Ion-Exchange Doping of Semiconducting Single-Walled Carbon Nanotubes

Fuente: arXiv
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Autores principales: Hawkey, Angus, Dash, Aditya, Rodríguez-Martínez, Xabier, Zhao, Zhiyong, Champ, Anna, Lindenthal, Sebastian, Zharnikov, Michael, Kemerink, Martijn, Zaumseil, Jana
Formato: Preprint
Publicado: 2025
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author Hawkey, Angus
Dash, Aditya
Rodríguez-Martínez, Xabier
Zhao, Zhiyong
Champ, Anna
Lindenthal, Sebastian
Zharnikov, Michael
Kemerink, Martijn
Zaumseil, Jana
author_facet Hawkey, Angus
Dash, Aditya
Rodríguez-Martínez, Xabier
Zhao, Zhiyong
Champ, Anna
Lindenthal, Sebastian
Zharnikov, Michael
Kemerink, Martijn
Zaumseil, Jana
contents Semiconducting single-walled carbon nanotubes (SWCNTs) are a promising thermoelectric material with high power factors after chemical p- or n-doping. Understanding the impact of dopant counterions on charge transport and thermoelectric properties of nanotube networks is essential to further optimize doping methods and to develop better dopants. Here, we utilize ion-exchange doping to systematically vary the size of counterions in thin films of small and large diameter, polymer-sorted semiconducting SWCNTs with AuCl3 as the initial p-dopant and investigate the impact of ion size on conductivity, Seebeck coefficients and power factors. Larger anions are found to correlate with higher electrical conductivities and improved doping stability, while no significant effect on the power factors is found. Importantly, the effect of counterion size on the thermoelectric properties of dense SWCNT networks is not obscured by morphological changes upon doping. The observed trends of carrier mobilities and Seebeck coefficients can be explained by a random resistor model for the nanotube network that accounts for overlapping Coulomb potentials leading to the formation of an impurity band whose depth depends on the carrier density and counterion size. These insights can be applied more broadly to understand the thermoelectric properties of doped percolating disordered systems, including semiconducting polymers.
format Preprint
id arxiv_https___arxiv_org_abs_2503_16347
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ion-Exchange Doping of Semiconducting Single-Walled Carbon Nanotubes
Hawkey, Angus
Dash, Aditya
Rodríguez-Martínez, Xabier
Zhao, Zhiyong
Champ, Anna
Lindenthal, Sebastian
Zharnikov, Michael
Kemerink, Martijn
Zaumseil, Jana
Materials Science
Semiconducting single-walled carbon nanotubes (SWCNTs) are a promising thermoelectric material with high power factors after chemical p- or n-doping. Understanding the impact of dopant counterions on charge transport and thermoelectric properties of nanotube networks is essential to further optimize doping methods and to develop better dopants. Here, we utilize ion-exchange doping to systematically vary the size of counterions in thin films of small and large diameter, polymer-sorted semiconducting SWCNTs with AuCl3 as the initial p-dopant and investigate the impact of ion size on conductivity, Seebeck coefficients and power factors. Larger anions are found to correlate with higher electrical conductivities and improved doping stability, while no significant effect on the power factors is found. Importantly, the effect of counterion size on the thermoelectric properties of dense SWCNT networks is not obscured by morphological changes upon doping. The observed trends of carrier mobilities and Seebeck coefficients can be explained by a random resistor model for the nanotube network that accounts for overlapping Coulomb potentials leading to the formation of an impurity band whose depth depends on the carrier density and counterion size. These insights can be applied more broadly to understand the thermoelectric properties of doped percolating disordered systems, including semiconducting polymers.
title Ion-Exchange Doping of Semiconducting Single-Walled Carbon Nanotubes
topic Materials Science
url https://arxiv.org/abs/2503.16347