Bulk Separative Enrichment in Metallic or Semiconducting Single-Walled Carbon Nanotubes

Chen, Zhihong; Du, Xu; Du, Mao‐Hua; Rancken, C. Daniel; Cheng, Hai‐Ping; Rinzler, Andrew G.

doi:10.1021/nl0344763

Cited by 252 publications

(249 citation statements)

References 22 publications

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“…Maeda et al showed that m-SWCNTs could be highly concentrated to 87% by applying a dispersion-centrifugation process in a tetrahydrofuran solution of propylamine. 25 Similar results were also obtained in the m/s separation of SWCNTs by using bromine 26 and porphyrins 27 . The porphyrin and its derivates tend to attach onto the sidewalls of s-SWCNTs, making them enriched in the supernatant.…”

Section: Introductionsupporting

confidence: 73%

Selective Separation of Single-Walled Carbon Nanotubes in Solution

Li¹,

Li²

2011

Electronic Properties of Carbon Nanotubes

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Section: Introductionsupporting

confidence: 73%

Selective Separation of Single-Walled Carbon Nanotubes in Solution

Li¹,

Li²

2011

Electronic Properties of Carbon Nanotubes

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“…[56] These electronic transition differences, however, make SWNT sample homogeneity a major issue. For example, even if a SWNT sample has been separated according to type (met-versus sem-) and d t , [64][65][66][67][68][69][70] different chirality and modality nanotubes will contribute significant heterogeneity as the nanotube diameter gets smaller than 1.5−2 nm. This is expected to play a significant role in the reproducibility of advanced nanotube devices as the community continues the refinement in coupling a variety of biological stimuli to SWNT electronic transitions.…”

Section: Carbon Nanotube Propertiesmentioning

confidence: 99%

“…Advances in the SWNTs growth, [54,55] etching [147] and separation [64][65][66][67][68][69][70] processes could further improve nanotube-uniformity in terms of removing metallic SWNTs. Sem-enriched SWNTs with defined (n, m) chirality can be engineered to have their E ii transitions lined up appropriately with either the thin metal-plasmon resonance or the redox levels of analyte under investigation to further enhance sensitivity.…”

Section: Future Outlook and Concluding Remarksmentioning

confidence: 99%

Carbon Nanotubes for Electronic and Electrochemical Detection of Biomolecules

2007

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The unique electronic and optical properties of carbon nanotubes, in conjunction with their size and mechanically robust nature, make these nanomaterials crucial to the development of next-generation biosensing platforms. In this Review, we present recent innovations in carbon nanotube-assisted biosensing technologies, such as DNA-hybridization, protein-binding, antibody-antigen and aptamers. Following a brief introduction on the diameter-and chirality-derived electronic characteristics of single-walled carbon nanotubes, the discussion is focused on the two major schemes for electronic biodetection, namely biotransistor-and electrochemistry-based sensors. Key fabrication methodologies are contrasted in light of device operation and performance, along with strategies for amplifying the signal while minimizing nonspecific binding. This Review is concluded with a perspective on future optimization based on array integration as well as exercising a better control in nanotube structure and biomolecular integration.

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“…38 These provided potential routes to sort nanotubes by diameter or electronic structure. In our acid-doped samples, we did not observe any hint of such selectivity although this does not rule out the possibility with other dopants.…”

Section: Fig 2 ͑Color Online͒mentioning

confidence: 99%

Charge transfer and Fermi level shift inp-doped single-walled carbon nanotubes

et al. 2005

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The electronic properties of p-doped single-walled carbon nanotube ͑SWNT͒ bulk samples were studied by temperature-dependent resistivity and thermopower, optical reflectivity, and Raman spectroscopy. These all give consistent results for the Fermi level downshift ͑⌬E F ͒ induced by doping. We find ⌬E F Ϸ 0.35 eV and 0.50 eV for concentrated nitric and sulfuric acid doping respectively. With these values, the evolution of Raman spectra can be explained by variations in the resonance condition as E F moves down into the valence band. Furthermore, we find no evidence for diameter-selective doping, nor any distinction between doping responses of metallic and semiconducting tubes. DOI: 10.1103/PhysRevB.71.205423 PACS number͑s͒: 71.23.Ϫk, 61.48.ϩc, 73.63.Fg, 81.07.De The electronic spectra of single-wall carbon nanotubes ͑SWNTs͒ are dominated by van Hove singularities, manifestations of the 1-D structure. The location of the Fermi energy E F with respect to these singularities can be tuned by chemical ͑alkali metals, acids, halogens, …͒ 1 or electrochemical doping. 2 Doping response in bulk samples is complicated by the presence of metallic and semiconducting tubes and by diameter and chirality dispersion, both of which imply a distribution of initial work functions. 3,4 Further complications arise from tube-tube interactions in bundles or ropes. 5,6 Here we report a systematic study of chemically p-doped SWNTs combining resistivity, thermopower, reflectivity, and Raman spectroscopy. Experimental results from each of the above techniques have been reported before, but quantitative analysis of the Fermi level shift has not been routinely performed. Also, the consistency of experimental results from different techniques has never been carefully addressed. In this work, we compare data obtained for relatively weak and strong protonic acids, HNO 3 and H 2 SO 4 , respectively, in order to test consistency of results from different measurements. We discuss the results in terms of a rigid band model 7 whereby doping shifts E F without affecting the band structure. We assume all tubes in the undoped bulk sample have the same work function, and that E F is initially near the middle of the gap or pseudogap of semiconducting or metallic tubes, respectively. We also assume that doping is spatially uniform, with no energy barriers between metallic and semiconducting tubes. We find that this simplest of models gives consistent results for ⌬E F , the Fermi level shift upon doping. Using the experimentally determined ⌬E F values as input, the evolution of Raman spectra with doping can be simply explained by the variation of resonance conditions with E F , with no evidence for diameter-selective doping as recently proposed. [8][9][10] Samples were prepared from pulsed laser vaporization ͑PLV͒ 11 and HiPco SWNT. 12 The former have a narrow distribution of relatively large diameters, 13 1.36± 0.09 nm, while HiPco tubes have smaller average diameters extending over a broad range, 14 0.8 to 1.4 nm. Starting materials for the doping ex...

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Bulk Separative Enrichment in Metallic or Semiconducting Single-Walled Carbon Nanotubes

Cited by 252 publications

References 22 publications

Selective Separation of Single-Walled Carbon Nanotubes in Solution

Selective Separation of Single-Walled Carbon Nanotubes in Solution

Carbon Nanotubes for Electronic and Electrochemical Detection of Biomolecules

Charge transfer and Fermi level shift inp-doped single-walled carbon nanotubes

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