Qiang
Wu, Qi
Abaimov, Sergey G.
author_sort Lomov, Stepan V.
collection PubMed
description Temperature dependence of electrical conductivity/resistivity of CNT networks (dry or impregnated), which is characterised by a temperature coefficient of resistance (TCR), is experimentally observed to be negative, especially for the case of aligned CNT (A-CNT). The paper investigates the role of three phenomena defining the TCR, temperature dependence of the intrinsic conductivity of CNTs, of the tunnelling resistance of their contacts, and thermal expansion of the network, in the temperature range 300–400 K. A-CNT films, created by rolling down A-CNT forests of different length and described in Lee et al., Appl Phys Lett, 2015, 106: 053110, are investigated as an example. The modelling of the electrical conductivity is performed by the nodal analysis of resistance networks, coupled with the finite-element thermomechanical modelling of network thermal expansion. The calculated TCR for the film is about −0.002 1/K and is close to the experimentally observed values. Comparative analysis of the influence of the TCR defining phenomena is performed on the case of dry and impregnated films. The analysis shows that in both cases, for an A-CNT film at the studied temperature interval, the main factor affecting a network’s TCR is the TCR of the CNTs themselves. The TCR of the tunnelling contacts plays the secondary role; influence of the film thermal expansion is marginal. The prevailing impact of the intrinsic conductivity TCR on the TCR of the film is explained by long inter-contact segments of CNTs in an A-CNT network, which define the homogenised film conductivity.
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spelling pubmed-99215512023-02-12 Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena Lomov, Stepan V. Akmanov, Iskander S. Liu, Qiang Wu, Qi Abaimov, Sergey G. Polymers (Basel) Article Temperature dependence of electrical conductivity/resistivity of CNT networks (dry or impregnated), which is characterised by a temperature coefficient of resistance (TCR), is experimentally observed to be negative, especially for the case of aligned CNT (A-CNT). The paper investigates the role of three phenomena defining the TCR, temperature dependence of the intrinsic conductivity of CNTs, of the tunnelling resistance of their contacts, and thermal expansion of the network, in the temperature range 300–400 K. A-CNT films, created by rolling down A-CNT forests of different length and described in Lee et al., Appl Phys Lett, 2015, 106: 053110, are investigated as an example. The modelling of the electrical conductivity is performed by the nodal analysis of resistance networks, coupled with the finite-element thermomechanical modelling of network thermal expansion. The calculated TCR for the film is about −0.002 1/K and is close to the experimentally observed values. Comparative analysis of the influence of the TCR defining phenomena is performed on the case of dry and impregnated films. The analysis shows that in both cases, for an A-CNT film at the studied temperature interval, the main factor affecting a network’s TCR is the TCR of the CNTs themselves. The TCR of the tunnelling contacts plays the secondary role; influence of the film thermal expansion is marginal. The prevailing impact of the intrinsic conductivity TCR on the TCR of the film is explained by long inter-contact segments of CNTs in an A-CNT network, which define the homogenised film conductivity. MDPI 2023-01-29 /pmc/articles/PMC9921551/ /pubmed/36771980 http://dx.doi.org/10.3390/polym15030678 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Lomov, Stepan V.
Akmanov, Iskander S.
Liu, Qiang
Wu, Qi
Abaimov, Sergey G.
Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena
title Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena
title_full Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena
title_fullStr Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena
title_full_unstemmed Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena
title_short Negative Temperature Coefficient of Resistance in Aligned CNT Networks: Influence of the Underlying Phenomena
title_sort negative temperature coefficient of resistance in aligned cnt networks: influence of the underlying phenomena
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9921551/
https://www.ncbi.nlm.nih.gov/pubmed/36771980
http://dx.doi.org/10.3390/polym15030678
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