Electronic Structure and Scaling of Coulomb Defects in Carbon Nanotubes from Modified Hückel Calculations

Eckstein, Klaus H.; Hertel, Tobias

doi:10.1021/acs.jpcc.3c06007

Cited by 4 publications

(1 citation statement)

References 41 publications

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“…Accurate calculations which include extensive treatment of the correlation energy are not always necessary for the understanding of SWNTs interaction with molecules and adsorbates . SWNTs are topological systems where simple mathematical treatment can yield results with desired accuracy.…”

Section: Molecular Recognition Of Swnt Chirality Through Theoretical ...mentioning

confidence: 99%

Supramolecular-Based One-Pot Separation of Highly Pure Adsorbent-Free Semiconducting Single-Walled Carbon Nanotubes and Machine Learning-Based Nanotube Solubilization

Nakashima,

Nonoguchi,

Staykov

2024

Acc. Mater. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS: Carbon nanotubes are classified into single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes and multiwalled carbon nanotubes. Among these, SWNTs have remarkable electronic, mechanical, optical, chemical and thermal properties, which are derived from their one-dimensional extended πconjugated structures, and thus, they demonstrate a high potential toward the development of the next-generation nanoelectronics, (nano)bio, and energy and environmental materials and devices. Asproduced SWNTs are a mixture of semiconducting (sem-) and metallic (met-)-SWNTs; thus, chirality sorting is highly important. So far various methods have been presented for such a separation including (i) use of chemical adsorbents such as polyfluorenes (PFOs) and their analogues and (ii) physical methods including surfactant-aided density gradient ultracentrifugation (DGU), gel chromatography techniques, and the surfactant-aided aqueous two-phase extraction method. However, such methods are not simple, and the removal of the wrapped adsorbents on the SWNTs is very difficult. Thus, the development of a method to remove the adsorbent from the sorted SWNTs is highly important to obtain adsorbent-free pure sem-SWNTs.In this Account, we provide a summary of a one-pot highly efficient sem-SWNT sorting using a solubilizer and removal of the wrapped solubilizer/adsorbent from the surfaces of the sorted tubes to provide highly pure adsorbent-free sem-SWNTs, in which the design and synthesis of adsorbents that selectively sorts sem-SWNTs from as-produced SWNTs, a mixture of sem-SWNTs and met-SWNTs, with easy removal property by a suitable method are described. In particular, we demonstrate a solubilizer-free sem-SWNT sorting based on supramolecular chemistry. The development of easy/simple and an efficient adsorbent-free sem-SWNT sorting method is highly important for proper fundamental use and application of SWNTs in industry. In addition, we describe computer simulations for selective sem-SWNT sorting based on a DFT method; in particular, we summarize our density functional theory (DFT) approach for helical wrapping of flavin molecules on the (8,6)-SWNT, leading to successful SWNT chirality separation. Finally, the introduction of a machine learning approach for SWNT solubilization is summarized.

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Section: Molecular Recognition Of Swnt Chirality Through Theoretical ...mentioning

confidence: 99%

Supramolecular-Based One-Pot Separation of Highly Pure Adsorbent-Free Semiconducting Single-Walled Carbon Nanotubes and Machine Learning-Based Nanotube Solubilization

Nakashima,

Nonoguchi,

Staykov

2024

Acc. Mater. Res.

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Ion‐Exchange Doping of Semiconducting Single‐Walled Carbon Nanotubes

Hawkey,

Dash,

Rodríguez‐Martínez

et al. 2024

Advanced Materials

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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. This work utilizes 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 investigates 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.

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Onset of spin entanglement in doped carbon nanotubes studied by EPR

Sperlich,

Eckstein,

Oberndorfer

et al. 2024

The Journal of Chemical Physics

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Nanoscale semiconductors with isolated spin impurities have been touted as promising materials for their potential use at the intersection of quantum, spin, and information technologies. Electron paramagnetic resonance (EPR) studies of spins in semiconducting carbon nanotubes have overwhelmingly focused on spins more strongly localized by sp3-type lattice defects. However, the creation of such impurities is irreversible and requires specific reactions to generate them. Shallow charge impurities, on the other hand, are more readily and widely produced by simple redox chemistry, but have not yet been investigated for their spin properties. Here, we use EPR to study p-doped (6,5) semiconducting single-wall carbon nanotubes (s-SWNTs) and elucidate the role of impurity–impurity interactions in conjunction with exchange and correlation effects for the spin behavior of this material. A quantitative comparison of the EPR signals with phenomenological modeling combined with configuration interaction electronic structure calculations of impurity pairs shows that orbital overlap, combined with exchange and correlation effects, causes the EPR signal to disappear due to spin entanglement for doping levels corresponding to impurity spacings of 14 nm (at 30 K). This transition is predicted to shift to higher doping levels with increasing temperature and to lower levels with increasing screening, providing an opportunity for improved spin control in doped s-SWNTs.

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Electronic Structure and Scaling of Coulomb Defects in Carbon Nanotubes from Modified Hückel Calculations

Cited by 4 publications

References 41 publications

Supramolecular-Based One-Pot Separation of Highly Pure Adsorbent-Free Semiconducting Single-Walled Carbon Nanotubes and Machine Learning-Based Nanotube Solubilization

Supramolecular-Based One-Pot Separation of Highly Pure Adsorbent-Free Semiconducting Single-Walled Carbon Nanotubes and Machine Learning-Based Nanotube Solubilization

Ion‐Exchange Doping of Semiconducting Single‐Walled Carbon Nanotubes

Onset of spin entanglement in doped carbon nanotubes studied by EPR

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