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Sample records for antibody-functionalized single-walled carbon

  1. Detecting Lyme Disease Using Antibody-Functionalized Single-Walled Carbon Nanotube Transistors

    CERN Document Server

    Lerner, Mitchell B; Goldsmith, Brett R; Brisson, Dustin; Johnson, A T Charlie

    2013-01-01

    We examined the potential of antibody-functionalized single-walled carbon nanotube (SWNT) field-effect transistors (FETs) for use as a fast and accurate sensor for a Lyme disease antigen. Biosensors were fabricated on oxidized silicon wafers using chemical vapor deposition grown carbon nanotubes that were functionalized using diazonium salts. Attachment of Borrelia burgdorferi (Lyme) flagellar antibodies to the nanotubes was verified by Atomic Force Microscopy and electronic measurements. A reproducible shift in the turn-off voltage of the semiconducting SWNT FETs was seen upon incubation with Borrelia burgdorferi flagellar antigen, indicative of the nanotube FET being locally gated by the residues of flagellar protein bound to the antibody. This sensor effectively detected antigen in buffer at concentrations as low as 1 ng/ml, and the response varied strongly over a concentration range coinciding with levels of clinical interest. Generalizable binding chemistry gives this biosensing platform the potential to...

  2. Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells

    International Nuclear Information System (INIS)

    Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs) exhibit two unique optical properties that can be exploited for these applications, strong Raman signal for cancer cell detection and near-infrared (NIR) absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and demonstrated its dual functionality for both detection and selective destruction of cancer cells in an in vitro model consisting of HER2-expressing SK-BR-3 cells and HER2-negative MCF-7 cells. The complex was constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken IgY antibody, which is more specific and sensitive than mammalian IgGs. Raman signals were recorded on Raman spectrometers with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 5 W/cm2 for 2 min. Cell viability was examined by the calcein AM/ethidium homodimer-1 (EthD-1) staining. Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated SK-BR-3 cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast cancer cells without harming receptor-free cells. The cell death was effectuated without the need of internalization of SWNTs by the cancer cells, a finding that has not been reported previously. We have demonstrated that the HER2 IgY-SWNT complex specifically targeted HER2-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells. The complex can be potentially used for both detection and selective photothermal ablation of receptor-positive breast cancer cells without the need of internalization by the cells. Thus, the unique intrinsic properties of SWNTs combined with high specificity and sensitivity of IgY antibodies

  3. Scalable dielectrophoresis of single walled carbon nanotubes

    Science.gov (United States)

    Fitzhugh, William A.

    Single Walled Carbon Nanotubes (SWNTs) have attracted much attention as a candidate material for future nano-scale 'beyond silicon' devices. However industrial scale operations have been impeded by difficulties in separating the metallic and semiconducting species. This paper addresses the use of highly inhomogeneous alternating electric fields, dielectrophoresis, to isolate SWNT species in scaled systems. Both numerical and experimental methods will be discussed.

  4. Thermal Conductance for Single Wall Carbon Nanotubes

    OpenAIRE

    Zheng, Qing-Rong; Su, Gang; Jian WANG; Guo, Hong

    2002-01-01

    We report a theoretical analysis of the phonon thermal conductance, \\kappa (T), for single wall carbon nanotubes (SWCN). In a range of low temperatues up to 100K, \\kappa (T) of perfect SWCN is found to increase with temperature, approximately, in a parabolic fashion. This is qualitatively consistent with recent experimental measurements where the tube-tube interactions are negligibly weak. When the carbon-carbon bond length is slightly varied, \\kappa (T) is found to be qualitatively unaltered...

  5. Nicotine adsorption on single wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Girao, Eduardo C. [Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceara (Brazil); Fagan, Solange B.; Zanella, Ivana [Area de Ciencias Tecnologicas, Centro Universitario Franciscano - UNIFRA, 97010-032 Santa Maria, RS (Brazil); Filho, Antonio G. Souza, E-mail: agsf@fisica.ufc.br [Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceara (Brazil)

    2010-12-15

    This work reports a theoretical study of nicotine molecules interacting with single wall carbon nanotubes (SWCNTs) through ab initio calculations within the framework of density functional theory (DFT). Different adsorption sites for nicotine on the surface of pristine and defective (8,0) SWCNTs were analyzed and the total energy curves, as a function of molecular position relative to the SWCNT surface, were evaluated. The nicotine adsorption process is found to be energetically favorable and the molecule-nanotube interaction is intermediated by the tri-coordinated nitrogen atom from the nicotine. It is also predicted the possibility of a chemical bonding between nicotine and SWCNT through the di-coordinated nitrogen.

  6. Superconductivity in single wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    H Yavari

    2009-08-01

    Full Text Available   By using Greens function method we first show that the effective interaction between two electrons mediated by plasmon exchange can become attractive which in turn can lead to superconductivity at a high critical temperature in a singl wall carbon nanotubes (SWCNT. The superconducting transition temperature Tc for the SWCNT (3,3 obtained by this mechanism agrees with the recent experimental result. We also show as the radius of SWCNT increases, plasmon frequency becomes lower and leads to lower Tc.

  7. Hydrogen storage in single walled carbon nanotubes

    International Nuclear Information System (INIS)

    Claims have emerged recently, of high hydrogen storage capacities at room temperature and above, for carbons such as single-wall and multi-walled nanotubes. We have been unable to verify any claims of high capacities at room temperature and low pressure. For (10,10) single wall carbon nanotubes, we used a computer controlled Sievert's apparatus to measure an adsorption at RT of 0.07 wt% gravimetric density at 1 bar, typical of what is expected on the basis of BET surface area measurements for carbons. At high pressures of > 60 bar and temperatures of 80K gravimetric densities up to ∼ 8 wt% are obtained, but more typically ∼ 7 wt% after a few adsorption desorption cycles. These values and isotherm shapes can be attributed to rearrangement of the rope structure that is formed by condensed nanotubes. Certain fullerites can also exhibit adsorption/desorption cycle dependent capacity, ranging from 2.5 to 4 wt% at 80K and 120 bar. (author)

  8. Methods for Gas Sensing with Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Kaul, Anupama B. (Inventor)

    2013-01-01

    Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

  9. A new method of preparing single-walled carbon nanotubes

    Indian Academy of Sciences (India)

    S R C Vivekchand; A Govindaraj

    2003-10-01

    A novel method of purification for single-walled carbon nanotubes, prepared by an arc-discharge method, is described. The method involves a combination of acid washing followed by high temperature hydrogen treatment to remove the metal nanoparticles and amorphous carbon present in the as-synthesized singlewalled carbon nanotubes. The purified single-walled carbon nanotubes have been characterised by low-angle X-ray diffraction, electron microscopy, thermo-gravimetric analysis and Raman spectroscopy.

  10. Enhancement of semiconducting single-wall carbon nanotubes photoluminescence

    OpenAIRE

    Gaufrès, Etienne; Izard, Nicolas; Vivien, Laurent; Kazaoui, Saïd; Marris-Morini, Delphine; Cassan, Eric

    2009-01-01

    International audience Photoluminescence properties of semiconducting single wall carbon nanotubes (s-SWNT) thin films with different metallic single wall carbon nanotubes (m-SWNT) concentrations are reported. s-SWNT purified samples are obtained by polymer assisted selective extraction. We show that a few m-SWNT in the sample generates a drastic quenching of the emission. Therefore, highly purified s-SWNT films are a strongly luminescent material and a good candidate for future applications in...

  11. A Computational Experiment on Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Simpson, Scott; Lonie, David C.; Chen, Jiechen; Zurek, Eva

    2013-01-01

    A computational experiment that investigates single-walled carbon nanotubes (SWNTs) has been developed and employed in an upper-level undergraduate physical chemistry laboratory course. Computations were carried out to determine the electronic structure, radial breathing modes, and the influence of the nanotube's diameter on the…

  12. Photophysics of polymer-wrapped single-walled carbon nanotubes

    NARCIS (Netherlands)

    Gao, J; Loi, M.A.

    2010-01-01

    Single-walled carbon nanotubes (SWNTs) are successfully dispersed in two conjugated polymer poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) and poly[2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEHPPV) solutions. Steady-state and time-resolved photoluminescence spectroscopy in the near-infrare

  13. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  14. Chromatographic size separation of single-wall carbon nanotubes

    Science.gov (United States)

    Duesberg, G. S.; Muster, J.; Krstic, V.; Burghard, M.; Roth, S.

    The efficient purification of single-wall carbon nanotubes (SWNTs) is reported. Carbon nanospheres, metal particles, and amorphous carbon could be successfully removed by size exclusion chromatography (SEC) applied to surfactant stabilised dispersions of SWNT raw material. In addition, length separation of the tubes was achieved. The SWNTs obtained can be adsorbed in high densities onto chemically modified substrates. As determined by AFM investigations, the purified material consists of about equal fractions of both individual SWNTS and ropes of SWNTs.

  15. Structure of single-wall carbon nanotubes: a graphene helix.

    Science.gov (United States)

    Lee, Jae-Kap; Lee, Sohyung; Kim, Jin-Gyu; Min, Bong-Ki; Kim, Yong-Il; Lee, Kyung-Il; An, Kay Hyeok; John, Phillip

    2014-08-27

    Evidence is presented in this paper that certain single-wall carbon nanotubes are not seamless tubes, but rather adopt a graphene helix resulting from the spiral growth of a nano-graphene ribbon. The residual traces of the helices are confirmed by high-resolution transmission electron microscopy and atomic force microscopy. The analysis also shows that the tubular graphene material may exhibit a unique armchair structure and the chirality is not a necessary condition for the growth of carbon nanotubes. The description of the structure of the helical carbon nanomaterials is generalized using the plane indices of hexagonal space groups instead of using chiral vectors. It is also proposed that the growth model, via a graphene helix, results in a ubiquitous structure of single-wall carbon nanotubes. PMID:24838196

  16. Molecular mechanics applied to single-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Antonio Ferreira Ávila

    2008-09-01

    Full Text Available Single-walled carbon nanotubes, with stiffness of 1.0 TPa and strength of 60 GPa, are a natural choice for high strength materials. A problem, however, arises when experimental data are compiled. The large variability of experimental data leads to the development of numerical models denominated molecular mechanics, which is a "symbiotic" association of molecular dynamics and solid mechanics. This paper deals with molecular mechanics simulations of single-walled carbon nanotubes. To be able to evaluate the molecular mechanics model, the three major carbon nanotube configurations (armchair, zigzag and chiral were simulated. It was proven that the carbon nanotube configuration has influence on stiffness. By varying the radius, hence the curvature, the Young's modulus changed from 0.95 TPa to 5.5 TPa, and the Poisson's ratio ranged from 0.15 to 0.29. The numerical simulations were in good agreement with those presented in the literature.

  17. Simulations of nanosensors based on single walled carbon nanotubes

    International Nuclear Information System (INIS)

    The potential of single-walled carbon nanotubes as mass sensors is examined. The change in mass leads to proportional changes in the nanotube vibrational frequencies, which are monitored during atomistic simulations. We observed a frequency shift as a result of replacement of carbon C12 with its isotope C13. For a zigzag (12,0) nanotube of about 10 nm length, we found zeptogram sensitivity.

  18. Metallic single-walled carbon nanotubes for conductive nanocomposites.

    Science.gov (United States)

    Wang, Wei; Fernando, K A Shiral; Lin, Yi; Meziani, Mohammed J; Veca, L Monica; Cao, Li; Zhang, Puyu; Kimani, Martin M; Sun, Ya-Ping

    2008-01-30

    This article reports an unambiguous demonstration that bulk-separated metallic single-walled carbon nanotubes offer superior performance (consistently and substantially better than the as-produced nanotube sample) in conductive composites with poly(3-hexylthiophene) and also in transparent conductive coatings based on PEDOT:PSS. The results serve as a validation on the widely held view that the carbon nanotubes are competitive in various technologies currently dominated by conductive inorganic materials (such as indium tin oxide). PMID:18173271

  19. Assessing the pulmonary toxicity of single-walled carbon nanohorns

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, Rachel M [ORNL; Voy, Brynn H [ORNL; Glass-Mattie, Dana F [ORNL; Mahurin, Shannon Mark [ORNL; Saxton, Arnold [University of Tennessee, Knoxville (UTK); Donnel, Robert L. [University of Tennessee, Knoxville (UTK); Cheng, Mengdawn [ORNL

    2007-01-01

    Previous studies have suggested that single-walled carbon nanotubes (SWCNTs) may be pose a pulmonary hazard. We investigated the pulmonary toxicity of single-walled carbon nanohorns (SWCNHs), a relatively new carbon-based nanomaterial that is structurally similar to SWCNTs. Mice were exposed to 30 g of surfactant-suspended SWCNHs by pharyngeal aspiration and sacrificed 24 hours or 7 days post exposure. Total and differential cell counts and cytokine analysis of bronchoalveolar lavage fluid demonstrated a mild inflammatory response which was mitigated by day 7 post exposure. Whole lung microarray analysis demonstrated that SWCNH-exposure did not lead to robust changes in gene expression. Finally, histological analysis showed no evidence of granuloma formation or fibrosis following SWCNH aspiration. These combined results suggest that SWCNH is a relatively innocuous nanomaterial when delivered to mice in vivo using aspiration as a delivery mechanism.

  20. Assessing the pulmonary toxicity of single-walled carbon nanohorns

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, Rachel M [ORNL; Voy, Brynn H [ORNL; Glass-Mattie, Dana F [ORNL; Mahurin, Shannon Mark [ORNL; Saxton, Arnold [University of Tennessee, Knoxville (UTK); Donnel, Robert L. [University of Tennessee, Knoxville (UTK); Cheng, Mengdawn [ORNL

    2007-01-01

    Previous studies have suggested that single-walled carbon nanotubes (SWCNTs) may pose a pulmonary hazard. We investigated the pulmonary toxicity of single-walled carbon nanohorns (SWCNHs), a relatively new carbon-based nanomaterial that is structurally similar to SWCNTs. Mice were exposed to 30 {micro}g of surfactant-suspended SWCNHs or an equal volume of vehicle control by pharyngeal aspiration and sacrificed 24 hours or 7 days post-exposure. Total and differential cell counts and cytokine analysis of bronchoalveolar lavage fluid demonstrated a mild inflammatory response which was mitigated by day 7 post-exposure. Whole lung microarray analysis demonstrated that SWCNH-exposure did not lead to robust changes in gene expression. Finally, histological analysis showed no evidence of granuloma formation or fibrosis following SWCNH aspiration. These combined results suggest that SWCNH is a relatively innocuous nanomaterial when delivered to mice in vivo using aspiration as a delivery mechanism.

  1. Quantitative optical imaging of single-walled carbon nanotubes

    Science.gov (United States)

    Herman, Lihong H.

    The development and application of optical imaging tools and probing techniques have been the subject of exciting research. These tools and techniques allow for non-invasive, simple sample preparation and relatively fast measurement of electronic and optical properties. They also provided crucial information on optoelectronic device application and development. As the field of nanostructure research emerged, they were modified and employed to understand various properties of these structures at the diffraction limit of light. Carbon nanotubes, up to hundreds of micrometers long and several nanometers thin, are perfect for testing and demonstrating newly-developed optical measurement platforms for individual nanostructures, due to their heterogeneous nature. By employing two quantitative imaging techniques, wide-field on-chip Rayleigh scattering spectroscopy and spatial modulation confocal absorption microscopy, we investigate the optical properties of single-walled carbon nanotubes. These techniques allow us to obtain the Rayleigh scattering intensity, absolute absorption cross section, spatial resolution, and spectral information of single-walled carbon nanotubes. By probing the optical resonance of hundreds of single-walled carbon nanotubes in a single measurement, the first technique utilizes Rayleigh scattering mechanism to obtain the chirality of carbon nanotubes. The second technique, by using high numerical aperture oil immersion objective lenses, we measure the absolute absorption cross section of a single-walled carbon nanotube. Combining all the quantitative values obtained from these techniques, we observe various interesting and recently discovered physical behaviors, such as long range optical coupling and universal optical conductivity on resonance, and demonstrate the possibility of accurate quantitative absorption measurement for individual structures at nanometer scale.

  2. Preparation of single-walled carbon nanotube reinforced magnesia films

    OpenAIRE

    Du, C S; Pan, Ning

    2004-01-01

    Single-walled carbon nanotube (SWNT)/MgO composite films were fabricated by growing carbon nanotubes while simultaneously sintering a MgO film. The effect of iron and molybdenum concentrations in liquid catalysts and the effect of the density of carbon nanotubes in the composite films on the quality of the films were investigated. Microstructure analysis showed that SWNTs were uniformly grown in the MgO film. The presence of a controlled amount of carbon nanotubes in MgO films is believed to ...

  3. Single-Walled Carbon Nanotubes for Flexible Electronics and Sensors

    Institute of Scientific and Technical Information of China (English)

    Xiuyun SUN; Yugang SUN

    2008-01-01

    This article reviews the use of electronic quality single-walled carbon nanotubes grown via chemical vapor deposition (CVD) approaches at high temperatures as building blocks for fabricating flexible field-effect devices, such as thin-film transistors (TFTs) and chemical sensors. Dry transfer printing technique is developed for forming films of CVD nanotubes on low-temperature plastic substrates. Examples of TFTs with the use of nanotubes and thin dielectrics and hydrogen sensors with the use of nanotubes decorated with palladium nanoparticles are discussed in detail to demonstrate the promising potentiality of single-walled carbon nanotubes for building high performance flexible devices, which can find applications where traditional devices on rigid substrates are not suitable.

  4. Thermal properties of single-walled carbon nanotube crystal

    Institute of Scientific and Technical Information of China (English)

    Hu Li-Jun; Liu Ji; Liu Zheng; Qiu Cai-Yu; Zhou Hai-Qing; Sun Lian-Feng

    2011-01-01

    In this work,the thermal properties of a single-walled carbon nanotube (SWCNT) crystal are studied. The thermal conductivity of the SWCNT crystal is found to have a linear dependence on temperature in the temperature range from 1.9 K to 100.0 K. In addition,a peak (658 W/mK) is found at a temperature of about 100.0 K. The thermal conductivity decreases gradually to a value of 480 W/mK and keeps almost a constant in the temperature range from 100.0 K to 300.0 K. Meanwhile,the specific heat shows an obvious linear relationship with temperature in the temperature range from 1.9 K to 300.0 K. We discuss the possible mechanisms for these unique thermal properties of the single-walled carbon nanotube crystal.

  5. Reinforcement of Epoxies Using Single Walled Carbon Nanotubes

    Science.gov (United States)

    Krishnamoorti, Ramanan; Sharma, Jitendra; Chatterjee, Tirtha

    2008-03-01

    The reinforcement of bisphenol-A and bisphenol-F epoxies using single walled carbon nanotubes has been approached experimentally by understanding the nature of interactions between the matrices and nanotubes. Unassisted dispersions of single walled carbon nanotubes in epoxies were studied by a combination of radiation scattering (elastic small angle scattering and inelastic scattering), DSC based glass transition determination, melt rheology and solid-state mechanical testing in order to understand and correlate changes in local and global dynamics to the tailoring of composite mechanical properties. Significant changes in the glass transition temperature of the matrix can successfully account for changes in the viscoelastic properties of the epoxy dispersions for concentrations below the percolation threshold, while above the percolation threshold the network superstructure formed by the nanotubes controls the viscoelastic properties.

  6. Piezoresistance of Single Walled Carbon Nanotube in VHDL-AMS

    OpenAIRE

    Kolchuzhin, Vladimir; Markert, Erik; Wagner, Christian

    2015-01-01

    This tutorial deals with the model development of the piezoresistance of Single Walled Carbon Nanotubes (SWCNTs) as components at system level design. The framework VHDL-AMS (virtual hardware description language) is used for implementation and simulation. It is based on compact models to describe the components performing heterogeneous functions. The mechanical and electronical compact submodels of SWCNTs are based on the analytical models and lumped element models. The tutorial presents...

  7. Electrothermal flow in Dielectrophoresis of Single-Walled Carbon Nanotubes

    OpenAIRE

    Lin, Yuan; Shiomi, Junichiro; Maruyama, Shigeo; Amberg, Gustav

    2007-01-01

    We theoretically investigate the impact of the electrothermal flow on the dielectrophoretic separation of single-walled carbon nanotubes (SWNT). The electrothermal flow is observed to control the motions of semiconducting SWNTs in a sizeable domain near the electrodes under typical experimental conditions, therefore helping the dielectrophoretic force to attract semiconducting SWNTs in a broader range. Moreover, with the increase of the surfactant concentration, the electrothermal flow is enh...

  8. Titanium dioxide, single-walled carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yuan; Li, Gonghu; Gray, Kimberly; Lueptow, Richard M.

    2015-07-14

    The present invention provides titanium dioxide/single-walled carbon nanotube composites (TiO.sub.2/SWCNTs), articles of manufacture, and methods of making and using such composites. In certain embodiments, the present invention provides membrane filters and ceramic articles that are coated with TiO.sub.2/SWCNT composite material. In other embodiments, the present invention provides methods of using TiO.sub.2/SWCNT composite material to purify a sample, such as a water or air sample.

  9. Material and structural instabilities of single-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    J. Wu; K. C. Hwang; J. Song; Y. Huang

    2008-01-01

    The nonlinear atomistic interactions usually involve softening behavior. Instability resulting directly from this softening are called the material instability, while those unrelated to this softening are called the structural instability. We use the finite-deformation shell theory based on the interatomic potential to show that the tension instability of single-wall carbon nanotubes is the material instability, while the compression and torsion instabilities are structural instability.

  10. Transparent, conductive and flexible single-walled carbon nanotube films

    OpenAIRE

    Kaskela, Antti

    2013-01-01

    Single-walled carbon nanotube (SWCNT) networks have a large application potential for future electronics as transparent conductive films. SWCNT networks (SWCNT-N) offer improved flexibility when compared to the current industry standard transparent conductive films (TCF), an example of which is indium tin oxide (ITO). SWCNTs can be synthesised from abundant raw materials, whereas indium supply is limited and has been a target of aggressive trade policies, thus increasing supply risks and price v...

  11. Improvements in Production of Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Balzano, Leandro; Resasco, Daniel E.

    2009-01-01

    A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has been to make progress toward converting the process from a batch mode to a continuous mode and to scaling of production to larger quantities. Efforts have also been made to optimize associated purification and dispersion post processes to make them effective at large scales and to investigate means of incorporating the purified products into composite materials. The ultimate purpose of the program is to enable the production of high-quality single-walled carbon nanotubes in quantities large enough and at costs low enough to foster the further development of practical applications. The fluidized bed used in this process contains mixed-metal catalyst particles. The choice of the catalyst and the operating conditions is such that the yield of single-walled carbon nanotubes, relative to all forms of carbon (including carbon fibers, multi-walled carbon nanotubes, and graphite) produced in the disproportionation reaction is more than 90 weight percent. After the reaction, the nanotubes are dispersed in various solvents in preparation for end use, which typically involves blending into a plastic, ceramic, or other matrix to form a composite material. Notwithstanding the batch nature of the unmodified prior fluidized-bed process, the fluidized-bed reactor operates in a continuous mode during the process. The operation is almost entirely automated, utilizing mass flow controllers, a control computer running software specific to the process, and other equipment. Moreover, an important inherent advantage of fluidized- bed reactors in general is that solid particles can be added to and removed from fluidized beds during operation. For these reasons, the process and equipment were amenable to

  12. Photophysics of polymer-wrapped single-walled carbon nanotubes

    OpenAIRE

    Gao, J.; Loi, M.A.

    2010-01-01

    Single-walled carbon nanotubes (SWNTs) are successfully dispersed in two conjugated polymer poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) and poly[2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEHPPV) solutions. Steady-state and time-resolved photoluminescence spectroscopy in the near-infrared and visible spectral regions are used to study the interaction of the dispersed carbon nanotube and the wrapped polymer in the nano-hybrids. The SWNTs infrared emission is the signatures of the s...

  13. Single-walled Carbon Nanotubes as Electrode Materials for Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    XU Bina; WU Feng; WANG Fang; CHEN Shi; CAO Gao-Ping; YANG Yu-Sheng

    2006-01-01

    Large-scale synthesized single-walled carbon nanotubes (SWNT) prepared by electric arc discharge method and a mixture of NiO and Y2O3 as catalyst have been used as electrode materials for supercapacitors. N2 adsorption/desorption measurement shows that the SWNT is a microporous and mesoporous material with specific surface area 435 m2g1.Thespecific capacitance of the nitric acid treated SWNT in aqueous electrolyte reaches as high as 105 F/g, which is a combination of electric double layer capacitance and pseudocapacitance. The SWNT-based capacitors also have good charge/discharge reversibility and cycling perdurability.

  14. Atomic size-limited intercalation into single wall carbon nanotubes

    International Nuclear Information System (INIS)

    Intercalation of single wall carbon nanotubes (SWNTs) provides an important tool to modify their electronic band structure. Using multiple excitation wavelength Raman spectroscopy, we demonstrate that intercalation into SWNT interiors can be limited by intercalant size resulting in an unusual material comprising SWNTs with varying charge density. In the particular case of iodine intercalation, larger SWNTs with iodine-filled interiors were found to carry significantly higher charge density as compared to smaller empty ones. This difference was used to separate the intercalated SWNT material into fractions with homogeneous charge density

  15. Zinc oxide catalyzed growth of single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    We demonstrate that zinc oxide can catalyze the growth of single-walled carbon nanotubes (SWNTs) with high efficiency by a chemical vapor deposition process. The zinc oxide nanocatalysts, prepared using a diblock copolymer templating method and characterized by atomic force microscopy (AFM), were uniformly spaced over a large deposition area with an average diameter of 1.7 nm and narrow size distribution. Dense and uniform SWNTs films with high quality were obtained by using a zinc oxide catalyst, as characterized by scanning electron microscopy (SEM), Raman spectroscopy, AFM, and high-resolution transmission electron microscopy (HRTEM).

  16. Photoinduced Absorption within Single-Walled Carbon Nanotube Systems

    OpenAIRE

    Glanzmann, Livia Noëmi; Mowbray, Duncan John; del Valle, Diana Gisell Figueroa; Scotognella, Francesco; Lanzani, Guglielmo; Rubio, Angel

    2016-01-01

    We study the photoabsorption properties of photoactive bulk polymer/ fullerene/nanotube heterojunctions in the near-infrared region. By combining pump-probe spectroscopy and linear response time-dependent density functional theory within the random phase approximation (TDDFT-RPA) we elucidate the excited state dynamics of the $E_{11}$ transition within (6,5) and (7,5) single-walled carbon nanotubes (SWNTs) and combined with poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C$_{61}$-buty...

  17. Single-Walled Carbon Nanotube/PMMA Composites

    Science.gov (United States)

    Du, Fangming; Fisher, John; Winey, Karen

    2003-03-01

    Single-walled carbon nanotubes (SWNTs) have demonstrated unique mechanical, thermal and electrical properties. Similar properties are expected for polymer/SWNT nanocomposites. A new processing method has been used to produce PMMA/SWNT composites, which provides better dispersion of SWNT in the polymer matrix. Optical microscopy of the samples show improved dispersion of SWNT in the PMMA matrix, which is the key factor of the composite performance. Aligned and unaligned composite samples have been made for both purified SWNT and functionalized SWNT with different SWNT loadings. The tensile, thermal conductivity, and electroconductivity measurements of these samples will be performed.

  18. Ultra-short suspended single-wall carbon nanotube transistors

    OpenAIRE

    Island, J. O.; Tayari, V.; Yigen, S.; McRae, A. C.; Champagne, A. R.

    2011-01-01

    We describe a method to fabricate clean suspended single-wall carbon nanotube (SWCNT) transistors hosting a single quantum dot ranging in length from a few 10s of nm down to $\\approx$ 3 nm. We first align narrow gold bow-tie junctions on top of individual SWCNTs and suspend the devices. We then use a feedback-controlled electromigration to break the gold junctions and expose nm-sized sections of SWCNTs. We measure electron transport in these devices at low temperature and show that they form ...

  19. Electrochemical Charging of Individual Single-Walled Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Farhat, H.; Kavan, Ladislav; Kong, J.; Sasaki, K.; Saito, R.; Dresselhaus, M. S.

    2009-01-01

    Roč. 3, č. 8 (2009), s. 2320-2328. ISSN 1936-0851 R&D Projects: GA ČR GC203/07/J067; GA AV ČR IAA400400804; GA AV ČR IAA400400911; GA AV ČR KAN200100801; GA MŠk ME09060 Institutional research plan: CEZ:AV0Z40400503 Keywords : single-walled carbon nanotubes * Raman spectroscopy * electrochemical gating * spectroelectrochemistry Subject RIV: CG - Electrochemistry Impact factor: 7.493, year: 2009

  20. Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase

    OpenAIRE

    Andõn, F. T.; Kapralov, A A; Yanamala, N.; Feng, W.; Baygan, Arjang; Chambers, B.J.; Hultenby, K.; Ye, Fei; Toprak, Muhammet S.; Brandner, B. D.; Fornara, Andrea; Klein-Seetharaman, J.; Kotchey, G. P.; Star, A.; Shvedova, Anna A.

    2013-01-01

    Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O 2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site)...

  1. Charge-induced strains in single-walled carbon nanotubes.

    Science.gov (United States)

    Li, Chun-Yu; Chou, Tsu-Wei

    2006-09-28

    This paper investigates the electromechanical coupling in single-walled carbon nanotubes. In the model system, the extra electric charge of the nanotube is assumed to be uniformly distributed on carbon atoms. The electrostatic interactions between charged carbon atoms are calculated using the Coulomb law. The deformation of the charged nanotube is obtained by using the molecular structural mechanics method and considering the electrostatic interactions as an external loading acting on carbon atoms. The axial strain is found to be a symmetric function of applied charge, and our predictions are in very good agreement with those from ab initio calculations. The present results indicate that the nanotube aspect ratio has a strong effect on the axial strain when the ratio is less than 10 and the general trend is that the strain increases with the aspect ratio. The peak axial and radial strains occur at nanotube diameters of around 1.2-1.5 nm. PMID:21727586

  2. Confinement in single walled carbon nanotubes investigated by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Thick films of single walled carbon nanotubes (SWCNTs) with different diameter and chirality distributions are characterized by combining transmission electron microscopy and spectroscopic ellipsometry. The dependence of the dielectric function with the increase of the SWCNT diameter occurs with a drastic redshift of the S11, S22 and M11 transition energies. The transfer integral parameter γ0 of SWCNT is also evaluated and analyzed. We demonstrate that parts of the optical properties of SWCNTs are attributed to a one dimensional confinement effect. - Highlights: • Ellipsometric measurements are performed on carbon nanotube thick films. • The complex dielectric functions of conventional carbon nanotubes are given. • Confinement effects explain the variations of dielectric function of nanotubes

  3. Confinement in single walled carbon nanotubes investigated by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Battie, Y., E-mail: yann.battie@univ-lorraine.fr [LCP-A2MC, Institut Jean Barriol, Université de Lorraine, 1 Bd Arago, 57070 Metz (France); Jamon, D. [Université de Lyon, Université Jean Monnet, EA 3523, Laboratoire Télécom Claude Chappe, 25 rue du Dr Rémy Annino, 42000 Saint Etienne (France); Lauret, J.S. [Laboratoire Aimé Cotton, UPR 3321, ENS Cachan, 94245 Cachan (France); Gu, Q.; Gicquel-Guézo, M. [FOTON, UMR 6082, INSA, Avenue des Buttes de Coësmes, 35043 Rennes (France); En Naciri, A. [LCP-A2MC, Institut Jean Barriol, Université de Lorraine, 1 Bd Arago, 57070 Metz (France); Loiseau, A. [Laboratoire d' étude des microstructures, ONERA-CNRS UMR 104, 29 Av. de la Division Leclerc, 92322 Chatillon (France)

    2014-11-28

    Thick films of single walled carbon nanotubes (SWCNTs) with different diameter and chirality distributions are characterized by combining transmission electron microscopy and spectroscopic ellipsometry. The dependence of the dielectric function with the increase of the SWCNT diameter occurs with a drastic redshift of the S{sub 11}, S{sub 22} and M{sub 11} transition energies. The transfer integral parameter γ{sub 0} of SWCNT is also evaluated and analyzed. We demonstrate that parts of the optical properties of SWCNTs are attributed to a one dimensional confinement effect. - Highlights: • Ellipsometric measurements are performed on carbon nanotube thick films. • The complex dielectric functions of conventional carbon nanotubes are given. • Confinement effects explain the variations of dielectric function of nanotubes.

  4. Elastic Properties of the Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    O.B. Protsenko

    2012-03-01

    Full Text Available In this paper the elastic properties of two main types of single-walled carbon nanotubes (armchair and zigzag were simulated by analytical molecular mechanics models. The aim of this work is investigation and comparison of Young’s modulus, shear modulus and Poisson’s ratio variations of different types of tubes as functions of diameter. We obtained a set of closed-form expressions for the size-dependent elastic properties of armchair (n, n and zigzag (n, 0 tubes, which are basic for constructing mathematical models. Using those models elastic properties of single-walled nanotubes were evaluated. It was predicted that zigzag tube is more sensitive to chirality then armchair. Young’s and shear modules of both tubes were decreasing with diameter increasing. Poisson’s ratio was ranging from 0.16 to 0.29 and from 0.32 to 0.42 for an armchair and zigzag tubes respectively, but it was independent on chirality. It can be seen that predicted values of elastic characteristics for zigzag tube are larger then that for armchair tube, especially for smaller tubes. Results of this research can be used for design, analysis and evaluating of functioning and creating new materials based on carbon nanotubes.

  5. Center for Applications of Single-Walled Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Resasco, Daniel E

    2008-02-21

    This report describes the activities conducted under a Congressional Direction project whose goal was to develop applications for Single-walled carbon nanotubes, under the Carbon Nanotube Technology Center (CANTEC), a multi-investigator program that capitalizes on OU’s advantageous position of having available high quality carbon nanotubes. During the first phase of CANTEC, 11 faculty members and their students from the College of Engineering developed applications for carbon nanotubes by applying their expertise in a number of areas: Catalysis, Reaction Engineering, Nanotube synthesis, Surfactants, Colloid Chemistry, Polymer Chemistry, Spectroscopy, Tissue Engineering, Biosensors, Biochemical Engineering, Cell Biology, Thermal Transport, Composite Materials, Protein synthesis and purification, Molecular Modeling, Computational Simulations. In particular, during this phase, the different research groups involved in CANTEC made advances in the tailoring of Single-Walled Carbon Nanotubes (SWNT) of controlled diameter and chirality by Modifying Reaction Conditions and the Nature of the catalyst; developed kinetic models that quantitatively describe the SWNT growth, created vertically oriented forests of SWNT by varying the density of metal nanoparticles catalyst particles, and developed novel nanostructured SWNT towers that exhibit superhydrophobic behavior. They also developed molecular simulations of the growth of Metal Nanoparticles on the surface of SWNT, which may have applications in the field of fuell cells. In the area of biomedical applications, CANTEC researchers fabricated SWNT Biosensors by a novel electrostatic layer-by-layer (LBL) deposition method, which may have an impact in the control of diabetes. They also functionalized SWNT with proteins that retained the protein’s biological activity and also retained the near-infrared light absorbance, which finds applications in the treatment of cancer.

  6. Single wall carbon nanotubes and their electrical properties

    Institute of Scientific and Technical Information of China (English)

    薛增泉; 刘惟敏; 侯士敏; 施祖进; 顾镇南; 刘虹雯; 赵兴钰; 张兆祥; 吴绵雷; 彭练矛; 吴全德

    2000-01-01

    Single-wall carbon nanotubes (SWCNTs) were synthesized and purified. A water colloid of SWCNTs was prepared and used to assemble SWCNTs onto a gold film surface. Scanning tunneling microscopy (STM) images showed that short SWCNTs stood on gold film surfaces. Using STM tips made of SWCNTs, a crystal grain image of a gold thin film and an atomic resolution image of highly oriented pyrolytic graphite were successfully obtained. The electrical properties of short SWCNTs, which stood on the surface of gold film, were measured using STM. That SWCNTs stand on gold thin films is a promising technique for studying structures and properties of carbon nanotubes, as well as assembling and fabricating high-intensity coherent electron sources, field emission flat panel display, tips for scanning probe microscopes, new nanoelectronic devices, etc.

  7. Single-Walled Carbon Nanohorns for Energy Applications

    Directory of Open Access Journals (Sweden)

    Zhichao Zhang

    2015-10-01

    Full Text Available With the growth of the global economy and population, the demand for energy is increasing sharply. The development of environmentally a benign and reliable energy supply is very important and urgent. Single-walled carbon nanohorns (SWCNHs, which have a horn-shaped tip at the top of single-walled nanotube, have emerged as exceptionally promising nanomaterials due to their unique physical and chemical properties since 1999. The high purity and thermal stability, combined with microporosity and mesoporosity, high surface area, internal pore accessibility, and multiform functionalization make SWCNHs promising candidates in many applications, such as environment restoration, gas storage, catalyst support or catalyst, electrochemical biosensors, drug carrier systems, magnetic resonance analysis and so on. The aim of this review is to provide a comprehensive overview of SWCNHs in energy applications, including energy conversion and storage. The commonly adopted method to access SWCNHs, their structural modifications, and their basic properties are included, and the emphasis is on their application in different devices such as fuel cells, dye-sensitized solar cells, supercapacitors, Li-ion batteries, Li-S batteries, hydrogen storage, biofuel cells and so forth. Finally, a perspective on SWCNHs’ application in energy is presented.

  8. Vertical semiconducting single-walled carbon nanotube Schottky diode

    International Nuclear Information System (INIS)

    This paper presents a vertical semiconducting single-walled carbon nanotube (s-SWCNT)-based Schottky device. For the first time, the author successfully demonstrated a vertical s-SWCNT Schottky diode on an anodized aluminum oxide (AAO) template. In the vertical pores of an AAO template s-SWCNTs were vertically grown and aligned. The vertical growth of s-SWCNTs inside the pores was achieved by successfully isolating the catalyst at the bottom of the pores by using redeposition enabled angled ion milling. The ends of the grown s-SWCNTs were coated with palladium and titanium to form Schottky and Ohmic contacts, respectively. The I-V characteristics of the vertical s-SWCNT paths engaging the Schottky and Ohmic contacts well demonstrated Schottky diode rectification.

  9. Printable Thin Film Supercapacitors Using Single-Walled Carbon Nanotubes

    KAUST Repository

    Kaempgen, Martti

    2009-05-13

    Thin film supercapacitors were fabricated using printable materials to make flexible devices on plastic. The active electrodes were made from sprayed networks of single-walled carbon nanotubes (SWCNTs) serving as both electrodes and charge collectors. Using a printable aqueous gel electrolyte as well as an organic liquid electrolyte, the performances of the devices show very high energy and power densities (6 W h/kg for both electrolytes and 23 and 70 kW/kg for aqueous gel electrolyte and organic electrolyte, respectively) which is comparable to performance in other SWCNT-based supercapacitor devices fabricated using different methods. The results underline the potential of printable thin film supercapacitors. The simplified architecture and the sole use of printable materials may lead to a new class of entirely printable charge storage devices allowing for full integration with the emerging field of printed electronics. © 2009 American Chemical Society.

  10. The synthesis and filling of single-walled carbon nanotubes

    CERN Document Server

    Friedrichs, S

    2002-01-01

    This thesis is concerned with the synthesis, properties and application of single-walled carbon nanotubes (SWNTs). The two main objectives of the work were the development of a continuous-flow synthesis of SWNTs, using chemical vapour deposition (CVD) techniques, and the application of the hollow SWNTs as moulds for the study of the crystallisation behaviour of inorganic materials in the confined space of their inner cavity. The latter study was mainly performed by interpreting high-resolution transmission electron microscopy (HRTEM) images of the filled SWNTs. A so-called focal series restoration approach, which enhances the resolution of the images and thereby increases the information content, was employed where possible. Chapter I reviews the previous work in the field of SWNTs and introduces their basic structure, symmetry, physical and mechanical properties and the common methods of SWNT synthesis. The chapter ends with an overview of the techniques used in the present work for the characterisation of c...

  11. Vertical semiconducting single-walled carbon nanotube Schottky diode

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sunghwan [Dankook University, Yongin (Korea, Republic of)

    2014-07-15

    This paper presents a vertical semiconducting single-walled carbon nanotube (s-SWCNT)-based Schottky device. For the first time, the author successfully demonstrated a vertical s-SWCNT Schottky diode on an anodized aluminum oxide (AAO) template. In the vertical pores of an AAO template s-SWCNTs were vertically grown and aligned. The vertical growth of s-SWCNTs inside the pores was achieved by successfully isolating the catalyst at the bottom of the pores by using redeposition enabled angled ion milling. The ends of the grown s-SWCNTs were coated with palladium and titanium to form Schottky and Ohmic contacts, respectively. The I-V characteristics of the vertical s-SWCNT paths engaging the Schottky and Ohmic contacts well demonstrated Schottky diode rectification.

  12. Synthesis and Hydrogen Storage in Single-walled Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Single-walled carbon nanotubes (SWNTs) were synthesized by a hydrogen arc discharge method. A high yield of gram quantity of SWNTs per hour was achieved. Tow kinds of SWNT products: web-like substance and thin films in large slices were obtained. Results of resonant Raman scattering measurements indicate that the SWNTs prepared have a wider diameter distribution and a larger mean diameter. Hydrogen uptake measurements of the two kinds of SWNT samples (both as prepared and pretreated) were carried out using a high pressure volumetric method,respectively. And a hydrogen storage capacity of 4 wt pct could be repeatedly achieved for the suitably pretreated SWNTs, which indicates that SWNTs may be a promising hydrogen storage material.

  13. G-Quadruplex Guanosine Gels and Single Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yuehua Yu

    2013-12-01

    Full Text Available Solubilization of single walled carbon nanotubes (SWNTs in aqueous gel phases formed by reversible, G-quadruplex self-assembly of guanosine monophosphate (GMP alone or with guanosine (Guo is described. Unlike other media and methods for aqueous solubilization of SWNTs, the guanosine gels (“G-gels” are found to readily disperse high (>mg/mL concentrations of individual rather than bundled SWNTs. SWNT dispersions in GMP alone precipitate in several hours and re-form upon shaking; however, dispersions in the binary GMP/Guo gels are indefinitely stable. Increasing GMP or KCl concentration in the binary gels increased the relative abundance of large diameter and semi-conducting SWNTs. Different gel compositions also displayed different selectivities toward SWNTs of different chiralities. These results indicate a strong connection between the self-assembled G-gels and the dimensions and structures of the SWNTs that they solubilize.

  14. Laser ablation process for single-walled carbon nanotube production

    Science.gov (United States)

    Arepalli, Sivaram

    2004-01-01

    Different types of lasers are now routinely used to prepare single-walled carbon nanotubes. The original method developed by researchers at Rice University used a "double-pulse laser oven" process. Several researchers have used variations of the lasers to include one-laser pulse (green or infrared), different pulse widths (ns to micros as well as continuous wave), and different laser wavelengths (e.g., CO2, or free electron lasers in the near to far infrared). Some of these variations are tried with different combinations and concentrations of metal catalysts, buffer gases (e.g., helium), oven temperatures, flow conditions, and even different porosities of the graphite targets. This article is an attempt to cover all these variations and their relative merits. Possible growth mechanisms under these different conditions will also be discussed.

  15. Radiation Protection Using Single-Wall Carbon Nanotube Derivatives

    Science.gov (United States)

    Tour, James M.; Lu, Meng; Lucente-Schultz, Rebecca; Leonard, Ashley; Doyle, Condell Dewayne; Kosynkin, Dimitry V.; Price, Brandi Katherine

    2011-01-01

    This invention is a means of radiation protection, or cellular oxidative stress mitigation, via a sequence of quenching radical species using nano-engineered scaffolds, specifically single-wall carbon nanotubes (SWNTs) and their derivatives. The material can be used as a means of radiation protection by reducing the number of free radicals within, or nearby, organelles, cells, tissue, organs, or living organisms, thereby reducing the risk of damage to DNA and other cellular components (i.e., RNA, mitochondria, membranes, etc.) that can lead to chronic and/or acute pathologies, including but not limited to cancer, cardiovascular disease, immuno-suppression, and disorders of the central nervous system. In addition, this innovation could be used as a prophylactic or antidote for accidental radiation exposure, during high-altitude or space travel where exposure to radiation is anticipated, or to protect from exposure from deliberate terrorist or wartime use of radiation- containing weapons.

  16. Structural anisotropy of magnetically aligned single wall carbon nanotube films

    International Nuclear Information System (INIS)

    Thick films of aligned single wall carbon nanotubes and ropes have been produced by filtration/deposition from suspension in strong magnetic fields. We measured mosaic distributions of rope orientations in the film plane, for samples of different thicknesses. For an ∼1 μm film the full width at half maximum (FWHM) derived from electron diffraction is 25 degree sign -28 degree sign . The FWHM of a thicker film (∼7 μm) measured by x-ray diffraction is slightly broader, 35±3 degree sign . Aligned films are denser than ordinary filter-deposited ones, and much denser than as-grown material. Optimization of the process is expected to yield smaller FWHMs and higher densities. (c) 2000 American Institute of Physics

  17. Single Wall Carbon Nanotube-polymer Solar Cells

    Science.gov (United States)

    Bailey, Sheila G.; Castro, Stephanie L.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

    2005-01-01

    Investigation of single wall carbon nanotube (SWNT)-polymer solar cells has been conducted towards developing alternative lightweight, flexible devices for space power applications. Photovoltaic devices were constructed with regioregular poly(3-octylthiophene)-(P3OT) and purified, >95% w/w, laser-generated SWNTs. The P3OT composites were deposited on ITO-coated polyethylene terapthalate (PET) and I-V characterization was performed under simulated AM0 illumination. Fabricated devices for the 1.0% w/w SWNT-P3OT composites showed a photoresponse with an open-circuit voltage (V(sub oc)) of 0.98 V and a short-circuit current density (I(sub sc)) of 0.12 mA/sq cm. Optimization of carrier transport within these novel photovoltaic systems is proposed, specifically development of nanostructure-SWNT complexes to enhance exciton dissociation.

  18. Single-Wall Carbon Nanotube Anodes for Lithium Cells

    Science.gov (United States)

    Hepp, Aloysius F.; Raffaelle, Ryne; Gennett, Tom; Kumta, Prashant; Maranchi, Jeff; Heben, Mike

    2006-01-01

    In recent experiments, highly purified batches of single-wall carbon nanotubes (SWCNTs) have shown promise as superior alternatives to the graphitic carbon-black anode materials heretofore used in rechargeable thin-film lithium power cells. The basic idea underlying the experiments is that relative to a given mass of graphitic carbon-black anode material, an equal mass of SWCNTs can be expected to have greater lithium-storage and charge/discharge capacities. The reason for this expectation is that whereas the microstructure and nanostructure of a graphitic carbon black is such as to make most of the interior of the material inaccessible for intercalation of lithium, a batch of SWCNTs can be made to have a much more open microstructure and nanostructure, such that most of the interior of the material is accessible for intercalation of lithium. Moreover, the greater accessibility of SWCNT structures can be expected to translate to greater mobilities for ion-exchange processes and, hence, an ability to sustain greater charge and discharge current densities.

  19. Amorphous carbon contamination monitoring and process optimization for single-walled carbon nanotube integration

    International Nuclear Information System (INIS)

    We detail the monitoring of amorphous carbon deposition during thermal chemical vapour deposition of carbon nanotubes and propose a contamination-less process to integrate high-quality single-walled carbon nanotubes into micro-electromechanical systems. The amorphous content is evaluated by confocal micro-Raman spectroscopy and by scanning/transmission electron microscopy. We show how properly chosen process parameters can lead to successful integration of single-walled nanotubes, enabling nano-electromechanical system synthesis

  20. Enhanced Raman Microprobe Imaging of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Hadjiev, V. G.; Arepalli, S.; Nikolaev, P.; Jandl, S.; Yowell, L.

    2003-01-01

    We explore Raman microprobe capabilities to visualize single wall carbon nanotubes (SWCNTs). Although this technique is limited to a micron scale, we demonstrate that images of individual SWCNTs, bundles or their agglomerates can be generated by mapping Raman active elementary excitations. We measured the Raman response from carbon vibrations in SWCNTs excited by confocal scanning of a focused laser beam. Carbon vibrations reveal key characteristics of SWCNTs as nanotube diameter distribution (radial breathing modes, RBM, 100-300 cm(exp -1)), presence of defects and functional groups (D-mode, 1300-1350 cm(exp -1)), strain and oxidation states of SWCNTs, as well as metallic or semiconducting character of the tubes encoded in the lineshape of the G-modes at 1520-1600 cm(exp - 1). In addition, SWCNTs are highly anisotropic scatterers. The Raman response from a SWCNT is maximal for incident light polarization parallel to the tube axis and vanishing for perpendicular directions. We show that the SWCNT bundle shape or direction can be determined, with some limitations, from a set of Raman images taken at two orthogonal directions of the incident light polarization.

  1. Effect of chemical potential on the computer simulation of hydrogen storage in single walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Hong; WANG; Shaoqing; CHENG; Huiming

    2004-01-01

    Grand canonical Monte Carlo molecular simulations were carried out for hydrogen adsorption in single-walled carbon nanotubes. It was found that variations in chemical potential may result in a great change in the hydrogen storage capacity of single-walled carbon nanotubes. Hydrogen adsorption isotherms of single-walled carbon nanotubes at 298.15 K were calculated using a modified chemical potential, and the result obtained is closer to the experimental results. By comparing the experimental and simulation results, it is proposed that chemical adsorption may exist for hydrogen adsorption in single-walled carbon nanotubes.

  2. Economic assessment of single-walled carbon nanotube processes

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, J. A., E-mail: jaisaacs@coe.neu.ed [Northeastern University, NSF Center for High-rate Nanomanufacturing (United States); Tanwani, A. [Infojini Solutions Inc. (United States); Healy, M. L. [Babcock Power Inc. (United States); Dahlben, L. J. [Northeastern University, NSF Center for High-rate Nanomanufacturing (United States)

    2010-02-15

    The carbon nanotube market is steadily growing and projected to reach $1.9 billion by 2010. This study examines the economics of manufacturing single-walled carbon nanotubes (SWNT) using process-based cost models developed for arc, CVD, and HiPco processes. Using assumed input parameters, manufacturing costs are calculated for 1 g SWNT for arc, CVD, and HiPco, totaling $1,906, $1,706, and $485, respectively. For each SWNT process, the synthesis and filtration steps showed the highest costs, with direct labor as a primary cost driver. Reductions in production costs are calculated for increased working hours per day and for increased synthesis reaction yield (SRY) in each process. The process-based cost models offer a means for exploring opportunities for cost reductions, and provide a structured system for comparisons among alternative SWNT manufacturing processes. Further, the models can be used to comprehensively evaluate additional scenarios on the economics of environmental, health, and safety best manufacturing practices.

  3. Single-wall carbon nanotube chemical attachment at platinum electrodes

    Science.gov (United States)

    Rosario-Castro, Belinda I.; Contés-de-Jesús, Enid J.; Lebrón-Colón, Marisabel; Meador, Michael A.; Scibioh, M. Aulice; Cabrera, Carlos R.

    2010-11-01

    Self-assembled monolayer (SAM) techniques were used to adsorb 4-aminothiophenol (4-ATP) on platinum electrodes in order to obtain an amino-terminated SAM as the base for the chemical attachment of single-wall carbon nanotubes (SWCNTs). A physico-chemical, morphological and electrochemical characterizations of SWCNTs attached onto the modified Pt electrodes was done by using reflection-absorption infrared spectroscopy (RAIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and cyclic voltammetry (CV) techniques. The SWNTs/4-ATP/Pt surface had regions of small, medium, and large thickness of carbon nanotubes with heights of 100-200 nm, 700 nm to 1.5 μm, and 1.0-3.0 μm, respectively. Cyclic voltammetries (CVs) in sulfuric acid demonstrated that attachment of SWNTs on 4-ATP/Pt is markedly stable, even after 30 potential cycles. CV in ruthenium hexamine was similar to bare Pt electrodes, suggesting that SWNTs assembly is similar to a closely packed microelectrode array.

  4. Broadband Spectroscopic Thermoacoustic Characterization of Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Daniel R. Bauer

    2015-01-01

    Full Text Available Carbon nanotubes have attracted interest as contrast agents for biomedical imaging because they strongly absorb electromagnetic radiation in the optical and microwave regions. This study applies thermoacoustic (TA imaging and spectroscopy to measure the frequency-dependent absorption profile of single-walled carbon nanotubes (SWNT in the ranges of 2.7–3.1 GHz and 7–9 GHz using two tunable microwave sources. Between 7 and 9 GHz, the peak TA signal for solutions containing semiconducting and metallic SWNTs increased monotonically with a slope of 1.75 AU/GHz (R2=0.95 and 2.8 AU/GHz (R2=0.93, respectively, relative to a water baseline. However, after compensating for the background signal from water, it was revealed that the TA signal from metallic SWNTs increased exponentially within this frequency band. Results suggest that TA imaging and spectroscopy could be a powerful tool for quantifying the absorption properties of SWNTs and optimizing their performance as contrast agents for imaging or heat sources for thermal therapy.

  5. Third Harmonic Generation from Aligned Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Morris, Darius T., Jr.

    Optical properties of single-wall carbon nanotubes (SWCNTs) have been extensively studied during the last decade, and much basic knowledge has been accumulated on how light emission, scattering, and absorption occur in the realm of linear optics. However, their nonlinear optical properties remain largely unexplored. Here, we have observed strong third harmonic generation from highly aligned SWCNTs with intense mid-infrared radiation. Through power dependent experiments, we have determined the absolute value of the third-order nonlinear optical susceptibility, chi(3), of our SWCNT film to be 6.92 x 10--12 esu, which is three orders of magnitude larger than that of the fused silica reference sample we used. Furthermore, through polarization-dependent third harmonic generation experiments, all the nonzero tensor elements of chi(3) have also been extracted. The contribution of the weaker tensor elements to the overall chi (3) signal has been calculated to be approximately 1/6 of that of the dominant c3z zzz component. These results open up new possibilities for application of carbon nanotubes in optoelectronics.

  6. Resonant Raman effect in single-wall carbon nanotubes

    International Nuclear Information System (INIS)

    A resonant Raman study of single-wall carbon nanotubes (SWNT) using several laser lines between 0.94 and 3.05 eV is presented. A detailed lineshape analysis shows that the bands associated with the nanotube radial breathing mode are composed of a sum of individual peaks whose relative intensities depend strongly on the laser energy, in agreement with prior work. On the other hand, the shape of the Raman bands associated with the tangential C - C stretching motions in the 1500 - 1600 cm-1 range does not depend significantly on the laser energy for laser excitation energies in the ranges 0.94 - 1.59 eV and 2.41 - 3.05 eV. However, new C - C stretching modes are observed in the spectra collected using laser excitations with energies close to 1.9 eV. The new results are discussed in terms of the difference between the 1D electronic density of states for the semiconducting and metallic carbon nanotubes. copyright 1998 Materials Research Society

  7. Optical properties of armchair (7, 7) single walled carbon nanotubes

    International Nuclear Information System (INIS)

    Full potential linearized augmented plane waves method with the generalized gradient approximation for the exchange-correlation potential was applied to calculate the optical properties of (7, 7) single walled carbon nanotubes. The both x and z directions of the incident photons were applied to estimate optical gaps, dielectric function, electron energy loss spectroscopies, optical conductivity, optical extinction, optical refractive index and optical absorption coefficient. The results predict that dielectric function, ε (ω), is anisotropic since it has higher peaks along z-direction than x-direction. The static optical refractive constant were calculated about 1.4 (z-direction) and 1.1 (x- direction). Moreover, the electron energy loss spectroscopy showed a sharp π electron plasmon peaks at about 6 eV and 5 eV for z and x-directions respectively. The calculated reflection spectra show that directions perpendicular to the tube axis have further optical reflection. Moreover, z-direction indicates higher peaks at absorption spectra in low range energies. Totally, increasing the diameter of armchair carbon nanotubes cause the optical band gap, static optical refractive constant and optical reflectivity to decrease. On the other hand, increasing the diameter cause the optical absorption and the optical conductivity to increase. Moreover, the sharp peaks being illustrated at optical spectrum are related to the 1D structure of CNTs which confirm the accuracy of the calculations

  8. Reinforced Thermoplastic Polyimide with Dispersed Functionalized Single Wall Carbon Nanotubes

    Science.gov (United States)

    Lebron-Colon, Marisabel; Meador, Michael A.; Gaier, James R.; Sola, Francisco; Scheiman, Daniel A.; McCorkle, Linda S.

    2010-01-01

    Molecular pi-complexes were formed from pristine HiPCO single-wall carbon nanotubes (SWCNTs) and 1-pyrene- N-(4- N'-(5-norbornene-2,3-dicarboxyimido)phenyl butanamide, 1. Polyimide films were prepared with these complexes as well as uncomplexed SWCNTs and the effects of nanoadditive addition on mechanical, thermal, and electrical properties of these films were evaluated. Although these properties were enhanced by both nanoadditives, larger increases in tensile strength and thermal and electrical conductivities were obtained when the SWCNT/1 complexes were used. At a loading level of 5.5 wt %, the Tg of the polyimide increased from 169 to 197 C and the storage modulus increased 20-fold (from 142 to 3045 MPa). The addition of 3.5 wt % SWCNT/1 complexes increased the tensile strength of the polyimide from 61.4 to 129 MPa; higher loading levels led to embrittlement and lower tensile strengths. The electrical conductivities (DC surface) of the polyimides increased to 1 x 10(exp -4) Scm(exp -1) (SWCNT/1 complexes loading level of 9 wt %). Details of the preparation of these complexes and their effects on polyimide film properties are discussed.

  9. Sorting centimetre-long single-walled carbon nanotubes

    Science.gov (United States)

    Yu, Woo Jong; Chae, Sang Hoon; Vu, Quoc An; Lee, Young Hee

    2016-08-01

    While several approaches have been developed for sorting metallic (m) or semiconducting (s) single-walled carbon nanotubes (SWCNTs), the length of SWCNTs is limited within a micrometer, which restricts excellent electrical performances of SWCNTs for macro-scale applications. Here, we demonstrate a simple sorting method of centimetre-long aligned m- and s-SWCNTs. Ni particles were selectively and uniformly coated along the 1-cm-long m-SWCNTs by applying positive gate bias during electrochemical deposition with continuous electrolyte injection. To sort s-SWCNTs, the Ni coating was oxidized to form insulator outer for blocking of current flow through inner m-SWCNTs. Sorting of m-SWCNTs were demonstrated by selective etching of s-SWCNTs via oxygen plasma, while the protected m-SWCNTs by Ni coating remained intact. The series of source-drain pairs were patterned along the 1-cm-long sorted SWCNTs, which confirmed high on/off ratio of 104–108 for s-SWCNTs and nearly 1 for m-SWCNTs.

  10. Single-walled carbon nanotube based molecular switch tunnel junctions.

    Science.gov (United States)

    Diehl, Michael R; Steuerman, David W; Tseng, Hsian-Rong; Vignon, Scott A; Star, Alexander; Celestre, Paul C; Stoddart, J Fraser; Heath, James R

    2003-12-15

    This article describes two-terminal molecular switch tunnel junctions (MSTJs) which incorporate a semiconducting, single-walled carbon nanotube (SWNT) as the bottom electrode. The nanotube interacts noncovalently with a monolayer of bistable, nondegenerate [2]catenane tetracations, self-organized by their supporting amphiphilic dimyristoylphosphatidyl anions which shield the mechanically switchable tetracations from a two-micrometer wide metallic top electrode. The resulting 0.002 micron 2 area tunnel junction addresses a nanometer wide row of approximately 2000 molecules. Active and remnant current-voltage measurements demonstrated that these devices can be reconfigurably switched and repeatedly cycled between high and low current states under ambient conditions. Control compounds, including a degenerate [2]catenane, were explored in support of the mechanical origin of the switching signature. These SWNT-based MSTJs operate like previously reported silicon-based MSTJs, but differently from similar devices incorporating bottom metal electrodes. The relevance of these results with respect to the choice of electrode materials for molecular electronics devices is discussed. PMID:14714382

  11. Resonance Raman Optical Activity of Single Walled Chiral Carbon Nanotubes.

    Science.gov (United States)

    Nagy, Péter R; Koltai, János; Surján, Péter R; Kürti, Jenő; Szabados, Ágnes

    2016-07-21

    Resonance (vibrational) Raman Optical Activity (ROA) spectra of six chiral single-walled carbon nanotubes (SWCNTs) are studied by theoretical means. Calculations are performed imposing line group symmetry. Polarizability tensors, computed at the π-electron level, are differentiated with respect to DFT normal modes to generate spectral intensities. This computational protocol yields a ROA spectrum in good agreement with the only experiment on SWCNT, available at present. In addition to the conventional periodic electric dipole operator we introduce magnetic dipole and electric quadrupole operators, suitable for conventional k-space calculations. Consequences of the complex nature of the wave function on the scattering cross section are discussed in detail. The resonance phenomenon is accounted for by the short time approximation. Involvement of fundamental vibrations in the region of the intermediate frequency modes is found to be more notable in ROA than in Raman spectra. Calculations indicate exceptionally strong resonance enhancement of SWCNT ROA signals. Resonance ROA profile of the (6,5) tube shows an interesting sign change that may be exploited experimentally for SWCNT identification. PMID:27315548

  12. Concentration of lysozyme/single-walled carbon nanotube dispersions.

    Science.gov (United States)

    Horn, Daniel W; Davis, Virginia A

    2016-03-01

    The dispersion of single-walled carbon nanotubes (SWNT) in aqueous solutions of biological materials enables the production of bulk films and fibers that combine natural biological activity with SWNT's intrinsic mechanical, thermal, and electrical properties. In this work, we report the rheology and phase behavior of concentrated lysozyme (LSZ)/SWNT dispersions. Even at low concentration, the LSZ's globular structure causes a deviation from the rheological behavior expected of rigid rods such as SWNT. With increasing concentration, stabilized SWNT typically form lyotropic liquid crystalline phases. However, in this case, the LSZ results in depletion attraction and the formation of large dense SWNT aggregates surrounded by a LSZ network. At intermediate concentrations, the microstructure and rheological properties are a complex function of the initial dispersion state, the absolute concentrations, and the LSZ to SWNT ratio. The rheological effects of concentrating mixtures comprised of aggregates, a range of bundle sizes, and individual SWNT were compared to the effects of concentrating supernatants comprised solely of individual SWNT and small bundles. In general, lysozyme concentration has the greatest impact on dispersion viscoelasticity. However, the inherent viscosity was a function of SWNT concentration; data from both initial mixtures and supernatants spanning two orders of magnitude in concentration could be collapsed onto a single master curve. This work provides a foundation for exploring the behavior of other globular protein-SWNT dispersions. PMID:26722820

  13. Phonon and thermal properties of achiral single wall carbon nanotubes

    Indian Academy of Sciences (India)

    Prapti Saxena; Sankar P Sanyal

    2006-08-01

    A detailed theoretical study of the phonon and thermal properties of achiral single wall carbon nanotubes has been carried out using force constant model considering up to third nearest-neighbor interactions. We have calculated the phonon dispersions, density of states, radial breathing modes (RBM) and the specific heats for various zigzag and armchair nanotubes, with radii ranging from 2.8 Å to 11.0 Å. A comparative study of phonon spectrum with measured Raman data reveals that the number of Raman active modes for a tube does not depend on the number of atoms present in the unit cell but on its chirality. Calculated phonon modes at the zone center more or less accurately predicted the Raman active modes. The radial breathing mode is of particular interest as for a specific radius of a nanotube it is found to be independent of its chirality. We have also calculated the variation of RBM and G-band modes for tubes of different radii. RBM shows an inverse dependence on the radius of the tube. Finally, the values of specific heat are calculated for various nanotubes at room temperature and it was found that the specific heat shows an exponential dependence on the diameter of the tube.

  14. Hypergolic fuel detection using individual single walled carbon nanotube networks

    International Nuclear Information System (INIS)

    Accurate and reliable detection of hypergolic fuels such as hydrazine (N2H4) and its derivatives is vital to missile defense, aviation, homeland security, and the chemical industry. More importantly these sensors need to be capable of operation at low temperatures (below room temperature) as most of the widely used chemical sensors operate at high temperatures (above 300 deg. C). In this research a simple and highly sensitive single walled carbon nanotube (SWNT) network sensor was developed for real time monitoring of hydrazine leaks to concentrations at parts per million levels. Upon exposure to hydrazine vapor, the resistance of the air exposed nanotubes (p-type) is observed to increase rapidly while that of the vacuum-degassed nanotubes (n-type) is observed to decrease. It was found that the resistance of the sample can be recovered through vacuum pumping and exposure to ultraviolet light. The experimental results support the electrochemical charge transfer mechanism between the oxygen redox couple of the ambient and the Fermi level of the SWNT. Theoretical results of the hydrazine-SWNT interaction are compared with the experimental observations. It was found that a monolayer of water molecules on the SWNT is necessary to induce strong interactions between hydrazine and the SWNT by way of introducing new occupied states near the bottom of the conduction band of the SWNT.

  15. Oxygen-Assisted Synthesis of Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Gul, O.; Rajapakse, Arith; Collins, Philip

    2013-03-01

    Water-assisted chemical vapor deposition (CVD) has become a standard synthesis method for high quality single-walled carbon nanotubes (SWCNTs). Some drawbacks of the water-assisted method, however, include good control of water concentrations in the feedstock and poor control of SWCNT diameters below 2.0 nm. Here, we describe a variation of water-assisted CVD that uses dry feedstocks with a small, controlled quantity of molecular oxygen. Reactions of oxygen with hydrogen in the reaction zone provide all the benefits of water-assisted growth at the substrate while maintaining dry valves and flowmeters. In addition, the oxygen-based technique allows water concentrations in the system to be varied precisely and with short time constants. Perhaps because of the improved control, we find that the SWCNT diameter can be easily tuned by changing the oxygen concentration during the growth phase. Changing the oxygen concentration over the range of 0.5% to 1% varied the resulting SWCNT diameters from 1.5 to 0.5 nm, with typical diameter distributions less than +/- 30%. Control of SWCNT growth within this diameter range is ideal for probing opto-electronic properties of individual SWCNTs and SWCNT devices.

  16. Low-temperature growth of single-wall carbon nanotubes

    International Nuclear Information System (INIS)

    The low-temperature synthesis (450-560 deg. C) of single-walled carbon nanotubes (SWCNTs) on a triple-layered catalyst, Al/Fe/Mo, was performed using aromatic hydrocarbon radicals which were produced from the pyrolysis of C2H2. Two approaches were used; in the first, these hydrocarbon radicals were produced using a high-temperature heater (830 deg. C), but the substrate where the SWCNTs were grown was placed on a thermal insulator above it such that the substrate was at a much lower temperature. In the second approach, a heated nozzle system operating at 830 deg. C was used to introduce the hydrocarbon radicals onto the substrate which was located a few centimetres below it. Both these approaches rely on the thermal dissociation and recombination of C2H2 for the formation of complex high-order radicals, i.e. C6H9, C5H9, C6H13, whose presence was confirmed by in situ mass spectroscopy. The density of SWCNTs deposited could be correlated directly with the concentration of these precursors

  17. Ultrathin single-walled carbon nanotube network framed graphene hybrids.

    Science.gov (United States)

    Wang, Rui; Hong, Tu; Xu, Ya-Qiong

    2015-03-11

    Graphene and single-walled carbon nanotubes (SWNTs) have shown superior potential in electronics and optoelectronics because of their excellent thermal, mechanical, electronic, and optical properties. Here, a simple method is developed to synthesize ultrathin SWNT-graphene films through chemical vapor deposition. These novel two-dimensional hybrids show enhanced mechanical strength that allows them to float on water without polymer supporting layers. Characterizations by Raman spectroscopy and transmission electron microscopy indicate that SWNTs can interlace as a concrete backbone for the subsequent growth of monolayer graphene. Optical and electrical transport measurements further show that SWNT-graphene hybrids inherit high optical transparency and superior electrical conductivity from monolayer graphene. We also explore the local optoelectronic properties of SWNT-graphene hybrids through spatially resolved photocurrent microscopy and find that the interactions between SWNTs and graphene can induce a strong photocurrent response in the areas where SWNTs link different graphene domains together. These fundamental studies may open a door for engineering optoelectronic properties of SWNT-graphene hybrids by controlling the morphologies of the SWNT frames. PMID:25686199

  18. Endohedral Volume Control for Improved Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Campo, Jochen; Fagan, Jeffrey

    Liquid-phase processing of single-wall carbon nanotubes (SWCNTs) generally results in the exposure of their core volumes to the environment (opening) due to energy input necessary for purification and solubilization. For aqueous processing this results in SWCNTs routinely getting filled with water, which is detrimental to several properties. Importantly, water filling leads to significant redshifts to, and inhomogeneous broadening of, the electronic transitions of the SWCNTs, as well as a substantial decrease to their fluorescence quantum efficiency. Selection of (remaining) empty (end-capped) SWCNTs to avoid these adverse effects is possible by means of ultracentrifugation, but is a natively low yield process. In this work, SWCNTs are prefilled with linear alkanes or similar organic compounds, serving as a passive, highly homogeneous spacer, blocking the ingestion of water and hence preventing the detrimental consequences. Moreover, the low dielectric nature of the alkane core only weakly affects the local electronic wavefunction of the SWCNTs, effectively simulating empty core conditions and hence yielding much more resolved optical spectra with blue shifted peak positions compared to water filled SWCNTs. It is demonstrated that a wide variety of linear as well as cyclic alkanes can be applied for this purpose, in combination with various SWCNT materials.

  19. Anharmonic effects in single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    We have investigated the temperature and excitation energy dependence of Raman spectra of single-wall carbon nanotubes (SWCNTs). The measured Raman shifts for D and G bands of SWCNTs show a softening behavior upon increasing temperature (83-733 K). A theoretical model is developed to study the frequency shifts for these two Raman modes as a function of temperature; the calculated results agree well with the experimental data. The calculation indicates that the virtual optical-phonon couplings dominate contributions to the temperature variance of frequency shifts for D and G bands of SWCNTs while the pure-volume effect is very weak. Measurements of peak positions and linewidths of D and G bands are also carried out at three different excitation wavelengths (325, 514.5 and 785 nm). It is found that not only does the peak position of the D band exhibit a linear increase, but also the linewidth of the G band does upon increasing excitation energy. In addition, we also measure the relative intensity ratios of the D band to the G band (ID/IG) with temperature and excitation energy in this work

  20. Electrical characterization of single-wall carbon nanotubes

    Science.gov (United States)

    Berliocchi, Marco; Brunetti, Francesca; Di Carlo, Aldo; Lugli, Paolo; Orlanducci, Silvia; Terranova, Maria Letizia

    2003-04-01

    Single Wall Carbon Nanotubes (SWCNTs) based nanotechnology appears to be promising for future nanoelectronics. The SWCNT may be either metallic or semiconducting and both metallic and semiconducting types of SWCNTs have been observed experimentally. This gives rise to intriguing possibilities to put together semiconductor-semiconductor and semiconductor-metal junctions for diodes and transistors. The potential for nanotubes in nanoelectronics devices, displays and nanosensors is enormous. However, in order to realize the potential of SWCNTs, it is critical to understand the properties of charge transport and to control phase purity, elicity and arrangement according to specific architectures. We have investigated the electrical properties of various SWCNTs samples whit different organization: bundles of SWCNTs, SWCNT fibres and different membranes and tablets obtained using SWCNTs purified and characterized. Electrical characterizations were carried out by a 4155B Agilent Semiconductor Parameter Analyser. In order to give a mechanical stability to SWCNTs fibres and bundles we have used a nafion matrix coating, so an electrical characterization has been performed on samples with and without this layer. I-V measurements were performed in vacuum and in air using aluminium interdigitated coplanar-electrodes (width=20mm or 40mm) on glass substrates. The behaviour observed is generally supralinear with currents of the order of mA in vacuum and lower values in air with the exception of the tablet samples where the behaviour is ohmic, the currents are higher and similar values of current are detected in air and vacuum.

  1. Selective coherent phonon mode generation in single wall carbon nanotubes

    CERN Document Server

    Nugraha, Ahmad R T; Saito, Riichiro

    2016-01-01

    The ultrafast pulse-train technique is theoretically investigated to enhance a specific coherent phonon mode while suppressing the other phonon modes generated in single wall carbon nanotubes (SWNTs). In particular, we focus on the selectivity of the radial breathing mode (RBM) and the G-band for a given SWNT. We find that if the repetition period matches with integer multiple of the RBM phonon period, the RBM amplitude could be enhanced while the amplitudes of the other modes are suppressed. As for the G-band, when we apply a repetition rate of half-integer multiple of the RBM period, the RBM could be suppressed because of destructive interference, while the G-band still survives. It is also possible to keep the G-band and suppress the RBM by applying a repetition rate that matches with integer multiple of the G-band phonon period. However, in this case we have to use a large number of laser pulses.

  2. Elastomer Filled With Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Files, Bradley S.; Forest, Craig R.

    2004-01-01

    Experiments have shown that composites of a silicone elastomer with single-wall carbon nanotubes (SWNTs) are significantly stronger and stiffer than is the unfilled elastomer. The large strengthening and stiffening effect observed in these experiments stands in contrast to the much smaller strengthening effect observed in related prior efforts to reinforce epoxies with SWNTs and to reinforce a variety of polymers with multiple-wall carbon nanotubes (MWNTs). The relative largeness of the effect in the case of the silicone-elastomer/SWNT composites appears to be attributable to (1) a better match between the ductility of the fibers and the elasticity of the matrix and (2) the greater tensile strengths of SWNTs, relative to MWNTs. For the experiments, several composites were formulated by mixing various proportions of SWNTs and other filling materials into uncured RTV-560, which is a silicone adhesive commonly used in aerospace applications. Specimens of a standard "dog-bone" size and shape for tensile testing were made by casting the uncured elastomer/filler mixtures into molds, curing the elastomer, then pressing the specimens from a "cookie-cutter" die. The results of tensile tests of the specimens showed that small percentages of SWNT filler led to large increases in stiffness and tensile strength, and that these increases were greater than those afforded by other fillers. For example, the incorporation of SWNTs in a proportion of 1 percent increased the tensile strength by 44 percent and the modulus of elasticity (see figure) by 75 percent. However, the relative magnitudes of the increases decreased with increasing nanotube percentages because more nanotubes made the elastomer/nanotube composites more brittle. At an SWNT content of 10 percent, the tensile strength and modulus of elasticity were 125 percent and 562 percent, respectively, greater than the corresponding values for the unfilled elastomer.

  3. Wiring-up hydrogenase with single-walled carbon nanotubes.

    Science.gov (United States)

    McDonald, Timothy J; Svedruzic, Drazenka; Kim, Yong-Hyun; Blackburn, Jeffrey L; Zhang, S B; King, Paul W; Heben, Michael J

    2007-11-01

    Many envision a future where hydrogen is the centerpiece of a sustainable, carbon-free energy supply. For example, the energy in sunlight may be stored by splitting water into H2 and O2 using inorganic semiconductors and photoelectrochemical approaches or with artificial photosynthetic systems that seek to mimic the light absorption, energy transfer, electron transfer, and redox catalysis that occurs in green plants. Unfortunately, large scale deployment of artificial water-splitting technologies may be impeded by the need for the large amounts of precious metals required to catalyze the multielectron water-splitting reactions. Nature provides a variety of microbes that can activate the dihydrogen bond through the catalytic activity of [NiFe] and [FeFe] hydrogenases, and photobiological approaches to water splitting have been advanced. One may also consider a biohybrid approach; however, it is difficult to interface these sensitive, metalloenzymes to other materials and systems. Here we show that surfactant-suspended carbon single-walled nanotubes (SWNTs) spontaneously self-assemble with [FeFe] hydrogenases in solution to form catalytically active biohybrids. Photoluminescence excitation and Raman spectroscopy studies show that SWNTs act as molecular wires to make electrical contact to the biocatalytic region of hydrogenase. Hydrogenase mediates electron injection into nanotubes having appropriately positioned lowest occupied molecular orbital levels when the H2 partial pressure is varied. The hydrogenase is strongly attached to the SWNTs, so mass transport effects are eliminated and the absolute potential of the electronic levels of the nanotubes can be unambiguously measured. Our findings reveal new nanotube physics and represent the first example of "wiring-up" an hydrogenase with another nanoscale material. This latter advance offers a nonprecious metal route to the design of new biohybrid architectures and building blocks for hydrogen-related technologies

  4. Photovoltaic device using single wall carbon nanotubes and method of fabricating the same

    Science.gov (United States)

    Biris, Alexandru S.; Li, Zhongrui

    2012-11-06

    A photovoltaic device and methods for forming the same. In one embodiment, the photovoltaic device has a silicon substrate, and a film comprising a plurality of single wall carbon nanotubes disposed on the silicon substrate, wherein the plurality of single wall carbon nanotubes forms a plurality of heterojunctions with the silicon in the substrate.

  5. Study on the Microwave Permittivity of Single-Walled Carbon Nanotube

    Science.gov (United States)

    Liu, Xiaolai; Zhao, Donglin

    2009-01-01

    In this article, we studied the microwave permittivity of the complex of the single-walled carbon nanotube and paraffin in 2-18GHz. In the range, the dielectric loss of single-walled carbon nanotube is higher, and the real part and the imaginary part of the dielectric constant decrease with the increase of frequency, and the dielectric constant…

  6. Superemission in vertically-aligned single-wall carbon nanotubes

    Science.gov (United States)

    Khmelinskii, Igor; Makarov, Vladimir

    2016-09-01

    Presently we used two samples of vertically aligned single-wall carbon nanotubes (VA SWCNTs) with parallelepiped geometry, sized 0.02 cm × 0.2 cm × 1.0 cm and 0.2 cm × 0.2 cm × 1.0 cm. We report absorption and emission properties of the VA SWCNTs, including strong anisotropy in both their absorption and emission spectra. We found that the emission spectra extend from the middle-IR range to the near-IR range, with such extended spectra being reported for the first time. Pumping the VA SWCNTs in the direction normal to their axis, superemission (SE) was observed in the direction along their axis. The SE band maximum is located at 7206 ± 0.4 cm-1. The energy and the power density of the superemission were estimated, along with the diffraction-limited divergence. At the pumping energy of 3 mJ/pulse, the SE energy measured by the detector was 0.74 mJ/pulse, corresponding to the total SE energy of 1.48 mJ/pulse, with the energy density of 18.5 mJ cm-2/pulse and the SE power density of 1.2 × 105 W cm-2/pulse. We report that a bundle of VA SWCNTs is an emitter with a relatively small divergence, not exceeding 3.9 × 10-3 rad. We developed a theoretical approach to explain such absorption and emission spectra. The developed theory is based on the earlier proposed SSH theory, which we extended to include the exchange interactions between the closest SWCNT neighbors. The developed theoretical ideas were implemented in a homemade FORTRAN code. This code was successfully used to calculate and reproduce the experimental spectra and to determine the SWCNT species that originate the respective absorption bands, with acceptable agreement between theory and experiment.

  7. Noncovalent functionalization of single-walled carbon nanotubes with porphyrins

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouk, María; Basiuk, Vladimir A. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México D.F. (Mexico); Basiuk, Elena V., E-mail: elenagd@unam.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México D.F. (Mexico); Álvarez-Zauco, Edgar [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510 México D.F. (Mexico); Martínez-Herrera, Melchor [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México D.F. (Mexico); Rojas-Aguilar, Aaron [Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2508, San Pedro Zacatenco, 07360 México D.F. (Mexico); Puente-Lee, Iván [Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510 México D.F. (Mexico)

    2013-06-15

    The covalent and noncovalent interactions of porphyrins and related tetraazamacrocyclic compounds with single-walled carbon nanotubes (SWNTs) is a subject of increasing research effort, directed toward the design of novel hybrid nanomaterials combining unique electronic and optical properties of both molecular species. In this report, we used different experimental techniques as well as molecular mechanics (MM) calculations to analyze the adsorption of meso-tetraphenylporphine (or 5,10,15,20-tetraphenyl-21H,23H-porphine, H{sub 2}TPP) and its complexes with Ni(II) and Co(II) (NiTPP and CoTPP, respectively), as well as hemin (a natural porphyrin), onto the surface of SWNTs. Altogether, the results suggested that all four porphyrin species noncovalently interact with SWNTs, forming hybrid nanomaterials. Nevertheless, of all four porphyrin species, the strongest interaction with SWNTs occurs in the case of CoTPP, which is able to intercalate and considerably disperse SWNT bundles, and therefore absorb onto the surface of individual SWNTs. In contrast, NiTPP, CoTPP and hemin, due to a weaker interaction, are unable to do so and therefore are only capable to adsorb onto the surface of SWNT bundles. According to the scanning tunneling microscopy (STM) imaging and MM results, the adsorption of CoTPP onto SWNT sidewalls results in the formation of porphyrin arrays in the shape of long-period interacting helixes with variable periodicity, possibly due to different diameters and chiralities of SWNTs present in the samples. Since the remaining porphyrin species were found to adsorb onto the surface of SWNT bundles, the precise geometry of the corresponding porphyrin/SWNT complexes is difficult to characterize.

  8. Noncovalent functionalization of single-walled carbon nanotubes with porphyrins

    International Nuclear Information System (INIS)

    The covalent and noncovalent interactions of porphyrins and related tetraazamacrocyclic compounds with single-walled carbon nanotubes (SWNTs) is a subject of increasing research effort, directed toward the design of novel hybrid nanomaterials combining unique electronic and optical properties of both molecular species. In this report, we used different experimental techniques as well as molecular mechanics (MM) calculations to analyze the adsorption of meso-tetraphenylporphine (or 5,10,15,20-tetraphenyl-21H,23H-porphine, H2TPP) and its complexes with Ni(II) and Co(II) (NiTPP and CoTPP, respectively), as well as hemin (a natural porphyrin), onto the surface of SWNTs. Altogether, the results suggested that all four porphyrin species noncovalently interact with SWNTs, forming hybrid nanomaterials. Nevertheless, of all four porphyrin species, the strongest interaction with SWNTs occurs in the case of CoTPP, which is able to intercalate and considerably disperse SWNT bundles, and therefore absorb onto the surface of individual SWNTs. In contrast, NiTPP, CoTPP and hemin, due to a weaker interaction, are unable to do so and therefore are only capable to adsorb onto the surface of SWNT bundles. According to the scanning tunneling microscopy (STM) imaging and MM results, the adsorption of CoTPP onto SWNT sidewalls results in the formation of porphyrin arrays in the shape of long-period interacting helixes with variable periodicity, possibly due to different diameters and chiralities of SWNTs present in the samples. Since the remaining porphyrin species were found to adsorb onto the surface of SWNT bundles, the precise geometry of the corresponding porphyrin/SWNT complexes is difficult to characterize.

  9. Single-walled carbon nanotube networks in conductive composite materials.

    Science.gov (United States)

    Bârsan, Oana A; Hoffmann, Günter G; van der Ven, Leo G J; de With, G Bert

    2014-01-01

    Electrically conductive composite materials can be used for a wide range of applications because they combine the advantages of a specific polymeric material (e.g., thermal and mechanical properties) with the electrical properties of conductive filler particles. However, the overall electrical behaviour of these composite materials is usually much below the potential of the conductive fillers, mainly because by mixing two different components, new interfaces and interphases are created, changing the properties and behaviours of both. Our goal is to characterize and understand the nature and influence of these interfaces on the electrical properties of composite materials. We have improved a technique based on the use of sodium carboxymethyl cellulose (CMC) to disperse single-walled carbon nanotubes (SWCNTs) in water, followed by coating glass substrates, and drying and removing the CMC with a nitric acid treatment. We used electron microscopy and atomic force microscopy techniques to characterize the SWCNT films, and developed an in situ resistance measurement technique to analyse the influence of both the individual components and the mixture of an epoxy/amine system on the electrical behaviour of the SWCNTs. The results showed that impregnating a SWCNT network with a polymer is not the only factor that affects the film resistance; air exposure, temperature, physical and chemical properties of the individual polymer components, and also the formation of a polymeric network, can all have an influence on the macroscopic electrical properties of the initial SWCNT network. These results emphasize the importance of understanding the effects that each of the components can have on each other before trying to prepare an efficient polymer composite material. PMID:25430670

  10. Preparation of Nickel-Copper Bilayers Coated on Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Zhong Zheng

    2015-01-01

    Full Text Available Due to oxidizability of copper coating on carbon nanotubes, the interfacial bond strength between copper coating and its matrix is weak, which leads to the reduction of the macroscopic properties of copper matrix composite. The electroless coating technics was applied to prepare nickel-copper bilayers coated on single-walled carbon nanotubes. The coated single-walled carbon nanotubes were characterized through transmission electron microscope spectroscopy, field-emission electron microscope spectroscopy, X-ray diffractometry, and thermogravimetric analysis. The results demonstrated that the nickel-copper bilayers coated on single-walled carbon nanotubes possessed higher purity of unoxidized copper fine-grains than copper monolayers.

  11. Investigation on single carbon atom transporting through the single-walled carbon nanotube by MD simulation

    International Nuclear Information System (INIS)

    The single carbon atom transporting through the single-walled carbon nanotube has been studied by molecular-dynamics (MD) simulation. We got different trajectories of the carbon atom by changing the input parameters. The simulation results indicate that the single carbon atom with low energy can transport through the carbon nanotube under some input conditions and result in different trajectories being straight line or 'rosette' or circular. (authors)

  12. Antimicrobial Biomaterials based on Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Aslan, Seyma

    Biomaterials that inactivate bacteria are needed to eliminate medical device infections. We investigate the antimicrobial nature of single-walled carbon nanotubes (SWNT) incorporated within biomedical polymers. In the first part, we focus on SWNT dispersed in the common biomedical polymer poly(lactic-co-glycolic acid) (PLGA) as a potential antimicrobial biomaterial. We find Escherichia coli and Staphylococcus epidermidis viability and metabolic activity to be significantly diminished in the presence of SWNT-PLGA, and to correlate with SWNT length and concentration. Up to 98 % of bacteria die within one hour of SWNT-PLGA versus 15-20% on pure PLGA. Shorter SWNT are found to be more toxic, possibly due to an increased density of open tube ends. In the second part, we investigate the antimicrobial activity of SWNT layer-by-layer (LbL) assembled with the polyelectrolytes poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA). The dispersibility of SWNT in aqueous solution is significantly improved via the biocompatible nonionic surfactant polyoxyethylene(20)sorbitan monolaurate (Tween 20) and the amphiphilic polymer phospholipid-poly(ethylene glycol) (PL-PEG). Absorbance spectroscopy and transmission electron microscopy (TEM) show SWNT with either Tween 20 or PL-PEG in aqueous solution to be well dispersed. Quartz crystal microgravimetry with dissipation (QCMD) measurements show both SWNT-Tween and SWNT-PL-PEG to LbL assemble with PLL and PGA into multilayer films, with the PL-PEG system yielding the greater final SWNT content. Bacterial inactivation rates are significantly higher (up to 90%) upon 24 hour incubation with SWNT containing films, compared to control films (ca. 20%). In the third part, we study the influence of bundling on the LbL assembly of SWNT with charged polymers, and on the antimicrobial properties of the assembled film. QCMD measurements show the bundled SWNT system to adsorb in an unusually strong fashion—to an extent three times greater than that

  13. Single Walled Carbon Nanohorns as Photothermal Cancer Agents

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, John [Virginia Polytechnic Institute and State University (Virginia Tech); Sarkar, Saugata [Virginia Polytechnic Institute and State University (Virginia Tech); Zhang, Jianfei [Virginia Polytechnic Institute and State University (Virginia Tech); Do, Thao [Virginia Polytechnic Institute and State University (Virginia Tech); Manson, Mary kyle [Virginia Polytechnic Institute and State University (Virginia Tech); Campbell, Tom [Virginia Polytechnic Institute and State University (Virginia Tech); Puretzky, Alexander A [ORNL; Rouleau, Christopher M [ORNL; More, Karren Leslie [ORNL; Geohegan, David B [ORNL; Rylander, Christopher [Virginia Polytechnic Institute and State University (Virginia Tech); Dorn, Harry C [Virginia Polytechnic Institute and State University (Virginia Tech); Rylander, Nichole M [Virginia Polytechnic Institute and State University (Virginia Tech)

    2011-01-01

    Nanoparticles have significant potential as selective photo-absorbing agents for laser based cancer treatment. This study investigates the use of single walled carbon nanohorns (SWNHs) as thermal enhancers when excited by near infrared (NIR) light for tumor cell destruction. Absorption spectra of SWNHs in deionized water at concentrations of 0, 0.01, 0.025, 0.05, 0.085, and 0.1 mg/ml were measured using a spectrophotometer for the wavelength range of 200-1,400 nm. Mass attenuation coefficients were calculated using spectrophotometer transmittance data. Cell culture media containing 0, 0.01, 0.085, and 0.333 mg/ml SWNHs was laser irradiated at 1,064 nm wavelength with an irradiance of 40 W/cm{sup 2} for 0-5 minutes. Temperature elevations of these solutions during laser irradiation were measured with a thermocouple 8 mm away from the incident laser beam. Cell viability of murine kidney cancer cells (RENCA) was measured 24 hours following laser treatment with the previously mentioned laser parameters alone or with SWNHs. Cell viability as a function of radial position was determined qualitatively using trypan blue staining and bright field microscopy for samples exposed to heating durations of 2 and 6 minutes alone or with 0.085 mg/ml SWNHs. A Beckman Coulter Vi-Cell instrument quantified cell viability of samples treated with varying SWNH concentration (0, 0.01, 0.085, and 0.333 mg/ml) and heating durations of 0-6 minutes. Spectrophotometer measurements indicated inclusion of SWNHs increased light absorption and attenuation across all wavelengths. Utilizing SWNHs with laser irradiation increased temperature elevation compared to laser heating alone. Greater absorption and higher temperature elevations were observed with increasing SWNH concentration. No inherent toxicity was observed with SWNH inclusion. A more rapid and substantial viability decline was observed over time in samples exposed to SWNHs with laser treatment compared with samples experiencing laser

  14. Structural characterization of macroscopic single-walled carbon nanotube materials

    Science.gov (United States)

    Zhou, Wei

    In this thesis, we studied the structural properties of macroscopic materials of single-walled carbon nanotubes (SWNTs) in the form of fibers, films and suspensions. We characterized the preferred orientations in partially aligned SWNT fibers and films, combining x-ray fiber diagram and polarized Raman scattering. Our texture model consists of an aligned fraction, characterized by the angular distribution width of tube axes, plus a completely unaligned fraction. For neat fibers extruded from SWNT/superacid suspensions through a small orifice, the distribution width and the aligned fraction both improve with decreasing orifice diameter. For magnetic field-aligned SWNT films deposited from surfactant suspensions, the aligning effects of deposition and external magnetic field force in the film plane are additive, the out-of-plane mosaic being narrower than the in-plane one. SWNTs dispersed in superacid or aqueous surfactant solutions are precursors for many applications. In oleum, SWNTs can be charged and protonated by H 2SO4 molecules. X-ray scattering indicates that H2SO 4 molecules align along nanotube axes to form cylindrical shells wrapped around nanotubes. This finding establishes the validity of a long-standing important but still debated physical chemistry concept, "structured solvent shells surrounding dissolved ions". Differential scanning calorimetry confirms that the partly ordered H2SO4 molecules are a new phase, with distinct freezing/melting behavior. X-ray scattering at low temperature further shows that crystallization of the bulk-like acid surrounding the structured shells is templated by the SWNTs. The specific orientation of the acid crystallites provides solid evidence for direct protonation of SWNT. We studied the morphologies of SWNT suspensions using small-angle neutron scattering. We observed rigid rod behavior from SWNTs dispersed in water using sodium dodecylbenzene sulfonate surfactant, suggesting that SWNTs exist mainly as individual tube

  15. The synthesis and filling of single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    This thesis is concerned with the synthesis, properties and application of single-walled carbon nanotubes (SWNTs). The two main objectives of the work were the development of a continuous-flow synthesis of SWNTs, using chemical vapour deposition (CVD) techniques, and the application of the hollow SWNTs as moulds for the study of the crystallisation behaviour of inorganic materials in the confined space of their inner cavity. The latter study was mainly performed by interpreting high-resolution transmission electron microscopy (HRTEM) images of the filled SWNTs. A so-called focal series restoration approach, which enhances the resolution of the images and thereby increases the information content, was employed where possible. Chapter I reviews the previous work in the field of SWNTs and introduces their basic structure, symmetry, physical and mechanical properties and the common methods of SWNT synthesis. The chapter ends with an overview of the techniques used in the present work for the characterisation of carbon nanotube samples by giving a description of the high-resolution transmission electron microscopy (HRTEM) techniques and the digital image processing method. Other physical measurement techniques used, such as Raman spectroscopy and thermogravimetric analysis (TGA), are discussed with reference to their application for the characterisation of carbon nanotubes. Chapter II describes the development of an improved synthesis strategy for SWNTs. A continuous-flow chemical vapour deposition (CVD) method was explored using carbon monoxide or mixtures of methane and hydrogen as the carbon feedstock gas and introducing various volatile organometallic compounds to catalyse the formation of SWNTs. In this study, a special water-cooled copper nozzle was designed and built so as to prevent the premature decompositiont (disproportionation) of the reactants (the carbon monoxide gas) and to allow their direct introduction into the centre of the hot reaction zone. A

  16. High-speed countercurrent chromatography for purification of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Ying Cai; Zhi Hong Yan; Ying Chun Lv; Min Zi; Li Ming Yuan

    2008-01-01

    A new chromatographic purification of single-walled carbon nanotubes using high-speed countercurrent chromatography is reported.The purification was accomplished on the basis of experiment that dispersed the single-walled carbon nanotubes with sodium dodecyl sulfate,and the result mixture was separated using the two phase system composed of n-butanol/water=1/1 (v/v).The sizes of SWNTs separated were observed by scanning electron microscopy.The results demonstrated that the high-speed countercurrent chromatography possessed a good efficency for purification of single-walled carbon nanotubes.

  17. Preparation of Nickel-Copper Bilayers Coated on Single-Walled Carbon Nanotubes

    OpenAIRE

    Zhong Zheng; Shan Zhao; Shijie Dong; Lianjie Li; Anchun Xiao; Sinian Li

    2015-01-01

    Due to oxidizability of copper coating on carbon nanotubes, the interfacial bond strength between copper coating and its matrix is weak, which leads to the reduction of the macroscopic properties of copper matrix composite. The electroless coating technics was applied to prepare nickel-copper bilayers coated on single-walled carbon nanotubes. The coated single-walled carbon nanotubes were characterized through transmission electron microscope spectroscopy, field-emission electron microscope s...

  18. Polyvinylchloride-Single-Walled Carbon Nanotube Composites: Thermal and Spectroscopic Properties

    Directory of Open Access Journals (Sweden)

    Mircea Chipara

    2012-01-01

    Full Text Available Nanocomposites of single-walled carbon nanotubes dispersed within polyvinylchloride have been obtained by using the solution path. High-power sonication was utilized to achieve a good dispersion of carbon nanotubes. Thermogravimetric analysis revealed that during the synthesis, processing, or thermal analysis of these nanocomposites the released chlorine is functionalizing the single-walled carbon nanotubes. The loading of polyvinylchloride by single-walled carbon nanotubes increases the glass transition temperature of the polymeric matrix, demonstrating the interactions between macromolecular chains and filler. Wide Angle X-Ray Scattering data suggested a drop of the crystallite size and of the degree of crystallinity as the concentration of single-walled carbon nanotubes is increased. The in situ chlorination and amorphization of nanotube during the synthesis (sonication step is confirmed by Raman spectroscopy.

  19. Coupled thermo-mechanics of single-wall carbon nanotubes

    CERN Document Server

    Scarpa, Fabrizio; Peng, Hua-Xin; Remillat, Chrystel; Adhikari, Sondipon

    2010-01-01

    The temperature-dependent transverse mechanical properties of single-walled nanotubes are studied using a molecular mechanics approach. The stretching and bond angle force constants describing the mechanical behaviour of the sp^{2} bonds are resolved in the temperature range between 0 K and 1600 K, allowing to identify a temperature dependence of the nanotubes wall thickness. We observe a decrease of the stiffness properties (axial and shear Young's modulus) with increasing temperatures, and an augmentation of the transverse Poisson's ratio, with magnitudes depending on the chirality of the nanotube. Our closed-form predictions compare well with existing Molecular Dynamics simulations.

  20. ANALYSIS OF MATERIAL MECHANICAL PROPERTIES FOR SINGLE-WALLED CARBON NANOTUBES

    Institute of Scientific and Technical Information of China (English)

    Fu Yiming; Xu Xiaoxian

    2005-01-01

    Abstract The carbon-carbon bond between two nearest-neighboring atoms is modeled as a beam and the single-walled carbon nanotubes are treated as the space frame structures in order to analyze the mechanical properties of carbon nanotubes. Based on the theory of TersoffBrenner force field, the energy relationships between the carbon-carbon bond and the beam model are obtained, and the stiffness parameters of the beam are determined. By applying the present model, the Young's moduli of the single-walled carbon nanotubes with different tube diameters are determined. And the present results are compared with available data.

  1. The effect of oxidation on structural and electrical properties of single wall carbon nanotubes

    OpenAIRE

    Marković Zoran M.; Peruško Davor B.; Tošić Dragana D.; Romčević Nebojša Z.; Dramićanin Miroslav D.; Nikolić Zoran M.; Marković Todorović Biljana M.

    2011-01-01

    Single wall carbon nanotubes (SWCNTs) represent an important group of nanomaterials with attractive electrical, chemical, and mechanical properties. In this work we have investigated the structural, optical and electrical properties of single wall carbon nanotube films deposited on copper substrate and then transferred to polymethyl methacrylate (PMMA). The properties of deposited films were varied by changing different parameters: substrate temperature, deposition time and electric fie...

  2. Effect of oxygen adsorption on the electrochemical oxidative corrosion of single-walled carbon nanotubes

    OpenAIRE

    Tominaga, Masato; Yatsugi, Yuto; Togami, Makoto; トミナガ, マサト; ヤツギ, ユウト; トガミ, マコト; 冨永, 昌人; 矢次, 祐人; 戸上, 純

    2014-01-01

    The effect of adsorbed molecular oxygen on the oxidative corrosion of single-walled carbon nanotubes in aqueous solution was investigated by Raman spectroscopy. Adsorbed molecular oxygen affected nucleation and growth in the electrochemical oxidative corrosion of single-walled carbon nanotubes in aqueous electrolyte. Nucleation and growth began at defect sites in the presence of adsorbed oxygen, but occurred randomly in the absence of adsorbed oxygen. This insight furthers our understanding o...

  3. Synthesis of single wall carbon nanotubes from a lamellar type aluminophosphate (AlPO4-L)

    Indian Academy of Sciences (India)

    N Venkatathri

    2008-08-01

    Single wall carbon nanotubes are synthesized from a lamellar type aluminophosphate, AlPO4-L. The lamellar aluminophosphate was synthesized from hexamethyleneimine template. The latter was calcined at argon atmosphere for 12 h at 600°C. The resulting carbonaceous material was treated with 1 N H2SO4 to remove the aluminophosphate skeleton. Characterization of the resulting carbon revealed to contain single walled nanotubes. These nanotubes are applicable to store more hydrogen.

  4. Metal coating effect on thermal diffusivity of single-walled carbon nanotube

    OpenAIRE

    Inoue, Shuhei; Matsumura, Yukihiko

    2010-01-01

    Recently a functionalized single-walled carbon nanotube (SWCNT) that is modified by metal atoms was experimentally developed. Single-walled carbon nanotube is known to exhibit exceptional thermal conductivity; however, there is no report about a functionalized SWCNT. In this study, thermal diffusivity of metal-coated SWCNT was derived using molecular dynamics. Consequently, thermal diffusivity exhibited 10 times smaller than uncoated SWCNT. On the other hand, the heat conduction on the metal ...

  5. Improved synthesis of carbon nanotubes with junctions and of single-walled carbon nanotubes

    OpenAIRE

    Deepak, FL; Govindaraj, A.; Rao, CNR

    2006-01-01

    Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Y-junction carbon nanotubes with smaller diameters than those obtained by the pyrolysis of organometallic-thiophene mixtures. In the presence of water vapour, the pyrolysis of organometallic-hydrocarbon mixtures yields single-walled nanotubes, as well as relatively narrow-diameter carbon nanotubes with Y-junctions. Pyrolysis-of organometallic-hydrocarbon mixtures, in the absence of water vapour, only gives ...

  6. Improved synthesis of carbon nanotubes with junctions and of single-walled carbon nanotubes

    Indian Academy of Sciences (India)

    F L Deepak; A Govindaraj; C N R Rao

    2006-01-01

    Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Yjunction carbon nanotubes with smaller diameters than those obtained by the pyrolysis of organometallicthiophene mixtures. In the presence of water vapour, the pyrolysis of organometallic-hydrocarbon mixtures yields single-walled nanotubes, as well as relatively narrow-diameter carbon nanotubes with Y-junctions. Pyrolysis of organometallic-hydrocarbon mixtures, in the absence of water vapour, only gives nanotubes with T- and Y-junctions.

  7. Single walled carbon nanotube network—Tetrahedral amorphous carbon composite film

    International Nuclear Information System (INIS)

    Single walled carbon nanotube network (SWCNTN) was coated by tetrahedral amorphous carbon (ta-C) using a pulsed Filtered Cathodic Vacuum Arc system to form a SWCNTN—ta-C composite film. The effects of SWCNTN areal coverage density and ta-C coating thickness on the composite film properties were investigated. X-Ray photoelectron spectroscopy measurements prove the presence of high quality sp3 bonded ta-C coating on the SWCNTN. Raman spectroscopy suggests that the single wall carbon nanotubes (SWCNTs) forming the network survived encapsulation in the ta-C coating. Nano-mechanical testing suggests that the ta-C coated SWCNTN has superior wear performance compared to uncoated SWCNTN

  8. Single walled carbon nanotube network—Tetrahedral amorphous carbon composite film

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Ajai, E-mail: ajai.iyer@aalto.fi; Liu, Xuwen; Koskinen, Jari [Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, POB 16200, 00076 Espoo (Finland); Kaskela, Antti; Kauppinen, Esko I. [NanoMaterials Group, Department of Applied Physics, School of Science, Aalto University, POB 15100, 00076 Espoo (Finland); Johansson, Leena-Sisko [Department of Forest Products Technology, School of Chemical Technology, Aalto University, POB 16400, 00076 Espoo (Finland)

    2015-06-14

    Single walled carbon nanotube network (SWCNTN) was coated by tetrahedral amorphous carbon (ta-C) using a pulsed Filtered Cathodic Vacuum Arc system to form a SWCNTN—ta-C composite film. The effects of SWCNTN areal coverage density and ta-C coating thickness on the composite film properties were investigated. X-Ray photoelectron spectroscopy measurements prove the presence of high quality sp{sup 3} bonded ta-C coating on the SWCNTN. Raman spectroscopy suggests that the single wall carbon nanotubes (SWCNTs) forming the network survived encapsulation in the ta-C coating. Nano-mechanical testing suggests that the ta-C coated SWCNTN has superior wear performance compared to uncoated SWCNTN.

  9. Single-Wall Carbon Nanotube Growth from Graphite Layers-a Tight Binding Molecular Dynamics Simulation

    Institute of Scientific and Technical Information of China (English)

    Yuntuan FANG; Min ZHU; Yongshun WANG

    2003-01-01

    The growth of single-wall carbon nanotube from graphite layers is studied by tight binding molecular dynamics simulation. Given temperature of 2500 K or 3500 K and an interval of 0.25 nm for the two layers of graphite, a single-wall carbon nanotube with a zigzag shell will be produced. On the other conditions the carbon nanotube cannot grow or grows with too many defects. All carbon nanotube ends have pentagons which play an important role during the tube ends closing.

  10. Collision-induced fusion of two single-walled carbon nanotubes: A quantitative study

    Science.gov (United States)

    Zhang, Chao; Mao, Fei; Meng, Xiang-Rui; Wang, Dong-Qi; Zhang, Feng-Shou

    2016-07-01

    The coalescence processes of two (6, 0) single-walled carbon nanotubes are investigated via coaxial collision based on the self-consistent-charge density-functional tight-binding molecular dynamics method. According to the structure characteristics of the nanotubes, five impact cases are studied to explore the coalescence processes of the nanotubes. The simulation shows that various kinds of carbon nanomaterials, such as graphene sheets, graphene nanoribbons, and single-walled carbon nanotubes with larger diameters, are created after collision. Moreover, some defects formed in the carbon nanomaterials can be eliminated, and even the final configurations which are originally fragmented can almost become intact structures by properly quenching and annealing.

  11. Electron spin resonance investigations on ion beam irradiated single-wall carbon nanotubes

    International Nuclear Information System (INIS)

    ESR investigations on single-wall carbon nanotubes irradiated with accelerated protons, helium ions, and neon ions are reported. All spectra were accurately simulated assuming that the resonance line is a convolution of up to 4 lines originating from catalyst residues, amorphous carbon, and electrons delocalized over the conducting domains of nanotubes. The faint line observed in irradiated nanotubes at g > 2.25 was assigned to magnetic impurities. However, there are no sufficient data to confirm that this line is connected to radiation-induced magnetism in carbon nanotubes. The generation of paramagnetic defects due to the bombardment of single-wall carbon nanotubes by accelerated ions is reported. These data correlate with previous Raman and thermal investigations on the same single-wall carbon nanotubes and reveals their sensitivity to ionizing radiation. The temperature dependence of ESR spectra in the range 25-250 K was used to identify the components of the ESR spectra

  12. Direct observation of spin-injection in tyrosinate-functionalized single-wall carbon nanotubes

    NARCIS (Netherlands)

    Tsoufis, Theodoros; Ampoumogli, Asem; Gournis, Dimitrios; Georgakilas, Vasilios; Jankovic, Lubos; Christoforidis, Konstantinos C.; Deligiannakis, Yiannis; Mavrandonakis, Andreas; Froudakis, George E.; Maccallini, Enrico; Rudolf, Petra; Mateo-Alonso, Aurelio; Prato, Maurizio

    2014-01-01

    In this work, we report on the interaction of a tyrosinate radical with single wall carbon nanotubes (CNT). The tyrosinate radical was formed from tyrosine (ester) by Fenton's reagent and, reacted in situ with carbon nanotubes resulting in novel tyrosinated carbon nanotube derivatives. The covalent

  13. Single-walled carbon nanotube incorporated novel three phase carbon/epoxy composite with enhanced properties.

    Science.gov (United States)

    Rana, Sohel; Alagirusamy, Ramasamy; Joshi, Mangala

    2011-08-01

    In the present work, single-walled carbon nanotubes were dispersed within the matrix of carbon fabric reinforced epoxy composites in order to develop novel three phase carbon/epoxy/single-walled carbon nanotube composites. A combination of ultrasonication and high speed mechanical stirring at 2000 rpm was used to uniformly disperse carbon nanotubes in the epoxy resin. The state of carbon nanotube dispersion in the epoxy resin and within the nanocomposites was characterized with the help of optical microscopy and atomic force microscopy. Pure carbon/epoxy and three phase composites were characterized for mechanical properties (tensile and compressive) as well as for thermal and electrical conductivity. Fracture surfaces of composites after tensile test were also studied in order to investigate the effect of dispersed carbon nanotubes on the failure behavior of composites. Dispersion of only 0.1 wt% nanotubes in the matrix led to improvements of 95% in Young's modulus, 31% in tensile strength, 76% in compressive modulus and 41% in compressive strength of carbon/epoxy composites. In addition to that, electrical and thermal conductivity also improved significantly with addition of carbon nanotubes. PMID:22103118

  14. Single-Walled Carbon Nano tubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

    International Nuclear Information System (INIS)

    The possibility of using single-walled carbon nanotubes (SWCNTs) aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k) for S.aureus and E.coli determined from batch adsorption study was found to be 9 x108 and 2 x108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.

  15. Single-Walled Carbon Nanotubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

    Directory of Open Access Journals (Sweden)

    Venkata K. K. Upadhyayula

    2008-01-01

    Full Text Available The possibility of using single-walled carbon nanotubes (SWCNTs aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k for S.aureus and E.coli determined from batch adsorption study was found to be 9×108 and 2×108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.

  16. Computational and experimental studies of the interaction between single-walled carbon nanotubes and folic acid

    DEFF Research Database (Denmark)

    Castillo, John J.; Rozo, Ciro E.; Castillo-León, Jaime; Rindzevicius, Tomas; Svendsen, Winnie Edith; Rozlosnik, Noemi; Boisen, Anja; O, Fernando Martínez

    2013-01-01

    This work involved the preparation of a conjugate between single-walled carbon nanotubes and folic acid that was obtained without covalent chemical functionalization using a simple “one pot” synthesis method. Subsequently, the conjugate was investigated by a computational hybrid method: our own...... Nlayered Integrated Molecular Orbital and Molecular Mechanics (B3LYP(6–31G(d):UFF)). The results confirmed that the interaction occurred via hydrogen bonding between protons of the glutamic moiety from folic acid and π electrons from the carbon nanotubes. The single-walled carbon nanotube-folic acid...

  17. Conjugated Polymer-Assisted Dispersion of Single-Wall Carbon Nanotubes : The Power of Polymer Wrapping

    NARCIS (Netherlands)

    Samanta, Suman Kalyan; Fritsch, Martin; Scherf, Ullrich; Gomulya, Widianta; Bisri, Satria Zulkarnaen; Loi, Maria Antonietta

    2014-01-01

    CONSPECTUS: The future application of single-walled carbon nanotubes (SWNTs) in electronic (nano)devices is closely coupled to the availability of pure, semiconducting SWNTs and preferably, their defined positioning on suited substrates. Commercial carbon nanotube raw mixtures contain metallic as we

  18. Key roles of carbon solubility in single-walled carbon nanotube nucleation and growth

    Science.gov (United States)

    He, Maoshuai; Amara, Hakim; Jiang, Hua; Hassinen, Jukka; Bichara, Christophe; Ras, Robin H. A.; Lehtonen, Juha; Kauppinen, Esko I.; Loiseau, Annick

    2015-11-01

    Elucidating the roles played by carbon solubility in catalyst nanoparticles is required to better understand the growth mechanisms of single-walled carbon nanotubes (SWNTs). Here, we highlight that controlling the level of dissolved carbon is of key importance to enable nucleation and growth. We first performed tight binding based atomistic computer simulations to study carbon incorporation in metal nanoparticles with low solubilities. For such metals, carbon incorporation strongly depends on their structures (face centered cubic or icosahedral), leading to different amounts of carbon close to the nanoparticle surface. Following this idea, we then show experimentally that Au nanoparticles effectively catalyze SWNT growth when in a face centered cubic structure, and fail to do so when icosahedral. Both approaches emphasize that the presence of subsurface carbon in the nanoparticles is necessary to enable the cap lift-off, making the nucleation of SWNTs possible.Elucidating the roles played by carbon solubility in catalyst nanoparticles is required to better understand the growth mechanisms of single-walled carbon nanotubes (SWNTs). Here, we highlight that controlling the level of dissolved carbon is of key importance to enable nucleation and growth. We first performed tight binding based atomistic computer simulations to study carbon incorporation in metal nanoparticles with low solubilities. For such metals, carbon incorporation strongly depends on their structures (face centered cubic or icosahedral), leading to different amounts of carbon close to the nanoparticle surface. Following this idea, we then show experimentally that Au nanoparticles effectively catalyze SWNT growth when in a face centered cubic structure, and fail to do so when icosahedral. Both approaches emphasize that the presence of subsurface carbon in the nanoparticles is necessary to enable the cap lift-off, making the nucleation of SWNTs possible. Electronic supplementary information (ESI

  19. Process for separating metallic from semiconducting single-walled carbon nanotubes

    Science.gov (United States)

    Sun, Ya-Ping (Inventor)

    2008-01-01

    A method for separating semiconducting single-walled carbon nanotubes from metallic single-walled carbon nanotubes is disclosed. The method utilizes separation agents that preferentially associate with semiconducting nanotubes due to the electrical nature of the nanotubes. The separation agents are those that have a planar orientation, .pi.-electrons available for association with the surface of the nanotubes, and also include a soluble portion of the molecule. Following preferential association of the separation agent with the semiconducting nanotubes, the agent/nanotubes complex is soluble and can be solubilized with the solution enriched in semiconducting nanotubes while the residual solid is enriched in metallic nanotubes.

  20. Single-walled carbon nanotubes modified by ionic liquid as antiwear additives of thermoplastics

    OpenAIRE

    Carrión, F.J.; Espejo, C.; Sanes, J.; Bermúdez, M.D.

    2010-01-01

    Abstract Pristine single-walled carbon nanotubes (CNTs) were dispersed in the room-temperature ionic liquid (IL) 1-octyl, 3-methylimidazolium tetrafluoroborate ([OMIM]BF4) by grinding and ultrasounds. Excess IL was removed to obtain single-walled carbon nanotubes modified by [OMIM]BF4 (mCNTs). mCNTs were added in a 1wt.% to polystyrene (PS), polymethylmethacrylate (PMMA) and polycarbonate (PC) to obtain PS+mCNT, PMMA+mCNT and PC+mCNT. The dry tribological performance of the new nan...

  1. Investigation on vibration of single-walled carbon nanotubes by variational iteration method

    Science.gov (United States)

    Ahmadi Asoor, A. A.; Valipour, P.; Ghasemi, S. E.

    2016-02-01

    In this paper, the variational iteration method (VIM) has been used to investigate the non-linear vibration of single-walled carbon nanotubes (SWCNTs) based on the nonlocal Timoshenko beam theory. The accuracy of results is examined by the fourth-order Runge-Kutta numerical method. Comparison between VIM solutions with numerical results leads to highly accurate solutions. Also, the behavior of deflection and frequency in vibrations of SWCNTs are studied. The results show that frequency of single walled carbon nanotube versus amplitude increases by increasing the values of B.

  2. Molecular Dynamics Simulations of the Thermal Conductivity of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Osman, M.; Srivastava, Deepak; Govindan,T. R. (Technical Monitor)

    2000-01-01

    Carbon nanotubes (CNT) have very attractive electronic, mechanical. and thermal properties. Recently, measurements of thermal conductivity in single wall CNT mats showed estimated thermal conductivity magnitudes ranging from 17.5 to 58 W/cm-K at room temperature. which are better than bulk graphite. The cylinderical symmetry of CNT leads to large thermal conductivity along the tube axis, additionally, unlike graphite. CNTs can be made into ropes that can be used as heat conducting pipes for nanoscale applications. The thermal conductivity of several single wall carbon nanotubes has been calculated over temperature range from l00 K to 600 K using non-equilibrium molecular dynamics using Tersoff-Brenner potential for C-C interactions. Thermal conductivity of single wall CNTs shows a peaking behavior as a function of temperature. Dependence of the peak position on the chirality and radius of the tube will be discussed and explained in this presentation.

  3. Effects of Two Purification Pretreatments on Electroless Copper Coating over Single-Walled Carbon Nanotubes

    OpenAIRE

    Zhong Zheng; Lianjie Li; Shijie Dong; Anchun Xiao; Shixuan Sun; Sinian Li

    2014-01-01

    To achieve the reinforcement of copper matrix composite by single-walled carbon nanotubes, a three-step-refluxing purification of carbon nanotubes sample with HNO3-NaOH-HCl was proposed and demonstrated. A previously reported purification process using an electromagnetic stirring with H2O2/HCl mixture was also repeated. Then, the purified carbon nanotubes were coated with copper by the same electroless plating process. At the end, the effects of the method on carbon nanotubes themselves and o...

  4. Electronic transport properties of metallic single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    曹觉先; 颜晓红; 肖杨; 丁建文

    2003-01-01

    We have calculated the differential conductance of metallic carbon nanotubes by the scatter matrix method. It is found that the differential conductance of metallic nanotube-based devices oscillates as a function of the bias voltage between the two leads and the gate voltage. Oscillation period T is directly proportional to the reciprocal of nanotube length. In addition, we found that electronic transport properties are sensitive to variation of the length of the nanotube.

  5. Selective Etching of Thin Single-Walled Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Dunsch, L.

    2009-01-01

    Roč. 131, č. 12 (2009), s. 4529-4534. ISSN 0002-7863 R&D Projects: GA AV ČR IAA400400804; GA ČR GC203/07/J067; GA AV ČR IAA400400911 Institutional research plan: CEZ:AV0Z40400503 Keywords : carbon nanotubes * Raman spectroelectrochemistry * Raman spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 8.580, year: 2009

  6. Excitonic nonlinearities in single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, D.T.; Voisin, C.; Roussignol, P. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, UPMC, Universite Paris Diderot, CNRS UMR8551, Paris (France); Roquelet, C.; Lauret, J.S. [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan (France); Cassabois, G. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, UPMC, Universite Paris Diderot, CNRS UMR8551, Paris (France); Laboratoire Charles Coulomb, UMR5221, Universite Montpellier 2, Montpellier (France); CNRS, Laboratoire Charles Coulomb, UMR5221, Montpellier (France)

    2012-05-15

    Excitons are composite bosons that allow a fair description of the optical properties in solid state systems. The quantum confinement in nanostructures enhances the excitonic effects and impacts the exciton-exciton interactions, which tailor the performances of classical and quantum optoelectronic devices, such as lasers or single-photon emitters. The excitonic nonlinearities exhibit significant differences between organic and inorganic compounds. Tightly bound Frenkel excitons in molecular crystals are for instance affected by an efficient exciton-exciton annihilation (EEA). This Auger process also governs the population relaxation dynamics in carbon nanotubes that share many physical properties with organic materials. Here, we show that this similarity breaks down for the excitonic decoherence in carbon nanotubes. Original nonlinear spectral-hole burning experiments bring evidence of pure dephasing induced by exciton-exciton scattering (EES) in the k-space. This mechanism controls the exciton collision-induced broadening, as for Wannier excitons in inorganic semiconductors. We demonstrate that this singular behavior originates from the intrinsic one-dimensionality of excitons in carbon nanotubes, which display unique hybrid features of organic and inorganic systems. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Random telegraph noise in metallic single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hyun-Jong; Woo Uhm, Tae; Won Kim, Sung; Gyu You, Young; Wook Lee, Sang; Ho Jhang, Sung, E-mail: shjhang@konkuk.ac.kr [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Campbell, Eleanor E. B. [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); EaStCHEM, School of Chemistry, Edinburgh University, West Mains Road, Edinburgh EH9 3JJ (United Kingdom); Woo Park, Yung [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2014-05-12

    We have investigated random telegraph noise (RTN) observed in individual metallic carbon nanotubes (CNTs). Mean lifetimes in high- and low-current states, τ{sub high} and τ{sub low}, have been studied as a function of bias-voltage and gate-voltage as well as temperature. By analyzing the statistics and features of the RTN, we suggest that this noise is due to the random transition of defects between two metastable states, activated by inelastic scattering with conduction electrons. Our results indicate an important role of defect motions in the 1/f noise in CNTs.

  8. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Mottaghitalab, Fatemeh [Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Farokhi, Mehdi [National cell bank of Iran, Pasteur Institute, Tehran (Iran, Islamic Republic of); Atyabi, Fatemeh [Department of Pharmaceutical Nanoechnology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Omidvar, Ramin [Department of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali, E-mail: mashokrgozar@pasteur.ac.ir [National cell bank of Iran, Pasteur Institute, Tehran (Iran, Islamic Republic of); Sadeghizadeh, Majid, E-mail: sadeghma@modares.ac.ir [Department Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of)

    2015-06-01

    Highlights: • Increasing the cytocompatibility of single walled carbon nanotube by loading fibronectin. • Enhancing the hydrophilicity and nanosurface roughness of single walled carbon nanotube after loading fibronectin. • Fibronectin makes the surface properties of single walled carbon nanotube more suitable for cell proliferation and growth. - Abstract: Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT.

  9. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    International Nuclear Information System (INIS)

    Highlights: • Increasing the cytocompatibility of single walled carbon nanotube by loading fibronectin. • Enhancing the hydrophilicity and nanosurface roughness of single walled carbon nanotube after loading fibronectin. • Fibronectin makes the surface properties of single walled carbon nanotube more suitable for cell proliferation and growth. - Abstract: Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT

  10. Molecular Dynamics Simulation of Formaldehyde Adsorption and Diffusion in Single-Wall Carbon Nanotube

    Institute of Scientific and Technical Information of China (English)

    Pin Lv; Zhenan Tang; Jun Yu; Yanbing Xue

    2006-01-01

    For gas sensor application, adsorption and diffusion of formaldehyde gas in single-wall carbon nanotube were investigated by using molecular dynamics simulation. The conformations of formaldehyde molecule adsorbed in carbon nanotube were optimized according to principle of minimum energy. The axis of conformatiot is parallel to the axis of carbon nanotube and about 0.3 nm~0.4 nm away from carbon nanotube wall. The conformation, which is different from that of the formaldehyde molecule in the gas-phase, rotates around carbon nanotube axis. The adsorption energy and diffusivity of formaldehyde molecule in single-wall carbon nanotube is of-56.2 kJ/mol and of 0.2× 10-4 cm2/s, respectively.

  11. Properties of electrophoretically deposited single wall carbon nanotube films

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Junyoung; Jalali, Maryam; Campbell, Stephen A., E-mail: campb001@umn.edu

    2015-08-31

    This paper describes techniques for rapidly producing a carbon nanotube thin film by electrophoretic deposition at room temperature and determines the film mass density and electrical/mechanical properties of such films. The mechanism of electrophoretic deposition of thin layers is explained with experimental data. Also, film thickness is measured as a function of time, electrical field and suspension concentration. We use Rutherford backscattering spectroscopy to determine the film mass density. Films created in this manner have a resistivity of 2.14 × 10{sup −3} Ω·cm, a mass density that varies with thickness from 0.12 to 0.54 g/cm{sup 3}, and a Young's modulus between 4.72 and 5.67 GPa. The latter was found to be independent of thickness from 77 to 134 nm. We also report on fabricating free-standing films by removing the metal seed layer under the CNT film, and selectively etching a sacrificial layer. This method could be extended to flexible photovoltaic devices or high frequency RF MEMS devices. - Highlights: • We explain the electrophoretic deposition process and mechanism of thin SWCNT film deposition. • Characterization of the SWCNT film properties including density, resistivity, transmittance, and Young's modulus. • The film density and resistivity are found to be a function of the film thickness. • Techniques developed to create free standing layers of SW-CNTs for flexible electronics and mechanical actuators.

  12. Single-Walled Carbon Nanotubes Acting as Controllable Transport Channels

    Institute of Scientific and Technical Information of China (English)

    HUANG Bo-Da; XIA Yue-Yuan; ZHAO Ming-Wen; LI Feng; LIU Xiang-Dong; JI Yan-Ju; SONG Chen; TAN Zhen-Yu; LIU Hui

    2004-01-01

    @@ The motion and equilibrium distribution of water molecules adsorbed inside neutral and negatively charged singlewalled carbon nanotubes (SWNTs) have been studied using molecular dynamics simulations (MDSs) at room temperature based on CHARMM (Chemistry at HARvard Molecular Mechanics) potential parameters. We find that water molecules have a conspicuous electropism phenomenon and regular tubule patterns inside and outside the charged tube wall. The analyses of the motion behaviour of water molecules in the radial and axial directions show that by charging the SWNT, the adsorption efficiency is greatly enhanced, and the electric field produced by the charged SWNTs prevents water molecules from flowing out of the nanotube. However, water molecules can travel through the neutral SWNT in a fluctuating manner. This indicates that by electrically charging and uncharging the SWNTs, one can control the adsorption and transport behaviour of polar molecules in SWNTs for using as a stable storage medium or long transport channels. The transport velocity can be tailored by changing the charge on the SWNTs, which may have a further application as modulatable transport channels.

  13. Properties of electrophoretically deposited single wall carbon nanotube films

    International Nuclear Information System (INIS)

    This paper describes techniques for rapidly producing a carbon nanotube thin film by electrophoretic deposition at room temperature and determines the film mass density and electrical/mechanical properties of such films. The mechanism of electrophoretic deposition of thin layers is explained with experimental data. Also, film thickness is measured as a function of time, electrical field and suspension concentration. We use Rutherford backscattering spectroscopy to determine the film mass density. Films created in this manner have a resistivity of 2.14 × 10−3 Ω·cm, a mass density that varies with thickness from 0.12 to 0.54 g/cm3, and a Young's modulus between 4.72 and 5.67 GPa. The latter was found to be independent of thickness from 77 to 134 nm. We also report on fabricating free-standing films by removing the metal seed layer under the CNT film, and selectively etching a sacrificial layer. This method could be extended to flexible photovoltaic devices or high frequency RF MEMS devices. - Highlights: • We explain the electrophoretic deposition process and mechanism of thin SWCNT film deposition. • Characterization of the SWCNT film properties including density, resistivity, transmittance, and Young's modulus. • The film density and resistivity are found to be a function of the film thickness. • Techniques developed to create free standing layers of SW-CNTs for flexible electronics and mechanical actuators

  14. Analytic Solution of Charge Density of Single Wall Carbon Nanotube under Conditions of Field Electron Emission

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-Bing; WANG Wei-Liang

    2006-01-01

    We derive the analytic solution of induced electrostatic potential along single wall carbon nanotubes. Under the hypothesis of constant density of states in the charge-neutral level, we are able to obtain the linear density of excess charge in an external Geld parallel to the tube axis.

  15. Analytic solution of charge density of single wall carbon nanotube in conditions of field electron emission

    OpenAIRE

    Li, Zhibing; Wang, Weiliang

    2006-01-01

    We derived the analytic solution of induced electrostatic potential along single wall carbon nanotubes. Under the hypothesis of constant density of states in the charge-neutral level, we are able to obtain the linear density of excess charge in an external field parallel to the tube axis.

  16. Structural profiling and biological performance of phospholipid-hyaluronan functionalized single-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Dvash, Ram; Khatchatouriants, Artium; Solmesky, Leonardo J;

    2013-01-01

    In spite of significant insolubility and toxicity, carbon nanotubes (CNTs) erupt into the biomedical research, and create an increasing interest in the field of nanomedicine. Single-walled CNTs (SWCNTs) are highly hydrophobic and have been shown to be toxic while systemically administrated. Thus,...

  17. Plasma excitations in a single-walled carbon nanotube with an external transverse magnetic field

    Indian Academy of Sciences (India)

    K A Vijayalakshmi; T P Nafeesa Baby

    2013-02-01

    The effect of different uniform transverse external magnetic fields in plasma frequency when propagated parallel to the surface of the single-walled metallic carbon nanotubes is studied. The classical electrodynamics as well as Maxwell’s equations are used in the calculations. Equations are developed for both short- and long-wavelength limits and the variations are studied graphically.

  18. One-step synthesis of fluorescently labelled, single-walled carbon nanotubes.

    Science.gov (United States)

    Guaragno, Michelle L; Gottardi, Riccardo; Fedorchak, Morgan V; Roy, Abhijit; Kumta, Prashant N; Little, Steven R

    2015-12-18

    Single-walled carbon nanotubes (SWNTs) can be labelled with functional moieties that endow them with a number of unique characteristics, which can be applicable to biomedical applications such as imaging. Herein we describe a facile, one-step esterification process to functionalize SWNT with fluorescein. PMID:26458421

  19. Monte Carlo simulation of hydrogen physisorption in K-doped single walled carbon nanotube array

    International Nuclear Information System (INIS)

    Properties of hydrogen physisorption in K-doped single walled carbon nanotube array (SWCNTA) are investigated in detail by grand canonical Monte Carlo simulation. The optimization of hydrogen storage capacity at 293 K and 10 MPa as a function of K-doping schemes, K atoms' doped-sites, and SWCNTA configuration is discussed.

  20. In situ optical spectroelectrochemistry of single-walled carbon nanotube thin films

    Czech Academy of Sciences Publication Activity Database

    Zukalová, Markéta; Tarábek, Ján; Kalbáč, Martin; Kavan, Ladislav; Dunsch, L.

    2008-01-01

    Roč. 12, č. 10 (2008), s. 1279-1284. ISSN 1432-8488 R&D Projects: GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : uv-vis spectroelectrochemistry * cyclic voltammetry * single-walled carbon nanotubes * thin film s * doping Subject RIV: CG - Electrochemistry Impact factor: 1.597, year: 2008

  1. Scanning gate imaging of two coupled quantum dots in single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Two coupled single wall carbon nanotube quantum dots in a multiple quantum dot system were characterized by using a low temperature scanning gate microscopy (SGM) technique, at a temperature of 170 mK. The locations of single wall carbon nanotube quantum dots were identified by taking the conductance images of a single wall carbon nanotube contacted by two metallic electrodes. The single electron transport through single wall carbon nanotube multiple quantum dots has been observed by varying either the position or voltage bias of a conductive atomic force microscopy tip. Clear hexagonal patterns were observed in the region of the conductance images where only two sets of overlapping conductance rings are visible. The values of coupling capacitance over the total capacitance of the two dots, Cm/C1(2) have been extracted to be 0.21 ∼ 0.27 and 0.23 ∼ 0.28, respectively. In addition, the interdot coupling (conductance peak splitting) has also been confirmed in both conductance image measurement and current–voltage curves. The results show that a SGM technique enables spectroscopic investigation of coupled quantum dots even in the presence of unexpected multiple quantum dots. (paper)

  2. Efficient organometallic spin filter between single-wall carbon nanotube or graphene electrodes

    DEFF Research Database (Denmark)

    Koleini, Mohammad; Paulsson, Magnus; Brandbyge, Mads

    2007-01-01

    We present a theoretical study of spin transport in a class of molecular systems consisting of an organometallic benzene-vanadium cluster placed in between graphene or single-wall carbon-nanotube-model contacts. Ab initio modeling is performed by combining spin density functional theory and...

  3. Environmental Detection of Single-Walled Carbon Nanotubes Utilizing Near-Infrared Fluorescence

    Science.gov (United States)

    There are a growing number of applications for carbon nanotubes (CNT) in modern technologies and, subsequently, growth in production of CNT has expanded rapidly. Single-walled CNT (SWCNT) consist of a graphene sheet rolled up into a tube. With growing manufacture and use, the ...

  4. Effectiveness of sorting single-walled carbon nanotubes by diameter using polyfluorene derivatives

    NARCIS (Netherlands)

    Gao, J.; Kwak, M.; Wildeman, J.; Hermann, A.; Loi, M. A.; Herrmann, A.

    2011-01-01

    Semiconducting single-walled carbon nanotubes (SWCNTs) sorted by conjugated polymers are of great interest for electronic and optoelectronic applications Here we demonstrate by optical methods that the selectivity of conjugated polymers for semiconducting SWCNTs is influenced by the structure of the

  5. Tuning the physical parameters towards optimal polymer-wrapped single-walled carbon nanotubes dispersions

    NARCIS (Netherlands)

    Gao, J.; Annema, R.; Loi, M. A.

    2012-01-01

    Solubilization of single-walled carbon nanotubes (SWNTs) has been essential for the understanding of their physical properties. Ultrasonication followed by centrifugation has been generally used for the preparation of SWNT dispersion in presence of different surfactants or conjugated polymers. Howev

  6. Effect of medium dielectric constant on the physical properties of single-walled carbon nanotubes

    NARCIS (Netherlands)

    Gao, J.; Gomulya, W.; Loi, M. A.

    2013-01-01

    The photophysical properties of semiconducting single walled carbon nanotubes (SWNTs) in different environments are analyzed by steady-state and time-resolved photoluminescence (PL) spectroscopy. The PL emission of SWNTs shows a red shift with the increase of the dielectric constant of the environme

  7. Polyazines and Polyazomethines with Didodecylthiophene Units for Selective Dispersion of Semiconducting Single-Walled Carbon Nanotubes

    NARCIS (Netherlands)

    Gomulya, Widianta; Derenskyi, Vladimir; Kozma, Erika; Pasini, Mariacecilia; Loi, Maria Antonietta

    2015-01-01

    Polymer wrapped single-walled carbon nanotubes (SWNTs) have been demonstrated to be a very effi cient technique to obtain high purity semiconducting SWNT solutions. However, the extraction yield of this technique is low compared to other techniques. Poly-alkyl-thiophenes have been reported to show h

  8. Computational and experimental studies of the interaction between single-walled carbon nanotubes and folic acid

    DEFF Research Database (Denmark)

    Castillo, John J.; Rozo, Ciro E.; Castillo-León, Jaime;

    2013-01-01

    This work involved the preparation of a conjugate between single-walled carbon nanotubes and folic acid that was obtained without covalent chemical functionalization using a simple “one pot” synthesis method. Subsequently, the conjugate was investigated by a computational hybrid method: our own N...

  9. Effects of phosphorus-doping upon the electronic structures of single wall carbon nanotubes

    OpenAIRE

    Chen, Aqing; Shao, QingYi; Lin, Zhicheng

    2011-01-01

    The phosphorus-doped single wall carbon nanotube (PSWCNT) is studied by using First-Principle methods based on Density Function Theory (DFT). The formation energy, total energy, band structure, geometry structure and density of states are calculated. It is found that the formation energy of the P-doped single carbon nanotubes increases with diameters; the total energy of carbon nanotubes with the same diameter decreases as the doping rate increases. The effects of impurity position on the im-...

  10. A 66 fs highly stable single wall carbon nanotube mode locked fiber laser

    International Nuclear Information System (INIS)

    We demonstrate a highly stable mode locked fiber laser based on single wall carbon nanotubes. The mode locking is achieved by the evanescent field interaction of the propagating light with a single wall carbon nanotube saturable absorber in a microfiber. The pulse width is 66 fs, which, to the best of our knowledge, is the shortest pulse achieved in a carbon nanotube mode locked fiber laser. The maximum average output power is 26 mW, which is about 20 times larger than that of a typical carbon nanotube mode locked fiber laser. The center of the wavelength is 1555 nm, with 54 nm spectral width. The repetition rate is 146 MHz. To investigate the laser’s stability, the output pulses are monitored for 120 h and there is no significant degradation of the laser spectral width or shape. (paper)

  11. A Facile Route to Metal Oxides/Single-Walled Carbon Nanotube Macrofilm Nanocomposites for Energy Storage

    OpenAIRE

    Cao, Zeyuan; Wei, Bingqing

    2015-01-01

    Nanocomposites consisting of transition-metal oxides and carbon nanomaterials with a desired size and structure are highly demanded for high-performance energy storage devices. Here, a facile two-step and cost-efficient approach relying on directly thermal treatment of chemical vapor deposition products is developed as a general synthetic method to prepare a family of metal oxides [MxOy (M = Fe, Co, Ni)]/single-walled carbon nanotube (SWNT) macrofilm nanocomposites. The MxOy nanoparticles obt...

  12. The dynamics simulation of Ne atom injected into single-wall carbon nanotube

    International Nuclear Information System (INIS)

    The dynamical processes of Ne atom injected into single-wall carbon nanotube (SWCNT) are modeled with molecular dynamics simulations. The threshold energies to encapsulate rare-gas atoms in SWCNT are presented. The range of tube radius for stable oscillation is revealed, which is independent of the type of carbon nanotubes. And the oscillatory frequency is sensitive to the change in the diameter, the length and chirality of the tube

  13. Phthalimide containing donor-acceptor polymers for effective dispersion of single-walled carbon nanotubes

    OpenAIRE

    Baris Yilmaz; Josiah Bjorgaard; Zhenghuan Lin; Muhammet E. Köse

    2015-01-01

    Single-walled carbon nanotubes have been dispersed by novel phthalimide containing donor-acceptor type copolymers in organic media. Brominated phthalimide comonomer has been copolymerized with several electron rich structures using Suzuki and Stille coupling reactions. Carbon nanotube dispersion capability of the resultant polymers has been assessed by exploiting the non-covalent interaction of nanotube surface with the pi-system of conjugated backbone of polymers. Four polymers have been fou...

  14. Thermal rectification of a single-wall carbon nanotube: a molecular dynamics study

    OpenAIRE

    Foulaadvand, M. Ebrahim; Saeedi, Azadeh; Yousefi, Farrokh; Khadesadr, Saeed

    2014-01-01

    We have investigated the thermal rectification phenomenon in a single-wall mass graded carbon nanotube by molecular dynamics simulation. Second generation Brenner potential has been used to model the inter atomic carbon interaction. Fixed boundary condition has been taken into account. We compare our findings to a previous study by Alaghemandi et al which has been done with a different potential and boundary condition. The dependence of the rectification factor $R$ on temperature, nanotube di...

  15. Local-gated single-walled carbon nanotube field effect transistors assembled by AC dielectrophoresis

    OpenAIRE

    Stokes, Paul; Khondaker, Saiful I.

    2007-01-01

    We present a simple and scalable technique for the fabrication of solution processed & local gated carbon nanotube field effect transistors (CNT-FETs). The approach is based on directed assembly of individual single wall carbon nanotube from dichloroethane via AC dielectrophoresis (DEP) onto pre-patterned source and drain electrodes with a local aluminum gate in the middle. Local-gated CNT-FET devices display superior performance compared to global back gate with on-off ratios 10^4 and maximu...

  16. Fabrication of spintronics device by direct synthesis of single-walled carbon nanotubes from ferromagnetic electrodes

    International Nuclear Information System (INIS)

    We describe an alternative method for realizing a carbon nanotube spin field-effect transistor device by the direct synthesis of single-walled carbon nanotubes (SWNTs) on substrates by alcohol catalytic chemical vapor deposition. We observed hysteretic magnetoresistance (MR) at low temperatures due to spin-dependent transport. In these devices, the maximum ratio in resistance variation of MR was found to be 1.8%.

  17. Fabrication of spintronics device by direct synthesis of single-walled carbon nanotubes from ferromagnetic electrodes

    Directory of Open Access Journals (Sweden)

    Mohd Ambri Mohamed, Nobuhito Inami, Eiji Shikoh, Yoshiyuki Yamamoto, Hidenobu Hori and Akihiko Fujiwara

    2008-01-01

    Full Text Available We describe an alternative method for realizing a carbon nanotube spin field-effect transistor device by the direct synthesis of single-walled carbon nanotubes (SWNTs on substrates by alcohol catalytic chemical vapor deposition. We observed hysteretic magnetoresistance (MR at low temperatures due to spin-dependent transport. In these devices, the maximum ratio in resistance variation of MR was found to be 1.8%.

  18. Small Diameter Few- Walled Carbon Nanotubes: An Alternative for Single Walled nanotubes in Bulk Applications

    Institute of Scientific and Technical Information of China (English)

    Jie Liu

    2005-01-01

    @@ 1Introduction Although Single walled carbon nanotubes have shown tremendous potential in many applications due to their unique electrical and mechanical properties, the lack of a large scale synthesis method at low cost is still the main limiting factor for the realization of the full potential of this unique materials. On the other hand, multiwalled carbon nanotubes are being made in tons per year quantity and found their application in conducting plastic and other bulk applications.

  19. Purification of Single-walled Carbon Nanotubes Grown by a Chemical Vapour Deposition (CVD) Method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A procedure for purification of single-walled carbon nanotubes(SWNTs) grown by the chemical vapour deposition (CVD) of carbon monooxide has been developed. Based on the result from TGA/DTA of as-prepared sample, the oxidation temperature was determined. The process included sonication, oxidation and acid washing steps. The purity and yield after purification were determined and estimated by TEM. Moreover, for the first time, a loop structure for CVD SWNTs has been observed.

  20. Spectroscopy of Individual Single-Walled Carbon Nanotubes and their Synthesis via Chemical Vapor Deposition

    OpenAIRE

    Kiowski, Oliver

    2008-01-01

    A chemical vapor deposition (CVD) reactor was designed, built and used to grow vertically and horizontally aligned carbon nanotube arrays. The as-grown nanotubes were investigated on a single tube level using nearinfrared photoluminescence (PL) microscopy as well as Raman, atomic force and scanning electron microscopy (SEM). For photoluminescence excitation (PLE) spectroscopy of individual, semiconducting single-walled carbon nanotubes (SWNTs), a specialized PL set-up was constructed.

  1. Bio-defunctionalization of Functionalized Single-Walled Carbon Nanotubes in Mice

    OpenAIRE

    Yang, Sheng-Tao; Wang, Haifang; Meziani, Mohammed J.; Liu, Yuanfang; Wang, Xin; Sun, Ya-Ping

    2009-01-01

    Chemically modified carbon nanotubes with hydrophilic functionalities such as polyethylene glycols (PEGs) are widely pursued for potential biological and biomedical applications. In this study, PEGylated single-walled carbon nanotubes (PEG-SWNT) were intravenously administrated into mice to study their bio-defunctionalization in vivo by using complementary Raman and photoluminescence measurements. There was meaningful defunctionalization of PEG-SWNT in liver over time, but not in spleen under...

  2. Quantized magnetic moment at the edge of a single-walled carbon nanotube

    OpenAIRE

    Jeng, Horng-Tay; Oshikawa, Masaki; Lin, Hsiu-Hau

    2010-01-01

    We investigate many-body effects near the edge of a single-walled carbon nanotube and find it turns magnetic with quantized edge moment solely depends on the chiral vector, i.e. the topology of the carbon nanotube. The distribution of the edge moment reveals an approximate supersymmetry even in a realistic model. Our findings demonstrate crucial importance of the interplay between the electronic correlation and the edge morphology. The edge moment provides an excellent candidate for nanomagne...

  3. Evaluation of single-walled carbon nanohorns as sorbent in dispersive micro solid-phase extraction

    International Nuclear Information System (INIS)

    Highlights: ► The potential of single walled carbon nanohorns in dispersive solid phase microextraction has been evaluated. ► The method was characterized for the extraction of PAHs from waters. ► Single walled carbon nanohorns were better extractant than carbon nanotubes and carbon nanocones. ► The limits of detection were adequate for the target analytes in environmental waters. - Abstract: A new dispersive micro solid-phase extraction method which uses single-walled carbon nanohorns (SWNHs) as sorbent is proposed. The procedure combines the excellent sorbent properties of the nanoparticles with the efficiency of the dispersion of the material in the sample matrix. Under these conditions, the interaction with the analytes is maximized. The determination of polycyclic aromatic hydrocarbons was selected as model analytical problem. Two dispersion strategies were evaluated, being the functionalization via microwave irradiation better than the use of a surfactant. The extraction was accomplished by adding 1 mL of oxidized SWHNs (o-SWNHs) dispersion to 10 mL of water sample. After extraction, the mixture was passed through a disposable Nylon filter were the nanoparticles enriched with the PAHs were retained. The elution was carried out with 100 μL of hexane. The limits of detection achieved were between 30 and 60 ng L−1 with a precision (as repeatability) better than 12.5%. The recoveries obtained for the analytes in three different water samples were acceptable in all instances. The performance of o-SWNHs was favourably compared with that provided by carboxylated single-walled carbon nanotubes and thermally treated carbon nanocones.

  4. Storage of hydrogen on single-walled carbon nanotubes and other carbon structures

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, E.; Chahine, R.; Benard, P.; Cossement, D.; Lafi, L.; Melancon, E.; Bose, T.K. [Institut de recherche sur l' hydrogene, Universite du Quebec a Trois-Rivieres, C.P. 500, G9A 5H7, Trois-Rivieres, Quebec (Canada); Desilets, S. [R and D pour la defense Canada - Valcartier, 2459, boulevard Pie-XI Nord, G3J 1X5, Val-Belair, Quebec (Canada)

    2004-04-01

    The sorption of hydrogen on carbon structures and nanostructures offers a way to reduce the storage pressure of hydrogen with respect to compression storage while achieving interesting gravimetric storage densities. The most readily available carbon structures, activated carbons, can achieve reproducible, high gravimetric storage densities under cryogenic operating conditions: 5-6% at 35 bar and 77 K, in excess of the normal density that would be present in the pore volume under compression at the same temperature and pressure. We discuss and compare the adsorption of hydrogen on high specific surface activated carbons, nanofibres and nanotubes from experimental and theoretical considerations. In particular, we present gravimetric and volumetric hydrogen sorption measurements on single-walled carbon nanotubes (SWNTs) at (1 bar, 77 K) and (1 bar, 295 K) within the context of our ongoing work on the storage of hydrogen on activated carbon and carbon nanostructures. BET surface area and XRD characterization results on SWNTs are also presented. The experiments were performed on as received, chemically treated and metal-incorporated SWNT samples. Hydrogen sorption capacities measured on treated samples ranged from {proportional_to}0 to about 1 wt. % at 1 bar and 295 K and reached about 4 wt. % at 1 bar and 77 K. Our results show that under certain conditions, SWNTs have better hydrogen uptake performance than large surface area activated carbons. (orig.)

  5. Dynamic elastic modulus of single-walled carbon nanotubes in different thermal environments

    International Nuclear Information System (INIS)

    This Letter reports the result of investigation on the effect of loading rate (strain rate) on mechanical properties of armchair and zigzag nanotubes in different thermal environments, based on the molecular structural mechanics model in which the primary bonds between two nearest-neighboring carbon atoms are treaded as dimensional 2-node Euler-Bernoulli beam considering the effect of environmental temperature on force constant values of the bonds stretching, bonds angle bending and torsional resistance. Nanoscale finite element simulations of the dynamic Young's modulus of single-walled carbon nanotubes under different strain rates and environmental temperatures reveal that the dynamic Young's modulus of the single-walled carbon nanotubes increases with the increase of strain rate, and decreases significantly with the increase of environment temperature. It is significant that the dynamic Young's modulus of zigzag nanotubes is more sensitive to strain rate and environmental temperature due to the tube chirality

  6. Manifestation of Structure of Electron Bands in Double-Resonant Raman Spectra of Single-Walled Carbon Nanotubes.

    Science.gov (United States)

    Stubrov, Yurii; Nikolenko, Andrii; Gubanov, Viktor; Strelchuk, Viktor

    2016-12-01

    Micro-Raman spectra of single-walled carbon nanotubes in the range of two-phonon 2D bands are investigated in detail. The fine structure of two-phonon 2D bands in the low-temperature Raman spectra of the mixture and individual single-walled carbon nanotubes is considered as the reflection of structure of their π-electron zones. The dispersion behavior of 2D band fine structure components in the resonant Raman spectra of single-walled carbon nanotube mixture is studied depending on the energy of excitating photons. The role of incoming and outgoing electron-phonon resonances in the formation of 2D band fine structure in Raman spectra of single-walled carbon nanotubes is analyzed. The similarity of dispersion behavior of 2D phonon bands in single-walled carbon nanotubes, one-layer graphene, and bulk graphite is discussed. PMID:26729220

  7. Preparation of Isolated Single-walled Carbon Nanotubes with High Hydrogen Storage Capacity

    Institute of Scientific and Technical Information of China (English)

    张艾飞; 刘吉平; 吕广庶; 刘华

    2006-01-01

    Isolated single-walled carbon nanotubes with high proportion of opening tips were synthesized by using alcohol as carbon source. The mechanism of cutting action of oxygen was proposed to explain its growth. Compared with carbon nanotubes synthesized with benzene as carbon source, their specific surface area was heightened by approximately 2.2 times (from 200.5 to 648 m2/g) and the hydrogen storage capacity was increased by approximately 6.5 times (from 0.95 to 7.17%, ω)which had exceeded DOE energy standard of vehicular hydrogen storage.

  8. Self-Assembly of Semiconducting Single-Walled Carbon Nanotubes into Dense, Aligned Rafts

    CERN Document Server

    Wu, Justin; Antaris, Alexander; Choi, Charina L; Xie, Liming; Wu, Yingpeng; Diao, Shuo; Chen, Changxin; Chen, Yongsheng; Dai, Hongjie

    2013-01-01

    Single-walled carbon nanotubes are promising nanoelectronic materials but face long-standing challenges including production of pure semiconducting SWNTs and integration into ordered structures. Here, highly pure semiconducting single-walled carbon nanotubes are separated from bulk materials and self-assembled into densely aligned rafts driven by depletion attraction forces. Microscopy and spectroscopy revealed a high degree of alignment and a high packing density of ~100 tubes/micron within SWNT rafts. Field-effect transistors made from aligned SWNT rafts afforded short channel (~150 nm long) devices comprised of tens of purely semiconducting SWNTs derived from chemical separation within a < 1 micron channel width, achieving unprecedented high on-currents (up to ~120 microamperes per device) with high on/off ratios. The average on-current was ~ 3-4 microamperes per tube. The results demonstrated densely aligned high quality semiconducting SWNTs for integration into high performance nanoelectronics.

  9. Covalently attached multilayer self-assemblies of single-walled carbon nanotubols and diazoresins

    Energy Technology Data Exchange (ETDEWEB)

    Shi Jiahua [Department of Chemistry, Renmin University of China, Beijing 100872 (China); Qin, Yujun [Department of Chemistry, Renmin University of China, Beijing 100872 (China); Luo Hongxia [Department of Chemistry, Renmin University of China, Beijing 100872 (China); Guo, Zhi-Xin [Department of Chemistry, Renmin University of China, Beijing 100872 (China); Woo, Hyung-Suk [Center for Organic Devices and Advanced Materials, Kyungsung University, Busan 608736 (Korea, Republic of); Park, Dong-Kyu [Center for Organic Devices and Advanced Materials, Kyungsung University, Busan 608736 (Korea, Republic of)

    2007-09-12

    Layer-by-layer (LBL) multilayer films have been constructed from multiple hydroxyl group directly modified single-walled carbon nanotubes (single-walled carbon nanotubols, SWNTols) and light-sensitive diazoresin (DR). Ultraviolet-visible (UV-vis) absorbance spectra confirm that the alternate assemblies of SWNTols and DR result in uniform film growth. Fourier transformed infrared (FT-IR) spectra of the films show that the main driving force for DR/SWNTol assembly is attributed to hydrogen bond attractions rather than electrostatic interactions. Upon UV irradiation, the hydrogen bonds of the multilayer films transform into covalent bonds, which significantly improves the stability of the DR/SWNTol multilayer films towards etching by polar solvent. Atomic force and scanning electron microscopies (AFM and SEM) indicate high structural homogeneity of the assembled composite films.

  10. Diameter and Temperature Dependence of Thermal Conductivity of Single-Walled Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    PAN Rui-Qin

    2011-01-01

    Temperature and diameter dependence of the thermal conductivity of several armchair single-walled carbon nan-otubes (SWNTs) are studied by nonequilibrium molecular dynamics method with Brenner II potential. The thermal conductivities are calculated at temperatures from WOK to 600K. It is found that the thermal conductivity decreases as the temperature increases and increases as the diameter of SWNT increases. The results demonstrate that these two phenomena are due to the onset of the Umklapp process.%@@ Temperature and diameter dependence of the thermal conductivity of several armchair single-walled carbon nan- otubes (SWNTs) are studied by nonequilibrium molecular dynamics method with Brenner Ⅱ potential.The thermal conductivities are calculated at temperatures from 100K to 600K.It is found that the thermal con- ductivity decreases as the temperature increases and increases as the diameter of SWNT increases.The results demonstrate that these two phenomena are due to the onset of the Umklapp process.

  11. G-quartet type self-assembly of guanine functionalized single-walled carbon nanotubes

    Science.gov (United States)

    Singh, Prabhpreet; Venkatesh, V.; Nagapradeep, N.; Verma, Sandeep; Bianco, Alberto

    2012-03-01

    The simple strategy of linking guanine to single-walled carbon nanotubes (CNTs) through covalent functionalization permitted generation of the alignment of the nanotubes into lozenges reminiscent of guanine quartets (G-quartets) in the presence of potassium ions as observed by atomic force microscopy.The simple strategy of linking guanine to single-walled carbon nanotubes (CNTs) through covalent functionalization permitted generation of the alignment of the nanotubes into lozenges reminiscent of guanine quartets (G-quartets) in the presence of potassium ions as observed by atomic force microscopy. Electronic supplementary information (ESI) available: Experimental procedures for the synthesis and characterization of the precursors and MWCNT conjugates. See DOI: 10.1039/c2nr11849a

  12. Covalently attached multilayer self-assemblies of single-walled carbon nanotubols and diazoresins

    International Nuclear Information System (INIS)

    Layer-by-layer (LBL) multilayer films have been constructed from multiple hydroxyl group directly modified single-walled carbon nanotubes (single-walled carbon nanotubols, SWNTols) and light-sensitive diazoresin (DR). Ultraviolet-visible (UV-vis) absorbance spectra confirm that the alternate assemblies of SWNTols and DR result in uniform film growth. Fourier transformed infrared (FT-IR) spectra of the films show that the main driving force for DR/SWNTol assembly is attributed to hydrogen bond attractions rather than electrostatic interactions. Upon UV irradiation, the hydrogen bonds of the multilayer films transform into covalent bonds, which significantly improves the stability of the DR/SWNTol multilayer films towards etching by polar solvent. Atomic force and scanning electron microscopies (AFM and SEM) indicate high structural homogeneity of the assembled composite films

  13. EPR investigation of N@C$_{70}$ in polycrystalline C$_{70}$ and single wall carbon nanotubes

    OpenAIRE

    Dinse, Klaus-Peter; Corzilius, Björn; Jakes, Peter; Weiden, Norbert; Agarwal, Suman

    2008-01-01

    Abstract Using multi frequency electron paramagnetic resonance (EPR) it was possible to determine the inherent fine structure (FS) interaction of nitrogen encapsulated in a C$_{70}$ cage. Confinement of N@C$_{70}$ in single wall carbon nanotubes (SWNT) of rather wide diameter does not significantly influence this value. The transition between isotropic molecular tumbling and immobilisation was found to occur at about 170~K in both matrices, indicating that the hindra...

  14. Atomistic Failure Mechanism of Single Wall Carbon Nanotubes with Small Diameters

    Institute of Scientific and Technical Information of China (English)

    JI Dong; GAO Xiang; KONG Xiang-Yang; LI Jia-Ming

    2007-01-01

    @@ Single wall carbon nanotubes with small diameters (< 5.0 (A)) subjected to bending deformation are simulated by orthogonal tight-binding molecular dynamics approach. Based on the calculations of C-C bond stretching and breaking in the bending nanotubes, we elucidate the atomistic failure mechanisms of nanotube with small diameters. In the folding zone of bending nanotube, a large elongation of C-C bonds occurs, accounting for the superelastic behaviour.

  15. Bridged single-walled carbon nanotube-based atomic-scale mass sensors

    Science.gov (United States)

    Ali-Akbari, H. R.; Shaat, M.; Abdelkefi, A.

    2016-08-01

    The potentials of carbon nanotubes (CNTs) as mechanical resonators for atomic-scale mass sensing are presented. To this aim, a nonlocal continuum-based model is proposed to study the dynamic behavior of bridged single-walled carbon nanotube-based mass nanosensors. The carbon nanotube (CNT) is considered as an elastic Euler-Bernoulli beam with von Kármán type geometric nonlinearity. Eringen's nonlocal elastic field theory is utilized to model the interatomic long-range interactions within the structure of the CNT. This developed model accounts for the arbitrary position of the deposited atomic-mass. The natural frequencies and associated mode shapes are determined based on an eigenvalue problem analysis. An atom of xenon (Xe) is first considered as a specific case where the results show that the natural frequencies and mode shapes of the CNT are strongly dependent on the location of the deposited Xe and the nonlocal parameter of the CNT. It is also indicated that the first vibrational mode is the most sensitive when the mass is deposited at the middle of a single-walled carbon nanotube. However, when deposited in other locations, it is demonstrated that the second or third vibrational modes may be more sensitive. To investigate the sensitivity of bridged single-walled CNTs as mass sensors, different noble gases are considered, namely Xe, argon (Ar), and helium (He). It is shown that the sensitivity of the single-walled CNT to the Ar and He gases is much lower than the Xe gas due to the significant decrease in their masses. The derived model and performed analysis are so needed for mass sensing applications and particularly when the detected mass is randomly deposited.

  16. Chirality dependence of the radial breathing phonon mode density in single wall carbon nanotubes

    OpenAIRE

    Vamivakas, A. N.; Yin, Y.; Walsh, A. G.; Unlu, M. S.; Goldberg, B. B.; Swan, A. K.

    2006-01-01

    A mass and spring model is used to calculate the phonon mode dispersion for single wall carbon nanotubes (SWNTs) of arbitrary chirality. The calculated dispersions are used to determine the chirality dependence of the radial breathing phonon mode (RBM) density. Van Hove singularities, usually discussed in the context of the single particle electronic excitation spectrum, are found in the RBM density of states with distinct qualitative differences for zig zag, armchair and chiral SWNTs. The in...

  17. Electromagnetic properties of single-walled carbon nanotubes investigated by microwave absorption

    OpenAIRE

    Corzilius, Björn

    2008-01-01

    Due to their unique properties, single-walled carbon nanotubes (SWNT) are very interesting candidates for the development of new electronic devices. Some of these properties, e.g., a possible transition to a superconducting phase or the existence of ordered magnetic states, are still under investigation and intensively discussed. Macroscopic amounts of SWNT can hitherto only be obtained as mixtures of tubes of different electronic properties. Therefore researchers have always been interested ...

  18. Large Deflections Mechanical Analysis of a Suspended Single-Wall Carbon Nanotube under Thermoelectrical Loading

    OpenAIRE

    Assaf Ya'akobovitz; Slava Krylov; Yael Hanein

    2011-01-01

    Following the recent progress in integrating single-wall carbon nanotubes (SWCNTs) into silicon-based micro-electromechanical systems (MEMS), new modeling tools are needed to predict their behavior under different loads, including thermal, electrical and mechanical. In the present study, the mechanical behavior of SWCNTs under thermoelectrical loading is analyzed using a large deflection geometrically nonlinear string model. The effect of the resistive heating was found to have a substantial ...

  19. Synthesis, electronic structure, and Raman scattering of phosphorus-doped single-wall carbon nanotubes

    International Nuclear Information System (INIS)

    Substitutional phosphorus doping in single-wall carbon nanotubes (SWNTs) is investigated by density functional theory and resonance Raman spectroscopy. Electronic structure calculations predict charge localization on the phosphorus atom, which is also responsible of generating non-dispersive valence and conduction bands close to the Fermi level. Analysis of electron and phonon renormalization in the double-resonance Raman process confirms the different nature of the phosphorus donor doping (localized) when compared to nitrogen substitutional doping (non-localized) in SWNTs

  20. Computer simulation of rare-gas atoms injection into single-wall carbon nanotube

    International Nuclear Information System (INIS)

    The process of rare-gas atoms (He, Ne, Ar) injected into single-wall carbon nanotube (SWNT) was modeled with molecular-dynamics simulations. The site dependence of the threshold energy of rare-gas atoms forming endohedral complexes was investigated, and the formation mechanism of some defects was revealed. The hole on the sidewall of the SWNT induced by incident rare-gas atoms can be healed by annealing at a certain temperature

  1. Effect of Topological Defects on Buckling Behavior of Single-walled Carbon Nanotube

    OpenAIRE

    Wang Guoxiu; Ranjbartoreh Ali

    2010-01-01

    Abstract Molecular dynamic simulation method has been employed to consider the critical buckling force, pressure, and strain of pristine and defected single-walled carbon nanotube (SWCNT) under axial compression. Effects of length, radius, chirality, Stone–Wales (SW) defect, and single vacancy (SV) defect on buckling behavior of SWCNTs have been studied. Obtained results indicate that axial stability of SWCNT reduces significantly due to topological defects. Critical buckling strain is ...

  2. Multiple helical configuration and quantity threshold of graphene nanoribbons inside a single-walled carbon nanotube

    OpenAIRE

    Yifan Li; Wei Chen; Hongru Ren; Xuyan Zhou; Hui Li

    2015-01-01

    Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the π-π stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwh...

  3. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

    OpenAIRE

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2010-01-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-...

  4. Electrical conductivity of single-wall carbon nanotube films in strong electric field

    OpenAIRE

    Seliuta, D; Subačius, L; Kašalynas, I; Shuba, M.; Paddubskaya, A.

    2013-01-01

    (Received 6 March 2013; accepted 26 April 2013; published online 14 May 2013) Carrier transport features in single-wall carbon nanotube (SWCNT) films under strong electric fields (up to 105 V/cm) are presented. Application of electrical pulses of nanosecond duration allowed to minimize Joule heating and resolve intrinsic nonlinearities with the electric field. Investigations within a wide range of temperatures—4.2–300 K—indicated that carrier localization as well as tunneling t...

  5. A study of single-walled carbon nanotubes modified by organics of the phthalocyanine category

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Organics of the phthalocyanine category have very good nonlinear optical properties. The single-walled carbon nanotubes were modified by using the phenoxy phthalocyanine. Characterization analysis was made by means of the transmission electron microscope (TEM), ultraviolet visible absorptive spectra, fluorescent spectra and Raman spectra. Under the TEM, it was observed that the composite looked like sugarcoated haws. By comparing the ultraviolet visible absorptive spectra before and after absorption, it was...

  6. Dielectrophoresis Aligned Single-Walled Carbon Nanotubes as pH Sensors

    OpenAIRE

    Wei Xue; Kan Kan Yeung; Martin, Caleb M.; Pengfei Li

    2011-01-01

    Here we report the fabrication and characterization of pH sensors using aligned single-walled carbon nanotubes (SWNTs). The SWNTs are dispersed in deionized (DI) water after chemical functionalization and filtration. They are deposited and organized on silicon substrates with the dielectrophoresis process. Electrodes with “teeth”-like patterns—fabricated with photolithography and wet etching—are used to generate concentrated electric fields and strong dielectrophoretic forces for the SWNTs to...

  7. Design and Fabrication of Single-Walled Carbon Nanonet Flexible Strain Sensors

    OpenAIRE

    Trung Kien Vu; Ru-Min Chao; Ya-Ting Huang; Chih-Chao Hsu; Shyh-Chour Huang

    2012-01-01

    This study presents a novel flexible strain sensor for real-time strain sensing. The material for strain sensing is single-walled carbon nanonets, grown using the alcohol catalytic chemical vapor deposition method, that were encapsulated between two layers of Parylene-C, with a polyimide layer as the sensing surface. All of the micro-fabrication was compatible with the standard IC process. Experimental results indicated that the gauge factor of the proposed strain sensor was larger than 4.5, ...

  8. Molecular Simulation of Hydrogen Adsorption Density in Single-Walled Carbon Nanotubes and Multilayer Adsorption Mechanism

    Institute of Scientific and Technical Information of China (English)

    Lianquan GUO; Changxiang MA; Shuai WANG; He MA; Xin LI

    2005-01-01

    The adsorption of hydrogen onto single-walled carbon nanotubes (SWCNTs) was studied by molecular dynamics (MD)sim.lation. It was found that the hydrogen molecules distribute regularly inside and outside of the tube. Density distribution was computed for H2 molecule. Theoretical analysis of the result showed the multilayer adsorption mechanism of SWCNTs. The storage of H2 in SWCNTs is computed, which provides essential theoretical reference for further study of hydrogen adsorption in SWCNTs.

  9. Vibrational Analysis of Curved Single-Walled Carbon Nanotube on a Pasternak Elastic Foundation

    DEFF Research Database (Denmark)

    Mehdipour, I.; Barari, Amin; Kimiaeifar, Amin;

    2012-01-01

    Continuum mechanics and an elastic beam model were employed in the nonlinear force vibrational analysis of an embedded, curved, single-walled carbon nanotube. The analysis considered the effects of the curvature or waviness and midplane stretching of the nanotube on the nonlinear frequency. By ut...... combination effects of waviness and stretching nonlinearity on the nonlinear frequency of the curved SWCNT with a small outer radius were larger than the straight one....

  10. Microbiosensors based on DNA modified single-walled carbon nanotube and Pt black nanocomposites

    OpenAIRE

    SHI, JIN; Cha, Tae-Gon; Claussen, Jonathan; Diggs, Alfred R.; Choi, Jong Hyun; Porterfield, D. Marshall

    2011-01-01

    Glucose and ATP biosensors have important applications in diagnostics and research. Biosensors based on conventional materials suffer from low sensitivity and low spatial resolution. Our previous work has shown that combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. The immobilization of SWCNTs on biosensors remains challenging due to the aqueous insolubility originating from van der Waals forces. In...

  11. Synthesis of single-walled carbon nanotube networks using monodisperse metallic nanocatalysts encapsulated in reverse micelles

    OpenAIRE

    Gayduchenko Igor A.; Fedorov Georgy E.; Ibragimov Ramil A.; Stepanova Tatiana S.; Gazaliev Arsen S.; Vysochanskiy Nikolay A.; Bobrov Yuri A.; Malovichko Anton M.; Sosnin Ilya M.; Bobrinetskiy Ivan I.

    2016-01-01

    We report on a method of synthesis of single-walled carbon nanotubes percolated networks on silicon dioxide substrates using monodisperse Co and Ni catalyst. The catalytic nanoparticles were obtained by modified method of reverse micelles of bis-(2-ethylhexyl) sulfosuccinate sodium in isooctane solution that provides the nanoparticle size control in range of 1 to 5 nm. The metallic nanoparticles of Ni and Co were characterized using transmission electron mi...

  12. Translocation of Single-Stranded DNA through Single-Walled Carbon Nanotubes1

    OpenAIRE

    Liu, Haitao; He, Jin; Tang, Jinyao; Liu, Hao; Pang, Pei; Cao, Di; Krstic, Predrag; Joseph, Sony; Lindsay, Stuart; Nuckolls, Colin

    2010-01-01

    We report the fabrication of devices in which one single-walled carbon nanotube (SWCNT) spans a barrier between two fluid reservoirs, enabling direct electrical measurement of ion transport through the tube. A fraction of the tubes pass anomalously high ionic currents. Electrophoretic transport of small single stranded DNA oligomers through these tubes is marked by large transient increases in ion current and was confirmed by PCR analysis. Each current pulse contains about 107 charges, an eno...

  13. Single-wall carbon nanotube dispersions stabilised with N-trimethyl-chitosan

    OpenAIRE

    Wise, A; Smith, James; Bouropoulos, N.; Yannopoulos, S.; Van der Merwe, Marisa; Fatouros, D.

    2008-01-01

    We report the noncovalent complexation of a biocompatible low substituted N-trimethyl chitosan (TMC), a cationic chitosan derivative, onto the graphitic surface of single-walled carbon nanotubes (SWCNTs). TMC was synthesized and characterized by 1H-NMR. A yield between the range of 34% and 56% was obtained with a degree of substitution of 19.7%. SWCNTs dispersed in TMC resulted in stable dispersions, which were further characterized by Atomic Force Microscopy (AFM) Raman Spectroscopy and ζ-po...

  14. Diameter-dependent bending dynamics of single-walled carbon nanotubes in liquids

    OpenAIRE

    Fakhri, Nikta; Tsyboulski, Dmitri A.; Cognet, Laurent; Weisman, R. Bruce; Pasquali, Matteo

    2009-01-01

    By relating nanotechnology to soft condensed matter, understanding the mechanics and dynamics of single-walled carbon nanotubes (SWCNTs) in fluids is crucial for both fundamental and applied science. Here, we study the Brownian bending dynamics of individual chirality-assigned SWCNTs in water by fluorescence microscopy. The bending stiffness scales as the cube of the nanotube diameter and the shape relaxation times agree with the semiflexible chain model. This suggests that SWCNTs may be the ...

  15. A triple quantum dot in a single-wall carbon nanotube

    DEFF Research Database (Denmark)

    Grove-Rasmussen, Kasper; Jørgensen, Henrik Ingerslev; Hayashi, T.;

    2008-01-01

    A top-gated single-wall carbon nanotube is used to define three coupled quantum dots in series between two electrodes. The additional electron number on each quantum dot is controlled by top-gate voltages allowing for current measurements of single, double, and triple quantum dot stability diagrams....... Simulations using a capacitor model including tunnel coupling between neighboring dots captures the observed behavior with good agreement. Furthermore, anticrossings between indirectly coupled levels and higher order cotunneling are discussed. Udgivelsesdato: April...

  16. Large magnetoresistance in single-walled carbon nanotubes contacted different ferromagnetic metal electrodes

    International Nuclear Information System (INIS)

    Magnetoresistance (MR) in single-walled carbon nanotubes (SWNTs) with different ferromagnetic source and drain electrodes (iron and cobalt) which have different coercivity was studied. Large MR ratio of 20% could be obtained at 8 K, while 1∼2% small MR ratio could be observed for the sample with the same ferromagnetic source and drain electrodes of Co. The MR ratio of 20% is very close to the theoretically predicted value of 26% for Co-Fe system

  17. Gold Nanoparticles as the Catalyst of Single-Walled Carbon Nanotube Synthesis

    OpenAIRE

    Yoshikazu Homma

    2014-01-01

    Gold nanoparticles have been proven to act as efficient catalysts for chemical reactions, such as oxidation and hydrogen production. In this review we focus on a different aspect of the catalysis of gold nanoparticles; single-walled carbon nanotube (SWCNT) synthesis. This is not a traditional meaning of catalytic reaction, but SWCNTs cannot be synthesized without nanoparticles. Previously, gold was considered as unsuitable metal species as the catalyst of SWCNT synthesis. However, gold nanopa...

  18. Functionalized single-walled carbon nanotubes/polypyrrole composites for amperometric glucose biosensors

    OpenAIRE

    Raicopol, Matei; Prună, Alina; Damian, Celina; Pilan, Luisa

    2013-01-01

    This article reports an amperometric glucose biosensor based on a new type of nanocomposite of polypyrrole (PPY) with p-phenyl sulfonate-functionalized single-walled carbon nanotubes (SWCNTs-PhSO3 −). An environmentally friendly functionalization procedure of the SWCNTs in the presence of substituted aniline and an oxidative species was adopted. The nanocomposite-modified electrode exhibited excellent electrocatalytic activities towards the reduction or oxidation of H2O2. This feature allowed...

  19. Gate-induced blueshift and quenching of photoluminescence in suspended single-walled carbon nanotubes

    OpenAIRE

    Yasukochi, S.; Murai, T.; Moritsubo, S.; Shimada, T; Chiashi, S.; Maruyama, S.; Kato, Y. K.

    2011-01-01

    Gate-voltage effects on photoluminescence spectra of suspended single-walled carbon nanotubes are investigated. Photoluminescence microscopy and excitation spectroscopy are used to identify individual nanotubes and to determine their chiralities. Under an application of gate voltage, we observe slight blueshifts in the emission energy. In addition, we find that the photoluminescence intensity decreases exponentially with gate voltage. Quenching of the K-momentum exciton emission is also obser...

  20. Radiative lifetimes and coherence lengths of one-dimensional excitons in single-walled carbon nanotubes

    OpenAIRE

    Miyauchi, Yuhei; Hirori, Hideki; Matsuda, Kazunari; Kanemitsu, Yoshihiko

    2009-01-01

    We evaluated the radiative lifetimes and the one-dimensional exciton coherence lengths in single-walled carbon nanotubes (SWNTs). The radiative lifetimes determined from simultaneous measurements of photoluminescence (PL) lifetimes and PL quantum yields range from ~3 to 10 ns, and slightly increase with the tube diameter. The exciton coherence lengths in SWNTs are of the order of 10 nm, as deduced from the experimentally obtained radiative lifetimes, and they are about ten times larger than t...

  1. Nonlinear Photoluminescence Properties of Trions in Hole-doped Single-walled Carbon Nanotubes

    OpenAIRE

    Akizuki, Naoto; Iwamura, Munechiyo; Mouri, Shinichiro; Miyauchi, Yuhei; Kawasaki, Tomohiro; Watanabe, Hiroshi; Suemoto, Tohru; Watanabe, Kouta; Asano, Kenichi; Matsuda, Kazunari

    2014-01-01

    We studied the excitation density dependence of photoluminescence (PL) spectra of excitons and trions (charged excitons) in hole-doped single-walled carbon nanotubes. We found that the PL intensity of trions exhibited a strong nonlinear saturation behavior as the excitation density increased, whereas that of excitons exhibited a weak sublinear behavior. The strong PL saturation of trions is attributed to depletion of doped holes that are captured by excitons in the formation processes. Moreov...

  2. Exciton diffusion in air-suspended single-walled carbon nanotubes

    OpenAIRE

    Moritsubo, S.; Murai, T.; Shimada, T; Murakami, Y.; Chiashi, S.; Maruyama, S.; Kato, Y. K.

    2010-01-01

    Direct measurements of the diffusion length of excitons in air-suspended single-walled carbon nanotubes are reported. Photoluminescence microscopy is used to identify individual nanotubes and to determine their lengths and chiral indices. Exciton diffusion length is obtained by comparing the dependence of photoluminescence intensity on the nanotube length to numerical solutions of diffusion equations. We find that the diffusion length in these clean, as-grown nanotubes is significantly longer...

  3. Exciton Diffusion in Air-Suspended Single-Walled Carbon Nanotubes

    OpenAIRE

    Moritsubo, S.; Murai, T.; Shimada, T; Murakami, Y.; Chiashi, S.; Maruyama, S.; Kato, Y. K.

    2010-01-01

    Direct measurements of the diffusion length of excitons in air-suspended single-walled carbon nanotubes are reported. Photoluminescence microscopy is used to identify individual nanotubes and to determine their lengths and chiral indices. Exciton diffusion length is obtained by comparing the dependence of photoluminescence intensity on the nanotube length to numerical solutions of diffusion equations. We find that the diffusion length in these clean, as-grown nanotubes is significantly longer...

  4. Photoluminescence from single walled carbon nanotubes: a comparison between suspended and micelle-encapsulated nanotubes

    OpenAIRE

    Lefebvre, J.; Fraser, J. M.; Homma, Y; Finnie, P.

    2003-01-01

    Single walled carbon nanotubes (SWNTs) are luminescent. Up to now, two preparation methods, both of which isolate individual SWNTs, have enabled the detection of nanotube bandgap photoluminescence (PL): encapsulation of individual SWNTs into surfactant micelles, and direct growth of individual SWNTs suspended in air between pillars. This paper compares the PL obtained from suspended SWNTs to published PL data obtained from encapsulated SWNTs. We find that emission peaks are blue-shifted by 28...

  5. Photoluminescence intermittency in an individual single-walled carbon nanotube at room temperature

    OpenAIRE

    Matsuda, K; Kanemitsu, Yoshihiko; Irie, K.; Saiki, T.; Someya, T; Miyauchi, Y.; Maruyama, S.

    2005-01-01

    We described the photoluminescence (PL) properties of individual micelle-encapsulated single-walled carbon nanotubes (SWNTs) at room temperature. Single PL peak from isolated individual SWNT with a chiral index of (6, 5) showed a linear increase and saturation behavior of the PL intensity. Unusual PL intensity fluctuation in the temporal evolutions of the PL intensity, referred to as PL intermittency, was seen with some SWNTs, while the PL intensity with most SWNTs remained at a constant ampl...

  6. Gate-induced blueshift and quenching of photoluminescence in suspended single-walled carbon nanotubes

    OpenAIRE

    Yasukochi, S.; Murai, T.; Moritsubo, S.; Shimada, T; Chiashi, S.; Maruyama, S.; Kato, Y. K.

    2011-01-01

    Gate-voltage effects on photoluminescence spectra of suspended single-walled carbon nanotubes are investigated. Photoluminescence microscopy and excitation spectroscopy are used to identify individual nanotubes and to determine their chiralities. Under an application of gate voltage, we observe slight blueshifts in the emission energy and strong quenching of photoluminescence. The blueshifts are similar for different chiralities investigated, suggesting extrinsic mechanisms. In addition, we f...

  7. Carbon nanobamboo: Junctions between left and right handed single walled carbon nanotubes

    International Nuclear Information System (INIS)

    Heating of organic molecules, for example, fullerenes encapsulated in single walled carbon nanotubes can result in the coalescence of the molecules forming an inner tube. The growth of tubes with different diameters and/or chiralities can start at different places at the same time. The formation of a junction between the two different tubes depends on many parameters. A special case is when the two tubes have the same chiralities, but opposite handedness. We have shown using topological and combinatorial arguments that at least two non-equivalent junctions can be formed in these cases, with different arrangements of the pentagons and heptagons in the junction. We optimized the geometry using first principles method and investigated the effect of the junction on the electronic density of states of the bamboo-type nanotube. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Selective Oxidation of Amorphous Carbon Layers without Damaging Embedded Single Wall Carbon Nanotube Bundles

    Science.gov (United States)

    Choi, Young Chul; Lim, Seong Chu

    2013-11-01

    Single wall carbon nanotubes (SWCNTs) were synthesized by arc discharge, and then purified by selective oxidation of amorphous carbon layers that were found to encase SWCNT bundles and catalyst metal particles. In order to remove selectively the amorphous carbon layers with SWCNTs being intact, we have systematically investigated the thermal treatment conditions; firstly, setting the temperature by measuring the activation energies of SWCNTs and amorphous carbon layers, and then, secondly, finding the optimal process time. As a consequence, the optimal temperature and time for the thermal treatment was found to be 460 °C and 20 min, respectively. The complete elimination of surrounding amorphous carbon layers makes it possible to efficiently disperse the SWCNT bundles, resulting in high absorbance of SWCNT-ink. The SWCNTs which were thermal-treated at optimized temperature (460 °C) and duration (20 min) showed much better crystallinity, dispersibility, and transparent conducting properties, compared with as-synthesized and the nanotubes thermal-treated at different experimental conditions.

  9. Mechanical Properties of Single-Walled (5,5) Carbon Nanotubes with Vacancy Defects

    Institute of Scientific and Technical Information of China (English)

    YUAN Shi-Jun; KONG Yong; LI Fa-Shen

    2007-01-01

    First-principles simulation is used to investigate the structural and mechanical properties of vacancy defective single-walled (5,5) carbon nanotubes. The relations of the defect concentration, distribution and characteristic of defects to Young's modulus of nanotubes are quantitatively studied. It is found that each dangling-bond structure (per supercell) decreases Young's modulus of nanotube by 6.1% for symmetrical distribution cases. However the concentrative vacancy structure with saturated atoms has less influence on carbon nanotubes. It is suggested that the mechanical properties of carbon nanotubes depend strongly upon the structure and relative position of vacancies in a certain defect concentration.

  10. Synthesis of dark brown single-walled carbon nanotubes and their characterization by HSQC-NMR

    Indian Academy of Sciences (India)

    Rahebeh Amiri; Hamidreza Rafiee; Ashkan Golshani; Firoozeh Chalabian

    2013-03-01

    We report here a simple and effective approach to the covalent attachment of single-walled carbon nanotubes (SWCNTs) and azo compounds. The functionalized SWCNTs prepared (through a radical mechanism) have been used for a diazonium coupling reaction. The results showed that the chemical method used has improved the processability and solubility of the carbon nanotubes. The dark brown SWCNTs obtained which can produce a yellow colour in organic solvents were characterized by different spectroscopic analyses. Heteronuclear single quantum coherence spectra (13C-1H HSQC) have been used to detect the carbon nanotube allylic protons. The morphology of the main product has been shown by scanning electron microscopy (SEM).

  11. The electronic properties of doped single walled carbon nanotubes and carbon nanotube sensors

    Directory of Open Access Journals (Sweden)

    E. Tetik

    2014-12-01

    Full Text Available We present ab initio calculations on the band structure and density of states of single wall semiconducting carbon nanotubes with high degrees (up to 25% of B, Si and N substitution. The doping process consists of two phases: different carbon nanotubes (CNTs for a constant doping rate and different doping rates for the zigzag (8, 0 carbon nanotube. We analyze the doping dependence of nanotubes on the doping rate and the nanotube type. Using these results, we select the zigzag (8, 0 carbon nanotube for toxic gas sensor calculation and obtain the total and partial densities of states for CNT (8, 0. We have demonstrated that the CNT (8, 0 can be used as toxic gas sensors for CO and NO molecules, and it can partially detect Cl2 toxic molecules but cannot detect H2S. To overcome these restrictions, we created the B and N doped CNT (8, 0 and obtained the total and partial density of states for these structures. We also showed that B and N doped CNT (8, 0 can be used as toxic gas sensors for such molecules as CO, NO, Cl2 and H2S.

  12. Growth of forest of single-walled carbon nanotubes at inhomogeneous fluxes from plasma

    International Nuclear Information System (INIS)

    The growth of forest of single-walled carbon nanotubes (SWCNTs) in plasma-enhanced chemical vapor deposition (PECVD) is studied using a deposition model. The inhomogeneity in deposition of neutrals from plasma on the SWCNTs, which is typical for growth of the nano structures in PECVD, is accounted for. It is investigated how the growth rate and the residence time of carbon atoms on SWCNT surfaces depend on the SWCNT length and the decay length characterizing deposition of neutral fluxes on the SWCNTs. The obtained results can be used for optimizing the synthesis of related nano assembles in low-temperature plasma-assisted nano fabrication

  13. Theoretical studies of C36 encapsulated in zigzag single-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The one-dimensional hybrid structures of C36 encapsulated in zigzag single-wall carbon nanotubes (C36@(n,0)) have been investigated using ab initio self-consistent-field crystal orbital method based on the density functional theory. The research focuses on the change of geometric and band structures for the nanotubes upon C36 encapsulation. The obtained results show that the introduction of C36 can modify the electronic properties of CNT. The diameter of carbon nanotube plays an important role in the geometric and electronic properties of the peapod structures.

  14. Dependence of Thermal Conductivity on Thickness in Single-Walled Carbon Nanotube Films.

    Science.gov (United States)

    Lee, Kyung-Min; Shrestha, Ramesh; Dangol, Ashesh; Chang, Won Seok; Coker, Zachary; Choi, Tae-Youl

    2016-01-01

    Herein, we report experimentally dependence of thermal conductivity on thickness of single walled carbon nanotubes (SWNTs) thin films; the measurements are based on the micropipette thermal sensor technique. Accurate and well resolved measurements of thermal conductivity made by the micropipette sensor showed a correlated behavior of thickness and thermal conductivity of CNT films that thermal conductivity decreased as thickness increased. The thickness dependence is explained by reduction of mean free path (MFP), which is induced by more intertubular junctions in more dense-packed carbon nanotube (CNT) networks; the thicker SWCNT films were revealed to have higher density. PMID:27398564

  15. Fabrication and electrical properties of single wall carbon nanotube channel and graphene electrode based transistors arrays

    Energy Technology Data Exchange (ETDEWEB)

    Seo, M.; Kim, H.; Kim, Y. H.; Yun, H.; McAllister, K.; Lee, S. W., E-mail: leesw@konkuk.ac.kr [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Na, J.; Kim, G. T. [School of Electrical Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Lee, B. J.; Kim, J. J.; Jeong, G. H. [Department of Nano Applied Engineering, Kangwon National University, Kangwon-do 200-701 (Korea, Republic of); Lee, I.; Kim, K. S. [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)

    2015-07-20

    A transistor structure composed of an individual single-walled carbon nanotube (SWNT) channel with a graphene electrode was demonstrated. The integrated arrays of transistor devices were prepared by transferring patterned graphene electrode patterns on top of the aligned SWNT along one direction. Both single and multi layer graphene were used for the electrode materials; typical p-type transistor and Schottky diode behavior were observed, respectively. Based on our fabrication method and device performances, several issues are suggested and discussed to improve the device reliability and finally to realize all carbon based future electronic systems.

  16. Field-ion microscopy observation of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    张兆祥; 张耿民; 杜民; 金新喜; 侯士敏; 孙建平; 顾镇南; 赵兴钰; 刘惟敏; 吴锦雷; 薛增泉

    2002-01-01

    Field-ion microscopy (FIM), a tool for surface analysis with atomic resolution, has been employed to observethe end structure of single-walled carbon nanotubes (SWCNTs). FIM images revealed the existence of open SWCNTends. Amorphous carbon atoms were also observed to occur around SWCNTs and traditional field evaporation failedto remove them. Heat treatment was found to be efficacious in altering the end structures of SWCNT bundles. Carbonand oxygen atoms released from heated tungsten filament are believed to be responsible for the decoration imposed onthe SWCNT ends.

  17. Thin film transistors of single-walled carbon nanotubes grown directly on glass substrates

    International Nuclear Information System (INIS)

    We report a transistor of randomly networked single-walled carbon nanotubes on a glass substrate. The carbon nanotube networks acting as the active components of the thin film transistor were selectively formed on the transistor channel areas that were previously patterned with catalysts to avoid the etching process for isolating nanotubes. The nanotube density was more than 50 μm-2, which is much larger than the percolation threshold. Transistors were successfully fabricated with a conducting and transparent ZnO for the back-side gate and the top-side gate. This allows the transparent electronics or suggests thin film applications of nanotubes for future opto-electronics

  18. Determination of the acidic sites of purified single-walled carbon nanotubes by acid base titration

    Science.gov (United States)

    Hu, H.; Bhowmik, P.; Zhao, B.; Hamon, M. A.; Itkis, M. E.; Haddon, R. C.

    2001-09-01

    We report the measurement of the acidic sites in three different samples of commercially available full-length purified single-walled carbon nanotubes (SWNTs) - as obtained from CarboLex (CLI), Carbon Solutions (CSI) and Tubes@Rice (TAR) - by simple acid-base titration methods. Titration of the purified SWNTs with NaOH and NaHCO 3 solutions was used to determine the total percentage of acidic sites and carboxylic acid groups, respectively. The total percentage of acidic sites in full length purified SWNTs from TAR, CLI and CSI are about 1-3%.

  19. Fabrication and electrical properties of single wall carbon nanotube channel and graphene electrode based transistors arrays

    International Nuclear Information System (INIS)

    A transistor structure composed of an individual single-walled carbon nanotube (SWNT) channel with a graphene electrode was demonstrated. The integrated arrays of transistor devices were prepared by transferring patterned graphene electrode patterns on top of the aligned SWNT along one direction. Both single and multi layer graphene were used for the electrode materials; typical p-type transistor and Schottky diode behavior were observed, respectively. Based on our fabrication method and device performances, several issues are suggested and discussed to improve the device reliability and finally to realize all carbon based future electronic systems

  20. Effective permittivity of single-walled carbon nanotube composites: Two-fluid model

    International Nuclear Information System (INIS)

    We develop an effective medium theory to obtain effective permittivity of a composite of two-dimensional (2D) aligned single-walled carbon nanotubes. Electronic excitations on each nanotube surface are modeled by an infinitesimally thin layer of a 2D electron gas represented by two interacting fluids, which takes into account different nature of the σ and π electrons. Calculations of both real and imaginary parts of the effective dielectric function of the system are presented, for different values of the filling factor and radius of carbon nanotubes

  1. Electrochemical Characterization of Films of Single-Walled Carbon Nanotubes and Their Possible Application in Supercapacitors

    OpenAIRE

    Liu, Chong-yang; Bard, Allen J.; Wudl, Fred; Weitz, Iris; Heath, James R.

    1999-01-01

    Films of single-wall carbon nanotubes (SWCNTs) were cast from suspensions in several solvents on the surface of a Pt or Au electrode. Cyclic voltammetry of the films in MeCN did not show well-resolved waves (as distinct from films of C_(60) prepared in a similar manner). However, the increase in the effective capacitance of the electrode with a SWCNT film at 0.5 V vs. an AgQRE was 283 F/g, which is about twice that of carbon electrodes in nonaqueous solvents.

  2. Immobilization of Lipase on Single Walled Carbon Nanotubes in Ionic Liquid

    International Nuclear Information System (INIS)

    A lipase from Pseudomonas cepacia was immobilized onto single walled carbon nanotubes (SWNTs) in two different ways in each of two solvent systems (buffer and ionic liquid). The most efficient immobilization was achieved in ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIM-BF4). In this procedure, carbon nanotubes were first functionalized noncovalently with 1-pyrenebutyric acid N-hydroxysuccinimide ester and then subject to the coupling reaction with the lipase in ionic liquid. The resulting immobilized enzyme displayed the highest activity in the transesterification of 1-phenylethyl alcohol in the presence of vinyl acetate in toluene

  3. Identification of excitonic phonon sideband by photoluminescence spectroscopy of single-walled carbon-13 nanotubes

    OpenAIRE

    Miyauchi, Yuhei; Maruyama, Shigeo

    2005-01-01

    We have studied photoluminescence (PL) and resonant Raman scatterings of single-walled carbon nanotubes (SWNTs) consisting of carbon-13 (SW13CNTs) synthesized from a small amount of isotopically modified ethanol. There was almost no change in the Raman spectra shape for SW13CNTs except for a downshift of the Raman shift frequency by the square-root of the mass ratio 12/13. By comparing photoluminescence excitation (PLE) spectra of SW13CNTs and normal SWNTs, the excitonic phonon sideband due t...

  4. Effective permittivity of single-walled carbon nanotube composites: Two-fluid model

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Engineering Physics, Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of); Department of Nano Sciences, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of); Zangeneh, Hamid Reza; Moghadam, Firoozeh Karimi [Department of Photonics, Faculty of Physics, University of Kashan, Kashan (Iran, Islamic Republic of)

    2015-12-15

    We develop an effective medium theory to obtain effective permittivity of a composite of two-dimensional (2D) aligned single-walled carbon nanotubes. Electronic excitations on each nanotube surface are modeled by an infinitesimally thin layer of a 2D electron gas represented by two interacting fluids, which takes into account different nature of the σ and π electrons. Calculations of both real and imaginary parts of the effective dielectric function of the system are presented, for different values of the filling factor and radius of carbon nanotubes.

  5. Single-walled carbon nanotubes modified carbon ionic liquid electrode for sensitive electrochemical detection of rutin

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhihong [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Sun Xiaoying; Zhuang Xiaoming [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zeng Yan [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Sun Wei, E-mail: sunwei@qust.edu.c [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Huang Xintang [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China)

    2010-11-01

    The single-walled carbon nanotubes (SWCNTs) modified carbon ionic liquid electrode (CILE) was designed and further used for the voltammetric detection of rutin in this paper. CILE was prepared by mixing graphite powder with ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate and liquid paraffin together. Based on the interaction of SWCNTs with IL present on the electrode surface, a stable SWCNTs film was formed on the CILE to get a modified electrode denoted as SWCNTs/CILE. The characteristics of SWCNTs/CILE were recorded by different methods including cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The electrochemical behaviors of rutin on the SWCNTs/CILE were investigated by cyclic voltammetry and differential pulse voltammetry. Due to the specific interface provided by the SWCNTs-IL film, the electrochemical response of rutin was greatly enhanced with a pair of well-defined redox peaks appeared in pH 2.5 phosphate buffer solution. The oxidation peak currents showed good linear relationship with the rutin concentration in the range from 1.0 x 10{sup -7} to 8.0 x 10{sup -4} mol/L with the detection limit as 7.0 x 10{sup -8} mol/L (3{sigma}). The SWCNTs/CILE showed the advantages such as excellent selectivity, improved performance, good stability and it was further applied to the rutin tablets sample detection with satisfactory results.

  6. The effect of oxidation on structural and electrical properties of single wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Marković Zoran M.

    2011-01-01

    Full Text Available Single wall carbon nanotubes (SWCNTs represent an important group of nanomaterials with attractive electrical, chemical, and mechanical properties. In this work we have investigated the structural, optical and electrical properties of single wall carbon nanotube films deposited on copper substrate and then transferred to polymethyl methacrylate (PMMA. The properties of deposited films were varied by changing different parameters: substrate temperature, deposition time and electric field strength. Atomic force microscopy (AFM has been used to study the deposition process of SWCNT films on copper substrate. AFM analysis has shown that sodium dodecyl sulfate (SDS micellas were deposited on copper substrate before carbon nanotubes because of their higher mobility. Raman spectroscopy revealed that SWCNTs deposited at elevated temperatures are oxidized. FTIR results showed that COOH groups and Cu2O were generated during electrophoretic process. The SWCNT films were transferred to PMMA substrate and they achieved a sheet resistance of 360 Ω/sq with 79% transparency at 550 nm wavelength and a strong adhesion to the substrate. The main reasons for higher values of sheet resistances of SWCNT thin films compared to those of other authors are oxidation of carbon nanotubes during electrophoresis and the presence of used surfactans in carbon matrix of deposited films.

  7. Effects of phosphorus-doping upon the electronic structures of single wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    CHEN AQing; SHAO QingYi; LIN ZhiCheng

    2009-01-01

    The phosphorus-doped single wall carbon nanotube (PSWCNT) is studied by using First-Principle methods based on Density Function Theory (DFT). The formation energy, total energy, band structure, geometry structure and density of states are calculated. It is found that the formation energy of the P-doped single carbon nanotubes increases with diameters; the total energy of carbon nanotubes with the same diameter decreases as the doping rate increases. The effects of impurity position on the im-purity level are discussed. It illustrates that the position of the impurity level may depend on the C-P-C bond angle. According to the above results, it is feasible to substitute a carbon atom with a phosphorus atom in SWCNT. It is also found that P-doped carbon nanotubes are N type semiconductor.

  8. Effects of phosphorus-doping upon the electronic structures of single wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The phosphorus-doped single wall carbon nanotube(PSWCNT) is studied by using First-Principle methods based on Density Function Theory(DFT).The formation energy,total energy,band structure,geometry structure and density of states are calculated.It is found that the formation energy of the P-doped single carbon nanotubes increases with diameters;the total energy of carbon nanotubes with the same diameter decreases as the doping rate increases.The effects of impurity position on the impurity level are discussed.It illustrates that the position of the impurity level may depend on the C-P-C bond angle.According to the above results,it is feasible to substitute a carbon atom with a phosphorus atom in SWCNT.It is also found that P-doped carbon nanotubes are N type semiconductor.

  9. Toxicology Study of Single-walled Carbon Nanotubes and Reduced Graphene Oxide in Human Sperm.

    Science.gov (United States)

    Asghar, Waseem; Shafiee, Hadi; Velasco, Vanessa; Sah, Vasu R; Guo, Shirui; El Assal, Rami; Inci, Fatih; Rajagopalan, Adhithi; Jahangir, Muntasir; Anchan, Raymond M; Mutter, George L; Ozkan, Mihrimah; Ozkan, Cengiz S; Demirci, Utkan

    2016-01-01

    Carbon-based nanomaterials such as single-walled carbon nanotubes and reduced graphene oxide are currently being evaluated for biomedical applications including in vivo drug delivery and tumor imaging. Several reports have studied the toxicity of carbon nanomaterials, but their effects on human male reproduction have not been fully examined. Additionally, it is not clear whether the nanomaterial exposure has any effect on sperm sorting procedures used in clinical settings. Here, we show that the presence of functionalized single walled carbon nanotubes (SWCNT-COOH) and reduced graphene oxide at concentrations of 1-25 μg/mL do not affect sperm viability. However, SWCNT-COOH generate significant reactive superoxide species at a higher concentration (25 μg/mL), while reduced graphene oxide does not initiate reactive species in human sperm. Further, we demonstrate that exposure to these nanomaterials does not hinder the sperm sorting process, and microfluidic sorting systems can select the sperm that show low oxidative stress post-exposure. PMID:27538480

  10. Photoinduced Spontaneous Free-Carrier Generation in Semiconducting Single-Walled Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jaehong [National Renewable Energy Lab. (NREL), Golden, CO (United States); Reid, Obadiah G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Univ. of Colorado, Boulder, CO (United States); Blackburn, Jeffrey L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Rumbles, Garry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Univ. of Colorado, Boulder, CO (United States)

    2015-11-04

    The strong quantum confinement and low dielectric screening impart single-walled carbon nanotubes with exciton-binding energies substantially exceeding kBT at room temperature. Despite these large binding energies, reported photoluminescence quantum yields are typically low and some studies suggest that photoexcitation of carbon nanotube excitonic transitions can produce free charge carriers. Here we report the direct measurement of long-lived free-carrier generation in chirality-pure, single-walled carbon nanotubes in a low dielectric solvent. Time-resolved microwave conductivity enables contactless and quantitative measurement of the real and imaginary photoconductance of individually suspended nanotubes. We found that the conditions of the microwave conductivity measurement allow us to avoid the complications of most previous measurements of nanotube free-carrier generation, including tube–tube/tube–electrode contact, dielectric screening by nearby excitons and many-body interactions. At low photon fluence (approximately 0.05 excitons per μm length of tubes), we directly observe free carriers on excitation of the first and second carbon nanotube exciton transitions.

  11. Terahertz Spectroscopy of Individual Single-Walled Carbon Nanotubes as a Probe of Luttinger Liquid Physics.

    Science.gov (United States)

    Chudow, Joel D; Santavicca, Daniel F; Prober, Daniel E

    2016-08-10

    Luttinger liquid theory predicts that collective electron excitations due to strong electron-electron interactions in a one-dimensional (1D) system will result in a modification of the collective charge-propagation velocity. By utilizing a circuit model for an individual metallic single-walled carbon nanotube as a nanotransmission line, it has been shown that the frequency-dependent terahertz impedance of a carbon nanotube can probe this expected 1D Luttinger liquid behavior. We excite terahertz standing-wave resonances on individual antenna-coupled metallic single-walled carbon nanotubes. The terahertz signal is rectified using the nanotube contact nonlinearity, allowing for a low-frequency readout of the coupled terahertz current. The charge velocity on the nanotube is determined from the terahertz spectral response. Our measurements show that a carbon nanotube can behave as a Luttinger liquid system with charge-propagation velocities that are faster than the Fermi velocity. Understanding what determines the charge velocity in low-dimensional conductors is important for the development of next generation nanodevices. PMID:27439013

  12. Electrochemical behaviour of different redox probes on single wall carbon nanotube buckypaper-modified electrodes

    International Nuclear Information System (INIS)

    In the present work, the electrochemical properties of single-walled carbon nanotube buckypapers (BPs) were examined in terms of carbon nanotubes nature and preparation conditions. The performance of the different free-standing single wall carbon nanotube sheets was evaluated via cyclic voltammetry of several redox probes in aqueous electrolyte. Significant differences are observed in the electron transfer kinetics of the buckypaper-modified electrodes for both the outer- and inner-sphere redox systems. These differences can be ascribed to the nature of the carbon nanotubes (nanotube diameter, chirality and aspect ratio), surface oxidation degree and type of functionalities. In the case of dopamine, ferrocene/ferrocenium, and quinone/hydroquinone redox systems the voltammetric response should be thought as a complex contribution of different tips and sidewall domains which act as mediators for the electron transfer between the adsorbate species and the molecules in solution. In the other redox systems only nanotube ends are active sites for the electron transfer. It is also interesting to point out that a higher electroactive surface area not always lead to an improvement in the electron transfer rate of various redox systems. In addition, the current densities produced by the redox reactions studied here are high enough to ensure a proper electrochemical signal, which enables the use of BPs in sensing devices

  13. Modelling of single walled carbon nanotube cylindrical structures with finite element method simulations

    Science.gov (United States)

    Günay, E.

    2016-04-01

    In this study, the modulus of elasticity and shear modulus values of single-walled carbon nanotubes SWCNTs were modelled by using both finite element method and the Matlab code. Initially, cylindrical armchair and zigzag single walled 3D space frames were demonstrated as carbon nanostructures. Thereafter, macro programs were written by the Matlab code producing the space truss for zigzag and armchair models. 3D space frames were introduced to the ANSYS software and then tension, compression and additionally torsion tests were performed on zigzag and armchair carbon nanotubes with BEAM4 element in obtaining the exact values of elastic and shear modulus values. In this study, two different boundary conditions were tested and especially used in torsion loading. The equivalent shear modulus data was found by averaging the corresponding values obtained from ten different nodal points on the nanotube path. Finally, in this study it was determined that the elastic constant values showed proportional changes by increasing the carbon nanotube diameters up to a certain level but beyond this level these values remained stable.

  14. Microwave-assisted functionalization of single-walled carbon nanotubes with 3-chloropropene

    International Nuclear Information System (INIS)

    We have reported a highly efficient approach to functionalize single-walled carbon nanotubes by electrophilic addition polymerization of 3-chloropropene under microwave irradiation. Using Lewis acids as catalysts, 3-chloropropene can undergo polymerization followed by hydrolysis with alkaline methanol, and thus the reaction results in the attachment of polymer chains and hydroxyl groups to the surface of the nanotubes. The resulting nanotubes were characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, high-resolution transmission electron microscopy, and atomic force microscopy. The result shows that 30 min of irradiation time is enough to bring the reaction to the end and a longer time did not improve the degree of functionalization.

  15. Diameter-dependent bending dynamics of single-walled carbon nanotubes in liquids

    Science.gov (United States)

    Fakhri, Nikta; Tsyboulski, Dmitri A.; Cognet, Laurent; Weisman, R. Bruce; Pasquali, Matteo

    2009-01-01

    By relating nanotechnology to soft condensed matter, understanding the mechanics and dynamics of single-walled carbon nanotubes (SWCNTs) in fluids is crucial for both fundamental and applied science. Here, we study the Brownian bending dynamics of individual chirality-assigned SWCNTs in water by fluorescence microscopy. The bending stiffness scales as the cube of the nanotube diameter and the shape relaxation times agree with the semiflexible chain model. This suggests that SWCNTs may be the archetypal semiflexible filaments, highly suited to act as nanoprobes in complex fluids or biological systems. PMID:19706503

  16. Electronic Durability of Flexible Transparent Films from Type-Specific Single-Wall Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Harris, J; Iyer, S; Bernhardt, A; Huh, JY; Hudson, S; Fagan, J; Hobbie, E.

    2011-12-11

    The coupling between mechanical flexibility and electronic performance is evaluated for thin films of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) deposited on compliant supports. Percolated networks of type-purified SWCNTs are assembled as thin conducting coatings on elastic polymer substrates, and the sheet resistance is measured as a function of compression and cyclic strain through impedance spectroscopy. The wrinkling topography, microstructure and transparency of the films are independently characterized using optical microscopy, electron microscopy, and optical absorption spectroscopy. Thin films made from metallic SWCNTs show better durability as flexible transparent conductive coatings, which we attribute to a combination of superior mechanical performance and higher interfacial conductivity.

  17. Electronic properties of single-walled carbon nanotubes filled with manganese halogenides

    Science.gov (United States)

    Kharlamova, M. V.

    2016-09-01

    In this work, single-walled carbon nanotubes (SWCNTs) were filled with manganese chloride and manganese bromide by a capillary filling method. The electronic properties of the filled SWCNTs were investigated by Raman spectroscopy and X-ray photoelectron spectroscopy. It was found that the encapsulated manganese halogenides led to hole doping of the SWCNTs due to the charge transfer from the nanotubes to the encapsulated compounds. The embedded MnCl2 had stronger doping effect on the SWCNTs than MnBr2.

  18. Stable double helical iodine chains inside single-walled carbon nanotubes

    Science.gov (United States)

    Yao, Zhen; Liu, Chun-Jian; Lv, Hang; Liu, Bing-Bing

    2016-08-01

    The helicity of stable double helical iodine chains inside single-walled carbon nanotubes (SWCNTs) is studied by calculating the systematic interaction energy. Our results present clear images of stable double helical structures inside SWCNTs. The optimum helical radius and helical angle increase and decrease with increasing diameter, respectively. The tube's diameter plays a leading role in the helicity of encapsulated structures, while the tube's chirality may induce different metastable structures. This study indicates that the observed double helical iodine chains in experiments are not necessarily the optimum structures, but may also be metastable structures.

  19. Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Daisuke Ogawa

    2014-01-01

    Full Text Available Thermally fragile tris(η5-cyclopentadienylerbium (ErCp3 molecules are encapsulated in single-wall carbon nanotubes (SWCNTs with high yield. We realized the encapsulation of ErCp3 with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3 molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+ is confirmed by X-ray absorption spectrum.

  20. Purification and Functionalization of Single-Walled Carbon Nano tubes through Different Treatment Procedures

    International Nuclear Information System (INIS)

    Single-walled carbon nano tubes (SWCNTs) were purified by the combined use of ultrasonic- and microwave-assisted acid digestion. The results show that the method efficiently eliminates impurities, reduces solvent consumption, and prevents damage to the structure of the SWCNTs. The purified SWCNTs were given functionalization treatments with a nitric acid/sulfuric acid mixture. These acid-treated SWCNTs (A-SWCNTs) were then grafted with 3-isocyanatopropyl triethoxysilane (A-SWCNTs-Si). The A-SWCNTs and A-SWCNTs-Si were used to improve interfacial interactions with polymers and to produce a well-dispersed SWCNT composite.

  1. Ultrafast carrier dynamics in purified and as-grown single-walled carbon nanotube films

    Institute of Scientific and Technical Information of China (English)

    Long Yong-Bing; Song Li; Zhang Chun-Yu; Wang Li; Fu Pan-Ming; Zhang Zhi-Guo; Xie Si-Shen; Wang Guo-Ping

    2005-01-01

    Ultrafast time-resolved optical transmissions in purified and as-grown single-walled carbon nanotube films are measured at a temperature of 200K. The signal of the purified sample shows a crossover from photobleaching to photoabsorption. The former and the latter are interpreted as the state filling and the red shift of the π-plasmon,respectively. The signal of the as-grown sample can be perfectly fitted by a single-exponential with a time constant of 232fs. The disappearance of the negative component in the as-grown sample is attributed to the charge transfer between the semiconducting nanotubes and the impurities.

  2. Synthesis of single-walled carbon nanotubes by the vertical floating catalyst method

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The vertical floating catalyst method is first used to produce single-walled carbon nanotubes (SWNTs)continuously on a large scale by a newly developed technique and pyrolysis of n-hexane. Diameter distributions, microstructure and purity of the SWNTs film, rope and web are measured by Raman spectroscopy and electron microscope.The results show that SWNTs product has a high degree of orientation, a wide distribution of diameters (0.7-2.0 nm)and high purity of > 80%.``

  3. Molecular dynamics simulation for flow characteristics in nanochannels and single walled carbon nanotubes

    International Nuclear Information System (INIS)

    Flows in graphite-, diamond- and silicon-walled nanochannels are discussed by performing molecular dynamics simulations. Flows in carbon nanotubes (CNTs) and graphene- walled nanochannels are also investigated. It is found that the flow rate in the graphite-walled channel tends to be the largest because of its slippery wall structure by the short bond length and the high molecular density of the CNTs. The flow rate in the single walled CNT at a very narrow diameter tends to increase although such a tendency is not seen in the graphene-walled channel.

  4. Thermoelectric properties of single-wall carbon nanotube films: Effects of diameter and wet environment

    Science.gov (United States)

    Hayashi, Daisuke; Ueda, Tomohiro; Nakai, Yusuke; Kyakuno, Haruka; Miyata, Yasumitsu; Yamamoto, Takahiro; Saito, Takeshi; Hata, Kenji; Maniwa, Yutaka

    2016-02-01

    The Seebeck coefficient S and the electrical resistivity ρ of single-wall carbon nanotube (SWCNT) films were investigated as a function of the SWCNT diameter and carrier concentration. The S and ρ significantly changed in humid environments through p-type carrier doping. Experiments, combined with theoretical simulations based on the non-equilibrium Green’s function theory, indicated that the power factor P can be increased threefold by the enrichment of semiconducting SWCNTs, but the nanotube diameter has little effect. The improvement of the film resistivity strongly enhances the film thermoelectric performance, manifested as increasing the value of P above 1200 µW/(m·K2).

  5. Terahertz response in single-walled carbon nanotube transistor: a real-time quantum dynamics simulation

    International Nuclear Information System (INIS)

    We use time-dependent quantum wavepacket methods to simulate ballistic electron transport in a single-walled carbon nanotube field-effect transistor at terahertz frequencies (∼100 GHz-10 THz). We observe an electron resonance phenomenon in a sub-picosecond-scale time domain. Our simulation results clearly show that the electron resonance corresponds to the formation of the resonance cavity and the interference of the electron wavepackets, which is directly supported by recent experimental measurements (Zhong et al 2008 Nat. Nanotechnol. 3 201).

  6. The Environmental Effect on the Dynamical Behaviors of Single-Walled Carbon Nanotube in Water

    OpenAIRE

    Yan Yan; Weizhong Li; Wenquan Wang

    2014-01-01

    The paper investigates the dynamical behaviors of single-walled carbon nanotube (SWCNT) in water, focusing on the effect of external environment (i.e., water) on SWCNT. The SWCNT-water system comprises three constituent parts, that is, the SWCNT, the absorbed layer of water molecules, and the water flow around the water layer. The SWCNT and the absorbed layer of water are modeled as two-layer thin shells coupled via the interlayer vdW interaction, and the water surrounding the absorbed water ...

  7. Self-assemblies of cationic porphyrins with functionalized water-soluble single-walled carbon nanotubes.

    Science.gov (United States)

    Kubát, Pavel; Lang, Kamil; Jandal, Pavel; Frank, Ota; Matulková, Irena; Sýkora, Jan; Civis, Svatopluk; Hof, Martin; Kavan, Ladislav

    2009-10-01

    5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin, 5,10,15,20-tetrakis(2-N-methylpyridyl)porphyrin, and 5,10,15,20-tetrakis(4-trimethylammoniophenyl)porphyrin form self-assemblies with single-walled carbon nanotubes (SWNT) functionalized by polyaminobenzene sulfonic acid. Both steady-state and time-resolved emission studies revealed efficient quenching of the excited singlet states of the porphyrins. Atomic force microscopy, fluorescence confocal microscopy, and fluorescence lifetime imaging allowed the visualization of individual bundles of SWNTs and the differentiation of porphyrin molecules at specific binding sites of SWNT. PMID:19908455

  8. Electronic durability of flexible transparent films from type-specific single-wall carbon nanotubes.

    Science.gov (United States)

    Harris, John M; Iyer, Ganjigunte R Swathi; Bernhardt, Anna K; Huh, Ji Yeon; Hudson, Steven D; Fagan, Jeffrey A; Hobbie, Erik K

    2012-01-24

    The coupling between mechanical flexibility and electronic performance is evaluated for thin films of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) deposited on compliant supports. Percolated networks of type-purified SWCNTs are assembled as thin conducting coatings on elastic polymer substrates, and the sheet resistance is measured as a function of compression and cyclic strain through impedance spectroscopy. The wrinkling topography, microstructure and transparency of the films are independently characterized using optical microscopy, electron microscopy, and optical absorption spectroscopy. Thin films made from metallic SWCNTs show better durability as flexible transparent conductive coatings, which we attribute to a combination of superior mechanical performance and higher interfacial conductivity. PMID:22148890

  9. Quasi-One-Dimensional Solid Lattice and Liquid hydrogen in Single-Walled carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    英敏菊; 夏曰源; 赵明文; 刘向东; 李峰; 黄博达; 谭震宇

    2003-01-01

    We study the H2 molecules confined in single-walled carbon nanotubes by using molecular dynamics simulations and ab initio calculations. It is found that the H2 molecules at zero-temperature with low density tend to condense. When the linear density of the H2 molecules in the tube increases, various quasi-one-dimensional solid lattices can be observed at Iow temperature. When the lattices are heated above room temperature, molecular H2 liquids with different density can be observed. The quenching behaviour of the H2 fluids is also examined.

  10. Interaction between single-walled carbon nanotubes and chromatography gel during size separation

    International Nuclear Information System (INIS)

    In this study, we investigate the underlying mechanism by which chromatography can be used for the separation of single-walled carbon nanotubes (SWNTs) on the basis of their diameter or length, with a view to optimizing this popular process. Using the knowledge gained through diffusion ordered spectroscopy nuclear magnetic resonance (DOSY NMR) analysis and chromatographic experiments, we demonstrate the feasibility of separating SWNTs on the basis of diameter and length simultaneously within the one chromatography column. These findings are of relevance not just to the understanding of SWNT separation processes, but also to the industrial use of size-separated SWNTs. (paper)

  11. Near-infrared fluorescent single walled carbon nanotube-chitosan composite: Interfacial strain transfer efficiency assessment

    Science.gov (United States)

    Mol Menamparambath, Mini; Arabale, Girish; Nikolaev, Pavel; Baik, Seunghyun; Arepalli, Sivaram

    2013-04-01

    Effective load transfer at the single walled carbon nanotube (SWCNT)-polymer interface is most desirable for mechanically reinforced polymer composites. Versatile layer-by-layer assembly technique achieved dispersion and uniform distribution of sodium carboxymethylcellulose (CMC)-solubilized SWCNTs within the polymer matrix. Electrostatic interaction between positively charged chitosan and negatively charged CMC facilitates design of an optically active biocompatible nanocomposite. Interfacial strain transfer efficiency of SWCNT-chitosan nanocomposite was assessed via SWCNT Raman and photoluminescence band shifts under uniaxial strain. Photoluminescence peak shift rates of individual semiconducting SWCNTs were investigated and compared with tight binding model calculations.

  12. Oxygen plasma effects on the electrical conductance of single-walled carbon nanotube bundles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sanghun; Kim, Ho-Jong; Ha, Dong Han [Center for Nano and Quantum Science, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Lee, Hyeong Rag [Department of Physics, Kyungpook National University, Buk-Gu, Daegu 702-701 (Korea, Republic of); Song, Jung-Hoon [Department of Physics, Kongju National University, Shinkwan-dong, Kongju 314-701 (Korea, Republic of); Yi, Sam Nyung, E-mail: dhha@kriss.re.k [Department of Applied Science, Korea Maritime University, Busan 606-791 (Korea, Republic of)

    2010-08-04

    We report the electrical properties of single-walled carbon nanotube bundles aligned between two electrodes with a gap of 8 {mu}m by the alternating current dielectrophoresis method. The resistance increased exponentially as the number of structural defects increased from the oxygen plasma treatment. However, no noticeable change was observed in the carrier concentration and tube-tube interaction. The resistance dependence on the plasma treatment time was explained on the basis of the localization of electron states at defect sites. The aspects of the defects were examined by measuring the effects of ammonia adsorption on the conductance of the device.

  13. Large scale 3D vertical assembly of single-wall carbon nanotubes at ambient temperatures

    International Nuclear Information System (INIS)

    We demonstrate three-dimensional directed assembly of single-wall carbon nanotubes (SWNT) into porous alumina nanotemplates on silicon substrates by means of electrophoresis and dielectrophoresis at ambient temperatures. Assembled SWNT provided an interconnection between the surface and base of the nanotemplate. I-V measurements clearly show that the connection between silicon and SWNT is established inside the templates. This technique is particularly useful for large scale, rapid, 3D assembly of SWNT over centimeter square areas under mild conditions for nanoscale electronics applications.

  14. Three-dimensional assembly of single-walled carbon nanotube interconnects using dielectrophoresis

    International Nuclear Information System (INIS)

    We present a hybrid approach that combines top-down fabrication with bottom-up directed assembly for making single-walled carbon nanotube (SWNT) based three-dimensional interconnects. The SWNTs are assembled using dielectrophoresis at room temperature on a microfabricated 3D platform. The two-terminal resistance of the assembled SWNTs at 10 Vpp assembly voltage is approximately 545 Ω. Simulation of the dielectrophoretic assembly is carried out to understand the behavior of the SWNTs during assembly. Encapsulation of these devices using a conformal pinhole-free parylene layer resulted in a decrease of the total resistance

  15. Universal empirical formula for optical transition energies of semiconducting single-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    G. R. Ahmed Jamal

    2016-01-01

    Full Text Available A general empirical relation for calculating first seven optical transition energies of semiconducting single wall carbon nanotubes (SWCNTs is proposed here for the first time. The proposed formula effectively relates first seven optical transition energies of semiconducting SWCNTs with their chiral indices (n, m through exponential form containing two specific terms (n+2m and (2n-m. Both mod 1 and mod 2 types of semiconducting tubes are considered here over a wide diameter range from 0.4 nm to 4.75 nm. It was observed that the proposed empirical relations can predict the recent experimental data of those optical transitions with high accuracy.

  16. Effect of Topological Defects on Buckling Behavior of Single-walled Carbon Nanotube

    Directory of Open Access Journals (Sweden)

    Wang Guoxiu

    2011-01-01

    Full Text Available Abstract Molecular dynamic simulation method has been employed to consider the critical buckling force, pressure, and strain of pristine and defected single-walled carbon nanotube (SWCNT under axial compression. Effects of length, radius, chirality, Stone–Wales (SW defect, and single vacancy (SV defect on buckling behavior of SWCNTs have been studied. Obtained results indicate that axial stability of SWCNT reduces significantly due to topological defects. Critical buckling strain is more susceptible to defects than critical buckling force. Both SW and SV defects decrease the buckling mode of SWCNT. Comparative approach of this study leads to more reliable design of nanostructures.

  17. Gold Nanoparticles as the Catalyst of Single-Walled Carbon Nanotube Synthesis

    Directory of Open Access Journals (Sweden)

    Yoshikazu Homma

    2014-03-01

    Full Text Available Gold nanoparticles have been proven to act as efficient catalysts for chemical reactions, such as oxidation and hydrogen production. In this review we focus on a different aspect of the catalysis of gold nanoparticles; single-walled carbon nanotube (SWCNT synthesis. This is not a traditional meaning of catalytic reaction, but SWCNTs cannot be synthesized without nanoparticles. Previously, gold was considered as unsuitable metal species as the catalyst of SWCNT synthesis. However, gold nanoparticles with diameters smaller than 5 nm were found to effectively produce SWCNTs. We discuss the catalysis of gold and related metals for SWCNT synthesis in comparison with conventional catalysts, such as iron, cobalt, and nickel.

  18. Explicit solution of the radial breathing mode frequency of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Tienchong Chang

    2007-01-01

    On the basis of a molecular mechanics model, an analytical solution of the radial breathing mode (RBM) frequency of single-walled carbon nanotubes (SWCNTs) is obtained. The effects of tube chirality and tube diameter on the RBM frequency are investigated and good agreement between the present results and existing data is found. The present analytical formula indicates that the chirality and size dependent elastic properties are responsible for the effects of the chirality and small size on the RBM frequency of an SWCNT.

  19. The lowest optical phonon mode of small single-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    CHEN Yan

    2015-08-01

    Full Text Available We demonstrate that the lowest optical phonon mode (LOM of the single-walled carbon nanotubes (SWCNTs is not always a E2g mode for achiral tube or E2 mode for chiral tube.For some small SWCNTs of which the periodic unit length along tube axis is larger than its circumference,the LOM is the standing wave along the tube axis.By the present numerical calculation based on empirical potential,we confirm that the energy of such an optical phonon mode is inversely proportional to the tube radius.

  20. Transparent and flexible high-performance supercapacitors based on single-walled carbon nanotube films

    Science.gov (United States)

    Kanninen, Petri; Dang Luong, Nguyen; Hoang Sinh, Le; Anoshkin, Ilya V.; Tsapenko, Alexey; Seppälä, Jukka; Nasibulin, Albert G.; Kallio, Tanja

    2016-06-01

    Transparent and flexible energy storage devices have garnered great interest due to their suitability for display, sensor and photovoltaic applications. In this paper, we report the application of aerosol synthesized and dry deposited single-walled carbon nanotube (SWCNT) thin films as electrodes for an electrochemical double-layer capacitor (EDLC). SWCNT films exhibit extremely large specific capacitance (178 F g‑1 or 552 μF cm‑2), high optical transparency (92%) and stability for 10 000 charge/discharge cycles. A transparent and flexible EDLC prototype is constructed with a polyethylene casing and a gel electrolyte.

  1. Fabrication of Dense Horizontally Aligned Arrays of Single-Wall Carbon Nanotubes from Vertically Aligned Arrays

    Science.gov (United States)

    Zheng, Gang; Wang, Xueshen; Li, Qunqing; Xie, Jing; Zhu, Zhendong; Zou, Yuan; Liu, Junku; Jiang, Kaili; Fan, Shoushan

    2011-01-01

    The as-grown vertically aligned single-wall carbon nanotube (SWNT) arrays are transferred from the original silicon substrate to a poly(ethylene terephthalate) (PET) substrate, which acts as a stamp. Thin SWNT films can be applied from the stamp to the target substrate and subsequently treated by an ultrasonic process to reduce their thickness to 6.6 nm. The transferred SWNT thin film retains the advantageous super-alignment and high-density properties of the vertical SWNT arrays. The linear density, transmittance, and square resistance of the thin film are as high as 15 tubes per micrometer, 99% at 550 nm, and 16 kΩ, respectively.

  2. Midgap luminescence centers in single-wall carbon nanotubes created by ultraviolet illumination

    Science.gov (United States)

    Iakoubovskii, Konstantin; Minami, Nobutsugu; Kim, Yeji; Miyashita, Kanae; Kazaoui, Said; Nalini, Balakrishnan

    2006-10-01

    The authors report the effect of ultraviolet (UV) illumination on optical properties of single-wall carbon nanotubes (SWCNTs) isolated using various dispersants. It is demonstrated that even weak UV light (˜1mW/cm2) can irreversibly alter the SWCNT structure, thus resulting in the emergence of hitherto unknown, redshifted photoluminescence (PL) peaks with concomitant reduction in some of the original PL peaks. These UV-induced changes are characterized in detail and attributed to the creation of midgap PL centers.

  3. Electronic modulations in a single wall carbon nanotube induced by the Au(111) surface reconstruction

    International Nuclear Information System (INIS)

    The structural and electronic structure of single wall carbon nanotubes adsorbed on Au(111) has been investigated by low-temperature scanning tunneling microscopy and spectroscopy. The nanotubes were dry deposited in situ in ultrahigh vacuum onto a perfectly clean substrate. In some cases, the native herringbone reconstruction of the Au(111) surface interacted directly with adsorbed nanotubes and produced long-range periodic oscillations in their local density of states, corresponding to charge transfer modulations along the tube axis. This effect, however, was observed not systematically for all tubes and only for semiconducting tubes

  4. Reinforcement of semicrystalline polymers with collagen-modified single walled carbon nanotubes

    Science.gov (United States)

    Bhattacharyya, Sanjib; Salvetat, Jean-Paul; Saboungi, Marie-Louise

    2006-06-01

    We report on the enhancement of the mechanical properties of single wall carbon nanotube (SWNT)-polyvinyl alcohol (PVA) composites through functionalization of SWNTs with denatured collagen. In addition to improving compatibility with the matrix, the denatured collagen layer was found to increase the PVA matrix crystallinity, which results in a dramatic enhancement of the Young's modulus (260%), tensile strength (300%), and toughness (700%) well above what can be expected with the classical rule of mixture. A supramolecular organization at the interface is associated with an increase of PVA crystallinity as shown by the x-ray diffraction and differential scanning calorimetry.

  5. Polarized resonance Raman spectroscopy of single-wall carbon nanotubes within a polymer under strain

    Science.gov (United States)

    Frogley, M. D.; Zhao, Q.; Wagner, H. D.

    2002-03-01

    The D* Raman band of single-wall carbon nanotubes aligned by shear flow in a polymer matrix has been measured as a function of tensile strain. The Raman intensity varies with the optical polarization direction, an effect which is used here to assess the degree of tube alignment. The strain dependence of the Raman shift depends strongly on the nanotube orientation and the polarization direction. We show that, using polarized light, unoriented nanotubes can be used as strain sensors so that no tube alignment is necessary and the strain can be measured in all directions in a single sample.

  6. Fatigue failure mechanisms of single-walled carbon nanotube ropes embedded in epoxy

    International Nuclear Information System (INIS)

    In this work, fatigue failure mechanisms of single-walled carbon nanotube (SWCNT) bundles embedded in epoxy matrix under repeated tensile load were studied. Observed damage and failure modes include: (1) splitting of SWCNT bundles, (2) kink formation and subsequent failure in SWCNTs, and (3) fracture of SWCNT bundles. Patterns of crack propagation under tension in SWCNTs were studied by molecular mechanics simulations, where defect-free SWCNTs and SWCNTs with two different modes of Stone-Wales defects were studied. It is demonstrated by the results of molecular mechanics simulation that the observed fracture surfaces of SWCNT can be reproduced reasonably well, suggesting possible fatigue failure mechanisms of SWCNT in the composite

  7. Transmission electron microscopy observations of fracture of single-wall carbon nanotubes under axial tension

    Science.gov (United States)

    Lourie, O.; Wagner, H. D.

    1998-12-01

    Well-aligned bundles of single-wall carbon nanotubes under tensile stresses were observed to fracture in real-time by transmission electron microscopy. The expansion of elliptical holes in the polymer matrix results in a tensile force in bridging nanotubes. The polymer matrix at both ends of the bundles deforms extensively under the tension force, and fracture of the nanotubes occurs in tension within the polymer hole region rather than in shear within the gripping polymer region at the ends of the bundles. This provides evidence of significant polymer-nanotube wetting and interfacial adhesion.

  8. Fatigue failure mechanisms of single-walled carbon nanotube ropes embedded in epoxy

    Science.gov (United States)

    Ren, Y.; Fu, Y. Q.; Liao, K.; Li, F.; Cheng, H. M.

    2004-04-01

    In this work, fatigue failure mechanisms of single-walled carbon nanotube (SWCNT) bundles embedded in epoxy matrix under repeated tensile load were studied. Observed damage and failure modes include: (1) splitting of SWCNT bundles, (2) kink formation and subsequent failure in SWCNTs, and (3) fracture of SWCNT bundles. Patterns of crack propagation under tension in SWCNTs were studied by molecular mechanics simulations, where defect-free SWCNTs and SWCNTs with two different modes of Stone-Wales defects were studied. It is demonstrated by the results of molecular mechanics simulation that the observed fracture surfaces of SWCNT can be reproduced reasonably well, suggesting possible fatigue failure mechanisms of SWCNT in the composite.

  9. Femtosecond Dynamics in Single Wall Carbon Nanotube/Poly(3-Hexylthiophene Composites

    Directory of Open Access Journals (Sweden)

    Alexandrou Ioannis

    2008-01-01

    Full Text Available AbstractFemtosecond transient absorption measurements on single wall carbon nanotube/poly(3-hexylthiophene composites are used to investigate the relaxation dynamics of this blended material. The influence of the addition of nanotubes in polymer matrix on the ultrashort relaxation dynamics is examined in detail. The introduction of nanotube/polymer heterojunctions enhances the exciton dissociation and quenches the radiative recombination of composites. The relaxation dynamics of these composites are compared with the fullerene derivative-polymer composites with the same matrix. These results provide explanation to the observed photovoltaic performance of two types of composites.

  10. Single-walled carbon nanotube buckypapers as electrocatalyst supports for methanol oxidation

    OpenAIRE

    Sieben, J.M.; Ansón Casaos, Alejandro; Martínez, M.Teresa; E. Morallón

    2013-01-01

    This work studies the use of various single-walled carbon nanotube (SWCNT) buckypapers as catalyst supports for methanol electro-oxidation in acid media. Buckypapers were obtained by vacuum filtration from pristine and oxidized SWCNT suspensions in different liquid media. Pt-Ru catalysts supported on the buckypapers were prepared by multiple potentiostatic pulses using a diluted solution of Pt and Ru salts (2 mM H2PtCl6 + 2 mM RuCl3) in acid media. The resulting materials were characterized v...

  11. Multi-functionalized single-walled carbon nanotubes as tumor cell targeting biological transporters

    International Nuclear Information System (INIS)

    Multi-functionalized single walled carbon nanotubes (SWNTs) were prepared and applied as tumor cell targeting biological transporters. A positive charge was introduced on SWNTs to get high loading efficiency of fluorescein (FAM) labeled short double strands DNA (20 base pairs). The SWNTs were encapsulated with the folic acid modified phospholipids for active targeting into tumor cell. The tumor cell-targeting properties of these multi-functionalized SWNTs were investigated by active targeting into mouse ovarian surface epithelial cells. The experimental results show that these multi-functionalized SWNTs have good tumor cell targeting property

  12. Record Endurance for Single-Walled Carbon Nanotube–Based Memory Cell

    Directory of Open Access Journals (Sweden)

    Yang Y

    2010-01-01

    Full Text Available Abstract We study memory devices consisting of single-walled carbon nanotube transistors with charge storage at the SiO2/nanotube interface. We show that this type of memory device is robust, withstanding over 105 operating cycles, with a current drive capability up to 10−6 A at 20 mV drain bias, thus competing with state-of-the-art Si-devices. We find that the device performance depends on temperature and pressure, while both endurance and data retention are improved in vacuum.

  13. Synthesis of Large Quantity Single-Walled Carbon Nanotubes by Arc Discharge

    Institute of Scientific and Technical Information of China (English)

    李振华; 王淼; 王新庆; 朱海滨; 卢焕明; 安藤义则

    2002-01-01

    We report on a new method to prepare large quantity single-walled carbon nanotubes (SWCNTs) with high purity.Using a Y-Ni powder composite graphite rod as an anode, at a given angle with the high-purity graphite cathode rod, a cloth-like deposit can be obtained by dc arc discharge in helium at high temperature, which contains about 60% SWCNTs. In this way, we can obtain a deposit of more than one gram in ten minutes. Transmission electron microscopy and Raman scattering have been used to observe the structure and morphology of the SWCNTs.

  14. Effects of environmental and exciton screening in single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    The ground-state exciton binding energy for single-walled carbon nanotubes (SWCNTs) in vacuum calculated ignoring the screening of Coulomb interaction appears to be much greater than the corresponding band gap. The most essential contributions to the screening of electron-hole (e-h) interaction potential in semiconducting SWCNTs, which return the ground-state exciton binding energy into the energy gap, are considered. Our estimates on the screening effects and exciton binding energies are in satisfactory agreement with the corresponding experimental data for concrete nanotubes.

  15. The reaction of lithium metal vapor with single walled carbon nanotubes of large diameters

    Czech Academy of Sciences Publication Activity Database

    Kalbáč, Martin; Kavan, Ladislav; Dunsch, L.

    2009-01-01

    Roč. 246, 11-12 (2009), s. 2428-2431. ISSN 0370-1972 R&D Projects: GA AV ČR IAA400400911; GA AV ČR KAN200100801; GA AV ČR IAA400400804; GA ČR GC203/07/J067; GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : lithium * single walled carbon nanotubes * Raman spectroscopy Subject RIV: CG - Electrochemistry Impact factor: 1.150, year: 2009

  16. Functionalization of single-walled carbon nanotubes with uracil, guanine, thymine and L-alanine

    Science.gov (United States)

    Silambarasan, D.; Iyakutti, K.; Vasu, V.

    2014-06-01

    Experimental investigation of functionalization of oxidized single-walled carbon nanotubes (OSWCNTs) with three nucleic acid bases such as uracil, guanine, thymine and one amino acid, L-alanine is carried out. Initially, the SWCNTs are oxidized by acid treatment. Further, the oxidized SWCNTs are effectively functionalized with aforementioned biological compounds by ultrasonication. The diameter of OSWCNTs has increased after the adsorption of biological compounds. The cumulative Π-Π stacking, hydrogen bond and polar interaction are the key factors to realize the adsorption. The amount of adsorption of each biological compound is estimated. The adsorption of guanine is more among all the four biological compounds.

  17. Interaction between methanol and single-walled carbon nanotubes: Density functional theory study

    International Nuclear Information System (INIS)

    Density functional calculations have been performed to investigate the dependence of methanol interaction with the side walls of single-walled carbon nanotubes (SWCNTs) on the nanotube's type, curvature and chirality. The author's results show that methanol prefers to be physically adsorbed on semiconducting CNTs in comparison with the metallic one. It was found that the binding energy of methanol is increased for adsorption on larger-diameter nanotubes. Furthermore, we find that when a methanol molecule was adsorbed on higher chiral angle nanotubes the binding energy was increased. The study of the electronic structures and Mulliken analysis indicate that the methanol and CNT are interacting rather weakly, consistent with recent experimental observation.

  18. A molecular mechanics approach for analyzing tensile nonlinear deformation behavior of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Yu Wang; Daining Fang; Ai Kah Soh; Bin Liu

    2007-01-01

    In this paper, by capturing the atomic informa-tion and reflecting the behaviour governed by the nonlin-ear potential function, an analytical molecular mechanics approach is proposed. A constitutive relation for single-walled carbon nanotubes (SWCNT's) is established to describe the nonlinear stress-strain curve of SWCNT's and to predict both the elastic properties and breaking strain of SWCNT's during tensile deformation. An analysis based on the virtual internal bond (VIB) model proposed by P. Zhang et al. is also presented for comparison. The results indicate that the proposed molecular mechanics approach is indeed an acceptable analytical method for analyzing the mechanical behavior of SWCNT's.

  19. The compressive buckling and size effect of single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yuzhou, E-mail: yuzhousun@126.com; Zhu, Yanzhi; Li, Dongxia [Department of Civil Engineering and Architecture, Zhongyuan University of Technology, Zhengzhou (China)

    2015-03-10

    A higher-order Bernoulli-Euler beam model is developed to investigate the compressive buckling and size effect of single-walled carbon nanotubes by using a higher-order continuum relationship that has been previously proposed by the present authors. The second-order deformation gradients with respect to the axial direction are also considered, and the beam parameters are obtained by calculating the constitutive response around the circumference. The critical compressive force is analytically provided, and the size effect is studied by estimating the contribution of the higher-order terms.

  20. Hydrogenation of single-wall carbon nanotubes using polyamine reagents: combined experimental and theoretical study.

    Science.gov (United States)

    Miller, Glen P; Kintigh, Jeremy; Kim, Eunja; Weck, Philippe F; Berber, Savas; Tomanek, David

    2008-02-20

    We combine experimental observations with ab initio calculations to study the reversible hydrogenation of single-wall carbon nanotubes using high boiling polyamines as hydrogenation reagents. Our calculations characterize the nature of the adsorption bond and identify preferential adsorption geometries at different coverages. We find the barrier for sigmatropic rearrangement of chemisorbed hydrogen atoms to be approximately 1 eV, thus facilitating surface diffusion and formation of energetically favored, axially aligned adsorbate chains. Chemisorbed hydrogen modifies the structure and stability of nanotubes significantly and increases the inter-tube distance, thus explaining the improved dispersability in solvents like methanol, ethanol, chloroform, and benzene. PMID:18220395

  1. Defect-Induced Photoluminescence from Dark Excitonic States in Individual Single-Walled Carbon Nanotubes

    OpenAIRE

    Harutyunyan, Hayk; Gokus, Tobias; Green, Alexander A.; Hersam, Mark C.; Allegrini, Maria; Hartschuh, Achim

    2009-01-01

    We show that new low-energy photoluminescence (PL) bands can be created in the spectra of semiconducting single-walled carbon nanotubes by intense pulsed excitation. The new bands are attributed to PL from different nominally dark excitons that are “brightened” because of a defect-induced mixing of states with different parity and/or spin. Time-resolved PL studies on single nanotubes reveal a significant reduction of the bright exciton lifetime upon brightening of the dark excitons. The lowes...

  2. Solution-phase synthesis of chromium-functionalized single-walled carbon nanotubes

    KAUST Repository

    Kalinina, Irina V.

    2015-03-01

    The solution phase reactions of single-walled carbon nanotubes (SWNTs) with Cr(CO)6 and benzene-Cr(CO)3 can lead to the formation of small chromium clusters. The cluster size can be varied from less than 1 nm to about 4 nm by increasing the reaction time. TEM images suggest that the clusters are deposited predominantly on the exterior walls of the nanotubes. TGA analysis was used to obtain the Cr content and carbon to chromium ratio in the Cr-complexed SWNTs. It is suggested that the carbon nanotube benzenoid structure templates the condensation of chromium atoms and facilitates the loss of carbon monoxide leading to well defined metal clusters.

  3. Simulation of Young's modulus of single-walled carbon nanotubes by molecular dynamics

    International Nuclear Information System (INIS)

    Based on molecular dynamics (MD) simulation, the Young's moduli of carbon nanotubes are studied. The inter-atomic short-range interaction and long-range interaction of carbon nanotubes are represented by a second generation reactive empirical bond order (REBO) potential and Lennard-Jones (LJ) potential, respectively. The obtained potential expression is used to calculate the total potential energies of carbon nanotubes. Three types of single-walled carbon nanotubes (SWCNTs), armchair, zigzag and chiral tubules, are calculated, respectively. The computational results show that the Young's moduli of SWCNTs are in the range of 929.8±11.5 GPa. From the simulation, the Young's moduli of SWCNTs are weakly affected by the tube chirality and tube radius. The numeric results are in good agreement with the existing experimental results

  4. Estimation of mechanical properties of single wall carbon nanotubes using molecular mechanics approach

    Indian Academy of Sciences (India)

    P Subba Rao; Sunil Anandatheertha; G Narayana Naik; G Gopalakrishnan

    2015-06-01

    Molecular mechanics based finite element analysis is adopted in the current work to evaluate the mechanical properties of Zigzag, Armchair and Chiral Single wall Carbon Nanotubes (SWCNT) of different diameters and chiralities. Three different types of atomic bonds, that is Carbon–Carbon covalent bond and two types of Carbon–Carbon van der Waals bonds are considered in the carbon nanotube system. The stiffness values of these bonds are calculated using the molecular potentials, namely Morse potential function and Lennard-Jones interaction potential function respectively and these stiffness’s are assigned to spring elements in the finite element model of the CNT. The geometry of CNT is built using a macro that is developed for the finite element analysis software. The finite element model of the CNT is constructed, appropriate boundary conditions are applied and the behavior of mechanical properties of CNT is studied.

  5. Excitonic signatures in the optical response of single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Voisin, Christophe; Berger, Sebastien; Cassabois, Guillaume; Roussignol, Philippe [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS UMR8551, UPMC, Universite Paris Diderot, 24 rue Lhomond, 75005 Paris (France); Berciaud, Stephane [IPCMS, UMR 7504, CNRS Universite de Strasbourg, 23 rue du Loess, 67034 Strasbourg (France); Yan, Hugen; Hone, James; Heinz, Tony F. [Physics, Mechanical Engineering and Electrical Engineering Departments, Columbia University, New York, NY (United States); Lauret, Jean-Sebastien [Laboratoire de Photonique Quantique et Moleculaire, Ecole Normale Superieure de Cachan, CNRS UMR 8537, Institut Dalembert, 61 Avenue Wilson, Cachan (France)

    2012-05-15

    The optical properties of single-wall carbon nanotubes (SWNTs) are dominated by the excitonic character of the transitions even at room temperature. The very peculiar properties of these excitons arise from both the one-dimensional (1D) nature of carbon nanotubes and from the electronic properties of graphene from which nanotubes are made. We first propose a brief qualitative review of the structure of the excitonic manifold and emphasize the role of dark states. We describe recent experimental investigations of this excitonic structure by means of temperature dependent PL measurements. We investigate the case of upper sub-bands and show that high-order optical transitions remain excitonic for large diameter nanotubes. A careful investigation of Rayleigh scattering spectra at the single nanotube level reveals clear exciton-phonon side-bands and Lorentzian line profiles for all semi-conducting nanotubes. In contrast, metallic nanotubes show an ambivalent behavior which is related to the reduced excitonic binding energy. Schematic of the exciton manifold in single-wall carbon nanotubes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Theoretical calculations of thermophysical properties of single-wall carbon nanotube bundles

    International Nuclear Information System (INIS)

    Carbon nanotube bundles are promising thermal interfacial materials due to their excellent thermal and mechanical characteristics. In this study, the phonon dispersion relations and density of states of the single-wall carbon nanotube bundles are calculated by using the force constant model. The calculation results show that the inter-tube interaction leads to a significant frequency raise of the low frequency modes. To verify the applied calculation method, the specific heat of a single single-wall carbon nanotube is calculated first based on the obtained phonon dispersion relations and the results coincide well with the experimental data. Moreover, the specific heat of the bundles is calculated and exhibits a slight reduction at low temperatures in comparison with that of the single tube. The thermal conductivity of the bundles at low temperatures is calculated by using the ballistic transport model. The calculation results indicate that the inter-tube interaction, i.e. van der Waals interaction, hinders heat transfer and cannot be neglected at extremely low temperatures. For (5, 5) bundles, the relative difference of the thermal conductivity caused by ignoring inter-tube effect reaches the maximum value of 26% around 17 K, which indicates the significant inter-tube interaction effect on the thermal conductivity at low temperatures. (condensed matter: structural, mechanical, and thermal properties)

  7. Length-dependent optical properties of single-walled carbon nanotube samples

    Energy Technology Data Exchange (ETDEWEB)

    Naumov, Anton V. [Department of Chemistry and Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Ensysce Biosciences, Inc., 7000 Fannin St., Houston, TX 77030 (United States); Tsyboulski, Dmitri A.; Bachilo, Sergei M. [Department of Chemistry and Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Weisman, R. Bruce, E-mail: weisman@rice.edu [Department of Chemistry and Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, Houston, TX 77005 (United States)

    2013-08-30

    Highlights: ► Length-independent absorption per atom in single-walled carbon nanotubes. ► Reduced fluorescence quantum yield for short nanotubes. ► Exciton quenching at nanotube ends, sidewall defects probably limits quantum yield. - Abstract: Contradictory findings have been reported on the length dependence of optical absorption cross sections and fluorescence quantum yields in single-walled carbon nanotubes (SWCNTs). To clarify these points, studies have been made on bulk SWCNT dispersions subjected to length fractionation by electrophoretic separation or by ultrasonication-induced scission. Fractions ranged from ca. 120 to 760 nm in mean length. Samples prepared by shear-assisted dispersion were subsequently shortened by ultrasonic processing. After accounting for processing-induced changes in the surfactant absorption background, SWCNT absorption was found constant within ±11% as average nanotube length changed by a factor of 3.8. This indicates that the absorption cross-section per carbon atom is not length dependent. By contrast, in length fractions prepared by both methods, the bulk fluorescence efficiency or average quantum yield increased with SWCNT average length and approached an apparent asymptotic limit near 1 μm. This result is interpreted as reflecting the combined contributions of exciton quenching by sidewall defects and by the ends of shorter nanotubes.

  8. Hydrogen adsorption on metal-organic frameworks (MOFs) and single-walled carbon nanotubes (SWNTs)

    International Nuclear Information System (INIS)

    'Full text:' In recent years, several novel carbon-based microporous materials such as single-walled carbon nanotubes (SWNTs) and metal-organic frameworks (MOFs) have been proposed as promising adsorbents for hydrogen. Hydrogen adsorption measurements on Al-, Cr- and Zn-based metal-organic frameworks (MOFs) and single-walled carbon nanotubes (SWNTs) are presented. The measurements were performed at temperatures ranging from 77 to 300K and pressures up to 50 atm using a volumetric approach. The maximum excess adsorption at 77K ranges from 2,8 to 3,9 wt % for the MOFs and from 1,5 to 2,5 wt % for the SWNTs. These values are reached at pressures below 40 atm. At room temperature and 40 atm, modest amounts of hydrogen are adsorbed (< 0,4 wt %). A Dubinin-Astakhov (DA) approach is used to investigate the measured adsorption isotherms and retrieve energetic and structural parameters. The adsorption enthalpy averaged over filling is found to be about 2,9 kJ/mol for the MOF-5 and about 3,6 - 4,2 kJ/mol for SWNTs. The uptake of hydrogen on SWNTs and MOF-5 appears to be due to physisorption and can be described, through the DA-model, by a traditional theory of micropore filling. (author)

  9. Theoretical calculations of thermophysical properties of single-wall carbon nanotube bundles

    Institute of Scientific and Technical Information of China (English)

    Miao Ting-Ting; Song Meng-Xuan; Ma Wei-Gang; Zhang Xing

    2011-01-01

    Carbon nanotube bundles are promising thermal interfacial materials due to their excellent thermal and mechanical characteristics. In this study, the phonon dispersion relations and density of states of the single-wall carbon nanotube bundles are calculated by using the force constant model. The calculation results show that the inter-tube interaction leads to a significant frequency raise of the low frequency modes. To verify the applied calculation method, the specific heat of a single single-wall carbon nanotube is calculated first based on the obtained phonon dispersion relations and the results coincide well with the experimental data. Moreover, the specific heat of the bundles is calculated and exhibits a slight reduction at low temperatures in comparison with that of the single tube. The thermal conductivity of the bundles at low temperatures is calculated by using the ballistic transport model. The calculation results indicate that the inter-tube interaction, i.e. van der Waals interaction, hinders heat transfer and cannot be neglected at extremely low temperatures. For (5, 5) bundles, the relative difference of the thermal conductivity caused by ignoring inter-tube effect reaches the maximum value of 26% around 17 K, which indicates the significant inter-tube interaction effect on the thermal conductivity at low temperatures.

  10. Systematical analysis of mode-locked fiber lasers using single-walled carbon nanotube saturable absorbers

    International Nuclear Information System (INIS)

    The output characteristics of the Er-doped mode-locked fiber laser using a single-walled carbon nanotube saturable absorber are investigated theoretically with a nonlinear Schrödinger equation and a saturable absorption equation using realistic parameters. Stable self-starting mode-locking pulses are achieved under net normal, net zero, and net anomalous cavity group velocity dispersion (GVD) respectively. A spectrum with a flat top is obtained from the net normal cavity GVD laser while a spectrum with Kelly side-bands is obtained from the net anomalous cavity GVD laser. The characteristics of the pulse duration changing with cavity GVD and modulation depth of the single-walled carbon nanotubes are discussed. The characteristics of the mode-locking pulses from net normal, net zero, and net anomalous cavity GVD mode-locked fiber lasers are compared. These systematical results are useful for designing mode-locked fiber lasers with saturable absorbers made by different kinds of carbon nano-materials

  11. Microwave and Millimeter Wave Properties of Vertically-Aligned Single Wall Carbon Nanotubes Films

    Science.gov (United States)

    Haddadi, K.; Tripon-Canseliet, C.; Hivin, Q.; Ducournau, G.; Teo, E.; Coquet, P.; Tay, B. K.; Lepilliet, S.; Avramovic, V.; Chazelas, J.; Decoster, D.

    2016-05-01

    We present the experimental determination of the complex permittivity of vertically aligned single wall carbon nanotubes (SWCNTs) films grown on quartz substrates in the microwave regime from 10 MHz up to 67 GHz, with the electrical field perpendicular to the main axis of the carbon nanotubes (CNTs), based on coplanar waveguide transmission line approach together with the measurement of the microwave impedance of top metalized vertically—aligned SWCNTs grown on conductive silicon substrates up to 26 GHz. From coplanar waveguide measurements, we obtain a real part of the permittivity almost equal to unity, which is interpreted in terms of low carbon atom density (3 × 1019 at/cm3) associated with a very low imaginary part of permittivity (grown CNTs bundles.

  12. Electron paramagnetic resonance investigation of purified catalyst-free single-walled carbon nanotubes.

    Science.gov (United States)

    Zaka, Mujtaba; Ito, Yasuhiro; Wang, Huiliang; Yan, Wenjing; Robertson, Alex; Wu, Yimin A; Rümmeli, Mark H; Staunton, David; Hashimoto, Takeshi; Morton, John J L; Ardavan, Arzhang; Briggs, G Andrew D; Warner, Jamie H

    2010-12-28

    Electron paramagnetic resonance of single-walled carbon nanotubes (SWCNTs) has been bedevilled by the presence of paramagnetic impurities. To address this, SWCNTs produced by laser ablation with a nonmagnetic PtRhRe catalyst were purified through a multiple step centrifugation process in order to remove amorphous carbon and catalyst impurities. Centrifugation of a SWCNT solution resulted in sedimentation of carbon nanotube bundles containing clusters of catalyst particles, while isolated nanotubes with reduced catalyst particle content remained in the supernatant. Further ultracentrifugation resulted in highly purified SWCNT samples with a narrow diameter distribution and almost no detectable catalyst particles. Electron paramagnetic resonance (EPR) signals were detected only for samples which contained catalyst particles, with the ultracentrifuged SWCNTs showing no EPR signal at X-band (9.4 GHz) and fields < 0.4 T. PMID:21082779

  13. Ab-initio calculation of n-doped single-walled carbon nanotubes

    Science.gov (United States)

    Margine, Elena R.; Crespi, Vincent H.

    2004-03-01

    We study charge-induced changes in shape and electronic structure for n-doped single-walled carbon nanotubes within density functional theory. A certain nearly free electron state is downshifted in the presence of extra electrons. A similar effect has been seen in potassium-doped carbon nanotubes [1], where the downshift was attributed to the hybridization of the nearly free electron state with the K 4s state. In the present calculation the negative charge is neutralized by a uniform positive background, so the downshift must arise from a different effect. The state crosses the Fermi level at a charge per carbon atom of 0.04 for all the tubes studied. Connections are made to recent experiments in the group of P. Eklund.[1]Yoshiyuki Miyamoto, Angel Rubio, X. Blase, Marvin L. Cohen, and Steven G. Louie PRL 74, 2993 (1995)

  14. XPS Protocol for the Characterization of Pristine and Functionalized Single Wall Carbon Nanotubes

    Science.gov (United States)

    Sosa, E. D.; Allada, R.; Huffman, C. B.; Arepalli, S.

    2009-01-01

    Recent interest in developing new applications for carbon nanotubes (CNT) has fueled the need to use accurate macroscopic and nanoscopic techniques to characterize and understand their chemistry. X-ray photoelectron spectroscopy (XPS) has proved to be a useful analytical tool for nanoscale surface characterization of materials including carbon nanotubes. Recent nanotechnology research at NASA Johnson Space Center (NASA-JSC) helped to establish a characterization protocol for quality assessment for single wall carbon nanotubes (SWCNTs). Here, a review of some of the major factors of the XPS technique that can influence the quality of analytical data, suggestions for methods to maximize the quality of data obtained by XPS, and the development of a protocol for XPS characterization as a complementary technique for analyzing the purity and surface characteristics of SWCNTs is presented. The XPS protocol is then applied to a number of experiments including impurity analysis and the study of chemical modifications for SWCNTs.

  15. Electromechanical properties of single-walled carbon nanotube devices on micromachined cantilevers

    International Nuclear Information System (INIS)

    We have investigated the electromechanical properties of single-walled carbon nanotubes (SWNTs) by constructing carbon nanotube transistors on micro-cantilevers. SWNTs and ultra-long carbon nanotubes (UNTs) were grown on free-standing Si3N4 membranes by using chemical vapor deposition, and electrical contacts were generated with electron beam lithography and lift-off. The cantilevers bearing SWNT devices were micromachined so that hybrid cantilevers with various spring constants were fabricated. To measure the electromechanical properties of the SWNTs, precisely controlled forces were generated by a microbalance and applied to the hybrid cantilever devices. Upon bending, the conductances of the metallic and large-gap semiconducting UNTs showed no notable change, whereas the conductances of the small-gap semiconducting UNTs and networks of SWNTs increased. Numerical simulations of bended SWNT made using a multiscale simulator supported the hypothesis that the small-gap semiconducting SWNTs undergo a metallic transformation upon bending. (paper)

  16. Electrochemical impedance-based DNA sensor using a modified single walled carbon nanotube electrode

    International Nuclear Information System (INIS)

    Carbon nanotubes have become promising functional materials for the development of advanced electrochemical biosensors with novel features which could promote electron-transfer with various redox active biomolecules. This paper presents the detection of Salmonella enterica serovar Typhimurium using chemically modified single walled carbon nanotubes (SWNTs) with single stranded DNA (ssDNA) on a polished glassy carbon electrode. Hybridization with the corresponding complementary ssDNA has shown a shift in the impedance studies due to a higher charge transfer in ssDNA. The developed biosensor has revealed an excellent specificity for the appropriate targeted DNA strand. The methodologies to prepare and functionalize the electrode could be adopted in the development of DNA hybridization biosensor.

  17. Electrochemical impedance-based DNA sensor using a modified single walled carbon nanotube electrode

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Jessica E. [Department of Mechanical Engineering, University of South Florida, Tampa, FL (United States); Nanomaterials and Nanomanufacturing Research Center, University of South Florida, Tampa, FL (United States); Pillai, Shreekumar [Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL (United States); Ram, Manoj Kumar, E-mail: mkram@usf.edu [Department of Mechanical Engineering, University of South Florida, Tampa, FL (United States); Nanomaterials and Nanomanufacturing Research Center, University of South Florida, Tampa, FL (United States); Kumar, Ashok [Department of Mechanical Engineering, University of South Florida, Tampa, FL (United States); Nanomaterials and Nanomanufacturing Research Center, University of South Florida, Tampa, FL (United States); Singh, Shree R. [Center for NanoBiotechnology Research, Alabama State University, Montgomery, AL (United States)

    2011-07-20

    Carbon nanotubes have become promising functional materials for the development of advanced electrochemical biosensors with novel features which could promote electron-transfer with various redox active biomolecules. This paper presents the detection of Salmonella enterica serovar Typhimurium using chemically modified single walled carbon nanotubes (SWNTs) with single stranded DNA (ssDNA) on a polished glassy carbon electrode. Hybridization with the corresponding complementary ssDNA has shown a shift in the impedance studies due to a higher charge transfer in ssDNA. The developed biosensor has revealed an excellent specificity for the appropriate targeted DNA strand. The methodologies to prepare and functionalize the electrode could be adopted in the development of DNA hybridization biosensor.

  18. Radius dependence of the melting temperature of single-walled carbon nanotubes: molecular-dynamics simulations

    International Nuclear Information System (INIS)

    We have investigated the radius dependence of the melting temperature of single-walled carbon nanotubes (SWCNTs) by classical molecular-dynamics (MD) simulations using the environment-dependent interatomic potential (EDIP) proposed by Marks. Here we define the 'melting temperature' as a temperature at which there occurs a thermal instability of SWCNTs. We have carried out molecular-dynamics simulations at several temperatures for carbon nanotubes with various radii and estimated the 'melting temperature' based on the temperature dependence of the radial distribution functions, mean-square displacements and atomic configurations. It is shown that the 'melting temperature' of SWCNTs decreases with decreasing radius. The origin of this radius dependence of the melting temperature of SWCNTs is discussed in relation to the stability of SWCNTs energetically based on the strain energy of carbon nanotubes

  19. Visualizing the growth dynamics of individual single-wall carbon nanotubes

    DEFF Research Database (Denmark)

    Wagner, Jakob Birkedal; Zhang, Lili; He, Maoshuai;

    In order to meet the increasing demand of faster and more flexible electronics and optical devices and at the same time decrease the use of the critical metals, carbon based devices are in fast development. Single walled carbon nanotube (SWCNT) based electronics is a way of addressing the...... environment friendly approach of faster and better electronics. In order to exploit the potential of SWCNTs in the electronic industry fully, selective growth of either conducting or semiconducting tubes is of high importance. Understanding the mechanism for growth of SWCNTs is of great importance for...... around the studied sample at elevated temperature gives a unique way of monitoring gas-solid interactions such as CNT growth. Here we show the direct experimental evidence on the growth dynamics of SW-CNTs from Co/MgO catalysts using CO as carbon source inside the environmental TEM. The evolution of the...

  20. Selective adsorption of proteins on single-wall carbon nanotubes by using a protective surfactant.

    Science.gov (United States)

    Knyazev, Anton; Louise, Loïc; Veber, Michèle; Langevin, Dominique; Filoramo, Arianna; Prina-Mello, Adriele; Campidelli, Stéphane

    2011-12-16

    The dispersion of highly hydrophobic carbon materials such as carbon nanotubes in biological media is a challenging issue. Indeed, the nonspecific adsorption of proteins occurs readily when the nanotubes are introduced in biological media; therefore, a methodology to control adsorption is in high demand. To address this issue, we developed a bifunctional linker derived from pyrene that selectively enables or prevents the adsorption of proteins on single-wall carbon nanotubes (SWNTs). We demonstrated that it is possible to decrease or completely suppress the adsorption of proteins on the nanotube sidewall by using proper functionalization (either covalent or noncovalent). By subsequently activating the functional groups on the nanotube derivatives, protein adsorption can be recovered and, therefore, controlled. Our approach is simple, straightforward, and potentially suitable for other biomolecules that contain thio or amino groups available for coupling. PMID:22095560

  1. Comparative Study of Adsorption Isotherms of Vitamin C on Multi wall and single wall Carbon Nanotube

    Directory of Open Access Journals (Sweden)

    Azin Dehmolaei

    2014-03-01

    Full Text Available We have studied the interaction of Vitamin C solution on multi-wall and single-wall carbon nanotubeAfter investigated comparative study and assigned to Vitamin C adsorption isotherm. The adsorption equilibrium isotherms were fitted by Freundlich, Langmuir, and Temkin models. It was found that the Langmuirmodel described the adsorption process better than other two isotherm models. The amount of Antioxidant drug(Vitamin C adsorbed on Multi wallcarbon nanotube surface increased with the increase of the initial Antioxidant concentration. Based on the results, under similar conditions the efficiency of adsorption of Vitamin C by Multi-wall carbon nanotube(MWCNTs was more thansingle-wall carbon nanotube.

  2. Raman study on single-walled carbon nanotubes with different laser excitation energies

    Indian Academy of Sciences (India)

    S S Islam; Khurshed Ahmad Shah; H S Mavi; A K Shaukla; S Rath; Harsh

    2007-06-01

    The industrial use of carbon nanotubes is increasing day by day; therefore, it is very important to identify the nature of carbon nanotubes in a bundle. In this study, we have used the Raman spectroscopic analysis on vertically aligned single-walled carbon nanotubes (SWCNTs) grown by the chemical vapour deposition (CVD) technique. The grown sample is excited with two laser excitation wavelengths, 633 nm from He–Ne laser and 514.5 nm from Ar+ laser. Raman spectrum in the backscattering geometry provides the characteristic spectra of SWCNTs with its radial breathing mode (RBM), defect-induced disorder mode (D band), and highenergy modes (G and M bands). The Raman signal positions of the spectra in RBM, G and M bands confirm the grown sample to be of semiconducting type in nature.

  3. Interaction between fullerene halves Cn (n ≤ 40) and single wall carbon nanotube

    Science.gov (United States)

    Sharma, Amrish; Kaur, Sandeep; Mudahar, Isha

    2016-05-01

    We have investigated the structural and electronic properties of carbon nanotube with small fullerene halves Cn (n ≤ 40) which are covalently bonded to the side wall of an armchair single wall carbon nanotube (SWCNT) using first principle method based on density functional theory. The fullerene size results in weak bonding between fullerene halves and carbon nanotube (CNT). Further, it was found that the C-C bond distance that attaches the fullerene half and CNT is of the order of 1.60 Å. The calculated binding energies indicate the stability of the complexes formed. The HOMO-LUMO gaps and electron density of state plots points towards the metallicity of the complex formed. Our calculations on charge transfer reveal that very small amount of charge is transferred from CNT to fullerene halves.

  4. Electronic structure of single-walled carbon nanotubes inside helical DNA wraps

    Science.gov (United States)

    Snyder, Stacy; Rotkin, Slava

    2007-03-01

    Single stranded DNA can helically wrap a single-walled carbon nanotube (SWNT) leading to changes in electronic structure, which is the subject of our study. Other charged polymers may produce band gap modulation similar to that observed for DNA-SWNT complexes. For these hybrids we assume a regular helical wrap, the potential of which breaks the symmetry of the pristine SWNT. Band structure changes are modeled quantum mechanically using the tight binding method together with self-consistent electrostatics. Gap modulation and band structure symmetry-lowering effects may result in variation of the optical spectra, especially for (slightly forbidden) transverse optical transitions. The effect of environmental screening of charges is investigated. Self-consistent electrostatic calculations yield cohesion energy between a charged, regular wrap and a SWNT of the order of tenths of eV per DNA base [1]. [1] Snyder, S. E., and Rotkin, S. V., Polarization Component of Cohesion Energy in Single-Wall Carbon Nanotube-DNA Complexes, JETP Letters 84, 348 (2006).

  5. Composite of single walled carbon nanotube and sulfosalicylic acid doped polyaniline: a thermoelectric material

    Science.gov (United States)

    Jana Chatterjee, Mukulika; Banerjee, Dipali; Chatterjee, Krishanu

    2016-08-01

    Nanocomposites containing single walled carbon nanotubes (SWCNTs) and highly ordered polyaniline (PANI) have been synthesized employing an in situ polymerization using different weight percentages of single-walled carbon nanotube (SWCNT) as template and aniline as a reactant. The composites show homogeneously dispersed SWCNTs which are uniformly coated with PANI through a strong interface interaction. Structural characterization shows that the PANI cultivated along the surface of the SWCNTs in an ordered manner during the SWCNT-directed polymerization process. Measurements at room temperature displayed a significant enhancement in both the electrical conductivity and thermoelectric power which could be attributed to the more ordered chain structures of the PANI on SWCNT. As a result, the power factor of the composite is improved which increases with temperature. At the same time, the measured value of thermal conductivity at room temperature being lowest among the reported values, has resulted in best ZT at room temperature. The lowest value of thermal conductivity is attributed to the large phonon scattering due to the introduction of nanointerfaces.

  6. Selective uptake of single-walled carbon nanotubes by circulating monocytes for enhanced tumour delivery

    Science.gov (United States)

    Smith, Bryan Ronain; Ghosn, Eliver Eid Bou; Rallapalli, Harikrishna; Prescher, Jennifer A.; Larson, Timothy; Herzenberg, Leonore A.; Gambhir, Sanjiv Sam

    2014-06-01

    In cancer imaging, nanoparticle biodistribution is typically visualized in living subjects using `bulk' imaging modalities such as magnetic resonance imaging, computerized tomography and whole-body fluorescence. Accordingly, nanoparticle influx is observed only macroscopically, and the mechanisms by which they target cancer remain elusive. Nanoparticles are assumed to accumulate via several targeting mechanisms, particularly extravasation (leakage into tumour). Here, we show that, in addition to conventional nanoparticle-uptake mechanisms, single-walled carbon nanotubes are almost exclusively taken up by a single immune cell subset, Ly-6Chi monocytes (almost 100% uptake in Ly-6Chi monocytes, below 3% in all other circulating cells), and delivered to the tumour in mice. We also demonstrate that a targeting ligand (RGD) conjugated to nanotubes significantly enhances the number of single-walled carbon nanotube-loaded monocytes reaching the tumour (P < 0.001, day 7 post-injection). The remarkable selectivity of this tumour-targeting mechanism demonstrates an advanced immune-based delivery strategy for enhancing specific tumour delivery with substantial penetration.

  7. Decolorisation of Reactive Red 120 Dye by Using Single-Walled Carbon Nanotubes in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Edris Bazrafshan

    2013-01-01

    Full Text Available Dyes are one of the most hazardous chemical compound classes found in industrial effluents and need to be treated since their presence in water bodies reduces light penetration, precluding the photosynthesis of aqueous flora. In the present study, single-walled carbon nanotubes (SWCNTs was used as an adsorbent for the successful removal of Reactive Red 120 (RR-120 textile dye from aqueous solutions. The effect of various operating parameters such as initial concentration of dye, contact time, adsorbent dosage and initial pH was investigated in order to find the optimum adsorption conditions. Equilibrium isotherms were used to identify the possible mechanism of the adsorption process. The optimum pH for removing of RR-120 dye from aqueous solutions was found to be 5 and for this condition maximum predicted adsorption capacity for RR-120 dye was obtained as 426.49 mg/g. Also, the equilibrium data were also fitted to the Langmuir, Freundlich and BET equilibrium isotherm models. It was found that the data fitted to BET (R2=0.9897 better than Langmuir (R2=0.9190 and Freundlich (R2=0.8819 model. Finally it was concluded that the single-walled carbon nanotubes can be used for dye removal from aqueous solutions.

  8. Removal of Reactive Blue 29 Dye from Water by Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    M Jahangiri rad

    2011-01-01

    Full Text Available "n "nBackgrounds and Objectives: Anthraquinone dyes such as reactive blue29 in water resources and industrial wastewater effluents are one of the most environmental setbacks in many countries. Various methods have been considered to remove these dyes One of which is adsorption."nMaterials and Methods: All adsorption experiments were conducted in different pHs and various concentrations of adsorbents. The initial concentration of reactive blue 29 chosen in this study was 30mg/L.Adsorption isotherms were determined and correlated with Longmuir, Freundlich and BET models."nResults: The maximum adsorption capacity of reactive blue 29 onto single wall carbon nanotubes was 496mg/g.Results showed that the best pH for adsorption was 5 followed by pH3 and 8. Kinetic study showed that the equilibrium time for adsorption of RB 29 to SWCNT is 4 hr."nConclusion:According to the results obtained BET isotherm fitted well the experiment. It shows the adsorption of reactive blue 29 onto single wall carbon nanotubes is multilayers and the mechanism of SWCNTs adsorption toward RB29 is based on weak van der waals forces.

  9. Structural stability of transparent conducting films assembled from length purified single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    J. M. Harris; G. R. S. Iyer; D. O. Simien; J. A. Fagan; J. Y. Huh; J. Y. Chung; S. D. Hudson; J. Obrzut; J. F. Douglas; C. M. Stafford; E. K. Hobbie

    2011-01-01

    Single-wall carbon nanotube (SWCNT) films show significant promise for transparent electronics applications that demand mechanical flexibility, but durability remains an outstanding issue. In this work, thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are uniaxially and isotropically compressed by depositing them on prestrained polymer substrates. Upon release of the strain, the topography, microstructure, and conductivity of the films are characterized using a combination of optical/fluorescence microscopy, light scattering, force microscopy, electron microscopy, and impedance spectroscopy. Above a critical surface mass density, films assembled from nanotubes of well-defined length exhibit a strongly nonlinear mechanical response. The measured strain dependence reveals a dramatic softening that occurs through an alignment of the SWCNTs normal to the direction of prestrain, which at small strains is also apparent as an anisotropic increase in sheet resistance along the same direction. At higher strains, the membrane conductivities increase due to a compression-induced restoration of conductive pathways. Our measurements reveal the fundamental mode of elasto-plastic deformation in these films and suggest how it might be suppressed.

  10. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    Science.gov (United States)

    Yuan, Hengguang; Hu, Shanglian; Huang, Peng; Song, Hua; Wang, Kan; Ruan, Jing; He, Rong; Cui, Daxiang

    2011-12-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  11. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    Directory of Open Access Journals (Sweden)

    Huang Peng

    2011-01-01

    Full Text Available Abstract Herein we are the first to report that single-walled carbon nanotubes (SWCNTs exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  12. Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes

    Science.gov (United States)

    He, Xiaowei; Gao, Weilu; Xie, Lijuan; Li, Bo; Zhang, Qi; Lei, Sidong; Robinson, John M.; Hároz, Erik H.; Doorn, Stephen K.; Wang, Weipeng; Vajtai, Robert; Ajayan, Pulickel M.; Adams, W. Wade; Hauge, Robert H.; Kono, Junichiro

    2016-07-01

    The one-dimensional character of electrons, phonons and excitons in individual single-walled carbon nanotubes leads to extremely anisotropic electronic, thermal and optical properties. However, despite significant efforts to develop ways to produce large-scale architectures of aligned nanotubes, macroscopic manifestations of such properties remain limited. Here, we show that large (>cm2) monodomain films of aligned single-walled carbon nanotubes can be prepared using slow vacuum filtration. The produced films are globally aligned within ±1.5° (a nematic order parameter of ∼1) and are highly packed, containing 1 × 106 nanotubes in a cross-sectional area of 1 μm2. The method works for nanotubes synthesized by various methods, and film thickness is controllable from a few nanometres to ∼100 nm. We use the approach to create ideal polarizers in the terahertz frequency range and, by combining the method with recently developed sorting techniques, highly aligned and chirality-enriched nanotube thin-film devices. Semiconductor-enriched devices exhibit polarized light emission and polarization-dependent photocurrent, as well as anisotropic conductivities and transistor action with high on/off ratios.

  13. Functionalization of single-walled carbon nanotubes regulates their effect on hemostasis

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, A V; Aseychev, A V; Kostevich, V A; Gusev, A A; Gusev, S A; Vlasova, I I, E-mail: irina.vlasova@yahoo.com [Research Institute for Physico-Chemical Medicine, FMBA, M. Pirogovskaya Str. 1a, Moscow (Russian Federation)

    2011-04-01

    Applications of single-walled carbon nanotubes (SWNTs) in medical field imply the use of drug-coupled carbon nanotubes as well as carbon nanotubes functionalized with different chemical groups that change nanotube surface properties and interactions between nanotubes and cells. Covalent attachment of polyethylene glycol (PEG) to carboxylated single-walled carbon nanotubes (c-SWNT) is known to prevent the nanotubes from interaction with macrophages. Here we characterized nanotube's ability to stimulate coagulation processes in platelet-poor plasma (PPP), and evaluated the effect of SWNTs on platelet aggregation in platelet-rich plasma (PRP). Our study showed that PEG-SWNT did not affect the rate of clotting in PPP, while c-SWNT shortened the clot formation time five times compared to the control PPP. Since c-SWNT failed to accelerate coagulation in plasma lacking coagulation factor XI, it may be suggested that c-SWNT affects the contact activation pathway. In PRP, platelets responded to both SWNT types with irreversible aggregation, as evidenced by changes in the aggregate mean radius. However, the rate of aggregation induced by c-SWNT was two times higher than it was with PEG-SWNT. Cytological analysis also showed that c-SWNT was two times more efficient when compared to PEG-SWNT in aggregating platelets in PRP. Taken together, our results show that functionalization of nanoparticles can diminish their negative influence on blood cells. As seen from our data, modification of c-SWNT with PEG, when only a one percent of carbon atoms is bound to polymer (70 wt %), decreased the nanotube-induced coagulation in PRP and repelled the accelerating effect on the coagulation in PPP. Thus, when functionalized SWNTs are used for administration into bloodstream of laboratory animals, their possible pro-coagulant and pro-aggregating properties must be taken into account.

  14. Thermodynamics and structure of hydrogen, methane, argon, oxygen and carbon dioxide adsorbed on single wall carbon nanotube bundles

    International Nuclear Information System (INIS)

    Isosteric heat of adsorption and neutron diffraction measurements of hydrogen, methane, argon, oxygen and carbon dioxide adsorbed on single wall carbon nanotube bundles show that all adsorbates, except CO2, condense first on high-energy binding sites like the grooves and the widest interstitial channels and then on the outer rounded surface of the bundles. As for CO2, only one set of adsorption sites is observed, which is attributed to the grooves and/or the interstitial channels

  15. Initial stage of growth of single-walled carbon nanotubes: modeling and simulations

    International Nuclear Information System (INIS)

    Because there are different pathways to grow carbon nanotubes (CNTs), a common mechanism for the synthesis of CNTs does not likely exist. However, after carbon atoms are liberated from carbon-containing precursors by catalysts or from pure carbon systems, a common feature, the nucleation of CNTs by electron mediation, does appear. We studied this feature using the initial stage of growth of single wall CNTs (SWCNTs) by transition metal nano-particle catalysts as the working example. To circumvent the bottleneck due to the size and simulation time, we used a model in which the metal droplet is represented by a jellium, and the effect of collisions between the carbon atoms and atoms of the catalyst is captured by charge transfers between the jellium and the carbon. The simulations were performed using a transferable semi-empirical Hamiltonian to model the interactions between carbon atoms in jellium. We annealed different initial configurations of carbon clusters in jellium as well as in a vacuum. We found that in jellium, elongated open tubular structures, precursors to the growth of SWCNTs, are formed. Our model was also shown to be capable of mimicking the continued growth when more atoms were placed near the open end of the tubular structure. (paper)

  16. Effects of Two Purification Pretreatments on Electroless Copper Coating over Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Zhong Zheng

    2014-01-01

    Full Text Available To achieve the reinforcement of copper matrix composite by single-walled carbon nanotubes, a three-step-refluxing purification of carbon nanotubes sample with HNO3-NaOH-HCl was proposed and demonstrated. A previously reported purification process using an electromagnetic stirring with H2O2/HCl mixture was also repeated. Then, the purified carbon nanotubes were coated with copper by the same electroless plating process. At the end, the effects of the method on carbon nanotubes themselves and on copper coating were determined by transmission electron microscope spectroscopy, scanning electron microscope spectroscopy, X-ray diffractometry, thermogravimetric analysis, Fourier transformed infrared spectroscopy, and energy dispersive spectrometry. It was clearly confirmed that both of the two processes could remove most of iron catalyst particles and carbonaceous impurities without significant damage to carbon nanotubes. The thermal stability of the sample purified by H2O2/HCl treatment was slightly higher than that purified by HNO3-NaOH-HCl treatment. Nevertheless, the purification by HNO3-NaOH-HCl treatment was more effective for carboxyl functionalization on nanotubes than that by H2O2/HCl treatment. The Cu-coating on carbon nanotubes purified by both purification processes was complete, homogenous, and continuous. However, the Cu-coating on carbon nanotubes purified by H2O2/HCl was oxidized more seriously than those on carbon nanotubes purified by HNO3-NaOH-HCl treatment.

  17. Effect of charge on the stability of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    LUO; Ji; WU; Jinlei

    2004-01-01

    By using density-functional-theory based DMol3 code, the structure optimizations are performed on a short charged single-walled carbon nanotube. Results show that the total energy of the nanotube exhibits a parabolic variation with respect to the amount of extra charge, and one negatively charged nanotube has the lowest total energy; thus the carbon nanotube has a positive electron affinity. When the charge is small, the variation of the atomic structure of the nanotube is also small, and neglecting the atomic structure variation leads to the qualitatively correct properties of the total energy and the energy of the highest occupied molecular orbital. When the extra charge is large, the end structure of the nanotube will be first affected and form into a trumpet shape. With the increasing of the extra charge, the nanotube end gradually becomes unstable, and this may lead to the ultimate destruction of the nanotube.

  18. Growth dynamics of inner tubes inside cobaltocene-filled single-walled carbon nanotubes

    Science.gov (United States)

    Kharlamova, M. V.; Kramberger, Christian; Saito, Takeshi; Shiozawa, Hidetsugu; Pichler, Thomas

    2016-08-01

    We have synthesized cobaltocene-filled 1.7-nm-mean diameter single-walled carbon nanotubes (SWCNTs) and transformed them into double-walled carbon nanotubes by annealing at temperatures between 500 and 1000 °C for 2 h in vacuum. We analyze the temperature-dependent inner tube growth inside the filled SWCNTs by Raman spectroscopy. The changes in intensity of the Raman peaks of inner tubes with the diameters ranging from 0.832 to 1.321 nm with increasing annealing temperature are traced. It is revealed that the growth temperatures of larger diameter inner tubes are higher than the ones of smaller diameter tubes. A decrease in the diameter of the inner tubes by ~0.4 nm leads to a decrease in the growth temperature by ~200 °C.

  19. Self-assembly of single walled carbon nanotubes onto cotton to make conductive yarn

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Yee Yuan Tan; Chengwei Wu; S. Ravi P. Silva

    2012-01-01

    A simple,economical and scalable technique is demonstrated to make conductive yarn.Single walled carbon nanotubes (SWCNTs) are non-covalently functionalized with dye (Acid Red 91) and dispersed in water; while cotton yarn is treated with poly (ethylene imine).When the resulting yarn is immersed in the SWCNT dispersion,SWCNTs self-assemble onto the yarn due to electrostatic forces between the functionalized nanotubes and yarn.Scanning electron microscopy,transmission electron microscopy and Raman spectroscopy indicate the assembly of carbon nanotubes.The SWCNT functionalized yarn exhibits reasonable electrical conduction behaviour and are then used to make chemiresistors.The electrical resistance of the chemiresistors used as sensors increases on exposure to ammonia gas,which can be explained in terms of electron transfer between gas molecules and SWCNTs.

  20. Interfacial Surfactant Ordering in Thin Films of SDS-Encapsulated Single-Walled Carbon Nanotubes.

    Science.gov (United States)

    Das, Sushanta K; Sengupta, Sanghamitra; Velarde, Luis

    2016-01-21

    The molecular self-assembly of surfactants on the surface of single-walled carbon nanotubes (SWCNT) is currently a common strategy for the tuning of nanotube properties and the stabilization of carbon nanotube dispersions. Here, we report direct measurements of the degree of interfacial ordering for sodium dodecyl sulfate (SDS) surfactants adsorbed on colloidal, single-chirality enriched, SWCNTs within a solid film and investigate the dependence of surface alkyl chain order on the surfactant concentration in the precursor solution. The degree of order for the SWCNT-bound SDS molecules, is probed by vibrational sum frequency generation (VSFG) spectroscopy. We find concrete evidence for the presence of highly ordered surface structures at sufficiently high SDS concentrations, attributed here to cylindrical-like micelle assemblies with the SWCNT at the core. As the SDS concentration decreases, the interfacial order is found to decrease as well, generating a more disordered or random adsorption of surfactants on the nanotube surfaces. PMID:26730991

  1. Photon antibunching in single-walled carbon nanotubes at telecommunication wavelengths and room temperature

    International Nuclear Information System (INIS)

    We investigated the photoluminescence of individual air-suspended single-walled carbon nanotubes (SWNTs) from 6 to 300 K. Time-resolved and antibunching measurements over the telecommunication wavelength range were performed using a superconducting single-photon detector. We detected moderate temperature independent antibunching behavior over the whole temperature range studied. To investigate the exciton dynamics, which is responsible for the antibunching behavior, we measured excitation-power and temperature dependence of the photoluminescence spectra and lifetime decay curves. These measurements suggested an exciton confinement effect that is likely caused by high-dielectric amorphous carbon surrounding the SWNTs. These results indicate that SWNTs are good candidates for light sources in quantum communication technologies operating in the telecommunication wavelength range and at room temperature

  2. Electrochemical investigation of NO at single-wall carbon nanotubes modified electrodes

    Indian Academy of Sciences (India)

    Tingliang Xia; Hongmei Bi; Keying Shi

    2010-05-01

    The NO electro-oxidation was investigated at various single-wall carbon nanotubes (SWCNTs) modified electrodes by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Compared with the glassy carbon electrode, the SWCNTs modified electrodes possess higher electro-catalytic activity to NO electro-oxidation. CV results indicate that the peak current density of NO electro-oxidation at the SWCNT-COOH (SWCNTs with carboxyl groups) modified electrode is the highest and the peak potential is the most negative among the four kinds of electrodes. EIS indicates that the charge transfer resistance of NO electro-oxidation at the SWCNT-COOH modified electrode is the least. The determined factors (charge transfer and mass transfer of diffusion) of NO electro-oxidation are different in varied potential region. The mechanism of NO electro-oxidation reaction at the SWCNTs modified electrodes is also discussed.

  3. Role of the catalyst in the growth of single-wall carbon nanotubes.

    Science.gov (United States)

    Balbuena, Perla B; Zhao, Jin; Huang, Shiping; Wang, Yixuan; Sakulchaicharoen, Nataphan; Resasco, Daniel E

    2006-05-01

    Classical molecular dynamics simulations are carried out to analyze the physical state of the catalyst, and the growth of single-wall carbon nanotubes under typical temperature and pressure conditions of their experimental synthesis, emphasizing the role of the catalyst/substrate interactions. It is found that a strong cluster/substrate interaction increases the cluster melting point, modifying the initial stages of carbon dissolution and precipitation on the cluster surface. Experiments performed on model Co-Mo catalysts clearly illustrate the existence of an initial period where the catalyst is formed and no nanotube growth is observed. To quantify the nature of the Co-Mo2C interaction, quantum density functional theory is applied to characterize structural and energetic features of small Co clusters deposited on a (001) Mo2C surface, revealing a strong attachment of Co-clusters to the Mo2C surface, which may increase the melting point of the cluster and prevent cluster sintering. PMID:16792351

  4. Magnetic-field-induced diameter-selective synthesis of single-walled carbon nanotubes.

    Science.gov (United States)

    Su, Yanjie; Zhang, Yaozhong; Wei, Hao; Zhang, Liling; Zhao, Jiang; Yang, Zhi; Zhang, Yafei

    2012-03-01

    We report a facile and scalable approach to synthesize single-walled carbon nanotubes (SWNTs) with selected diameter distribution by applying a magnetic field perpendicular to the electric field in the arc plasma region. It is found that this magnetic field-induced diameter-selectivity strategy enables the control of the SWNTs with different diameter distributions in different regions, and the diameter-selective efficiency could be enhanced by modifying the direction of magnetic field. Our results indicate that the motions of the catalysts with different particle sizes, positive carbon ions and electrons are significantly influenced by the magnetic field and electromagnetic force, resulting in the different nucleation and growth processes of SWNTs due to the collective interactions between the magnetic field and arc plasma. This approach would enable a viable route towards the synthesis of SWNTs with desired diameter through the tuning of arc parameters in the arc discharge process. PMID:22301844

  5. Effects of residual aberrations explored on single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    The effects of geometric residual aberrations such as coma B2 and two-fold astigmatism A1 on the contrast in aberration corrected high resolution transmission electron microscopy (HRTEM) images are investigated on single-walled carbon nanotubes (SWNT). The individual aberrations are adjusted and set up manually using an imaging CS-corrector. We demonstrate how coma B2 can be recognized by an experienced user directly in the image and how it blurs the contrast. Even with uncorrected (resolution limiting) spherical aberration CS the coma B2 has to be considered and must be minimized. Limits for a tolerable coma are given. The experiments are confirmed by image simulations. -- Highlights: ► Individual effects of residual aberrations such as B2, A1, and CS are demonstrated. ► Experimental HRTEM and simulated images of carbon nanotubes are compared. ► A detection limit of 50 nm B2 in a single HRTEM image is determined.

  6. Molecular dynamics simulation of thermal conductivity of single-wall carbon nanotubes

    International Nuclear Information System (INIS)

    Based on equilibrium molecular dynamics (EMD) simulation method, the thermal conductivity of single-wall carbon nanotubes (SWNTs) dependent on tube length and temperature is investigated. Nonequilibrium molecular dynamics (NEMD) simulations are also carried out as comparison at 1000 K. Through extrapolation to an infinite system size, the data from the NEMD method are in the same order of the simulated results calculated from the EMD model. The effects of isotopic atom and vacancy on the thermal conductivity of carbon nanotubes (CNTs) are also investigated from EMD simulation results. It is demonstrated that the vacancy scattering on phonons is stronger than the isotopic atom doing at the same concentration, which causes more reduction on lattice thermal conductivity of CNTs

  7. Compressive characteristics of single walled carbon nanotube with water interactions investigated by using molecular dynamics simulation

    International Nuclear Information System (INIS)

    The elastic properties of single walled carbon nanotube (SWCNT) with surrounding water interactions are studied using molecular dynamics simulation technique. The compressive loading characteristic of carbon nanotubes (CNTs) in a fluidic medium such as water is critical for its role in determining the lifetime and stability of CNT based nano-fluidic devices. In this paper, we conducted a comprehensive analysis on the effect of geometry, chirality and density of encapsulated water on the elastic properties of SWCNT. Our studies show that defect density and distribution can strongly impact the compressive resistance of SWCNTs in water. Further studies were conducted on capped SWCNTs with varying densities of encapsulated water, which is necessary to understand the strength of CNT as a potential drug carrier. The results obtained from this paper will help determining the potential applications of CNTs in the field of nano-electromechanical systems (NEMS) such as nano-biological and nano-fluidic devices.

  8. Covalent sidewall functionalization of single-walled carbon nanotubes: a photoreduction approach.

    Science.gov (United States)

    Wei, Liangming; Zhang, Yafei

    2007-12-12

    Covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) via photoreduction of aromatic ketones by alcohols is reported for the first time. Irradiation of benzophenone, benzhydrol and SWNTs in benzene resulted in covalent attachment of benzhydrol to the sidewalls of the SWNTs. A variety of tools were used to characterize the functionalized SWNTs. Raman scattering, UV-visible and near-IR spectroscopy confirm the covalent nature of the sidewall functionalization. Attenuated total reflection (ATR) FTIR and NMR provided evidence for attachment of benzhydrol onto the sidewalls of nanotubes. Thermogravimetric analysis (TGA) showed that the degree of functionalization was about one benzhydrol in 52 sidewall carbons. A long-chain hydrocarbon marker (n-C(18)H(35)) was also grafted onto the functional groups by esterification reaction for high-resolution TEM (HRTEM) visualization. PMID:20442484

  9. Covalent sidewall functionalization of single-walled carbon nanotubes: a photoreduction approach

    International Nuclear Information System (INIS)

    Covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) via photoreduction of aromatic ketones by alcohols is reported for the first time. Irradiation of benzophenone, benzhydrol and SWNTs in benzene resulted in covalent attachment of benzhydrol to the sidewalls of the SWNTs. A variety of tools were used to characterize the functionalized SWNTs. Raman scattering, UV-visible and near-IR spectroscopy confirm the covalent nature of the sidewall functionalization. Attenuated total reflection (ATR) FTIR and NMR provided evidence for attachment of benzhydrol onto the sidewalls of nanotubes. Thermogravimetric analysis (TGA) showed that the degree of functionalization was about one benzhydrol in 52 sidewall carbons. A long-chain hydrocarbon marker (n-C18H35) was also grafted onto the functional groups by esterification reaction for high-resolution TEM (HRTEM) visualization

  10. Single-walled carbon nanotube networks for flexible and printed electronics

    International Nuclear Information System (INIS)

    Networks of single-walled carbon nanotubes (SWNTs) can be processed from solution and have excellent mechanical properties. They are highly flexible and stretchable. Depending on the type of nanotubes (semiconducting or metallic) they can be used as replacements for metal or transparent conductive oxide electrodes or as semiconducting layers for field-effect transistors (FETs) with high carrier mobilities. They are thus competitive alternatives to other solution-processable materials for flexible and printed electronics. This review introduces the basic properties of SWNTs, current methods for dispersion and separation of metallic and semiconducting SWNTs and techniques to deposit and pattern dense networks from dispersion. Recent examples of applications of carbon nanotubes as conductors and semiconductors in (opto-)electronic devices and integrated circuits will be discussed. (paper)

  11. Local-gated single-walled carbon nanotube field effect transistors assembled by AC dielectrophoresis

    International Nuclear Information System (INIS)

    We present a simple and scalable technique for the fabrication of solution processed and local-gated carbon nanotube field effect transistors (CNT-FETs). The approach is based on the directed assembly of individual single-walled carbon nanotubes from dichloroethane via AC dielectrophoresis (DEP) onto pre-patterned source and drain electrodes with a local aluminum gate in the middle. Local-gated CNT-FET devices display superior performance compared to a global back gate with on-off ratios >104 and maximum subthreshold swings of 170 mV/dec. The local bottom-gated DEP-assembled CNT-FETs will facilitate large-scale fabrication of complementary metal-oxide-semiconductor (CMOS) compatible nanoelectronic devices

  12. Compressive characteristics of single walled carbon nanotube with water interactions investigated by using molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, C.H., E-mail: chwong@ntu.edu.sg; Vijayaraghavan, V.

    2014-01-24

    The elastic properties of single walled carbon nanotube (SWCNT) with surrounding water interactions are studied using molecular dynamics simulation technique. The compressive loading characteristic of carbon nanotubes (CNTs) in a fluidic medium such as water is critical for its role in determining the lifetime and stability of CNT based nano-fluidic devices. In this paper, we conducted a comprehensive analysis on the effect of geometry, chirality and density of encapsulated water on the elastic properties of SWCNT. Our studies show that defect density and distribution can strongly impact the compressive resistance of SWCNTs in water. Further studies were conducted on capped SWCNTs with varying densities of encapsulated water, which is necessary to understand the strength of CNT as a potential drug carrier. The results obtained from this paper will help determining the potential applications of CNTs in the field of nano-electromechanical systems (NEMS) such as nano-biological and nano-fluidic devices.

  13. Controlling the growth of vertically aligned single walled carbon nanotubes from ethanol for electrochemical supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Azam, M.A.; Mohamed, M.A.; Shikoh, E.; Fujiwara, A.; Shimoda, T. [Japan Advanced Inst. of Science and Technology, Ishikawa (Japan)

    2010-07-01

    Single-walled carbon nanotubes (SWCNTs) have been proven suitable for use as electrodes in electrochemical capacitors (EC). In this study, alcohol catalytic chemical vapor deposition (ACCVD) was used to grow vertically-aligned SWCNTs (VASWCNTs). An aluminium oxide (Al{sub 2}O{sub 3})-supported cobalt (Co) catalyst and high purity ethanol carbon feedstock was used for the growth process. The Al layer and Co thin films were deposited using an electron beam evaporator. CNT growth was optimized using Si/SiO{sub 2} substrates. An atomic force microscope, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were used to characterize the synthesis of the catalyst nanoparticles and their subsequent growth. Raman spectrum of the samples demonstrated peaks of radial breathing mode (RBM) from 100 to 250 per cm. Results demonstrated that the CNTs were successfully grown on the conducting metal substrate using the ACCVD process. 4 refs.

  14. Torsional characteristics of graphene nanoribbons encapsulated in single-walled carbon nanotubes

    Science.gov (United States)

    Fang, Te-Hua; Chang, Win-Jin; Feng, Yu-Lun; Lu, Deng-Maw

    2016-09-01

    Molecular dynamics (MD) simulations were performed to study the torsional characteristics of a graphene nanoribbon encapsulated in a single-walled carbon nanotube (GNR@SWCNT) with different chiralities at different temperatures. Based on the simulations, the relationship between the shear stress and the twist angle was obtained. The maximum shear stress increases with an increase in chirality. However, the corresponding twist angle decreases with increasing chirality. GNR@SWCNT withstands a smaller twist angle compared with a single SWCNT. In addition, the interaction force between the GNR and the SWCNT increases with increasing temperature. GNR@SWCNT at an elevated temperature is easier to break during torsion with a lower twist angle. The results are valuable for the design of nanocomposites composed of carbon nanotubes and graphene materials.

  15. Enzymatic formation of carbohydrate rings catalyzed by single-walled carbon nanotubes.

    Science.gov (United States)

    Hyun, Moon Seop; Park, Jong Pil; Seo, Dongkyun; Chang, Sung-Jin; Lee, Seok Jae; Lee, Sang Yup; Kwak, Kyungwon; Park, Tae Jung

    2016-05-01

    Macrocyclic carbohydrate rings were formed via enzymatic reactions around single-walled carbon nanotubes (SWNTs) as a catalyst. Cyclodextrin glucanotransferase, starch substrate and SWNTs were reacted in buffer solution to yield cyclodextrin (CD) rings wrapped around individual SWNTs. Atomic force microscopy showed the resulting complexes to be rings of 12-50 nm in diameter, which were highly soluble and dispersed in aqueous solution. They were further characterized by Raman and Fourier transform infrared spectroscopy and molecular simulation using density functional theory calculation. In the absence of SWNT, hydrogen bonding between glucose units determines the structure of maltose (the precursor of CD) and produces the curvature along the glucose chain. Wrapping SWNT along the short axis was preferred with curvature in the presence of SWNTs and with the hydrophobic interactions between the SWNTs and CD molecules. This synthetic approach may be useful for the functionalization of carbon nanotubes for development of nanostructures. PMID:26946491

  16. Synthesis and characterization of platinum nanoparticles on single-walled Carbon nanotube 'nanopaper' support

    International Nuclear Information System (INIS)

    We prepared several samples of carbon-nanotube-supported Pt nanoparticles that are potentially promising electrocatalysts for hydrogen fuel cells. Commercially obtained single-walled carbon nanotubes (SWNTs) were characterized by Raman Spectroscopy, SEM, TEM, EDS, and XANES. This multi-technique characterization allowed us to quantify the size and composition of metal impurities (Mo, Co) in SWNTs, to choose the best method to remove them, and characterize the effectiveness of their removal. After synthesizing a 'nanopaper' (10-20 micrometer thick, free standing sheets of self-assembled SWNTs) we decorated it with Pt nanoparticles by electroless deposition. Formation of Pt nanoparticles was verified by EXAFS, and quantitative information about their size and structure was obtained.

  17. Enzyme-catalyzed oxidation facilitates the return of fluorescence for single-walled carbon nanotubes.

    Science.gov (United States)

    Chiu, Cheuk Fai; Barth, Brian A; Kotchey, Gregg P; Zhao, Yong; Gogick, Kristy A; Saidi, Wissam A; Petoud, Stéphane; Star, Alexander

    2013-09-11

    In this work, we studied enzyme-catalyzed oxidation of single-walled carbon nanotubes (SWCNTs) produced by the high-pressure carbon monoxide (HiPco) method. While oxidation via strong acids introduced defect sites on SWCNTs and suppressed their near-infrared (NIR) fluorescence, our results indicated that the fluorescence of SWCNTs was restored upon enzymatic oxidation, providing new evidence that the reaction catalyzed by horseradish peroxidase (HRP) in the presence of H2O2 is mainly a defect-consuming step. These results were further supported by both UV-vis-NIR and Raman spectroscopy. Therefore, when acid oxidation followed by HRP-catalyzed enzyme oxidation was employed, shortened (applications in cellular NIR imaging and drug delivery systems. PMID:23672715

  18. Controlled Growth of Semiconducting and Metallic Single-Wall Carbon Nanotubes.

    Science.gov (United States)

    Liu, Chang; Cheng, Hui-Ming

    2016-06-01

    Single-wall carbon nanotubes (SWCNTs) can be either semiconducting or metallic depending on their chiral angles and diameters. The use of SWCNTs in electronics has long been hindered by the fact that the as-prepared SWCNTs are usually a mixture of semiconducting and metallic ones. Therefore, controlled synthesis of SWCNTs with a uniform electrical type or even predefined chirality has been a focus of carbon nanotube research in recent years. In this Perspective, we summarize recent progress on the controlled growth of semiconducting and metallic SWCNTs by in situ selective etching and by novel catalyst design. The advantages and mechanisms of these approaches are analyzed, and the challenges are discussed. Finally, we predict possible breakthroughs and future trends in the controlled synthesis and applications of SWCNTs. PMID:27149629

  19. Optical properties of dimeric liquid crystals doped with single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Well oriented distinct local single crystals were grown in smectic C liquid crystal (LC) (heptyloxybenzoic acid – 7OBA) using predefined orientation of the single-walled carbon nanotubes (SWCNT). The SWCNT/SiOx/ITO/glass surface is found to cause a substantial enlargement of the smectic C distinct local single crystals and to reinforce both surface memory effect and surface anchoring. We synthesized and examined a set of nanocomposites, built of LC with hydrogen-bonded in dimers molecules (7OBA) and SWCNT. We found that the surface orientation strength and the interaction of the dimeric molecules with the carbon nanotubes play a decisive role for the type (symmetry), thermal stability and chirality of the LC states induced in the nanocomposites. As a result, a set of phase transitions and new phases (chiral smectic C, reentrant nematic, reentrant chiral nematic and a unique low-temperature chiral biaxial fluid smectic phase CG) not typical for pristine 7OBA were found.

  20. Growth of metal-catalyst-free nitrogen-doped metallic single-wall carbon nanotubes.

    Science.gov (United States)

    Li, Jin-Cheng; Hou, Peng-Xiang; Zhang, Lili; Liu, Chang; Cheng, Hui-Ming

    2014-10-21

    Nitrogen-doped (N-doped) single-wall carbon nanotubes (SWCNTs) were synthesized by chemical vapor deposition using SiOx nanoparticles as a catalyst and ethylenediamine as the source of both carbon and nitrogen. The N-doped SWCNTs have a mean diameter of 1.1 nm and a narrow diameter range, with 92% of them having diameters from 0.7 to 1.4 nm. Multi-wavelength laser Raman spectra and temperature-dependent electrical resistance indicate that the SWCNT sample is enriched with metallic nanotubes. These N-doped SWCNTs showed excellent electrocatalytic activity for the oxygen reduction reaction and highly selective and sensitive sensing ability for dopamine detection. PMID:25189467

  1. Swift heavy ion induced modifications of single walled carbon nanotube thin films

    Science.gov (United States)

    Vishalli; Raina, K. K.; Avasthi, D. K.; Srivastava, Alok; Dharamvir, Keya

    2016-04-01

    Thin films of single walled carbon nanotubes (SWCNTs) were prepared by Langmuir-Blodgett method and irradiated with swift heavy ions, carbon and nickel each of energy 60 MeV. The ion beams have different electronic energy loss (Se) values and the samples were exposed to various irradiation doses. The irradiated films were characterized using Raman and optical absorption spectroscopy. Raman spectroscopy results indicate the competing processes of defect creation and healing (annealing) of SWCNTs at lower fluences, while at higher fluences defect creation or damage dominates. In UV-Vis-NIR spectroscopy we find that there is decrease in the intensity of characteristic peaks with every increasing fluence, indicating decrease in the optically active states with irradiation.

  2. Energy Band Gap Study of Semiconducting Single Walled Carbon Nanotube Bundle

    Science.gov (United States)

    Elkadi, Asmaa; Decrossas, Emmanuel; El-Ghazaly, Samir

    2013-01-01

    The electronic properties of multiple semiconducting single walled carbon nanotubes (s-SWCNTs) considering various distribution inside a bundle are studied. The model derived from the proposed analytical potential function of electron density for na individual s-SWCNT is general and can be easily applied to multiple nanotubes. This work demonstrates that regardless the number of carbon nanotubes, the strong coupling occurring between the closet neighbors reduces the energy band gap of the bundle by 10%. As expected, the coupling is strongly dependent on the distance separating the s-SWCNTs. In addition, based on the developed model, it is proposed to enhance this coupling effect by applying an electric field across the bundle to significantly reduce the energy band gap of the bundle by 20%.

  3. Photon antibunching in single-walled carbon nanotubes at telecommunication wavelengths and room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Takumi, E-mail: endou@az.appi.keio.ac.jp; Ishi-Hayase, Junko; Maki, Hideyuki, E-mail: maki@appi.keio.ac.jp [Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522 (Japan)

    2015-03-16

    We investigated the photoluminescence of individual air-suspended single-walled carbon nanotubes (SWNTs) from 6 to 300 K. Time-resolved and antibunching measurements over the telecommunication wavelength range were performed using a superconducting single-photon detector. We detected moderate temperature independent antibunching behavior over the whole temperature range studied. To investigate the exciton dynamics, which is responsible for the antibunching behavior, we measured excitation-power and temperature dependence of the photoluminescence spectra and lifetime decay curves. These measurements suggested an exciton confinement effect that is likely caused by high-dielectric amorphous carbon surrounding the SWNTs. These results indicate that SWNTs are good candidates for light sources in quantum communication technologies operating in the telecommunication wavelength range and at room temperature.

  4. Ultrafast nonlinear photoresponse of single-wall carbon nanotubes: a broadband degenerate investigation

    Science.gov (United States)

    Xu, Shuo; Wang, Fengqiu; Zhu, Chunhui; Meng, Yafei; Liu, Yujie; Liu, Wenqing; Tang, Jingyi; Liu, Kaihui; Hu, Guohua; Howe, Richard C. T.; Hasan, Tawfique; Zhang, Rong; Shi, Yi; Xu, Yongbing

    2016-04-01

    Understanding of the fundamental photoresponse of carbon nanotubes has broad implications for various photonic and optoelectronic devices. Here, Z-scan and pump-probe spectroscopy performed across 600-2400 nm were combined to give a broadband `degenerate' mapping of the nonlinear absorption properties of single-wall carbon nanotubes (SWNTs). In contrast to the views obtained from non-degenerate techniques, sizable saturable absorption is observed from the visible to the near-infrared range, including the spectral regions between semiconducting excitonic peaks and metallic tube transitions. In addition, the broadband mapping unambiguously reveals a photobleaching to photoinduced absorption transition feature within the first semiconducting excitonic band ~2100 nm, quantitatively marking the long-wavelength cut-off for saturable absorption of the SWNTs investigated. Our findings present a much clearer physical picture of SWNTs' nonlinear absorption characteristics, and help provide updated design guidelines for SWNT based nonlinear optical devices.Understanding of the fundamental photoresponse of carbon nanotubes has broad implications for various photonic and optoelectronic devices. Here, Z-scan and pump-probe spectroscopy performed across 600-2400 nm were combined to give a broadband `degenerate' mapping of the nonlinear absorption properties of single-wall carbon nanotubes (SWNTs). In contrast to the views obtained from non-degenerate techniques, sizable saturable absorption is observed from the visible to the near-infrared range, including the spectral regions between semiconducting excitonic peaks and metallic tube transitions. In addition, the broadband mapping unambiguously reveals a photobleaching to photoinduced absorption transition feature within the first semiconducting excitonic band ~2100 nm, quantitatively marking the long-wavelength cut-off for saturable absorption of the SWNTs investigated. Our findings present a much clearer physical picture of

  5. Ion Transport Characteristics of Individual Single-walled Carbon Nanotubes Mimic Those of Biological Ion Channels

    Science.gov (United States)

    Amiri, Hasti; Shepard, Kenneth; Nuckolls, Colin

    2014-03-01

    Transmembrane ionic channels play a crucial role in vital cellular activities by regulating the transport of ions and fluid across the cell membrane. Their structural complexity and flexibility as well as their many unique operational features, however, make their investigation extremely difficult. The simple, atomically smooth and well-defined structure of carbon nanotubes (CNTs) provides an excellent template for studying molecular transport at nanoscale. Additionally, CNTs have been suggested as analogues to biological pores since they share several common features such as nanometer size diameter, hydrophobic core and ultrafast water flow. Functionalizing the nanotube entrance can also mimic the selectivity filter of ion channels. In this work, we experimentally study ionic transport through individual single-walled CNTs connecting two fluid reservoirs as a function of pore properties and electrolyte type and concentration. We provide strong evidence that the electrostatic potentials arising from the ionized carboxyl groups at the pore entrance significantly influence the ion permeation in a manner consistent with a simple electrostatic mechanism. Lastly, the similarities of ionic transport mechanisms between individual single-walled CNTs and protein ion channels are discussed.

  6. Mechanism of Synthesis of Ultra-Long Single Wall Carbon Nanotubes in Arc Discharge Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Keidar, Michael [George Washington University

    2013-06-23

    In this project fundamental issues related to synthesis of single wall carbon nanotubes (SWNTs), which is relationship between plasma parameters and SWNT characteristics were investigated. Given that among plasma-based techniques arc discharge stands out as very advantageous in several ways (fewer defects, high flexibility, longer lifetime) this techniques warrants attention from the plasma physics and plasma technology standpoint. Both experimental and theoretical investigations of the plasma and SWNTs synthesis were conducted. Experimental efforts focused on plasma diagnostics, measurements of nanostructures parameters, and nanoparticle characterization. Theoretical efforts focused to focus on multi-dimensional modeling of the arc discharge and single wall nanotube synthesis in arc plasmas. It was demonstrated in experiment and theoretically that controlling plasma parameters can affect nanostucture synthesis altering SWNT properties (length and diameter) and leading to synthesis of new structures such as a few-layer graphene. Among clearly identified parameters affecting synthesis are magnetic and electric fields. Knowledge of the plasma parameters and discharge characteristics is crucial for ability to control synthesis process by virtue of both magnetic and electric fields. New graduate course on plasma engineering was introduced into curriculum. 3 undergraduate students were attracted to the project and 3 graduate students (two are female) were involved in the project. Undergraduate student from Historically Black University was attracted and participated in the project during Summer 2010.

  7. Chemometric determination of the length distribution of single walled carbon nanotubes through optical spectroscopy

    International Nuclear Information System (INIS)

    Highlights: ► Optical spectroscopy is used as a convenient tool to analyze the length distribution of single walled carbon nanotubes. ► Advanced multivariate chemometric methods are compared, and the best methods can satisfactorily predict the length distribution. ► The entire length distribution, not just the mean, is modelled and calibrated. - Abstract: Current synthesis methods for producing single walled carbon nanotubes (SWCNTs) do not ensure uniformity of the structure and properties, in particular the length, which is an important quality indicator of SWCNTs. As a result, sorting SWCNTs by length is an important post-synthesis processing step. For this purpose, convenient analysis methods are needed to characterize the length distribution rapidly and accurately. In this study, density gradient ultracentrifugation was applied to prepare length-sorted SWCNT suspensions containing individualized surfactant-wrapped SWCNTs. The length of sorted SWCNTs was first determined by atomic force microscope (AFM), and their absorbance was measured in ultraviolet–visible near-infrared (UV–vis-NIR) spectroscopy. Chemometric methods are used to calibrate the spectra against the AFM-measured length distribution. The calibration model enables convenient analysis of the length distribution of SWCNTs through UV–vis-NIR spectroscopy. Various chemometric techniques are investigated, including pre-processing methods and non-linear calibration models. Extended inverted signal correction, extended multiplicative signal correction and Gaussian process regression are found to provide good prediction of the length distribution of SWCNTs with satisfactory agreement with the AFM measurements. In summary, spectroscopy in conjunction with advanced chemometric techniques is a powerful analytical tool for carbon nanotube research.

  8. Study on electroactive and electrocatalytic surfaces of single walled carbon nanotube-modified electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Salinas-Torres, David [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Huerta, Francisco [Departamento de Ingenieria Textil y Papelera, Universidad Politecnica de Valencia, Plaza Ferrandiz y Carbonell, 1. E-03801 Alcoy (Spain); Montilla, Francisco, E-mail: francisco.montilla@ua.e [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain); Morallon, Emilia [Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante, Universidad de Alicante, Apdo. de Correos 99, E-03080 Alicante (Spain)

    2011-02-01

    An investigation of the electrocatalysis of single-walled carbon nanotubes modified electrodes has been performed in this work. Nanotube-modified electrodes present a surface area much higher than the bare glassy carbon surfaces as determined by capacitance measurements. Several redox probes were selected for checking the reactivity of specific sites at the carbon nanotube surface. The presence of carbon nanotubes on the electrode improves the kinetics for all the reactions studied compared with the bare glassy carbon electrode with variations of the heterogeneous electron transfer rate constant up to 5 orders of magnitude. The most important effects are observed for the benzoquinone/hydroquinone and ferrocene/ferricinium redox couples, which show a remarkable improvement of their electron transfer kinetics on SWCNT-modified electrodes, probably due to strong {pi}-{pi} interaction between the organic molecules and the walls of the carbon nanotubes. For many of the reactions studied, less than 1% of the nanotube-modified electrode surface is transferring charge to species in solution. This result suggests that only nanotube tips are active sites for the electron transfer in such cases. On the contrary, the electroactive surface for the reactions of ferrocene and quinone is higher indicating that the electron transfer is produced also from the nanotube walls.

  9. Reptation dynamics of single-walled carbon nanotubes in a permanent network

    Science.gov (United States)

    Fakhri, Nikta; Mackintosh, Fred; Cognet, Laurent; Lounis, Brahim; Pasquali, Matteo

    2010-03-01

    Single-walled carbon nanotubes (SWCNTs) are an ideal system of semiflexible filaments with tunable bending stiffness. By exploiting their near-infrared fluorescence, we image directly the motion of SWCNTs in a network (agarose gel). We determine the SWCNT diameter (and bending stiffness) spectroscopically, and we control the network pore size by changing the agarose concentration. Image analysis shows clearly that SWCNTs move by reptation through the pore network. We quantify the dependence of SWCNTs mobility on SWCNT bending stiffness, length and pore sizes. Our results show conclusively that, even when the SWCNT length is much smaller than the persistence length, the flexibility of filaments enhances rotational diffusion. These results confirm earlier predictions of Odijk (1983), and show that the Doi-Edwards scaling fails to capture the filaments' motion. This study provides a fundamental understanding of reptation dynamics of semiflexible filaments.

  10. Attachment of functionalized single-walled carbon nanotubes (SWNTs) to silicon surfaces.

    Science.gov (United States)

    Zeng, Liling; Pattyn, Nancy; Barron, Andrew R

    2008-03-01

    Single-walled carbon nanotubes (SWNTs) were functionalized by direct fluorination and subsequent reaction with 6-aminohexanoic acid for water-soluble carboxylic acid functionalized SWNTs (AHA-SWNTs). Both of the compounds were used as precursors to attach SWNTs to APTES coated silicon surfaces. AHA-SWNTs in aqueous solution were reacted with APTES self-assembled monolayers (SAMs) with coupling reagents N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS). The surface coverage is a function of concentration of AHA-SWNTs, solvent and coupling method. While for the fluorinated SWNTs (F-SWNTs), direct addition of F-SWNTs to preformed APTES SAMs at 90 degrees C shows essentially no reaction, in contrast to the one-pot reaction of F-SWNTs with APTES molecules in the presence of SWNTs on a silicon substrate. This reaction route provides a convenient method to attach SWNTs to silicon surfaces. PMID:18468188

  11. Adhesion energy of single wall carbon nanotube loops on various substrates

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tianjun [Université de Lyon, Laboratoire de Physique, ENS de Lyon, CNRS-46, Allée d' Italie, Lyon 69364 (France); Department of Physics, Shaoxing University, 508 Huancheng West Rd., Shaoxing 312000 (China); Ayari, Anthony [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Bellon, Ludovic, E-mail: ludovic.bellon@ens-lyon.fr [Université de Lyon, Laboratoire de Physique, ENS de Lyon, CNRS-46, Allée d' Italie, Lyon 69364 (France)

    2015-04-28

    The physics of adhesion of one-dimensional nano structures such as nanotubes, nano wires, and biopolymers on different substrates is of great interest for the study of biological adhesion and the development of nano electronics and nano mechanics. In this paper, we present force spectroscopy experiments of individual single wall carbon nanotube loops using a home-made interferometric atomic force microscope. Characteristic force plateaus during the peeling process allow the quantitative measurement of the adhesion energy per unit length on various substrates: graphite, mica, platinum, gold, and silicon. Moreover, using a time-frequency analysis of the deflection of the cantilever, we estimate the dynamic stiffness of the contact, providing more information on the nanotube configurations and its intrinsic mechanical properties.

  12. Near-complete phase transfer of single-wall carbon nanotubes by covalent functionalization

    Indian Academy of Sciences (India)

    Bhalchandra Kakade; Sanjay Patil; Bhaskar Sathe; Suresh Gokhale; Vijayamohanan Pillai

    2008-11-01

    We describe here an efficient phase transfer of single wall carbon nanotubes (SWNTs) from aqueous to non-aqueous media using a unique amide functionalization route, where water soluble SWNTs (2.6 mg/mL) are effectively transferred to solvents like chloroform, toluene and CS2. A maximum of 30 wt% of oxygenated groups have been generated on the side walls by rapid microwave treatment, leading to a solubility of more than 2.6 mg/mL in water. Approximate surface amine coverage of 50% has been accomplished after oxalyl chloride treatment as inferred from thermogravimetry and X-ray photoelectron spectroscopy by controlling several key parameters associated with the extent of functionalization including purity of the sample, temperature and time.

  13. Photoinduced charge transfer and acetone sensitivity of single-walled carbon nanotube-titanium dioxide hybrids.

    Science.gov (United States)

    Ding, Mengning; Sorescu, Dan C; Star, Alexander

    2013-06-19

    The unique physical and chemical properties of single-walled carbon nanotubes (SWNTs) make them ideal building blocks for the construction of hybrid nanostructures. In addition to increasing the material complexity and functionality, SWNTs can probe the interfacial processes in the hybrid system. In this work, SWNT-TiO2 core/shell hybrid nanostructures were found to exhibit unique electrical behavior in response to UV illumination and acetone vapors. By experimental and theoretical studies of UV and acetone sensitivities of different SWNT-TiO2 hybrid systems, we established a fundamental understanding on the interfacial charge transfer between photoexcited TiO2 and SWNTs as well as the mechanism of acetone sensing. We further demonstrated a practical application of photoinduced acetone sensitivity by fabricating a microsized room temperature acetone sensor that showed fast, linear, and reversible detection of acetone vapors with concentrations in few parts per million range. PMID:23734594

  14. Torsional vibration of single-walled carbon nanotubes using doublet mechanics

    Science.gov (United States)

    Fatahi-Vajari, Alireza; Imam, Ali

    2016-08-01

    This paper investigates the torsional vibration of single-walled carbon nanotubes (SWCNTs) using a new approach based on doublet mechanics (DM) incorporating explicitly scale parameter and chiral effects. A fourth-order partial differential equation that governs the torsional vibration of nanotubes is derived. Using DM, an explicit equation for the natural frequency in terms of geometrical and mechanical property of CNTs is obtained for both the Zigzag and Armchair nanotube for the torsional vibration mode. It is shown that chiral effects along with the scale parameter play a significant role in the vibration behavior of SWCNTs in torsional vibration mode. Such effects decrease the natural frequency obtained by DM compared to the classical continuum mechanics and nonlocal theory predictions. However, with increase in the length and/or the radius of the tube, the effect of the chiral and scale parameter on the natural frequency decreases.

  15. Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field.

    Science.gov (United States)

    García-García, Amanda; Vergaz, Ricardo; Algorri, José F; Zito, Gianluigi; Cacace, Teresa; Marino, Antigone; Otón, José M; Geday, Morten A

    2016-01-01

    Single-wall carbon nanotubes (SWCNT) are anisotropic nanoparticles that can cause modifications in the electrical and electro-optical properties of liquid crystals. The control of the SWCNT concentration, distribution and reorientation in such self-organized fluids allows for the possibility of tuning the liquid crystal properties. The alignment and reorientation of CNTs are studied in a system where the liquid crystal orientation effect has been isolated. Complementary studies including Raman spectroscopy, microscopic inspection and impedance studies were carried out. The results reveal an ordered reorientation of the CNTs induced by an electric field, which does not alter the orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules. PMID:27547599

  16. X-ray Absorption Improvement of Single Wall Carbon Nanotube through Gadolinium Encapsulation

    Science.gov (United States)

    Alimin; Narsito, I.; Kartini; Santosa, S. J.

    2016-02-01

    X-ray absorption improvement of single-wall carbon nanotube (SWCNT) through gadolinium (Gd) encapsulation has been studied. The liquid phase adsorption using ethanol has been performed for the doping treatment. The Gd-doped SWCNT (Gd@SWCNT) was characterized by nitrogen adsorption isotherms, Raman spectroscopy, Transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) techniques. A relatively high residual weight of Gd@SWCNT compared to non-doped SWCNT (n-SWCNT) indicated that Gd has been doped in the nanotube. Even though Gd nanoparticles could not be observed clearly by TEM image, however, a significant decrease of nitrogen uptakes at low pressure and RBM (Radial Breathing Mode) upshift of Raman spectra of Gd@SWCNT specimen suggest that the metal nanoparticles might be encapsulated in the internal tube spaces of the nanotube. It was found that Gd-doped in the SWCNT increased significantly mass attenuation coefficient of the nanotube.

  17. Single-walled carbon nanotube electromechanical switching behavior with shoulder slip

    International Nuclear Information System (INIS)

    Several electromechanical devices, each consisting of a small bundle of single-walled carbon nanotubes suspended over an actuation electrode, have been fabricated and operated electrically. The nanotubes are assembled on the electrodes using dielectrophoresis, a potential high-rate nanomanufacturing process. A large decrease in the threshold voltage was seen after the first actuation. This is a result of the nanotubes sliding inward on their supports as they are pulled down toward the actuation electrode, leaving slack in the nanotube bundle for subsequent actuations. The electrical measurements agree well with an electromechanical model that uses a literature-reported value of the shear stress between the nanotubes and the SiO2 shoulders. Electrical measurements were performed in dry nitrogen as a large build-up of contamination was seen when the measurements were performed in lab air. We present measurements as well as a detailed mechanics model that support the interpretation of the data.

  18. Non-radiative Exciton Decay in Single-walled Carbon Nanotubes

    Science.gov (United States)

    Harrah, Mark; Swan, Anna

    2010-03-01

    Experiments have shown step-wise changes in the fluorescence intensity from single-walled carbon nanotubes [1,2]. It has been proposed that the underlying mechanism for the step-wise changes is diffusion-limited quenching of excitons at defects [1]. This property has been used to demonstrate single-molecule detection for biological applications [3]. We perform a Monte-Carlo simulation of nanotube fluorescence with a diffusion-limited quenching model. The fluorescence intensity is seen to depend on the mean-square distance between defects, implying a nonlinear dependence on the number of defects. The intensity for consecutive defect counts can overlap depending on the positions of the defects. [4pt] [1] Cognet, L. et al. Science 316, 1465-1468 (2007).[0pt] [2] Jin, H. et al. Nano Lett. 8, 4299-4304 (2008).[0pt] [3] Heller, D. A. et al. Nature Nanotech. 4, 114-120 (2009).

  19. ULTRAHIGH MAGNETIC FIELD OPTICAL STUDY OF SINGLE-WALLED CARBON NANOTUBES FILM

    Directory of Open Access Journals (Sweden)

    Mukhtar Effendi

    2012-02-01

    Full Text Available Excitons in Single-Walled Carbon Nanotubes (SWNTs have emerged as an ideal candidate for exploring one-dimensional (1-D exciton physics. Exciton states which dominate optical properties of SWNTs even at room temperature, are not clarify yet. The optical absorption spectra of aligned SWNTs films under ultra high magnetic fields up to 190 T are examined to investigate this issue. Shifting and splitting of the absorption peaks due to Aharonov-Bohm effect was observed clearly above 80 T in the configuration where the magnetic fields were applied in parallel to the alignment of SWNTs. The lowest singlet exciton state has been determined through the analysis of energy splitting of excitons by the application of magnetic fields.   Keywords: blue shift, optically active, optically inactive, red shift, single-turn coil system

  20. Nonlinear free vibration of single walled Carbone NanoTubes conveying fluid

    Directory of Open Access Journals (Sweden)

    Azrar A.

    2014-04-01

    Full Text Available Nonlinear free vibration of single-walled carbon nanotubes (CNTs conveying fluid are modeled and numerically simulated based on von Kármán geometric nonlinearity and Eringen’s nonlocal elasticity theory. The CNTs are modelled as nanobeams where the effects of transverse shear deformation and rotary inertia are considered within the framework of Timoshenko beam theory. The governing equations and boundary conditions are derived using the Hamilton’s principle and the nonlinear equation of motion is solved by the Galerkin’s method. The small scale parameter and the fluid-tube interaction effects on the dynamic behaviours of the CNT-fluid system as well as the instabilities induced by the fluid-velocity can be investigated. The critical fluid-velocity and frequency-amplitude relationships as well as the flutter and divergence instability types and the associated time responses are obtained based on the presented methodological approach.

  1. Investigation on optical absorption properties of ion irradiated single walled carbon nanotubes

    International Nuclear Information System (INIS)

    In the present study change in the optical absorption properties of single walled carbon nanotubes (SWCNTs) under nickel ion (60 MeV) irradiation at various fluences has been investigated. Langmuir Blodgett technique is used to deposit SWCNT thin film of uniform thickness. AFM analysis shows a network of interconnected bundles of nanotubes. UV-Vis-NIR absorption spectra indicate that the sample mainly contain SWCNTs of semiconducting nature. It has been found in absorption spectra that there is decrease in the intensity of the characteristic SWCNT peaks with increase in fluence. At fluence value 1×1014 ions/cm2 there is almost complete suppression of the characteristic SWCNTs peaks.The decrease in the optical absorption with increase in fluence is due to the increase in the disorder in the system which leads to the decrease in optically active states

  2. Debundling of single-walled carbon nanotubes by using natural polyelectrolytes

    International Nuclear Information System (INIS)

    Natural polyelectrolytes (NPs), including sodium lignosulfonate, humic acid and so forth, are reported for the first time to solubilize single-walled carbon nanotubes (SWNTs) in water through a noncovalent interaction. A variety of methods, including transmission electron microscopy (TEM), visible-near-infrared (vis-NIR) spectra, Raman spectra and zeta potential measurements, were used to characterize the NP-dispersed SWNT solutions. It is found that the SWNTs can be exfoliated into thin bundles or individual tubes, even at NP concentrations as low as 0.15 mg ml-1. Their high performance is attributed to the abundance of aromatic groups and ionized groups in the NP molecules. This method of solubilization opens the way for exploiting new natural materials as SWNT solubilizers and may find applications in nanocomposites, self-assembly, and so forth

  3. Light radiation through a transparent cathode plate with single-walled carbon nanotube field emitters

    International Nuclear Information System (INIS)

    In the conventional carbon nanotube backlight units (CNT-BLUs), light passes through the phosphor-coated anode glass plate, which thus faces closely the thin film transistor (TFT) backplate of a liquid crystal display panel. This configuration makes heat dissipation structurally difficult because light emission and heat generation occur simultaneously at the anode. We propose a novel configuration of a CNT-BLU where the cathode rather than the anode faces the TFT backplate by turning it upside down. In this design, light passes through the transparent cathode glass plate while heating occurs at the anode. We demonstrated a novel design of CNT-BLU by fabricating transparent single-walled CNT field emitters on the cathode and by coating a reflecting metal layer on the anode. This study hopefully provides a clue to solve the anode-heating problem which would be inevitably confronted for high-luminance and large-area CNT-BLUs.

  4. Effects of non-hydrostatic pressure on electrical resistance of bundled single-wall carbon nanotubes

    International Nuclear Information System (INIS)

    Recent studies have shown that single wall carbon nanotubes (SWCNT) exhibit a sequence of phase transitions and demonstrate a high structural stability up to 35 GPa of quasi-hydrostatic pressure [1] beyond which an irreversible structural transformation occurs. Here we report on the study of electrical resistance of SWCNTs at pressures up to 34 GPa in the temperature range of 293 – 395 K. In the pressure range 10–25 GPathe rate of resistance change decreases considerably. We associate such behavior of the resistance with a structural modification of the SWCNTs or/and change of the conductivity character at high pressure. Raman spectra of the samples recovered after 30 GPa exhibit a large increase of defect concentration in the CNTs. Isobaric temperature dependences of the CNT resistance R(T) measured in the temperature range 300–400 K reveal some changes with pressure whereas the semiconducting character of the R(T) remains unaltered

  5. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    Science.gov (United States)

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-01

    We demonstrate that a nonperturbative framework for the treatment of the excitations of single-walled carbon nanotubes based upon a field theoretic reduction is able to accurately describe experiment observations of the absolute values of excitonic energies. This theoretical framework yields a simple scaling function from which the excitonic energies can be read off. This scaling function is primarily determined by a single parameter, the charge Luttinger parameter of the tube, which is in turn a function of the tube chirality, dielectric environment, and the tube's dimensions, thus expressing disparate influences on the excitonic energies in a unified fashion. We test this theory explicitly on the data reported by Dukovic et al. [Nano Lett. 5, 2314 (2005), 10.1021/nl0518122] and Sfeir et al. [Phys. Rev. B 82, 195424 (2010), 10.1103/PhysRevB.82.195424] and so demonstrate the method works over a wide range of reported excitonic spectra.

  6. Detection of Sugar-Lectin Interactions by Multivalent Dendritic Sugar Functionalized Single-Walled Carbon Nanotubes

    CERN Document Server

    Vasu, K S; Bagul, R S; Jayaraman, N; Sood, A K; 10.1063/1.4739793

    2012-01-01

    We show that single walled carbon nanotubes (SWNT) decorated with sugar functionalized poly (propyl ether imine) (PETIM) dendrimer is a very sensitive platform to quantitatively detect carbohydrate recognizing proteins, namely, lectins. The changes in electrical conductivity of SWNT in field effect transistor device due to carbohydrate - protein interactions form the basis of present study. The mannose sugar attached PETIM dendrimers undergo charge - transfer interactions with the SWNT. The changes in the conductance of the dendritic sugar functionalized SWNT after addition of lectins in varying concentrations were found to follow the Langmuir type isotherm, giving the concanavalin A (Con A) - mannose affinity constant to be 8.5 x 106 M-1. The increase in the device conductance observed after adding 10 nM of Con A is same as after adding 20 \\muM of a non - specific lectin peanut agglutinin, showing the high specificity of the Con A - mannose interactions. The specificity of sugar-lectin interactions was chara...

  7. Design and Manufacture of Silver-Selective Electrode Based on Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Khoorshid Mehdizadeh

    2015-06-01

    Full Text Available The present research explores the design and manufacture of coated ion-selective membranes on graphite electrodes with selectivity towards silver cations.Single- walled carbon nanotube N-6- aminohexylamide ,was used as the ionophore.The electrode was manufactured in a concentration range of 1×10-6to1×10-2 , , resulting in a Nernst response with a gradient of 59.1±0.5 mv/decade . In this work, the effects of membrane composition, pH of the solution, temperature and non-aqueous environment were investigated on the performance of the electrodes Furthermore, the response time of the electrode and the electrode response reversibility were calculated using both static and dynamic methods. This electrode can be applied in ethanol environments of up to 25% and in dioxane environments of up to 25% volume-volume without hindrance. The electrode response time was less than 18 seconds.

  8. Network single-walled carbon nanotube biosensors for fast and highly sensitive detection of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Hu Pingan; Zhang Jia; Wen Zhenzhong [Research Centre for Micro/Nanotechnology, Harbin Institute of Technology, No. 2 YiKuang Street, Harbin 150080 (China); Zhang Can, E-mail: hupa@hit.edu.cn [Centre for Advanced Photonics and Electronics, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2011-08-19

    Detection of proteins is powerfully assayed in the diagnosis of diseases. A strategy for the development of an ultrahigh sensitivity biosensor based on a network single-walled carbon nanotube (SWNT) field-effect transistor (FET) has been demonstrated. Metallic SWNTs (m-SWNTs) in the network nanotube FET were selectively removed or cut via a carefully controlled procedure of electrical break-down (BD), and left non-conducting m-SWNTs which magnified the Schottky barrier (SB) area. This nanotube FET exhibited ultrahigh sensitivity and fast response to biomolecules. The lowest detection limit of 0.5 pM was achieved by exploiting streptavidin (SA) or a biotin/SA pair as the research model, and BD-treated nanotube biosensors had a 2 x 10{sup 4}-fold lower minimum detectable concentration than the device without BD treatment. The response time is in the range of 0.3-3 min.

  9. Increasing amperometric biosensor sensitivity by length fractionated single-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Tasca, Federico; Gorton, Lo; Wagner, Jakob Birkedal;

    2008-01-01

    In this work the sensitivity-increasing effect of single-walled carbon nanotubes (SWCNTs) in amperometric biosensors, depending on their average length distribution, was studied. For this purpose the SWCNTs were oxidatively shortened and subsequently length separated by size exclusion...... chromatography. Transmission electron micrographs of different fractions of SWCNTs were collected. Diaphorase ``wired'' to an osmium redox polymer was blended with the shortened SWCNTs of different lengths. Depending on the average length of the SWCNTs the sensitivity of the amperometric biosensor model system...... limit was 1 mu M. The biosensor exhibited excellent electrocatalytic properties. Even at relatively high NADH concentrations the oxidative current was limited by the diffusion rate of NADH. (C) 2008 Elsevier B.V. All rights reserved....

  10. Amperometric Low-Potential Detection of Malic Acid Using Single-Wall Carbon Nanotubes Based Electrodes

    Directory of Open Access Journals (Sweden)

    Camelia Bala

    2008-03-01

    Full Text Available The electrocatalytical property of single-wall carbon nanotube (SWNTmodified electrode toward NADH detection was explored by cyclic voltammetry andamperometry techniques. The experimental results show that SWNT decrease theovervoltage required for oxidation of NADH (to 300 mV vs. Ag/AgCl and this propertymake them suitable for dehydrogenases based biosensors. The behavior of the SWNTmodified biosensor for L-malic acid was studied as an example for dehydrogenasesbiosensor. The amperometric measurements indicate that malate dehydrogenase (MDHcan be strongly adsorbed on the surface of the SWNT-modified electrode to form anapproximate monolayer film. Enzyme immobilization in Nafion membrane can increasethe biosensor stability. A linear calibration curve was obtained for L-malic acidconcentrations between 0.2 and 1mM.

  11. Large Deflections Mechanical Analysis of a Suspended Single-Wall Carbon Nanotube under Thermoelectrical Loading

    Directory of Open Access Journals (Sweden)

    Assaf Ya'akobovitz

    2011-01-01

    Full Text Available Following the recent progress in integrating single-wall carbon nanotubes (SWCNTs into silicon-based micro-electromechanical systems (MEMS, new modeling tools are needed to predict their behavior under different loads, including thermal, electrical and mechanical. In the present study, the mechanical behavior of SWCNTs under thermoelectrical loading is analyzed using a large deflection geometrically nonlinear string model. The effect of the resistive heating was found to have a substantial influence on the SWCNTs behavior, including significant enhancement of the strain (up to the millistrains range and buckling due to the thermal expansion. The effect of local buckling sites was also studied and was found to enhance the local strain. The theoretical and numerical results obtained in the present study demonstrate the importance of resistive heating in the analysis of SWCNTs and provide an additional insight into the unique mechanics of suspended SWCNTs.

  12. On the Interfacial Properties of Polymers/Functionalized Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Ansari, R.; Rouhi, S.; Ajori, S.

    2016-06-01

    Molecular dynamics (MD) simulations is used to study the adsorption of polyethylene (PE) and poly(ethylene oxide) (PEO) on the functionalized single-walled carbon nanotubes (SWCNTs). The effects of functionalization factor weight percent on the interaction energies of polymer chains with nanotubes are studied. Besides, the influences of different functionalization factors on the SWCNT/polymer interactions are investigated. It is shown that for both types of polymer chains, the largest interaction energies associates with the random O functionalized nanotubes. Besides, increasing temperature results in increasing the nanotube/polymer interaction energy. Considering the final shapes of adsorbed polymer chains on the SWCNTs, it is observed that the adsorbed conformations of PE chains are more contracted than those of PEO chains.

  13. Single-Walled Carbon Nanotube Network Field Effect Transistor as a Humidity Sensor

    Directory of Open Access Journals (Sweden)

    Prasantha R. Mudimela

    2012-01-01

    Full Text Available Single-walled carbon nanotube network field effect transistors were fabricated and studied as humidity sensors. Sensing responses were altered by changing the gate voltage. At the open channel state (negative gate voltage, humidity pulse resulted in the decrease of the source-drain current, and, vice versa, the increase in the source-drain current was observed at the positive gate voltage. This effect was explained by the electron-donating nature of water molecules. The operation speed and signal intensity was found to be dependent on the gate voltage polarity. The positive or negative change in current with humidity pulse at zero-gate voltage was found to depend on the previous state of the gate electrode (positive or negative voltage, respectively. Those characteristics were explained by the charge traps in the gate dielectric altering the effective gate voltage, which influenced the operation of field effect transistor.

  14. One-step preparation of water-soluble single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    A novel one-step process using potassium persulfate (KPS) as oxidant is proposed in this paper to prepare water-soluble single-walled carbon nanotubes (SWNTs). The process without the need for organic solvents and acids is a low-cost, eco-friendly, facile method. Morphology observation by atomic force microscopy (AFM) indicates that the KPS-treated SWNTs were effectively debundled without obvious shortening in their length. The functional groups and thermal stability of the treated SWNTs were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). XPS results show that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups were formed on the surfaces of the SWNTs, while the TGA results reveal that the quantity of the functional groups can reach to approximately 20%.

  15. Evaluation of nonlocal parameter in the vibrations of single-walled carbon nanotubes with initial strain

    Science.gov (United States)

    Arash, B.; Ansari, R.

    2010-06-01

    Based upon a nonlocal shell model accounting for the small-scale effects, the vibration characteristics of single-walled carbon nanotubes (SWCNTs) with different boundary conditions subjected to initial strain are studied in this paper. The set of governing equations of motion is numerically solved by a method that emerged from incorporating the radial point interpolation approximation within the framework of the generalized differential quadrature method. The effectiveness of the present nonlocal shell model is assessed by the molecular dynamics simulations as a benchmark of good accuracy. Accordingly, nonlocal parameters for clamped and cantilever SWCNTs with thicknesses of 0.066 and 0.34 nm are proposed due to the uncertainty that exists in defining nanotube wall thickness. The simulation results show that the resonant frequencies of SWCNTs are very sensitive to the initial strain, although small.

  16. Coupling between flexural modes in free vibration of single-walled carbon nanotubes

    Science.gov (United States)

    Liu, Rumeng; Wang, Lifeng

    2015-12-01

    The nonlinear thermal vibration behavior of a single-walled carbon nanotube (SWCNT) is investigated by molecular dynamics simulation and a nonlinear, nonplanar beam model. Whirling motion with energy transfer between flexural motions is found in the free vibration of the SWCNT excited by the thermal motion of atoms where the geometric nonlinearity is significant. A nonlinear, nonplanar beam model considering the coupling in two vertical vibrational directions is presented to explain the whirling motion of the SWCNT. Energy in different vibrational modes is not equal even over a time scale of tens of nanoseconds, which is much larger than the period of fundamental natural vibration of the SWCNT at equilibrium state. The energy of different modes becomes equal when the time scale increases to the microsecond range.

  17. Theoretical analysis on nonlinear vibration of fluid flow in single-walled carbon nanotube

    Science.gov (United States)

    Valipour, P.; Ghasemi, S. E.; Khosravani, Mohammad Reza; Ganji, D. D.

    2016-04-01

    In this study, the concept of nonlocal continuum theory is used to characterize the nonlinear vibration of an embedded single-walled carbon nanotube. The Pasternak-type model is employed to simulate the interaction of the SWNTs. The parameterized perturbation method is used to solve the corresponding nonlinear differential equation. The effects of the vibration amplitude, flow velocity, nonlocal parameter, and stiffness of the medium on the nonlinear frequency variation are presented. The result shows that by increasing the Winkler constant, the nonlinear frequency decreases, especially for low vibration amplitudes. In addition, it is resulted that influence of the nonlocal parameter is greater at higher flow velocities in comparison with lower flow velocities.

  18. Si-coated single-walled carbon nanotubes under axial loads: An atomistic simulation study

    International Nuclear Information System (INIS)

    The mechanical properties of the Si-coated imperfect (5, 5) single-walled carbon nanotube (SWCNT), the imperfect (5, 5) SWCNT and several perfect armchair SWCNTs under axial loads were investigated using molecular dynamics simulation. The interactions between atoms were modeled using the empirical Tersoff potential and the Tersoff-Brenner potential coupled with the Lennard-Jones potential. We get Young's modulus of the defective (5, 5) nanotube with and without the Si coating under axial tension 1107.92 and 1076.02 GPa, respectively. The results also show that the structure failure of the Si-coated imperfect (5, 5) SWCNT under axial compression occurs at a slightly higher strain than for the perfect (5, 5) SWCNT. Therefore, we can confirm the protective effect of Si as a coating material for defective SWCNTs. We also obtain the critical buckling strains of perfect SWCNTs

  19. Coupling between flexural modes in free vibration of single-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Rumeng Liu

    2015-12-01

    Full Text Available The nonlinear thermal vibration behavior of a single-walled carbon nanotube (SWCNT is investigated by molecular dynamics simulation and a nonlinear, nonplanar beam model. Whirling motion with energy transfer between flexural motions is found in the free vibration of the SWCNT excited by the thermal motion of atoms where the geometric nonlinearity is significant. A nonlinear, nonplanar beam model considering the coupling in two vertical vibrational directions is presented to explain the whirling motion of the SWCNT. Energy in different vibrational modes is not equal even over a time scale of tens of nanoseconds, which is much larger than the period of fundamental natural vibration of the SWCNT at equilibrium state. The energy of different modes becomes equal when the time scale increases to the microsecond range.

  20. Titanium coverage on a single-wall carbon nanotube: molecular dynamics simulations

    International Nuclear Information System (INIS)

    The minimum energy structures of Ti covered (8,0) single-wall carbon nanotube (SWNT) have been investigated theoretically. Using available experimental data and the results of density functional theory calculations, we first parametrized a reliable empirical many-body potential energy function (PEF) for the CTi binary system. The PEF used in the calculations includes two- and three-body atomic interactions. Then performing molecular dynamics simulations at 1 and 300 K, we obtained the minimum-energy configurations for Ti covered (8,0)-SWNT. The configurations reported here include low and high coverage of Ti on nanotubes. We have found that one layer of Ti did not distort the nanotube significantly, whereas two-layer coverage showed an interesting feature: the second layer of Ti pushed the first layer inside the wall of nanotube, but the general shape of the nanotube was not affected so much

  1. Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy

    Science.gov (United States)

    Umeyama, Tomokazu; Baek, Jinseok; Sato, Yuta; Suenaga, Kazu; Abou-Chahine, Fawzi; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

    2015-07-01

    The close solid-state structure-property relationships of organic π-aromatic molecules have attracted interest due to their implications for the design of organic functional materials. In particular, a dimeric structure, that is, a unit consisting of two molecules, is required for precisely evaluating intermolecular interactions. Here, we show that the sidewall of a single-walled carbon nanotube (SWNT) represents a unique molecular dimer platform that can be directly visualized using high-resolution transmission electron microscopy. Pyrene is chosen as the π-aromatic molecule; its dimer is covalently linked to the SWNT sidewalls by aryl addition. Reflecting the orientation and separation of the two molecules, the pyrene dimer on the SWNT exhibits characteristic optical and photophysical properties. The methodology discussed here--form and probe molecular dimers--is highly promising for the creation of unique models and provides indispensable and fundamental information regarding molecular interactions.

  2. Versatile visualization of individual single-walled carbon nanotubes with near-infrared fluorescence microscopy.

    Science.gov (United States)

    Tsyboulski, Dmitri A; Bachilo, Sergei M; Weisman, R Bruce

    2005-05-01

    Fluorescence microscopy in the near-infrared between 950 and 1600 nm has been developed as a novel method to image and study single-walled carbon nanotubes (SWNTs) in a variety of environments. Intrinsic photoluminescence of disaggregated pristine SWNTs was excited by a diode laser and detected with a two-dimensional InGaAs photodiode array. Individual nanotubes were visualized with a spatial resolution of ca. 1 microm and characterized with polarization measurements and emission spectroscopy. Spatially resolved emission spectra allowed (n,m) identification of single nanotubes and revealed small environmentally induced spectral shifts between segments of long tubes. Nanotube motions in aqueous surfactant were visualized with a time resolution of 50 ms and used to estimate the diffusion coefficient. PMID:15884905

  3. Dynamics of individual single-walled carbon nanotubes in water by real-time visualization.

    Science.gov (United States)

    Duggal, Rajat; Pasquali, Matteo

    2006-06-23

    Individual single-walled carbon nanotubes (SWNTs) in aqueous suspension are visualized directly by fluorescence video microscopy. The fluorescent tagging is simple, biocompatible, and does not modify the SWNTs. The dynamics of individual SWNTs in water are observed and quantified for the first time. We measure the confined rotational diffusion coefficient and find it in reasonable agreement with predictions based on confined diffusion of dilute Brownian rods. We determine the critical concentration at which SWNTs in suspensions start interacting. By analyzing the fluctuating shape of SWNTs in the 3 to 5 microm range, we determine that their persistence length ranges between 32 and 174 microm, in agreement with theoretical estimates; thus, commonly available SWNTs in liquids can be considered as rigid Brownian rods in the absence of imposed external fields or self-attractive forces. PMID:16907258

  4. Dispersion of single-walled carbon nanotubes modified with poly-l-tyrosine in water.

    Science.gov (United States)

    Kojima, Mio; Chiba, Tomoka; Niishima, Junichiro; Higashi, Toshiaki; Fukuda, Takahiro; Nakajima, Yoshikata; Kurosu, Shunji; Hanajiri, Tatsuro; Ishii, Koji; Maekawa, Toru; Inoue, Akira

    2011-01-01

    In this study, complexes composed of poly-l-tyrosine (pLT) and single-walled carbon nanotubes (SWCNTs) were produced and the dispersibility of the pLT/SWCNT complexes in water by measuring the ζ potential of the complexes and the turbidity of the solution were investigated. It is found that the absolute value of the ζ potential of the pLT/SWCNT complexes is as high as that of SWCNTs modified with double-stranded DNA (dsDNA) and that the complexes remain stably dispersed in the water at least for two weeks. Thermogravimetry analysis (TGA) and visualization of the surface structures of pLT/SWCNT complexes using an atomic force microscope (AFM) were also carried out. PMID:21711636

  5. Functionalization of oxidized single-walled carbon nanotubes with 4-benzo-9-crown-3 ether

    Indian Academy of Sciences (India)

    Ardeshir Khazaei; Maryam Kiani Borazjani; Khadijeh Mansouri Moradian

    2012-09-01

    Functionalization of oxidized single-walled carbon nanotubes (SWCNTs) by a zwitterionic interaction (COO−NH$^{+}_{3}$) between protonated amine on crown ether and an oxyanion from a carboxylic acid group on SWCNT has been described. This ionic interaction has led to a considerable increase in the solubility of SWCNTs in both organic and aqueous solvents such as ethanol, dimethyl sulphoxide, dimethylformamide, and H2O. The highest solubility was attained in DMF and DMSO. The ionic bonded 4-benzo-9-crown-3 ether allowed the hosting of Li+. The ionic bond of crown ether (4-(benzo-9-crown-3)) to SWCNT was identified and confirmed by infrared spectroscopy, transmission electron-microscopy, atomic force microscopy and thermogravimetric analysis methods.

  6. 0.8 nm single wall carbon nanotubes for wideband ultrafast pulse generation

    Science.gov (United States)

    Kang, Z.; Xu, Y.; Jia, Z. X.; Qin, G. S.; Qin, W. P.

    2016-04-01

    We demonstrate wideband ultrafast optical pulse generation at 1, 1.56 and 2 μm by using single polymer composite saturable absorber (SA) based on 0.8 nm single wall carbon nanotubes (SWCNTs). The SWCNTs were mixed with sodium carboxymethylcellulose (NaCMC) to form SWCNT SA films. The film then integrated into ytterbium-(Yb-), erbium-(Er-) and thulium-(Tm-) doped ring fiber laser cavities. Using this film, we achieve 380 ps, 830 fs, and 1.24 ps mode-locked pulses at 1035, 1560, and 1933 nm, respectively. These results suggest that 0.8 nm SWCNTs are potentially useful as optical elements in wideband fiber lasers.

  7. Colored semitransparent conductive coatings consisting of monodisperse metallic single-walled carbon nanotubes.

    Science.gov (United States)

    Green, Alexander A; Hersam, Mark C

    2008-05-01

    Single-walled carbon nanotubes (SWNTs) are promising materials for transparent conduction as a result of their exceptional electrical, optical, mechanical, and chemical properties. However, since current synthetic methods yield polydisperse mixtures of SWNTs, the performance of SWNT transparent conductive films has previously been hindered by semiconducting species. Here, we describe the performance of transparent conductors produced using predominantly metallic SWNTs. Compared with unsorted material, films enriched in metallic SWNTs can enhance conductivity by factors of over 5.6 in the visible and 10 in the infrared. Moreover, by using monodisperse metallic SWNTs sorted with angstrom-level resolution in diameter, semitransparent conductive coatings with tunable optical transmittance can be produced. PMID:18393537

  8. Aggregated single-walled carbon nanotubes attenuate the behavioural and neurochemical effects of methamphetamine in mice

    Science.gov (United States)

    Xue, Xue; Yang, Jing-Yu; He, Yi; Wang, Li-Rong; Liu, Ping; Yu, Li-Sha; Bi, Guo-Hua; Zhu, Ming-Ming; Liu, Yue-Yang; Xiang, Rong-Wu; Yang, Xiao-Ting; Fan, Xin-Yu; Wang, Xiao-Min; Qi, Jia; Zhang, Hong-Jie; Wei, Tuo; Cui, Wei; Ge, Guang-Lu; Xi, Zheng-Xiong; Wu, Chun-Fu; Liang, Xing-Jie

    2016-07-01

    Methamphetamine (METH) abuse is a serious social and health problem worldwide. At present, there are no effective medications to treat METH addiction. Here, we report that aggregated single-walled carbon nanotubes (aSWNTs) significantly inhibited METH self-administration, METH-induced conditioned place preference and METH- or cue-induced relapse to drug-seeking behaviour in mice. The use of aSWNTs alone did not significantly alter the mesolimbic dopamine system, whereas pretreatment with aSWNTs attenuated METH-induced increases in extracellular dopamine in the ventral striatum. Electrochemical assays suggest that aSWNTs facilitated dopamine oxidation. In addition, aSWNTs attenuated METH-induced increases in tyrosine hydroxylase or synaptic protein expression. These findings suggest that aSWNTs may have therapeutic effects for treatment of METH addiction by oxidation of METH-enhanced extracellular dopamine in the striatum.

  9. Electrochemical lithium-ion storage properties of quinone molecules encapsulated in single-walled carbon nanotubes.

    Science.gov (United States)

    Ishii, Yosuke; Tashiro, Kosuke; Hosoe, Kento; Al-Zubaidi, Ayar; Kawasaki, Shinji

    2016-04-21

    We investigated the electrochemical lithium-ion storage properties of 9,10-anthraquinone (AQ) and 9,10-phenanthrenequinone (PhQ) molecules encapsulated in the inner hollow core of single-walled carbon nanotubes (SWCNTs). The structural properties of the obtained encapsulated systems were characterized by electron microscopy, synchrotron powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. We found that almost all quinone molecules encapsulated in the SWCNTs can store Li-ions reversibly. Interestingly, the undesired capacity fading, which comes from the dissolution of quinone molecules into the electrolyte, was suppressed by the encapsulation. It was also found that the overpotential of AQ was decreased by the encapsulation, probably due to the high-electric conductivity of SWCNTs. PMID:27030581

  10. Surface conductance modulation of single-walled carbon nanotubes and effects on dielectrophoresis

    International Nuclear Information System (INIS)

    Dielectrophoresis has received considerable attention for separating nanotubes according to electronic types. Here we examine the effects of surface conductivity of semiconducting Single-Walled carbon NanoTubes (SWNT), induced by ionic surfactants, on the sign of dielectrophoretic force. The crossover frequency of semiconducting SWNT increases rapidly as the conductivity ratio between the particle and medium increases, leading to an incomplete separation of ionic surfactant suspended SWNT at an electric field frequency of 10 MHz. The surface charge of SWNT is neutralized by an equimolar mixture of anionic surfactant Sodium Dodecyl Sulfate (SDS) and cationic surfactant CetylTrimethylAmmonium Bromide (CTAB), resulting in negative dielectrophoresis of semiconducting species at 10 MHz. A comparative Raman spectroscopy study shows a nearly complete separation of metallic SWNT

  11. Design and Fabrication of Single-Walled Carbon Nanonet Flexible Strain Sensors

    Directory of Open Access Journals (Sweden)

    Trung Kien Vu

    2012-03-01

    Full Text Available This study presents a novel flexible strain sensor for real-time strain sensing. The material for strain sensing is single-walled carbon nanonets, grown using the alcohol catalytic chemical vapor deposition method, that were encapsulated between two layers of Parylene-C, with a polyimide layer as the sensing surface. All of the micro-fabrication was compatible with the standard IC process. Experimental results indicated that the gauge factor of the proposed strain sensor was larger than 4.5, approximately 2.0 times greater than those of commercial gauges. The results also demonstrated that the gauge factor is small when the growth time of SWCNNs is lengthier, and the gauge factor is large when the line width of the serpentine pattern of SWCNNs is small.

  12. Ionic liquid coated single-walled carbon nanotube buckypaper as supercapacitor electrode

    Institute of Scientific and Technical Information of China (English)

    Chao Zheng; Weizhong Qian; Yuntao Yu; Fei Wei

    2013-01-01

    Effect of stacking structure of single-walled carbon nanotubes (SWCNTs) on its performance as electrode of supercapacitor was investigated in the present work.Considering SWCNTs easily formed bundles due to strong van de Waals attraction between tubes,we proposed first dispersion of SWCNTs by ionic liquids (ILs) of 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMIMBF4),followed by fabrication of buckypaper by compression.The debundling effect of ILs on SWCNTs increased the interface between electrode and electrolyte,decreased electrical resistance,and,consequently,increased performance of the supercapacitor.Since ILs,used to disperse SWCNTs,also functioned as electrolyte in supercapacitor,our method is a simple way to prepare buckypaper electrode with high performance.

  13. Charge trapping in aligned single-walled carbon nanotube arrays induced by ionizing radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Esqueda, Ivan S., E-mail: isanchez@isi.edu [Information Sciences Institute, University of Southern California, Arlington, Virginia 22203 (United States); Cress, Cory D. [Electronics Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States); Che, Yuchi; Cao, Yu; Zhou, Chongwu [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States)

    2014-02-07

    The effects of near-interfacial trapping induced by ionizing radiation exposure of aligned single-walled carbon nanotube (SWCNT) arrays are investigated via measurements of gate hysteresis in the transfer characteristics of aligned SWCNT field-effect transistors. Gate hysteresis is attributed to charge injection (i.e., trapping) from the SWCNTs into radiation-induced traps in regions near the SWCNT/dielectric interface. Self-consistent calculations of surface-potential, carrier density, and trapped charge are used to describe hysteresis as a function of ionizing radiation exposure. Hysteresis width (h) and its dependence on gate sweep range are investigated analytically. The effects of non-uniform trap energy distributions on the relationship between hysteresis, gate sweep range, and total ionizing dose are demonstrated with simulations and verified experimentally.

  14. Investigation on optical absorption properties of ion irradiated single walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vishalli,, E-mail: vishalli-2008@yahoo.com; Dharamvir, Keya, E-mail: keya@pu.ac.in [Department of Physics, Panjab University, Chandigarh (India); Kaur, Ramneek; Raina, K. K. [Materials Research Laboratory, School of Physics and Materials Science, Thapar University, Patiala (India); Avasthi, D. K. [Materials Science Group, Inter University Accelerator Centre, ArunaAsaf Ali Marg, NewDelhi (India); Jeet, Kiran [Electron Microscopy and Nanoscience laboratory, Punjab Agriculture University, Ludhiana (India)

    2015-08-28

    In the present study change in the optical absorption properties of single walled carbon nanotubes (SWCNTs) under nickel ion (60 MeV) irradiation at various fluences has been investigated. Langmuir Blodgett technique is used to deposit SWCNT thin film of uniform thickness. AFM analysis shows a network of interconnected bundles of nanotubes. UV-Vis-NIR absorption spectra indicate that the sample mainly contain SWCNTs of semiconducting nature. It has been found in absorption spectra that there is decrease in the intensity of the characteristic SWCNT peaks with increase in fluence. At fluence value 1×10{sup 14} ions/cm{sup 2} there is almost complete suppression of the characteristic SWCNTs peaks.The decrease in the optical absorption with increase in fluence is due to the increase in the disorder in the system which leads to the decrease in optically active states.

  15. Pulse gas alignment and AFM manipulation of single-wall carbon nanotube

    Institute of Scientific and Technical Information of China (English)

    TIAN XiaoJun; WANG YueChao; XI Ning; DONG ZaiLi; TUNG Steve

    2008-01-01

    In the fabrication process of nanoelectronic device arrays based on single-wall carbon nanotube (SWCNT), oriented alignment of SWCNTs and property modification of metallic SWCNTs in the array are the key problems to be solved. Pulse gas alignment with substrate downward tilt is proposed to realize the controllable alignment of SWCNTs. Experimental results demonstrate that 84% SWCNTs are aligned in -15°- 15° angular to the pulse gas direction. A modified nanomanipulation technology based on atomic force microscope (AFM) is utilized to perform various kinds of SWCNT manipulation, such as SWCNT separation from the "Y" CNT, catalyst removal from the SWCNT end, continual nano buckles fabrication on SWCNT and even stretching to break, which provides a feasible way to modify the size, shape and the electrical property of SWCNTs.

  16. Molecular dynamics simulation of the test of single-walled carbon nanotubes under tensile loading

    Institute of Scientific and Technical Information of China (English)

    FU ChenXin; CHEN YunFei; JIAO JiWei

    2007-01-01

    Molecular dynamics (MD) simulations were performed to do the test of single-walled carbon nanotubes (SWCNT) under tensile loading with the use of Brenner potential to describe the interactions of atoms in SWCNTs. The Young's modulus and tensile strength for SWCNTs were calculated and the values found are 4.2 TPa and 1.40―1.77 TPa, respectively. During the simulation, it was found that if the SWCNTs are unloaded prior to the maximum stress, the stress-strain curve for unloading process overlaps with the loading one, showing that the SWCNT's deformation up to its fracture point is completely elastic. The MD simulation also demonstrates the fracture process for several types of SWCNT and the breaking mechanisms for SWCNTs were analyzed based on the energy and structure behavior.

  17. Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Yasumitsu Miyata

    2011-01-01

    Full Text Available We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample.

  18. Fabrication and electrochemical properties of free-standing single-walled carbon nanotube film electrodes

    Institute of Scientific and Technical Information of China (English)

    Niu Zhi-Qiang; Ma Wen-Jun; Dong Hai-Bo; Li Jin-Zhu; Zhou Wei-Ya

    2011-01-01

    An easily manipulative approach was presented to fabricate electrodes using free-standing single-walled carbon nanotube (SWCNT) films grown directly by chemical vapor deposition. Electrochemical properties of the electrodes were investigated. In comparison with the post-deposited SWCNT papers, the directly grown SWCNT film electrodes manifested enhanced electrochemical properties and sensitivity of sensors as well as excellent electrocatalytic activities. A transition from macroelectrode to nanoelectrode behaviours was observed with the increase of scan rate. The heat treatment of the SWCNT film electrodes increased the current signals of electrochemical analyser and background current, because the heat-treatment of the SWCNTs in air could create more oxide defects on the walls of the SWCNTs and make the surfaces of SWCNTs more hydrophilic. The excellent electrochemical properties of the directly grown and heat-treated free-standing SWCNT film electrodes show the potentials in biological and electrocatalytic applications.

  19. Adatom complexes and self-healing mechanisms on graphene and single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Tsetseris, Leonidas [ORNL; Pantelides, Sokrates T [ORNL

    2009-01-01

    Point defects play a role in the functionalization, chemical activation, carrier transport, and nano-engineering of graphitic systems. Here, we use first-principles calculations to describe several processes that alter the properties of graphene and single-wall carbon nanotubes (SWCNTs) in the presence of self-interstitials (SI's). We find that, while two or four SI's are stabilized in hillock-like structures that stay idle unless the system is heated to very high temperatures, clustering of three C adatoms leads to the formation of mobile protrusions on graphene and large enough SWCNTs. For different SI concentrations and SWCNT size, the interplay between mobile and immobile species may favor one of the two competing processes, self-healing or formation of adatom superstructures.

  20. Suspended single-walled carbon-nanotube field-effect transistor for gas sensing application

    Science.gov (United States)

    Wada, Yukiko; Fujita, Yoshihiro; Takei, Kuniharu; Arie, Takayuki; Akita, Seiji

    2015-06-01

    We investigate the pressure dependence of transfer characteristics of suspended single-walled carbon-nanotube field-effect transistors. We find that the gate bias around the charge neutral point with low drain current is appropriate for gas sensing application, while the high gate bias condition with high drain current that induces Joule heating in the suspended region for the desorption of the adsorbed molecules is preferable for the vacuum gauge application based on the heat exchange surrounding gas molecules, where the temperature at the suspended channel is investigated based on the simple one-dimensional heat transport model. We also revealed that the pressure dependence of the channel conductance at the gate bias around the charge neutral point can be explained by the Langmuir isotherm.

  1. Selective fabrication of quasi-parallel single-walled carbon nanotubes on silicon substrates

    International Nuclear Information System (INIS)

    We have fabricated single-walled carbon nanotube (SWNT) arrays, about 85% of which are semiconducting. Fe nanoparticles, which were used as a catalyst, were produced simply and cheaply from Wistar rat blood. The SWNT arrays generally grow parallel to the gas flow. Hundreds of devices with varying SWNT density in the channel were measured and we found that the on-off ratio for such devices with the quasi-parallel, semiconducting-rich SWNTs in the channel can be easily increased via an electrical breakdown method. Thus, large-scale fabrication of FET devices is possible simply by controlling the width of the channel. Finally, we determined that the mobility of the devices reached 3900 cm2 V-1 s-1.

  2. Tuning the driving force for exciton dissociation in single-walled carbon nanotube heterojunctions

    Science.gov (United States)

    Ihly, Rachelle; Mistry, Kevin S.; Ferguson, Andrew J.; Clikeman, Tyler T.; Larson, Bryon W.; Reid, Obadiah; Boltalina, Olga V.; Strauss, Steven H.; Rumbles, Garry; Blackburn, Jeffrey L.

    2016-06-01

    Understanding the kinetics and energetics of interfacial electron transfer in molecular systems is crucial for the development of a broad array of technologies, including photovoltaics, solar fuel systems and energy storage. The Marcus formulation for electron transfer relates the thermodynamic driving force and reorganization energy for charge transfer between a given donor/acceptor pair to the kinetics and yield of electron transfer. Here we investigated the influence of the thermodynamic driving force for photoinduced electron transfer (PET) between single-walled carbon nanotubes (SWCNTs) and fullerene derivatives by employing time-resolved microwave conductivity as a sensitive probe of interfacial exciton dissociation. For the first time, we observed the Marcus inverted region (in which driving force exceeds reorganization energy) and quantified the reorganization energy for PET for a model SWCNT/acceptor system. The small reorganization energies (about 130 meV, most of which probably arises from the fullerene acceptors) are beneficial in minimizing energy loss in photoconversion schemes.

  3. Transverse electric field–induced deformation of armchair single-walled carbon nanotube

    Directory of Open Access Journals (Sweden)

    Yuan Ningyi

    2010-01-01

    Full Text Available Abstract The deformation of armchair single-walled carbon nanotube under transverse electric field has been investigated using density functional theory. The results show that the circular cross-sections of the nanotubes are deformed to elliptic ones, in which the tube diameter along the field direction is increased, whereas the diameter perpendicular to the field direction is reduced. The electronic structures of the deformed nanotubes were also studied. The ratio of the major diameter to the minor diameter of the elliptic cross-section was used to estimate the degree of the deformation. It is found that this ratio depends on the field strength and the tube diameter. However, the field direction has little role in the deformation. (See supplementary material 1 Electronic supplementary material The online version of this article (doi:10.1007/s11671-010-9617-y contains supplementary material, which is available to authorized users. Click here for file

  4. Interaction of [FeFe]-hydrogenases with single-walled carbon nanotubes

    Science.gov (United States)

    Svedruzic Chang, Drazenka; McDonald, Timothy J.; Kim, Yong-Hyun; Blackburn, Jeffrey L.; Heben, Michael J.; King, Paul W.

    2007-09-01

    Single-walled carbon nanotubes (SWNT) are promising candidates for use in energy conversion devices as an active photo-collecting elements, for dissociation of bound excitons and charge-transfer from photo-excited chromophores, or as molecular wires to transport charge. Hydrogenases are enzymes that efficiently catalyze the reduction of protons from a variety of electron donors to produce molecular hydrogen. Hydrogenases together with SWNT suggest a novel biohybrid material for direct conversion of sunlight into H II. Here, we report changes in SWNT optical properties upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum and Chlamydomonas reinhardtii. We find evidence that novel and stable charge-transfer complexes are formed under conditions of the hydrogenase catalytic turnover, providing spectroscopic handles for further study and application of this hybrid system.

  5. Controlled nanostructure and high loading of single-walled carbon nanotubes reinforced polycarbonate composite

    International Nuclear Information System (INIS)

    This paper presents an effective technique to fabricate thermoplastic nanocomposites with high loading of well-dispersed single-walled carbon nanotubes (SWNTs). SWNT membranes were made from a multi-step dispersion and filtration method, and then impregnated with polycarbonate solution to make thermoplastic nanocomposites. High loading of nanotubes was achieved by controlling the viscosity of polycarbonate solution. SEM and AFM characterization results revealed the controlled nanostructure in the resultant nanocomposites. Dynamic mechanical property tests indicated that the storage modulus of the resulting nanocomposites at 20 wt% nanotubes loading was improved by a factor of 3.4 compared with neat polycarbonate material. These results suggest the developed approach is an effective way to fabricate thermoplastic nanocomposites with good dispersion and high SWNT loading

  6. Microfabrication and characterization of spray-coated single-wall carbon nanotube film strain gauges

    International Nuclear Information System (INIS)

    We present the design, fabrication, and characterization results of single-wall carbon nanotube (SWCNT) film strain gauges for potential applications as highly sensitive strain, weight, or pressure sensors on the macro-scale. A batch microfabrication process was developed for practical device construction and packaging using spray-coated SWCNTs and a conventional semiconductor process. The prototype was characterized using a commercial metal foil gauge with tensile and compressive testing on a binocular load cell. Our test results demonstrated that the proposed SWCNT film gauges have a linear relationship between resistance changes and externally applied strain. The gauge factor ranged from 7.0 to 16.4 for four different micro-grid configurations, indicating that the maximum strain sensitivity of the prototype was approximately eight times greater than that of commercial gauges.

  7. One-Dimensional Organic-Inorganic Nanocomposite Synthesized with Single-Walled Carbon Nanotube Templates

    Directory of Open Access Journals (Sweden)

    Wei Li

    2014-08-01

    Full Text Available This study reports on single-walled carbon nanotubes (SWCNT as templates for the preparation of 1D porous organic-inorganic hybrid composites. The in situ deposited SWCNT were sputter coated with Sn metal and thermally oxidized in air to form a SnO2/SWCNT nanowire framework on SiO2/Si substrate. Poly(acrylic acid (PAA was coated onto this scaffold through UV light-induced radical polymerization, which resulted in the final formation of hybrid composites. The structures of hybrid composites were investigated by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, and Raman spectroscopy. The results show that PAA was successfully coated and the structural advantage of nanowire was fairly maintained, which indicates that this framework is very stable for organic functionalization in solution. The simplicity of this method for the formation of porous organic-inorganic hybrid composites provides a potential application for nanoelectronic devices.

  8. Dysprosium-Catalyzed Growth of Single-Walled Carbon Nanotube Arrays on Substrates

    Directory of Open Access Journals (Sweden)

    Qian Yong

    2009-01-01

    Full Text Available Abstract In this letter, we report that dysprosium is an effective catalyst for single-walled carbon nanotubes (SWNTs growth via a chemical vapor deposition (CVD process for the first time. Horizontally superlong well-oriented SWNT arrays on SiO2/Si wafer can be fabricated by EtOH-CVD under suitable conditions. The structure and properties are characterized by scanning electron microscopy, transition electron microscopy, Raman spectroscopy and atomic force microscopy. The results show that the SWNTs from dysprosium have better structural uniformity and better conductivity with fewer defects. This rare earth metal provides not only an alternative catalyst for SWNTs growth, but also a possible method to generate high percentage of superlong semiconducting SWNT arrays for various applications of nanoelectronic device.

  9. A Comprehensive Review on Separation Methods and Techniques for Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Naoki Komatsu

    2010-06-01

    Full Text Available Structural control of single-walled carbon nanotubes (SWNTs is attracting enormous interest in view of their applications to nanoelectronics and nanooptics. Actually, more than 200 papers regarding separation of SWNTs have been published since 1998. In this review, they are classified into the following five sections according to the separation methods; electrophoresis, centrifugation, chromatography, selective solubilization and selective reaction. In each method, all literature is summarized in tables showing the separated objects (metallic/semiconducting (M/S, length, diameter, (n, m structure and/or handedness, the production process of the used SWNTs (CoMoCAT, HiPco, arc discharge and/or laser vaporization and the employed chemicals, such as detergents and polymers. Changes in annual number of publications related to this subject are also discussed.

  10. Acute toxicity of a mixture of copper and single-walled carbon nanotubes to Daphnia magna.

    Science.gov (United States)

    Kim, Ki T; Klaine, Stephen J; Lin, Sijie; Ke, Pu C; Kim, Sang D

    2010-01-01

    Nanomaterials released into the environment will interact with many materials including other contaminants. This may influence bioavailability and fate of both the nanoparticles and the other contaminants. The present study examined the effect of a combination of soluble copper and surface-modified single-walled carbon nanotubes (SWNTs) on Daphnia magna. Lysophosphatidylcholine (LPC) was used to modify the surface of SWNTs, reducing the surface hydrophobicity of the tubes and thereby producing a stable aqueous nanoparticle suspension. The toxicity of the nanoparticle-copper (Cu) mixture was determined to be additive. The addition of nontoxic concentration of LPC-SWNTs enhanced the uptake and toxicity of copper. Greater amounts of Cu were shown to accumulate in D. magna upon addition of 0.5 and 1.0 mg/L LPC-SWNTs. PMID:20821426

  11. Near-infrared electroluminescent devices using single-wall carbon nanotubes thin flms

    Science.gov (United States)

    Kazaoui, S.; Minami, N.; Nalini, B.; Kim, Y.; Takada, N.; Hara, K.

    2005-11-01

    We have fabricated near-infrared electroluminescent (EL) devices utilizing single-wall carbon nanotubes (SWNTs) finely dispersed in a polymer, such as poly[2-methoxy-5-(2'-ethylhexyloxy]-1,4-phenylenevinylene (MEHPPV). Al/SWNT-MEHPPV/indium tin oxide thin-film devices exhibit a very promising EL response over a broad spectrum, including the range of 900-1600nm. From the analysis of the optical absorption, photoluminescence and EL spectra, as well as the current-voltage characteristics, we demonstrate that those devices exploit the intrinsic near-infrared light-emitting properties of semiconducting SWNTs and the electronic transport properties of SWNT-doped MEHPPV. Those achievements are essential for the future development of thin-film SWNT optoelectronic devices.

  12. Coupling between flexural modes in free vibration of single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    The nonlinear thermal vibration behavior of a single-walled carbon nanotube (SWCNT) is investigated by molecular dynamics simulation and a nonlinear, nonplanar beam model. Whirling motion with energy transfer between flexural motions is found in the free vibration of the SWCNT excited by the thermal motion of atoms where the geometric nonlinearity is significant. A nonlinear, nonplanar beam model considering the coupling in two vertical vibrational directions is presented to explain the whirling motion of the SWCNT. Energy in different vibrational modes is not equal even over a time scale of tens of nanoseconds, which is much larger than the period of fundamental natural vibration of the SWCNT at equilibrium state. The energy of different modes becomes equal when the time scale increases to the microsecond range

  13. Cu/single-walled carbon nanotube laminate composites fabricated by cold rolling and annealing

    International Nuclear Information System (INIS)

    The remarkable mechanical, electrical and thermal properties of single-walled carbon nanotubes (SWCNTs) have attracted extensive research interest as structural and functional materials. In particular, SWCNTs have been used to reinforce polymers and ceramic composites and great progress has been made. For metal matrix composites, the limitation of the conventional manufacturing process and the difficulty in dispersing nanotubes within metal matrices hinder the development of metal matrix composites. In this paper, we demonstrate a successful fabrication of Cu/SWCNT laminate composites by combined techniques of cold rolling and annealing, using 19 layers of large-area SWCNT films sandwiched between 20 layers of Cu thin foils. The tensile strength and Young's modulus of the resultant laminate composites are 361 MPa and 132 GPa, respectively, exhibiting an improvement over the comparative pure Cu foils processed under identical conditions. These results suggest that good interfacial adhesions between nanotubes and the Cu matrix have been achieved after the rolling-annealing-rolling processes

  14. Cu/single-walled carbon nanotube laminate composites fabricated by cold rolling and annealing

    Science.gov (United States)

    Li, Yan-Hui; Housten, William; Zhao, Yimin; Qiu Zhu, Yan

    2007-05-01

    The remarkable mechanical, electrical and thermal properties of single-walled carbon nanotubes (SWCNTs) have attracted extensive research interest as structural and functional materials. In particular, SWCNTs have been used to reinforce polymers and ceramic composites and great progress has been made. For metal matrix composites, the limitation of the conventional manufacturing process and the difficulty in dispersing nanotubes within metal matrices hinder the development of metal matrix composites. In this paper, we demonstrate a successful fabrication of Cu/SWCNT laminate composites by combined techniques of cold rolling and annealing, using 19 layers of large-area SWCNT films sandwiched between 20 layers of Cu thin foils. The tensile strength and Young's modulus of the resultant laminate composites are 361 MPa and 132 GPa, respectively, exhibiting an improvement over the comparative pure Cu foils processed under identical conditions. These results suggest that good interfacial adhesions between nanotubes and the Cu matrix have been achieved after the rolling-annealing-rolling processes.

  15. Molecular design of strong single-wall carbon nanotube/polyelectrolyte multilayer composites

    Science.gov (United States)

    Mamedov, Arif A.; Kotov, Nicholas A.; Prato, Maurizio; Guldi, Dirk M.; Wicksted, James P.; Hirsch, Andreas

    2002-11-01

    The mechanical failure of hybrid materials made from polymers and single-wall carbon nanotubes (SWNT) is primarily attributed to poor matrix-SWNT connectivity and severe phase segregation. Both problems can be successfully mitigated when the SWNT composite is made following the protocol of layer-by-layer assembly. This deposition technique prevents phase segregation of the polymer/SWNT binary system, and after subsequent crosslinking, the nanometre-scale uniform composite with SWNT loading as high as 50 wt% can be obtained. The free-standing SWNT/polyelectrolyte membranes delaminated from the substrate were found to be exceptionally strong with a tensile strength approaching that of hard ceramics. Because of the lightweight nature of SWNT composites, the prepared free-standing membranes can serve as components for a variety of long-lifetime devices.

  16. Toughening of epoxy matrices with reduced single-walled carbon nanotubes.

    Science.gov (United States)

    Martinez-Rubi, Yadienka; Ashrafi, Behnam; Guan, Jingwen; Kingston, Christopher; Johnston, Andrew; Simard, Benoit; Mirjalili, Vahid; Hubert, Pascal; Deng, Libo; Young, Robert J

    2011-07-01

    Reduced single-walled carbon nanotubes (r-SWCNT) are shown to react readily at room temperature under inert atmosphere conditions with epoxide moieties, such as those in triglycidyl p-amino phenol (TGAP), to produce a soft covalently bonded interface around the SWCNT. The soft interface is compatible with the SWCNT-free cross-linked cured matrix and acts as a toughener for the composite. Incorporation of 0.2 wt % r-SWCNT enhances the ultimate tensile strength, toughness and fracture toughness by 32, 118, and 40%, respectively, without change in modulus. A toughening rate (dK(IC)/dwt(f)) of 200 MPa m(0.5) is obtained. The toughening mechanism is elucidated through dynamic mechanical analyses, Raman spectroscopy and imaging, and stress-strain curve analyses. The method is scalable and applicable to epoxy resins and systems used commercially. PMID:21612292

  17. CVD-grown horizontally aligned single-walled carbon nanotubes: synthesis routes and growth mechanisms.

    Science.gov (United States)

    Ibrahim, Imad; Bachmatiuk, Alicja; Warner, Jamie H; Büchner, Bernd; Cuniberti, Gianaurelio; Rümmeli, Mark H

    2012-07-01

    Single-walled carbon nanotubes (SWCNTs) have attractive electrical and physical properties, which make them very promising for use in various applications. For some applications however, in particular those involving electronics, SWCNTs need to be synthesized with a high degree of control with respect to yield, length, alignment, diameter, and chirality. With this in mind, a great deal of effort is being directed to the precision control of vertically and horizontally aligned nanotubes. In this review the focus is on the latter, horizontally aligned tubes grown by chemical vapor deposition (CVD). The reader is provided with an in-depth review of the established vapor deposition orientation techniques. Detailed discussions on the characterization routes, growth parameters, and growth mechanisms are also provided. PMID:22619167

  18. Nanoscale finite element models for vibrations of single-walled carbon nanotubes:atomistic versus continuum

    Institute of Scientific and Technical Information of China (English)

    R ANSARI; S ROUHI; M ARYAYI

    2013-01-01

    By the atomistic and continuum finite element models, the free vibration behavior of single-walled carbon nanotubes (SWCNTs) is studied. In the atomistic finite element model, the bonds and atoms are modeled by the beam and point mass elements, respectively. The molecular mechanics is linked to structural mechanics to determine the elastic properties of the mentioned beam elements. In the continuum finite element approach, by neglecting the discrete nature of the atomic structure of the nanotubes, they are modeled with shell elements. By both models, the natural frequencies of SWCNTs are computed, and the effects of the geometrical parameters, the atomic structure, and the boundary conditions are investigated. The accuracy of the utilized methods is verified in comparison with molecular dynamic simulations. The molecular structural model leads to more reliable results, especially for lower aspect ratios. The present analysis provides valuable information about application of continuum models in the investigation of the mechanical behaviors of nanotubes.

  19. All-printed and transparent single walled carbon nanotube thin film transistor devices

    Science.gov (United States)

    Sajed, Farzam; Rutherglen, Christopher

    2013-09-01

    We present fully transparent single-walled all-carbon nanotube thin film transistors (SWCNT TFT) fabricated using low-cost inkjet printing methods. Such a demonstration provides a platform towards low cost fully printed transparent electronics. The SWCNT TFTs were printed with metallic and semiconducting SWCNT using a room temperature printing process, without the requirement of expensive cleanroom facilities. The unoptimized SWCNT TFTs fabricated exhibited an Ion/off ratio of 92 and mobility of 2.27 cm2V-1s-1 and transmissivity of 82%. The combination of both high electrical performance and high transparency make all-SWCNT TFTs desirable for next generation transparent display backplanes and products such as Google Glass.

  20. Atomic scale mass delivery driven by bend kink in single walled carbon nanotube

    International Nuclear Information System (INIS)

    The possibility of atomic scale mass delivery by bend kink in single walled carbon nanotube was investigated with the aid of molecular dynamics simulation. By keeping the bending angle while moving the tube end, the encapsulated atomic scale mass such as atom, molecule and atom group were successfully delivered through the nanotube. The van der Waals interaction between the encapsulated mass and the tube wall provided the driving force for the delivery. There were no dramatic changes in the van der Waals interaction, and a smooth and steady delivery was achieved when constant loading rate was applied. The influence of temperature on the atom group delivery was also analyzed. It is found raising temperature is harmful to the smooth movement of the atom group. However, the delivery rate can be promoted under higher temperature when the atom group is situated before the kink during the delivery.

  1. Polymer photovoltaic cell embedded with p-type single walled carbon nanotubes fabricated by spray process

    Science.gov (United States)

    Kim, Dal-Ho; Park, Jea-Gun

    2012-08-01

    In the current study, we fabricated polymer (poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61 butyric-acid methyl-ester (PCBM) blend) photovoltaic (PV) cells embedded with p-type single walled carbon nanotubes (SWCNTs) with tangled hair morphology. The power conversion efficiency (PCE) rapidly increased with SWCNT concentration of up to 6.83% coverage, and then decreased and saturated with increasing SWCNT concentration; i.e., the PCE peaks at 5.379%. This tendency is mainly associated with hole transport efficiency toward the transparent electrode (indium-tin-oxide (ITO)) via SWCNTs, directly determining the series resistance and shunt resistance of the polymer PV cells embedded with SWCNTs: the PV cell is increasing shunt resistance and decreasing series resistance.

  2. Molecular Dynamics for Elastic and Plastic Deformation of a Single-Walled Carbon Nanotube Under Nanoindentation

    Institute of Scientific and Technical Information of China (English)

    FANG Te-Hua; JIAN Sheng-Rui; CHUU Der-San

    2004-01-01

    @@ Mechanical characteristics of a suspended (10, 10) single-walled carbon nanotube (SWCNT) during atomic force microscopy (AFM) nanoindentation are investigated at different temperatures by molecular dynamics simulations.The results indicate that the Young modulus of the (10, 10) SWCNT under temperatures of 300-600K is 1.2-1.3 TPa. As the temperature increases, the Young modulus of the SWCNT increases, but the axial strain of the SWCNT decreases. The strain-induced spontaneous formation of the Stone-Wales defects and the rippled behaviour under inhomogeneous stress are studied. The rippled behaviour of the SWCNT is enhanced with the increasing axial strain. The adhesive phenomenon between the probe and the nanotube and the elastic recovery of the nanotube during the retraction are also investigated.

  3. Small Scale Effect on Thermal Vibration of Single-Walled Carbon Nanotubes with Nonlocal Boundary Condition

    Directory of Open Access Journals (Sweden)

    Li Ming

    2013-03-01

    Full Text Available In this study, a single beam model has been developed to analyze the thermal vibration of Single-Walled Carbon Nanotubes (SWCNT. The nonlocal elasticity takes into account the effect of small size into the formulation and the boundary condition. With exact solution of the dynamic governing equations, the thermal-vibrational characteristics of a cantilever SWCNT are obtained. Influence of nonlocal small scale effects, temperature change and vibration modes of the CNT on the frequency are investigated. The present study shows that the additional boundary conditions from small scale do not change natural frequencies at different temperature change. Thus for simplicity, one can apply the local boundary condition to replace the small scale boundary condition.

  4. Selective electroless coating of palladium nanoparticles on metallic single-walled carbon nanotube

    Science.gov (United States)

    Feng, Yiyu; Lv, Peng; Zhang, Xuequan; Li, Yu; Feng, Wei

    2010-08-01

    The selective electroless coating of palladium (Pd) nanoparticles on metallic single-walled carbon nanotube (SWNT) was studied. The remarkable increase in conductivity of SWNT/Pd films up to fourfold higher than pure SWNT was due to p-type doping and Ohmic contact. Metallic behavior of SWNT/Pd-Field effect transistor (on/off ratio=1.2) was attributed to more hole carriers and no electrostatic barrier between nanotube and Pd. G-band and radial breathing mode in Raman indicates a definitive increase in the proportion of metallic SWNT. Results indicate Pd are selectively coated on metallic SWNT with more negative potential allowing for the electroless Pd2+ reduction.

  5. Electromagnetic interference (EMI) shielding of single-walled carbon nanotube epoxy composites.

    Science.gov (United States)

    Li, Ning; Huang, Yi; Du, Feng; He, Xiaobo; Lin, Xiao; Gao, Hongjun; Ma, Yanfeng; Li, Feifei; Chen, Yongsheng; Eklund, Peter C

    2006-06-01

    Single-walled carbon nanotube (SWNT)-polymer composites have been fabricated to evaluate the electromagnetic interference (EMI) shielding effectiveness (SE) of SWNTs. Our results indicate that SWNTs can be used as effective lightweight EMI shielding materials. Composites with greater than 20 dB shielding efficiency were obtained easily. EMI SE was tested in the frequency range of 10 MHz to 1.5 GHz, and the highest EMI shielding efficiency (SE) was obtained for 15 wt % SWNT, reaching 49 dB at 10 MHz and exhibiting 15-20 dB in the 500 MHz to 1.5 GHz range. The EMI SE was found to correlate with the dc conductivity, and this frequency range is found to be dominated by reflection. The effects of SWNT wall defects and aspect ratio on the EMI SE were also studied. PMID:16771569

  6. A dislocation model for the pentagon-heptagon pair in zigzag single-walled carbon nanotubes

    Science.gov (United States)

    Wang, Shao Feng; Zhang, Hui Li; Zhi Wu, Xiao

    2010-06-01

    The pentagon-heptagon (5/7) pair in a zigzag single-walled carbon nanotube (SWCNT) is described as a dislocation by the modified Peierls-Nabarro (P-N) theory. The theory takes discrete effects, size effects and curvature effects into account. The bonds variation and shape distortion caused by 5/7 pair have been evaluated. It is found that the neck bond (shared bond) becomes longer while the shoulder bonds become shorter comparing with the one of the hexagons. The results show that the zigzag chain across the center of the 5/7 pair will bend slightly in the axis direction towards the heptagon, and the tube will be flattened where the 5/7 pair is located because of the appearance of the internal stress and nonzero curvature.

  7. Hydrogen Storage in Benzene Moiety Decorated Single-Walled Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bing-Yun; LIANG Qi-Min; SONG Chen; XIA Yue-Yuan; ZHAO Ming-wen; LIU Xiang-Dong; ZHANG Hong-Yu

    2006-01-01

    The hydrogen storage capacity of(5,5)single-walled carbon nanotubes(SWNTs)decorated chemically with benzene moieties is studied by using molecular dynamics simulations(MDSs)and density functional theory(DFT) calculations.It is found that benzene molecules colliding on (5,5) SWNTs at incident energy of 50 eV form very stable configurations of benzene moiety adsorption on the wall of SWNTs.The MDSs indicate that when the benzene moiety decorated(5,5)SWNTs and a pristine(5,5)SWNT are put in a box in which hydrogen molecules are filled to a pressure of~26 atm,the hydrogen storage capacity of the benzene moiety decorated(5,5)SWNT is about 4.7wt.% and that of the pristine (5,5) SwNT is nearly 3.9 wt.%.

  8. Direct Electrochemistry of Glucose Oxidase at a Gold Electrode Modified with Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yuan Zhuobin

    2003-12-01

    Full Text Available The direct electrochemistry of glucose oxidase (GOD was accomplished at a gold electrode modified with single-wall carbon nanotubes (SWNTs. A pair of welldefined redox peaks was obtained for GOD with the reduction peak potential at –0.465 V and a peak potential separation of 23 mV at pH 7.0. Both FT-IR spectra and the dependence of the reduction peak current on the scan rate revealed that GOD adsorbed onto the SWNT surfaces. The redox wave corresponds to the redox center of the flavin adenine dinucleotide(FAD of the GOD adsorbate. The electron transfer rate of GOD redox reaction was greatly enhanced at the SWNT-modified electrode. The peak potential was shown to be pH dependent. Verified by spectral methods, the specific enzyme activity of GOD adsorbates at the SWNTs appears to be retained.

  9. Single-walled carbon nanotubes functionalized by a series of dichlorocarbenes: DFT study

    Science.gov (United States)

    Petrushenko, Igor K.; Petrushenko, Konstantin B.

    2016-02-01

    The structural and elastic properties of neutral and ionized dichlorocarbene (CCl2) functionalized single-walled carbon nanotubes (SWCNTs) were studied using density functional theory (DFT). The Young’s modulus of ionized pristine SWCNTs is found to decrease in comparison to that of neutral models. The interesting effect of increase in Young’s modulus values of ionized functionalized SWCNTs is observed. We ascribe this feature to the concurrent processes of the bond elongation on ionization and the local deformation on cycloaddition. The strong dependence of the elasticity modulus on the number of addends is also observed. However, the CCl2-attached SWCNTs in their neutral and ionized forms remain strong enough to be suitable for the reinforcement of composites. In contrast to the elastic properties, the binding energies do not change significantly, irrespective of CCl2 coverage.

  10. Diameter Tuning of Single-Walled Carbon Nanotubes by Diffusion Plasma CVD

    Directory of Open Access Journals (Sweden)

    Toshiaki Kato

    2011-01-01

    Full Text Available We have realized a diameter tuning of single-walled carbon nanotubes (SWNTs by adjusting process gas pressures with plasma chemical vapor deposition (CVD. Detailed photoluminescence measurements reveal that the diameter distribution of SWNTs clearly shifts to a large-diameter region with an increase in the pressure during plasma CVD, which is also confirmed by Raman scattering spectroscopy. Based on the systematical investigation, it is found that the main diameter of SWNTs is determined by the pressure during the heating in an atmosphere of hydrogen and the diameter distribution is narrowed by adjusting the pressure during the plasma generation. Our results could contribute to an application of SWNTs to high-performance thin-film transistors, which requires the diameter-controlled semiconductor-rich SWNTs.

  11. Tuning the driving force for exciton dissociation in single-walled carbon nanotube heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Ihly, Rachelle; Mistry, Kevin S.; Ferguson, Andrew J.; Clikeman, Tyler T.; Larson, Bryon W.; Reid, Obadiah; Boltalina, Olga V.; Strauss, Steven H.; Rumbles, Garry; Blackburn, Jeffrey L.

    2016-04-25

    Understanding the kinetics and energetics of interfacial electron transfer in molecular systems is crucial for the development of a broad array of technologies, including photovoltaics, solar fuel systems and energy storage. The Marcus formulation for electron transfer relates the thermodynamic driving force and reorganization energy for charge transfer between a given donor/acceptor pair to the kinetics and yield of electron transfer. Here we investigated the influence of the thermodynamic driving force for photoinduced electron transfer (PET) between single-walled carbon nanotubes (SWCNTs) and fullerene derivatives by employing time-resolved microwave conductivity as a sensitive probe of interfacial exciton dissociation. For the first time, we observed the Marcus inverted region (in which driving force exceeds reorganization energy) and quantified the reorganization energy for PET for a model SWCNT/acceptor system. The small reorganization energies (about 130 meV, most of which probably arises from the fullerene acceptors) are beneficial in minimizing energy loss in photoconversion schemes.

  12. Coupling between flexural modes in free vibration of single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rumeng; Wang, Lifeng, E-mail: walfe@nuaa.edu.cn [State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, 210016 Nanjing (China)

    2015-12-15

    The nonlinear thermal vibration behavior of a single-walled carbon nanotube (SWCNT) is investigated by molecular dynamics simulation and a nonlinear, nonplanar beam model. Whirling motion with energy transfer between flexural motions is found in the free vibration of the SWCNT excited by the thermal motion of atoms where the geometric nonlinearity is significant. A nonlinear, nonplanar beam model considering the coupling in two vertical vibrational directions is presented to explain the whirling motion of the SWCNT. Energy in different vibrational modes is not equal even over a time scale of tens of nanoseconds, which is much larger than the period of fundamental natural vibration of the SWCNT at equilibrium state. The energy of different modes becomes equal when the time scale increases to the microsecond range.

  13. Antenna-coupled terahertz radiation from joule-heated single-wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    M. Muthee

    2011-12-01

    Full Text Available In this letter an experimental method is introduced that allows detection of terahertz (THz radiation from arrays of joule-heated Single-Walled Carbon Nanotubes (SWCNTs, by coupling this radiation through integrated antennas and a silicon lens. The radiation forms a diffraction-limited beam with a total maximum radiated power of 450 nW, significantly greater than the power estimated from Nyquist thermal noise (8 nW. The physical radiation process is unknown at this stage, but possible explanations for the high radiated power are discussed briefly. The emission has a typical bandwidth of 1.2 THz and can be tuned to different frequencies by changing the dimensions of the antennas. Arrays of the devices could be integrated in CMOS integrated circuits, and find application in THz systems, such as in near-range medical imaging.

  14. Non-covalent functionalization of single wall carbon nanotubes and graphene by a conjugated polymer

    KAUST Repository

    Jilili, Jiwuer

    2014-07-07

    We report first-principles calculations on the binding of poly[(9,9-bis-(6-bromohexylfluorene-2,7-diyl)-co-(benzene-1,4-diyl)] to a (8,0) single wall carbon nanotube (SWCNT) and to graphene. Considering different relative orientations of the subsystems, we find for the generalized gradient approximation a non-binding state, whereas the local density approximation predicts reasonable binding energies. The results coincide after inclusion of van der Waals corrections, which demonstrates a weak interaction between the polymer and SWCNT/graphene, mostly of van der Waals type. Accordingly, the density of states shows essentially no hybridization. The physisorption mechanism explains recent experimental observations and suggests that the conjugated polymer can be used for non-covalent functionalization.

  15. Roll to plate printed stretchable silver electrode using single walled carbon nanotube on elastomeric substrate.

    Science.gov (United States)

    Jung, Minhun; Noh, Jinsoo; Kim, Junseok; Kim, Donghwan; Cho, Gyoujin

    2013-08-01

    Stretchable electronics may open new applications in display, sensors and actuators. To attain the stretchable electronics, the ink formulation should be compatible with elastomeric substrates. Here, we present the formulation of silver nanoparticles and single walled carbon nanotubes (SWNTs) for printing stretchable silver electrodes on the elastomeric substrates. Highly conductive stretchable electrodes can be printed directly on the poly(styrene-b-butadiene-b-styrene) (PSBS) substrates by roll to plate (R2P) gravure printer. During the stretching test, R2P printed silver based stretchable electrodes show the high conductivity of 1000 S cm(-1) at 0.27 wt% of SWNT loading. Furthermore, the resistance of the printed silver electrode was not changed up to 15% of tensile strain. PMID:23882805

  16. Detecting Lyme disease using antibody-functionalized carbon nanotubes

    Science.gov (United States)

    Dailey, Jennifer; Lerner, Mitchell; Goldsmith, Brett; Brisson, Dustin; Johnson, A. T. Charlie

    2011-03-01

    We combine antibodies for Lyme flagellar protein with carbon nanotube transistors to create an electronic sensor capable of definitive detection of Lyme disease. Over 35,000 cases of Lyme disease are reported in the United States each year, of which more than 23 percent are originally misdiagnosed. Rational design of the coupling of the biological system to the electronic system gives us a flexible sensor platform which we can apply to several biological systems. By coupling these antibodies to carbon nanotubes in particular, we allow for fast, sensitive, highly selective, electronic detection. Unlike antibody or biomarker detection, bacterial protein detection leads to positive identification of both early and late stage bacterial infections, and is easily expandable to environmental monitoring.

  17. Sodium insertion/extraction from single-walled and multi-walled carbon nanotubes: The differences and similarities

    Science.gov (United States)

    Goonetilleke, Damian; Pramudita, James C.; Choucair, Mohammad; Rawal, Aditya; Sharma, Neeraj

    2016-05-01

    A comparative study on the sodium-ion insertion and extraction of commercially-available multi-wall and single-wall carbon nanotubes is reported. Single-wall carbon nanotubes exhibit charge/discharge capacities of 126 mA h g-1 and multi-wall carbon nanotubes produce a lower capacity of 28 mA h g-1 after 50 cycles at 25 mA g-1. To understand these differences, a combination of X-ray diffraction and solid state nuclear magnetic resonance measurements were performed at various states of sodium insertion and extraction.23Na nuclear magnetic resonance studies, a technique previously rarely used for characterising electrodes from sodium-ion batteries, shows differences in the sodium chemical environment near multi-wall compared to single-wall carbon nanotubes with distinct sodium sites found to be active during sodium insertion and extraction for the carbon nanotubes. Both types of carbon nanotubes show a similar amount of reversible sodium available for insertion/extraction reactions, but multi-wall carbon nanotubes feature half the initial insertion capacity relative to single-wall carbon nanotubes. The electrochemical performance of the carbon nanotube electrodes are discussed in relation to the observed mechanism of sodium insertion.

  18. Interaction of amidated single-walled carbon nanotubes with protein by multiple spectroscopic methods

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lili [China Pharmaceutical University, Nanjing 210009 (China); The Nursing College of Pingdingshan University, Pingdingshan 467000 (China); Lin, Rui [Yancheng Health Vocational and Technical College, Yancheng 224005 (China); He, Hua, E-mail: dochehua@163.com [China Pharmaceutical University, Nanjing 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, China Pharmaceutical University, Nanjing 210009 (China); Sun, Meiling, E-mail: sml-nir@sohu.com [China Pharmaceutical University, Nanjing 210009 (China); Jiang, Li; Gao, Mengmeng [China Pharmaceutical University, Nanjing 210009 (China)

    2014-01-15

    The aim of this work was to investigate the detailed interaction between BSA and amidated single walled carbon nanotubes (e-SWNTs) in vitro. Ethylenediamine (EDA) was successfully linked on the surface of single-walled carbon nanotubes (SWNTs) via acylation to improve their dispersion and to introduce active groups. Bovine serum albumin (BSA) was selected as the template protein to inspect the interaction of e-SWNTs with protein. Decreases in fluorescence intensity of BSA induced by e-SWNTs demonstrated the occurrence of interaction between BSA and e-SWNTs. Quenching parameters and different absorption spectra for e-SWNTs–BSA show that the quenching effect of e-SWNTs was static quenching. Hydrophobic force had a leading contribution to the binding roles of BSA on e-SWNTs, which was confirmed by positive enthalpy change and entropy change. The interference of Na{sup +} with the quenching effect of e-SWNTs authenticated that electrostatic force existed in the interactive process simultaneously. The hydrophobicity of amino acid residues markedly increased with the addition of e-SWNTs viewed from UV spectra of BSA. The content of α-helix structure in BSA decreased by 6.8% due to the addition of e-SWNTs, indicating that e-SWNTs have an effect on the secondary conformation of BSA. -- Highlights: • The interaction between e-SWNTs and BSA was investigated by multiple spectroscopic methods. • Quenching mechanism was static quenching. • Changes in structure of BSA were inspected by synchronous fluorescence, UV–vis and CD spectrum.

  19. Impact of single-walled carbon nanotubes on the embryo: a brief review

    Directory of Open Access Journals (Sweden)

    Al Moustafa AE

    2016-01-01

    Full Text Available Ala-Eddin Al Moustafa,1–4 Etienne Mfoumou,5 Dacian E Roman,3 Vahe Nerguizian,6 Anas Alazzam,7 Ion Stiharu,3 Amber Yasmeen8 1College of Medicine & Biomedical Research Centre, Qatar University, Doha, Qatar; 2Oncology Department, McGill University, 3Mechanical and Industrial Engineering Department, Concordia University, Montreal, QC, Canada; 4Syrian Research Cancer Centre of the Syrian Society against Cancer, Aleppo, Syria; 5Nova Scotia Community College, Dartmouth, NS, 6École de Technologie Supérieure, Montreal, QC, Canada; 7Department of Mechanical Engineering, Khalifa University, Abu Dhabi, UAE; 8Segal Cancer Centre, Lady Davis Institute for Medical Research of the Sir Mortimer B. Davis-Jewish General Hospital, Montreal, QC, Canada Abstract: Carbon nanotubes (CNTs are considered one of the most interesting materials in the 21st century due to their unique physiochemical characteristics and applicability to various industrial products and medical applications. However, in the last few years, questions have been raised regarding the potential toxicity of CNTs to humans and the environment; it is believed that the physiochemical characteristics of these materials are key determinants of CNT interaction with living cells and hence determine their toxicity in humans and other organisms as well as their embryos. Thus, several recent studies, including ours, pointed out that CNTs have cytotoxic effects on human and animal cells, which occur via the alteration of key regulator genes of cell proliferation, apoptosis, survival, cell–cell adhesion, and angiogenesis. Meanwhile, few investigations revealed that CNTs could also be harmful to the normal development of the embryo. In this review, we will discuss the toxic role of single-walled CNTs in the embryo, which was recently explored by several groups including ours. Keywords: single-walled carbon nanotubes, embryo, toxicity

  20. The separation and substrate independent organization of single-wall carbon nanotubes

    Science.gov (United States)

    Chattopadhyay, Debjit D.

    Learning how to separate, purify and manipulate single wall carbon nanotubes (SWNTs) presents a unique challenge in material science. The processing-related difficulties of these long nano-fibers stem from their high aspect ratio, rigidity and the profound hydrophobic attractions along their tubular walls. Shortening them into discrete segments, with lengths from tens to hundreds of nanometers, presents a viable methodology to alleviate the shape-induced intractability. The thesis presents a route for the length fractionation of shortened-S WNTs, and most importantly provides a venue by which substantial separation of single wall carbon nanotubes (SWNTs) according to type (metallic versus semiconducting) has been achieved for HiPco and laser-ablated SWNTs. Herein I argue that stable dispersions of SWNTs with octadecylamine (ODA) in tetrahydrofuran (THF) originate from the physisorption and organization of ODA along the SWNT sidewalls in addition to the originally proposed zwitterion model. Furthermore, the reported affinity of amine groups for semiconducting SWNTs, as opposed to their metallic counterparts contributes additional stability to the physisorbed ODA. This provides a venue for the selective precipitation of metallic SWNTs upon increasing dispersion concentration, as indicated by Raman investigations. In addition, the thesis provides a novel metal-assisted self-organization of these nanosized objects into nano-forest geometries with dense perpendicular surface grafting, and demonstrates that such nanosized objects hold significant promise for the development of nanoscale sensors. Additionally, this dissertation provides a method for the complete elimination of catalytic impurities from SWNTs. Electrochemical actuators using such purified SWNTs have been characterized.

  1. Interaction of amidated single-walled carbon nanotubes with protein by multiple spectroscopic methods

    International Nuclear Information System (INIS)

    The aim of this work was to investigate the detailed interaction between BSA and amidated single walled carbon nanotubes (e-SWNTs) in vitro. Ethylenediamine (EDA) was successfully linked on the surface of single-walled carbon nanotubes (SWNTs) via acylation to improve their dispersion and to introduce active groups. Bovine serum albumin (BSA) was selected as the template protein to inspect the interaction of e-SWNTs with protein. Decreases in fluorescence intensity of BSA induced by e-SWNTs demonstrated the occurrence of interaction between BSA and e-SWNTs. Quenching parameters and different absorption spectra for e-SWNTs–BSA show that the quenching effect of e-SWNTs was static quenching. Hydrophobic force had a leading contribution to the binding roles of BSA on e-SWNTs, which was confirmed by positive enthalpy change and entropy change. The interference of Na+ with the quenching effect of e-SWNTs authenticated that electrostatic force existed in the interactive process simultaneously. The hydrophobicity of amino acid residues markedly increased with the addition of e-SWNTs viewed from UV spectra of BSA. The content of α-helix structure in BSA decreased by 6.8% due to the addition of e-SWNTs, indicating that e-SWNTs have an effect on the secondary conformation of BSA. -- Highlights: • The interaction between e-SWNTs and BSA was investigated by multiple spectroscopic methods. • Quenching mechanism was static quenching. • Changes in structure of BSA were inspected by synchronous fluorescence, UV–vis and CD spectrum

  2. Ab initio simulations of doped single-walled carbon nanotube sensors

    International Nuclear Information System (INIS)

    Graphical abstract: Ab initio calculations used to study O-doped and N-doped SWNT within the framework of the DFT. We introduced new type of gas sensor that can detect the presence of H2, Cl2, NO, and CO molecules. Band-gap narrowing occurs when the nanotube is doped with oxygen or nitrogen atoms. We proposed a new methodology of designing reliable, sensitive, and selective nanotube sensors. Highlights: ►Ab initio calculations used to study O-doped and N-doped SWNT within the framework of the DFT. ► We introduced new type of gas sensor that can detect the presence of H2, Cl2, NO, and CO molecules. ►Band-gap narrowing occurs when the nanotube is doped with oxygen or nitrogen atoms. ► We proposed a new methodology of designing reliable, sensitive, and selective nanotube sensors. - Abstract: The interactions between oxygen and nitrogen atoms with single-walled carbon nanotubes were investigated for nanotubes with two different geometrical configurations using first-principle calculations within the framework of the density functional theory. We introduced a new type of toxic gas sensor that can detect the presence of H2, Cl2, CO, and NO molecules. We also demonstrated that the sensitivity of this device can be controlled by the concentration of the dopants on the surface of the nanotube. In addition, the transport properties of the doped nanotube were studied for different concentrations of oxygen or nitrogen atoms that were randomly distributed on the surface of the single-walled carbon nanotube. We observed that small amounts of dopants can modify the electronic and transport properties of the nanotube and can lend metallic properties to the nanotube. Band-gap narrowing occurs when the nanotube is doped with either oxygen or nitrogen atoms.

  3. Optical heating and temperature determination of core-shell gold nanoparticles and single-walled carbon nanotube microparticles.

    Science.gov (United States)

    Yashchenok, Alexey; Masic, Admir; Gorin, Dmitry; Inozemtseva, Olga; Shim, Bong Sup; Kotov, Nicholas; Skirtach, Andre; Möhwald, Helmuth

    2015-03-18

    The real-time temperature measurement of nanostructured materials is particularly attractive in view of increasing needs of local temperature probing with high sensitivity and resolution in nanoelectronics, integrated photonics, and biomedicine. Light-induced heating and Raman scattering of single-walled carbon nanotubes with adsorbed gold nanoparticles decorating silica microparticles are reported, by both green and near IR lasers. The plasmonic shell is used as nanoheater, while the single-walled carbon nanotubes are Raman active and serve as a thermometer. Stokes and Anti-Stokes Raman spectra of single-walled carbon nanotubes serve to estimate the effective light-induced temperature rise on the metal nanoparticles. The temperature rise is constant with time, indicating stability of the adsorption density. The effective temperatures derived from Stokes and Anti-Stokes intensities are correlated with those measured in a heating stage. The resolution of the thermal experiments in our study was found to be 5-40 K. PMID:25367373

  4. Commensurate Phases of Kr Adsorbed on Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Mbaye, Mamadou T.; Maiga, Sidi M.; Gatica, Silvina M.

    2016-02-01

    In this paper, we show that Krypton atoms form a commensurate solid (CS) phase with a fractional coverage of one krypton atom per every four carbons on zigzag carbon nanotubes. This is a unique phase, different from the √{3} × √{3} R30° CS monolayer formed on graphite, which has a lower coverage of one krypton atom per every six carbons. Our prediction disagrees with experiments that observe in nanotubes the same solid structure found on graphite. In order to address this discrepancy, we simulated adsorption of Kr on zigzag and armchair single-walled carbon nanotubes with radii ranging from 4.7 to 28.83 Å. Our simulations confirm that the CS of coverage 1/4 forms on medium-sized zigzag nanotubes. We also found the 1/6-coverage solid on graphene, which represents the infinite-radius limit of a nanotube. Our findings are key to experiments of adsorption on nanotubes where the interpretation and justification of the results are based on the monolayer coverage, such as mass or conductance isotherms measurements.

  5. Effect of chemical treatment on the thermoelectric properties of single walled carbon nanotube networks

    Energy Technology Data Exchange (ETDEWEB)

    Piao, Mingxing; Alam, Mina Rastegar; Kim, Gyutae; Dettlaff-Weglikowska, Urszula; Roth, Siegmar [School of Electrical Engineering, WCU Flexible Nano-Systems, Korea University, Seoul (Korea, Republic of)

    2012-12-15

    Carbon nanotube networks showing superior electric properties, high chemical stability, strong mechanical properties, and flexibility are also known to exhibit thermoelectric effects. However, the experimental thermoelectric figure of merit, ZT, of pristine carbon nanotubes is typically in the range of 10{sup -3}-10{sup -2}, which is still not attractive for thermal energy conversion applications. In this work, we show possible ways to improve the thermoelectric properties of single walled carbon nanotubes (SWCNTs) by means of chemical treatments. In this study, we primarily investigated the effect of chemical treatment on the electrical conductivity and thermoelectric power (TEP) of the entangled network of nanotubes, also, known as ''buckypaper''. This chemical treatment increased the electrical conductivity due to p-type doping, thereby, showing a decrease in the TEP given by the Seebeck coefficient, whereas the n-type dopants changed the sign and value of the TEP from about 40 to -40 {mu}V K{sup -1}. Neutral polymers, in terms of doping, such as PVDF, PMMA, PVA, PS, and PC, were expected to hinder phonon transport through the nanotube network, increasing the Seebeck coefficient up to ca. 50 {mu}V K{sup -1}. Our results reveal the importance of chemical doping determining the sign and the magnitude of the TEP, and role of the polymer matrix in the development of more effective thermoelectric composites based on carbon nanotubes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Effect of chemical treatment on the thermoelectric properties of single walled carbon nanotube networks

    International Nuclear Information System (INIS)

    Carbon nanotube networks showing superior electric properties, high chemical stability, strong mechanical properties, and flexibility are also known to exhibit thermoelectric effects. However, the experimental thermoelectric figure of merit, ZT, of pristine carbon nanotubes is typically in the range of 10-3-10-2, which is still not attractive for thermal energy conversion applications. In this work, we show possible ways to improve the thermoelectric properties of single walled carbon nanotubes (SWCNTs) by means of chemical treatments. In this study, we primarily investigated the effect of chemical treatment on the electrical conductivity and thermoelectric power (TEP) of the entangled network of nanotubes, also, known as ''buckypaper''. This chemical treatment increased the electrical conductivity due to p-type doping, thereby, showing a decrease in the TEP given by the Seebeck coefficient, whereas the n-type dopants changed the sign and value of the TEP from about 40 to -40 μV K-1. Neutral polymers, in terms of doping, such as PVDF, PMMA, PVA, PS, and PC, were expected to hinder phonon transport through the nanotube network, increasing the Seebeck coefficient up to ca. 50 μV K-1. Our results reveal the importance of chemical doping determining the sign and the magnitude of the TEP, and role of the polymer matrix in the development of more effective thermoelectric composites based on carbon nanotubes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Properties of Cs-intercalated single wall carbon nanotubes investigated by 133Cs Nuclear Magnetic resonance

    KAUST Repository

    Schmid, Marc R.

    2012-11-01

    In the present study, we investigated Cs-intercalated single wall carbon nanotubes (SWCNTs) using 133Cs Nuclear Magnetic resonance. We show that there are two types of Cs cations depending on the insertion level. Indeed, at low concentrations, Static spectra analysis shows that the Cs (α)+ species are fully ionized, i.e. α equal ca.1, while at higher concentrations a second paramagnetically shifted line appears, indicating the formation of Cs (β)+ ions with β < α ∼ +1. At low concentrations and low temperatures the Cs (α)+ ions exhibit a weak hyperfine coupling to the SWCNT conduction electrons, whereas, at higher temperatures, a thermally activated slow-motion diffusion process of the Cs (α)+ ions occurs along the interstitial channels present within the carbon nanotube bundles. At high concentrations, the Cs (β)+ ions seem to occupy well defined positions relative to the carbon lattice. As a matter of fact, the Korringa relaxation behavior suggests a strong hyperfine coupling between Cs nuclei and conduction electrons in the carbon nanotubes and a partial charge transfer, which suggest a plausible Cs(6s)-C(2p) hybridization. © 2012 Elsevier Ltd. All rights reserved.

  8. Motion and energy dissipation of single-walled carbon nanotube on graphite by molecular dynamics simulation

    International Nuclear Information System (INIS)

    The motion and energy dissipation of carbon nanotubes (CNTs) have important influence on their application. This paper investigated the sliding of single-walled carbon nanotubes (SWCNTs) on a graphite substrate using molecular dynamics simulation. An interesting phenomenon was observed in the commensurate interface. The carbon nanotube slid in not only the initial velocity direction but also perpendicular to the initial velocity with only a slight rolling in the later stage of motion. The direction and distance of motion were related to the initial interfacial configuration when the CNT started to slide and presented a certain degree of randomness. This phenomenon could be attributed to the SWCNT not having a platform on the bottom, which caused a low interfacial potential barrier. Therefore, no obvious ‘stick-slip’ occurred. In the incommensurate state, the SWCNT slid on the graphite substrate in the initial direction for the process, and the velocity slowly decreased. The temperature slightly influenced the carbon nanotube’s motion mainly because of random thermal fluctuations. (papers)

  9. Threshold displacement energies in graphene and single-walled carbon nanotubes

    Science.gov (United States)

    Merrill, Andrew; Cress, Cory D.; Rossi, Jamie E.; Cox, Nathanael D.; Landi, Brian J.

    2015-08-01

    The threshold displacement energy Ed has been determined for graphene and 216 different (n , m ) single-walled carbon nanotube chiralities, with 5 ≤n ≤20 and 0 ≤m ≤n , under several model conditions using classical molecular dynamics. The model conditions vary by particle (electron or carbon ion), empirical potential (two parametrizations of Tersoff [J. Tersoff, Phys. Rev. B 39, 5566 (1989), 10.1103/PhysRevB.39.5566; L. Lindsay and D. A. Broido, Phys. Rev. B 81, 205441 (2010), 10.1103/PhysRevB.81.205441] and one of Brenner et al. [D. W. Brenner, O. A. Shenderova, J. A. Harrison, S. J. Stuart, B. Ni, and S. B. Sinnott, J. Phys.: Condens. Matter 14, 783 (2002), 10.1088/0953-8984/14/4/312]), and momentum transfer direction (towards or away from the nanotube axis). For electron irradiation simulations, Ed exhibits a smoothly varying chirality dependence and a characteristic curvature influenced by the momentum transfer direction. Changing the empirical potential shifts the magnitude of Ed, but the trend is preserved for electron simulations. However, the perturbation in the knock-on dynamics introduced by the carbon ion leads to Ed trends that diverge from the equivalent electron simulation. Thus, the ion interaction has a non-negligible effect on the dynamics of the collision and leads to Ed values that can distinctly vary depending on the selected carbon nanostructure.

  10. The Adsorption Properties of Bacillus atrophaeus Spores on Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    P. Cortes

    2009-01-01

    Full Text Available An adsorption equilibrium and a kinetic study of Bacillus atrophaeus on Single-Wall Carbon Nanotubes (SWCNTs were here performed to provide the basis for developing biosensor devices for detecting threatening micro-organisms in water supply systems. B. atrophaeus spores and carbon nanotubes were subjected to a batch adsorption process to document their equilibria and kinetics. Here, commercial nanotubes were either studied as received or were acid-purified before adsorption experiments. The Bacillus spores appear to show higher affinity towards the purified nanotubes than to the as-received nanomaterial. The effective diffusivity of the spores onto the purified nanotubes was found to be approximately 30 percent higher than onto the as-received nanotubes. It seems that the removal of amorphous carbon from the as-received nanotubes through a purification process yielded an intimate nantoubes-spore interaction as revealed by transmission electron microscopy. Freundlich model successfully correlated the adsorption equilibrium data for the nanotubes-spore interaction. Transmission electron micrographs showed extensive contact between the Bacillus and the purified nanotubes, but the association appeared less intimate between the spores and the as-received nanotubes.

  11. Phthalimide containing donor-acceptor polymers for effective dispersion of single-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Baris Yilmaz

    2015-08-01

    Full Text Available Single-walled carbon nanotubes have been dispersed by novel phthalimide containing donor-acceptor type copolymers in organic media. Brominated phthalimide comonomer has been copolymerized with several electron rich structures using Suzuki and Stille coupling reactions. Carbon nanotube dispersion capability of the resultant polymers has been assessed by exploiting the non-covalent interaction of nanotube surface with the pi-system of conjugated backbone of polymers. Four polymers have been found to be good candidates for individually dispersing nanotubes in solution. In order to identify the dispersed nanotube species, 2D excitation-emission map and Raman spectroscopy have been performed. Molecular dynamics modelling has been utilized to reveal the binding energies of dispersants with the nanotube surface and the simulation results have been compared with the experimental findings. Both experimental and theoretical results imply the presence of a complex mechanism that governs the extent of dispersion capacity and selectivity of each conjugated polymeric dispersant in solubilizing carbon nanotubes.

  12. Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics simulations

    International Nuclear Information System (INIS)

    Nonstationary heat conduction in a single-walled carbon nanotube was investigated by applying a local heat pulse with duration of subpicoseconds. The investigation was based on classical molecular dynamics simulations, where the heat pulse was generated as coherent fluctuations by connecting a thermostat to the local cell for a short duration. The heat conduction through the nanotube was observed in terms of spatiotemporal temperature profiles. Results of the simulations exhibit non-Fourier heat conduction where a distinct amount of heat is transported in a wavelike form. The geometry of carbon nanotubes allows us to observe such a phenomenon in the actual scale of the material. The resulting spatiotemporal profile was compared with the available macroscopic equations, the so-called non-Fourier heat conduction equations, in order to investigate the applicability of the phenomenological models to a quasi-one-dimensional system. The conventional hyperbolic diffusion equation fails to predict the heat conduction due to the lack of local diffusion. It is shown that this can be remedied by adopting a model with dual relaxation time. Further modal analyses using wavelet transformations reveal a significant contribution of the optical phonon modes to the observed wavelike heat conduction. The result suggests that, in carbon nanotubes with finite length where the long-wavelength acoustic phonons behave ballistically, even optical phonons can play a major role in the non-Fourier heat conduction

  13. Effects of temperature and torsion speed on torsional properties of single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs) are excellent candidates for torsional elements used in nanoelectro-mechanical systems (NEMS). Simulations show that after being twisted to a certain angle, they buckle and lose their mechanical strength. In this paper, classical molecular dynamics simulations are performed on single-walled carbon nanotubes (CNTs) to investigate the effects of torsion speed and temperature on CNT torsional properties. The AIREBO potential is employed to describe the bonded interactions between carbon atoms. The MD simulations clearly show that the buckling of CNTs in torsion is a reversible process, in which by unloading the buckled CNT in opposite direction, it returns to its original configuration. In addition, the numerical results reveal that the torsional shear modulus of CNTs increases by increasing the temperature and decreasing the torsion speed. Furthermore, the buckling torsion angle of CNTs increases by increasing the torsion speed and decreasing the temperature. Finally, it is observed that torsional properties of CNTs are highly affected by speed of twist and temperature of the nanotubes.

  14. Mechanical properties of non-reconstructed defective single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Scarpa, F [Advanced Composites Centre for Innovation and Science, University of Bristol, BS8 1TR Bristol (United Kingdom); Adhikari, S; Wang, C Y, E-mail: f.scarpa@bris.ac.u, E-mail: scarpa.fabrizio@gmail.co [School of Engineering, Swansea University, Swansea (United Kingdom)

    2009-07-21

    This paper describes the equivalent homogeneous uniaxial mechanical properties of defective single-wall carbon nanotubes. In particular, non-reconstructed defects that can be produced by ion or electronic irradiation have been considered. A discrete nonlinear finite-element approach based on the mechanical properties of individual carbon-carbon (C-C) bonds has been used. The individual C-C bonds in turn were simulated as beam structural elements. Extensive Monte Carlo based numerical simulation has been reported in the paper. The results show that the homogeneous elastic properties of the defective nanotubes can be qualitatively and quantitatively different from the pristine configurations. The defective nanotubes show a slight reduction in axial stiffness (Young's modulus), but large variations of Poisson's ratio outside the elastic bounds for isotropic materials, depending on the locations of the vacancies. The large fluctuations of Poisson's ratio can lead to extreme positive transversal contractions or to auxetic behaviour when the nanotubes are subjected to tensile loading. (fast track communication)

  15. Theoretical Investigation on the Solubilization in Water of Functionalized Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Michael Mananghaya

    2012-01-01

    Full Text Available An important technique to increase the solubility and reactivity of carbon nanotube is through functionalization. In this study, the effects of functionalization of some single-walled carbon nanotubes (SWCNTs were investigated with the aid of density functional theory. The SWCNT model used in the study consists of a finite, (5, 0 zigzag nanotube segment containing 60 C atoms with hydrogen atoms added to the dangling bonds of the perimeter carbons. There are three water-dispersible SWCNTs used in this study that were functionalized with (a formic acid, as a model of carboxylic acid, (b isophthalic acid, as a model aromatic dicarboxylic acid, and (c benzenesulfonic acid, as a model aromatic sulfonic acid. Binding energies of the organic radicals to the nanotubes are calculated, as well as the HOMO-LUMO gaps and dipole moments of both nanotubes and functionalized nanotubes. Binding was found out to be thermodynamically favorable. The functionalization increases the electrical dipole moments and results in an enhancement in the solubility of the nanotubes in water manifested through favorable changes in the free energies of solvation. This should lower the toxicity of nanotubes and improve their biocompatibility.

  16. Hydrothermally Oxidized Single-Walled Carbon Nanotube Networks for High Volumetric Electrochemical Energy Storage.

    Science.gov (United States)

    Liu, Tianyuan; Davijani, Amir A Bakhtiary; Sun, Jingying; Chen, Shuo; Kumar, Satish; Lee, Seung Woo

    2016-07-01

    Improving volumetric energy density is one of the major challenges in nanostructured carbon electrodes for electrochemical energy storage device applications. Herein, a simple hydrothermal oxidation process of single-walled carbon nanotube (SWNT) networks in dilute nitric acid is reported, enabling simultaneous physical densification and chemical functionalization of the as-assembled randomly-packed SWNT films. After the hydrothermal oxidation process, the density of the SWNT films increases from 0.63 to 1.02 g cm(-3) and a considerable amount of redox-active oxygen functional groups are introduced on the surface of the SWNTs. The functionalized SWNT films are used as positive electrodes against Li metal negative electrodes for potential Li-ion capacitors or Li-ion battery applications. The functionalized SWNT electrodes deliver high volumetric as well as gravimetric capacities, 154 Ah L(-1) and 152 mAh g(-1) , respectively, owing to the surface redox reactions between the introduced oxygen functional groups and Li ions. In addition, these electrodes exhibit a remarkable rate-capability by retaining its high capacity of 94 Ah L(-1) (92 mAh g(-1) ) at a high discharge rate of 10 A g(-1) . These results demonstrate the simple hydrothermal oxidation process as an attractive strategy for improving the volumetric performance of nanostructured carbon electrodes. PMID:27200509

  17. Functionalization of Single-Wall Carbon Nanotubes by Photo-Oxidation

    Science.gov (United States)

    Lebron-Colon, Marisabel; Meador, Michael A.

    2010-01-01

    new technique for carbon nanotube oxidation was developed based upon the photo-oxidation of organic compounds. The resulting method is more benign than conventional oxidation approaches and produces single-wall carbon nanotubes (SWCNTs) with higher levels of oxidation. In this procedure, an oxygen saturated suspension of SWNTs in a suitable solvent containing a singlet oxygen sensitizer, such as Rose Bengal, is irradiated with ultraviolet light. The resulting oxidized tubes are recovered by filtering the suspension, followed by washing to remove any adsorbed solvent and sensitizer, and drying in a vacuum oven. Chemical analysis by FT-infrared and x-ray photoelectron spectroscopy revealed that the oxygen content of the photo-oxidized SWCNT was 11.3 atomic % compared to 6.7 atomic % for SWCNT that had been oxidized by standard treatment in refluxing acid. The photo-oxidized SWCNT produced by this method can be used directly in various polymer matrixes, or can be further modified by chemical reactions at the oxygen functional groups and then used as additives. This method may also be suitable for use in oxidation of multiwall carbon nanotubes and graphenes.

  18. Theoretical Investigation on the Solubilization in Water of Functionalized Single-Wall Carbon Nano tubes

    International Nuclear Information System (INIS)

    An important technique to increase the solubility and reactivity of carbon nano tube is through functionalization. In this study, the effects of functionalization of some single-walled carbon nano tubes (SWCNTs) were investigated with the aid of density functional theory. The SWCNT model used in the study consists of a finite, (5, 0) zigzag nano tube segment containing 60 C atoms with hydrogen atoms added to the dangling bonds of the perimeter carbons. There are three water-dispersible SWCNTs used in this study that were functionalized with (a) formic acid, as a model of carboxylic acid, (b) isophthalic acid, as a model aromatic dicarboxylic acid, and (c) benzenesulfonic acid, as a model aromatic sulfonic acid. Binding energies of the organic radicals to the nano tubes are calculated, as well as the HOMO-LUMO gaps and dipole moments of both nano tubes and functionalized nano tubes. Binding was found out to be thermodynamically favorable. The functionalization increases the electrical dipole moments and results in an enhancement in the solubility of the nano tubes in water manifested through favorable changes in the free energies of solvation. This should lower the toxicity of nano tubes and improve their biocompatibility.

  19. Thermodynamics and structure of hydrogen, methane, argon, oxygen and carbon dioxide adsorbed on single wall carbon nanotube bundles

    Energy Technology Data Exchange (ETDEWEB)

    Bienfait, M.; Zeppenfeld, P.; Dupont-Pavlovsky, N.; Muris, M.; Johnson, M.; Wilson, T.; De Pies, M.; Vilches, O.E

    2004-07-15

    Isosteric heat of adsorption and neutron diffraction measurements of hydrogen, methane, argon, oxygen and carbon dioxide adsorbed on single wall carbon nanotube bundles show that all adsorbates, except CO{sub 2}, condense first on high-energy binding sites like the grooves and the widest interstitial channels and then on the outer rounded surface of the bundles. As for CO{sub 2}, only one set of adsorption sites is observed, which is attributed to the grooves and/or the interstitial channels.

  20. Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF6 electrolyte

    International Nuclear Information System (INIS)

    Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF6 non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g−1. - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, among others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g−1 at a scan rate of 1 mV s−1

  1. Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF{sub 6} electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Azam, M.A., E-mail: asyadi@utem.edu.my [Carbon Research Technology Research Group, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia); Jantan, N.H.; Dorah, N.; Seman, R.N.A.R.; Manaf, N.S.A. [Carbon Research Technology Research Group, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia); Kudin, T.I.T. [Ionics Materials & Devices Research Laboratory, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor (Malaysia); Yahya, M.Z.A. [Ionics Materials & Devices Research Laboratory, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor (Malaysia); National Defence University of Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia)

    2015-09-15

    Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF{sub 6} non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g{sup −1}. - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, among others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g{sup −1} at a scan rate of 1 mV s{sup −1}.

  2. Fiber Optic Chemical Nanosensors Based on Engineered Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    A. Cusano

    2008-09-01

    Full Text Available In this contribution, a review of the development of high-performance optochemical nanosensors based on the integration of carbon nanotubes with the optical fiber technology is presented. The paper first provide an overview of the amazing features of carbon nanotubes and their exploitation as highly adsorbent nanoscale materials for gas sensing applications. Successively, the attention is focused on the operating principle, fabrication, and characterization of fiber optic chemosensors in the Fabry-Perot type reflectometric configuration, realized by means of the deposition of a thin layer of single-walled carbon nanotubes (SWCNTs upon the distal end of standard silica optical fibers. This is followed by an extensive review of the excellent sensing capabilities of the realized SWCNTs-based chemical nanosensors against volatile organic compounds and other pollutants in different environments (air and water and operating conditions (room temperature and cryogenic temperatures. The experimental results reported here reveal that ppm and sub-ppm chemical detection limits, low response times, as well as fast and complete recovery of the sensor responses have been obtained in most of the investigated cases. This evidences the great potentialities of the proposed photonic nanosensors based on SWCNTs to be successfully employed for practical environmental monitoring applications both in liquid and vapor phase as well as for space. Furthermore, the use of novel SWCNTs-based composites as sensitive fiber coatings is proposed to enhance the sensing performance and to improve the adhesion of carbon nanotubes to the fiber surface. Finally, new advanced sensing configurations based on the use of hollow-core optical fibers coated and partially filled by carbon nanotubes are also presented.

  3. Spectroscopic studies on covalent functionalization of single-walled carbon nanotubes with glycine.

    Science.gov (United States)

    Deborah, M; Jawahar, A; Mathavan, T; Kumara Dhas, M; Benial, A Milton Franklin

    2014-10-22

    Single-walled carbon nanotubes (SWCNTs) have a great potential in a wide range of applications, but faces limitation in terms of dispersion feasibility. The functionalization process of SWCNTs with the amino acid, glycine involves oxidation reaction using a mild aqueous acid mixture of HNO3 and H2SO4 (1:3), via ultrasonication technique and the resulted oxidized SWCNTs were again treated with the amino acid glycine suspension. The resulted glycine functionalized carbon nanotubes have been characterized by XRD, UV-Vis, FTIR, EPR, SEM, and EDX, spectroscopic techniques. The enhanced XRD peak (002) intensity was observed for glycine functionalized SWCNTs compared with oxidized SWCNTs, which is likely due to sample purification by acid washing. The red shift was observed in the UV-Vis spectra of glycine functionalized SWCNTs, which reveals that the covalent bond formation between glycine molecule and SWCNTs. The functional groups of oxidized SWCNTs and glycine functionalized SWCNTs were identified and assigned. EPR results indicate that the unpaired electron undergoes reduction process in glycine functionalized SWCNTs. SEM images show that the increase in the diameter of the SWCNTs was observed for glycine functionalized SWCNTs, which indicates that the adsorption of glycine molecule on the sidewalls of oxidized SWCNTs. EDX elemental micro analysis confirms that the nitrogen element exists in glycine functionalized SWCNTs. The functionalization has been chosen due to CONH bioactive sites in glycine functionalized SWCNTs for future applications. PMID:25448929

  4. A theoretical study on the interaction of amphetamine and single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Interaction energy between several armchair CNTs and amphetamine is investigated. • The adsorption of amphetamine molecule is observed to be exothermic and physical in nature. • HOMO–LUMO for pure CNTs, amphetamine and their corresponded complexes are studied. • Density of states (DOS) near the Fermi level is calculated and presented. - Abstract: The adsorption of 1-phenyl-2-aminopropane (amphetamine) on the (4,4), (5,5), (6,6), and (7,7) single-walled carbon nanotubes (SWCNTs) has been theoretically investigated. The molecule has been located in different modes including parallel, perpendicular, and oblique on the outer surface of carbon nanotubes. The physisorption of amphetamine onto SWCNT sidewall is thermodynamically favored; as a consequence, it modulates the electronic properties of pristine nanotube in the vicinity of Fermi region. The adsorption energies for the parallel and oblique modes found in the range of −1.13 to −1.88 and −1.27 to −2.01 kcal/mol, respectively. Projected density of states (PDOS) and frontier orbital analysis in the vicinity of Fermi level region suggest the electronic states to be contributed from SWCNT rather than amphetamine molecule

  5. Functional long circulating single walled carbon nanotubes for fluorescent/photoacoustic imaging-guided enhanced phototherapy.

    Science.gov (United States)

    Xie, Lisi; Wang, Guohao; Zhou, Hao; Zhang, Fan; Guo, Zhide; Liu, Chuan; Zhang, Xianzhong; Zhu, Lei

    2016-10-01

    Nanotherapeutics have been investigated for years, but only modest survival benefits were observed clinic. This is partially attributed to the short and rapid elimination of nanodrug after intravenous administration. In this study, a long circulation single wall carbon nanotube (SWCNT) complex was successfully fabricated through a new SWCNT dispersion agent, evans blue (EB). The complex was endowed with fluorescent imaging and photodynamic therapy ability by self-assembly loading an albumin coupled fluorescent photosensitizer, Chlorin e6 (Ce6) via the high affinity between EB and albumin. The yielding multifunctional albumin/Ce6 loaded EB/carbon nanotube-based delivery system, named ACEC, is capable of providing fluorescent and photoacoustic imaging of tumors for optimizing therapeutic time window. Synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) were carried out as guided by imaging results at 24 h post-injection and achieved an efficient tumor ablation effect. Compared to PDT or PTT alone, the combined phototherapy managed to damage tumor and diminish tumor without recurrence. Overall, our study presents a SWCNT based theranostic system with great promising in dual modalities imaging guided PTT/PDT combined treatment of tumor. The applications of EB on SWCNT functionalization can be easily extended to the other nanomaterials for improving their in vivo stability and circulation time. PMID:27392290

  6. Dynamics of fragmentation and multiple vacancy generation in irradiated single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    The results from mass spectrometry of clusters sputtered from Cs+ irradiated single-walled carbon nanotubes (SWCNTs) as a function of energy and dose identify the nature of the resulting damage in the form of multiple vacancy generation. For pristine SWCNTs at all Cs+ energies, C2 is the most dominant species, followed by C3, C4 and C1. The experiments were performed in three stages: in the first stage, Cs+ energy E(Cs+) was varied. During the second stage, the nanotubes were irradiated continuously at E(Cs+) = 5 keV for 1,800 s. Afterwards, the entire sequence of irradiation energies was repeated to differentiate between the fragmentation patterns of the pristine and of heavily irradiated SWCNTs. The sputtering and normalized yields identify the quantitative and relative extent of the ion-induced damage by creating double, triple and quadruple vacancies; the single vacancies are least favored. Sputtering from the heavily irradiated SWCNTs occurs not only from the damaged and fragmented nanotubes, but also from the inter-nanotube structures that are grown due to the accumulation of the sputtered clusters. Similar irradiation experiments were performed with the multi-walled carbon nanotubes; the results confirmed the dominant C2 followed by C3, C4 and C1

  7. Silicon spectral response extension through single wall carbon nanotubes in hybrid solar cells

    KAUST Repository

    Del Gobbo, S.

    2013-01-01

    Photovoltaic devices based on single wall carbon nanotubes (SWCNTs) and n-silicon multiple heterojunctions have been fabricated by a SWCNT film transferring process. We report on the ability of the carbon nanotubes to extend the Si spectral range towards the near ultraviolet (UV) and the near infrared regions. Semiconducting and about metallic SWCNT networks have been studied as a function of the film sheet resistance, Rsh. Optical absorbance and Raman spectroscopy have been used to assign nanotube chirality and electronic character. This gave us hints of evidence of the participation of the metal nanotubes in the photocurrent generation. Moreover, we provide evidence that the external quantum efficiency spectral range can be modulated as a function of the SWCNT network sheet resistance in a hybrid SWCNT/Si solar cell. This result will be very useful to further design/optimize devices with improved performance in spectral regions generally not covered by conventional Si p-n devices. © 2013 The Royal Society of Chemistry.

  8. Molecular dynamics simulation of non-covalent single-walled carbon nanotube functionalization with surfactant peptides.

    Science.gov (United States)

    Barzegar, Abolfazl; Mansouri, Alireza; Azamat, Jafar

    2016-03-01

    Non-covalent functionalized single-walled carbon nanotubes (SWCNTs) with improved solubility and biocompatibility can successfully transfer drugs, DNA, RNA, and proteins into the target cells. Theoretical studies such as molecular docking and molecular dynamics simulations in fully atomistic scale were used to investigate the hydrophobic and aromatic π-π-stacking interaction of designing four novel surfactant peptides for non-covalent functionalization of SWCNTs. The results indicated that the designed peptides have binding affinity towards SWCNT with constant interactions during MD simulation times, and it can even be improved by increasing the number of tryptophan residues. The aromatic content of the peptides plays a significant role in their adsorption in SWCNT wall. The data suggest that π-π stacking interaction between the aromatic rings of tryptophan and π electrons of SWCNTs is more important than hydrophobic effects for dispersing carbon nanotubes; nevertheless SWCNTs are strongly hydrophobic in front of smooth surfaces. The usage of aromatic content of peptides for forming SWCNT/peptide complex was proved successfully, providing new insight into peptide design strategies for future nano-biomedical applications. PMID:26811869

  9. Dynamic interactions between poly(3-hexylthiophene) and single-walled carbon nanotubes in marginal solvent.

    Science.gov (United States)

    Luo, Yanqi; Santos, Franceska A; Wagner, Taylor W; Tsoi, Eric; Zhang, Shanju

    2014-06-01

    Interfacial interactions between conjugated polymers and carbon nanotubes are pivotal in determining the device performance of nanotube-based polymer electronic devices. Here, we report on interfacial structures and crystallization kinetics of poly(3-hexylthiophene) (P3HT) in the presence of single-walled carbon nanotubes (SWNTs) in anisole by means of transmission electron microscope (TEM) and ultraviolet-visible (UV-vis) absorption spectroscopy. Confined on SWNT surfaces, the P3HT forms nanofibril crystals perpendicular to the long axis of SWNTs. The equilibrium dissolution temperature of the P3HT crystals in anisole is determined to be 381 ± 10 K according to the Hoffman-Weeks extrapolation approach. Upon cooling, the polymer solution spontaneously undergoes a time-dependent chromism. Various kinetics factors such as crystallization temperature, concentration, and SWNT loading have been investigated. It is found that the growth rate (G) of the crystals scales with concentration (C) as G ∝ C(1.70±0.16). The Avrami model is utilized to analyze the nucleation mechanism and the Avrami exponents vary between 1.0 and 1.3. The Lauritzen-Hoffman theory is applied to study the chain-folding process. The fold surface free energy is calculated to be (5.28-11.9) × 10(-2) J m(-2). It is evident that the addition of 0.30 wt % SWNTs reduces the fold surface free energy by 55.6%. PMID:24856901

  10. Effects of residual aberrations explored on single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Biskupek, Johannes, E-mail: johannes.biskupek@uni-ulm.de [Central Facility of Electron Microscopy, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm (Germany); Hartel, Peter; Haider, Maximilian [CEOS GmbH, Englerstrasse 28, D-69126 Heidelberg (Germany); Kaiser, Ute [Central Facility of Electron Microscopy, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm (Germany)

    2012-05-15

    The effects of geometric residual aberrations such as coma B{sub 2} and two-fold astigmatism A{sub 1} on the contrast in aberration corrected high resolution transmission electron microscopy (HRTEM) images are investigated on single-walled carbon nanotubes (SWNT). The individual aberrations are adjusted and set up manually using an imaging C{sub S}-corrector. We demonstrate how coma B{sub 2} can be recognized by an experienced user directly in the image and how it blurs the contrast. Even with uncorrected (resolution limiting) spherical aberration C{sub S} the coma B{sub 2} has to be considered and must be minimized. Limits for a tolerable coma are given. The experiments are confirmed by image simulations. -- Highlights: Black-Right-Pointing-Pointer Individual effects of residual aberrations such as B{sub 2}, A{sub 1}, and C{sub S} are demonstrated. Black-Right-Pointing-Pointer Experimental HRTEM and simulated images of carbon nanotubes are compared. Black-Right-Pointing-Pointer A detection limit of 50 nm B{sub 2} in a single HRTEM image is determined.

  11. Separation and re-adhesion processes of two adhered single-walled carbon nanotube bundles

    International Nuclear Information System (INIS)

    Carbon nanotubes are desirable components of nanoelectromechanical (NEM) devices due to their excellent mechanical and electrical properties. In this study, dielectrophoresis, a potential high-rate nanomanufacturing process, was used to assemble single-walled carbon nanotube (SWCNT) bundles suspended over a trench. The intent was to assemble a single SWCNT bundle between two electrodes. However, it was observed that when two or more SWCNT bundles assembled across the trench, the bundles were attached together in a portion of the suspended section. This study models the separation and re-adhesion processes of two adhered SWCNT bundles as their internal tensions are varied using an atomic force microscope (AFM) tip. Two devices were selected with distinct SWCNT bundles. Observation of the force–distance measurements through applying an AFM tip at the middle of the suspended SWCNT bundles, in conjunction with continuum mechanics modelling, allowed the work of adhesion between the two nanotube bundles to be determined. As the force was applied by the AFM tip, the tension induced in each bundle increases sufficiently to partially overcome the adhesion between the bundles, thereby decreasing the adhesive length. The adhesive length then recovers due to the decrease in the induced tension during the unloading process. The average value of the work of adhesion between two adhered SWCNT bundles was determined to be 0.37 J m−2 according to the experimental data and modelling results. (paper)

  12. Effect of single-walled carbon nanotubes on primary immune cells in vitro

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Carbon nanotubes (CNTs) are emerging as innovative tools in nanobiotechnology.However,their toxic effects on environment and health have become an issue of great concern.The effect of single-walled carbon nanotubes (SWCNTs) on primary immune cells in vitro was studied in this paper.The results indicated that SWCNTs (25 and 50 pg/mL) could promote the proliferation of spleen cells.However,they had no significant effect on the proliferation of spleen cells at concentrations of 1 and 10 μg/mL.They also had no effect on T-lymphocyte proliferation stimulated by concanavalinA (ConA) at lower concentrations.Moreover,they turned to inhibit Tlymphocyte proliferation at higher concentrations.It was found that SWCNTs inhibited the B-lymphocyte proliferation stimulated by lipopolysaccharides (LPS) at concentrations of 1,10,25 and 50 μg/mL.What is more,they significantly decreased the Natural Killer (NK) cell activity compared with the control group at all tested concentrations.The results suggest that SWCNTs have possibly negative effects on immune cells in vitro.

  13. A Remote Sensor for Detecting Methane Based on Palladium-Decorated Single Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Guomin Li

    2013-07-01

    Full Text Available The remote detection of the concentration of methane at room temperature is performed by a sensor that is configured by the combination of radio frequency identification (RFID, and functionalized carbon nanotubes (CNTs. The proposed sensor is schemed as a thin film RFID tag in a polyethylene substrate, on which a metal trace dipole, a metal trace T impedance matching networks, a 0.5 µm-CMOS RF/DC rectifier chipset and a sensor head of palladium-decorated single walled carbon nanotubes (Pd-SWCNTs are surface mounted in cascade. The performances of the sensor are examined and described by the defined parameters of the received signal strength index (RSSI and the comparative analog identifier (∆AID. Results validate the sensor’s ability to detect molecules of methane at room temperature, showing that the RSSI can increase 4 dB and the ∆AID can increase 3% in response to methane concentrations ranging from zero to 100 ppm.

  14. A theoretical study on the interaction of amphetamine and single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Hafizi, Hamid [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Najafi Chermahini, Alireza, E-mail: anajafi@cc.iut.ac.ir [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mohammadnezhad, Gholamhossein [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Teimouri, Abbas [Chemistry Department, Payame Noor University (PNU), Tehran 19395-4697 (Iran, Islamic Republic of)

    2015-02-28

    Graphical abstract: - Highlights: • Interaction energy between several armchair CNTs and amphetamine is investigated. • The adsorption of amphetamine molecule is observed to be exothermic and physical in nature. • HOMO–LUMO for pure CNTs, amphetamine and their corresponded complexes are studied. • Density of states (DOS) near the Fermi level is calculated and presented. - Abstract: The adsorption of 1-phenyl-2-aminopropane (amphetamine) on the (4,4), (5,5), (6,6), and (7,7) single-walled carbon nanotubes (SWCNTs) has been theoretically investigated. The molecule has been located in different modes including parallel, perpendicular, and oblique on the outer surface of carbon nanotubes. The physisorption of amphetamine onto SWCNT sidewall is thermodynamically favored; as a consequence, it modulates the electronic properties of pristine nanotube in the vicinity of Fermi region. The adsorption energies for the parallel and oblique modes found in the range of −1.13 to −1.88 and −1.27 to −2.01 kcal/mol, respectively. Projected density of states (PDOS) and frontier orbital analysis in the vicinity of Fermi level region suggest the electronic states to be contributed from SWCNT rather than amphetamine molecule.

  15. In situ filling of metallic single-walled carbon nanotubes with ferrocene molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sauer, Markus; Shiozawa, Hidetsugu; Ayala, Paola; Ruiz-Soria, Georgina; Pichler, Thomas [Faculty of Physics, University of Vienna, 1090 Wien (Austria); Kataura, Hiromichi [Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8562 (Japan); Yanagi, Kazuhiro [Department of Physics, Tokyo Metropolitan University, Hachiouji, Tokyo 192-0397 (Japan); Krause, Stefan [BESSY II, 12489 Berlin (Germany)

    2012-12-15

    We present a stepwise in situ filling of metallic single-walled carbon nanotubes (SWCNTs) with a mean diameter of 1.4 nm with metallocenes and a concomitant characterisation of their electronic properties using photoemission spectroscopy (PES) and X-ray absorption spectroscopy (XAS) without breaking the ultra-high vacuum environment. The changes in the SWCNTs' electronic structure upon ferrocene (FeCp{sub 2}) filling are suggested by a broadening of the C 1s spectral line. Weak n-type charge transfer from the ferrocene to the SWCNT is evidenced by a reduction of the intensity of the first van Hove singularity (vHs) in the fine structure of the unoccupied density of states as well as an increase in the valency of Fe in the FeCp{sub 2} molecule. Additionally, we evidence the presence of clean ferrocene with a resonance photoemission study showing the appearance of electronic states of localised Fe 3d electrons. This gives further insight into the electrical properties of functionalised carbon nanotubes fabricated in a clean environment avoiding inclusion of impurities. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. A Facile Route to Metal Oxides/Single-Walled Carbon Nanotube Macrofilm Nanocomposites for Energy Storage

    Directory of Open Access Journals (Sweden)

    Zeyuan eCao

    2015-05-01

    Full Text Available Nanocomposites consisting of transition-metal oxides and carbon nanomaterials with a desired size and structure are highly demanded for high performance energy storage devices. Here, a facile two-step and cost-efficient approach relying on directly thermal treatment of chemical-vapor-deposition products is developed as a general synthetic method to prepare a family of metal oxides (MxOy (M=Fe, Co, Ni/single-walled carbon nanotube (SWNT macrofilm nanocomposites. The MxOy nanoparticles obtained are of 3-17 nm in diameter and homogeneously anchor on the free-standing SWNT macrofilms. NiO/SWNT also exhibits a high specific capacitance of 400 F g-1 and fast charge-transfer Faradaic redox reactions to achieve asymmetric supercapacitors with a high power and energy density. All MxOy/SWNT nanocomposites could deliver a high capacity beyond 1000 mAh g-1 and show excellent cycling stability for lithium-ion batteries. The impressive results demonstrate the promise for energy storage devices and the general approach may pave the way to synthesize other functional nanocomposites.

  17. Functional single-walled carbon nanotubes/chitosan conjugate for tumor cells targeting

    Science.gov (United States)

    Wu, Baoyan; Ou, Zhongmin; Xing, Da

    2009-08-01

    The application of single-walled carbon nanotubes (SWCNTs) in the field of biomedicine is becoming an exciting topic because of their flexible structure and propensity for chemical functionalization. In this assay, a novel noncovalently functional SWCNTs based on a natural biocompatible polymer chitosan has been developed for tumor cells targeting. First, SWCNTs were modified by chitosan (CHIT-SWCNT). Second, CHIT-SWCNT was coupled with fluorescein isothiocyanate (FITC), based on the reaction between the isothiocyanate group of FITC and the primary amino group of chitosan. Third, the FITC functionalized CHIT-SWCNT was conjugated with folic acid (FA) after activation with EDC/NHS, based on the reaction between the NHS group of FA and the primary free amino group of chitosan to construct the functional SWCNT/CHIT conjugate, CHIT-SWCNT-FA. The fluorescence CHIT-SWCNT-FA has been used to detect tumor cells with confocal microscopy imaging technology. Our experimental results indicate that the novel CHIT-SWCNT-FA is soluble and stable in PBS, and it can be readily transported inside tumor cells. Combining the intrinsic properties of carbon nanotubes and the versatility of chitosan, CHIT-SWCNT can be used as potential devices for targeted drug delivery and tumor cell sensing. The proposed assay could provide a feasible alternative to presently available functional SWCNTs in biological applications.

  18. Effect of gelatin on the water dispersion and centrifugal purification of single-walled carbon nanotubes

    Science.gov (United States)

    Hanium Maria, Kazi; Mieno, Tetsu

    2016-01-01

    We report a convenient and effective procedure for the water dispersion and purification of single-walled carbon nanotubes (SWNTs). The purification procedure involves a combination of dispersion and centrifugation, in which gelatin; an environmentally friendly material is used as a dispersing agent. It has been found that an aqueous solution of gelatin effectively disperses SWNTs for more than a month. Another advantage of using gelatin as a dispersing agent is that it can be easily removed by washing with water and filtration. The centrifugation procedure employs a centrifugal force of about 2500 times the gravitational force to separate the particles. Although carbonaceous and metallic impurities usually have higher density than SWNTs in arc-produced carbon soot, the centrifugation can easily remove impurities leaving undamaged SWNTs in solution when appropriate centrifugal force and a centrifugation time are used. Centrifugation is carried out for three times to sufficiently remove impurities. Finally, the SWNTs are separated from the gelatin by heating in water and filtering.

  19. Single Chirality (6,4) Single-Walled Carbon Nanotubes for Fluorescence Imaging with Silicon Detectors.

    Science.gov (United States)

    Antaris, Alexander L; Yaghi, Omar K; Hong, Guosong; Diao, Shuo; Zhang, Bo; Yang, Jiang; Chew, Leila; Dai, Hongjie

    2015-12-16

    Postsynthetic single-walled carbon nanotube (SWCNT) sorting methods such as density gradient ultracentrifugation, gel chromatography, and electrophoresis have all been inspired by established biochemistry separation techniques designed to separate subcellular components. Biochemistry separation techniques have been refined to the degree that parameters such as pH, salt concentration, and temperature are necessary for a successful separation, yet these conditions are only now being applied to SWCNT separation methodologies. Slight changes in pH produce radically different behaviors of SWCNTs inside a density gradient, allowing for the facile separation of ultrahigh purity (6,4) SWCNTs from as-synthesized carbon nanotubes. The (6,4) SWCNTs are novel fluorophores emitting below ≈900 nm and can be easily detected with conventional silicon-based charge-coupled device detectors without the need for specialized InGaAs cameras. The (6,4) SWCNTs are used to demonstrate their potential as a clinically relevant NIR-I fluorescence stain for the immunohistochemical staining of cells and cancer tissue sections displaying high endothelial growth factor receptor levels. PMID:26529611

  20. Vascular targeted single-walled carbon nanotubes for near-infrared light therapy of cancer

    International Nuclear Information System (INIS)

    A new approach for targeting carbon nanotubes to the tumor vasculature was tested using human endothelial cells and MCF-7 breast cancer cells in vitro. Single-walled carbon nanotubes were functionalized with the F3 peptide using a polyethylene glycol linker to target nucleolin, a protein found on the surface of endothelial cells in the vasculature of solid tumors. Confocal microscopy and Raman analysis confirmed that the conjugate was internalized by actively dividing endothelial cells. Dividing endothelial cells were used to mimic these cells in the tumor vasculature. Incubation with the conjugate for 8 h or more caused significant cell death in both actively dividing endothelial cells and MCF-7 breast cancer cells, an effect that is hypothesized to be due to the massive uptake of the conjugate. This targeted cell killing was further enhanced when coupled with near-infrared laser treatment. For confluent (non-dividing) endothelial cells, no cytotoxic effect was seen for incubation alone or incubation coupled with laser treatment. These results are promising and warrant further studies using this conjugate for cancer treatment in vivo.

  1. Single wall carbon nanotubes enter cells by endocytosis and not membrane penetration

    Directory of Open Access Journals (Sweden)

    Lösche Mathias

    2011-09-01

    Full Text Available Abstract Background Carbon nanotubes are increasingly being tested for use in cellular applications. Determining the mode of entry is essential to control and regulate specific interactions with cells, to understand toxicological effects of nanotubes, and to develop nanotube-based cellular technologies. We investigated cellular uptake of Pluronic copolymer-stabilized, purified ~145 nm long single wall carbon nanotubes (SWCNTs through a series of complementary cellular, cell-mimetic, and in vitro model membrane experiments. Results SWCNTs localized within fluorescently labeled endosomes, and confocal Raman spectroscopy showed a dramatic reduction in SWCNT uptake into cells at 4°C compared with 37°C. These data suggest energy-dependent endocytosis, as shown previously. We also examined the possibility for non-specific physical penetration of SWCNTs through the plasma membrane. Electrochemical impedance spectroscopy and Langmuir monolayer film balance measurements showed that Pluronic-stabilized SWCNTs associated with membranes but did not possess sufficient insertion energy to penetrate through the membrane. SWCNTs associated with vesicles made from plasma membranes but did not rupture the vesicles. Conclusions These measurements, combined, demonstrate that Pluronic-stabilized SWCNTs only enter cells via energy-dependent endocytosis, and association of SWCNTs to membrane likely increases uptake.

  2. Antimicrobial Activity of Single-Walled Carbon Nanotubes Suspended in Different Surfactants

    Directory of Open Access Journals (Sweden)

    Lifeng Dong

    2012-01-01

    Full Text Available We investigated the antibacterial activity of single-walled carbon nanotubes (SWCNTs dispersed in surfactant solutions of sodium cholate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate. Among the three surfactants, sodium cholate demonstrated the weakest antibacterial activity against Salmonella enterica, Escherichia coli, and Enterococcus faecium and thereby was used to disperse bundled SWCNTs in order to study nanotube antibiotic activity. SWCNTs exhibited antibacterial characteristics for both S. enterica and E. coli. With the increase of nanotube concentrations from 0.3 mg/mL to 1.5 mg/mL, the growth curves had plateaus at lower absorbance values whereas the absorbance value was not obviously affected by the incubation ranging from 5 min to 2 h. Our findings indicate that carbon nanotubes could become an effective alternative to antibiotics in dealing with drug-resistant and multidrug-resistant bacterial strains because of the physical mode of bactericidal action that SWCNTs display.

  3. Vascular targeted single-walled carbon nanotubes for near-infrared light therapy of cancer

    Science.gov (United States)

    Prickett, Whitney M.; Van Rite, Brent D.; Resasco, Daniel E.; Harrison, Roger G.

    2011-11-01

    A new approach for targeting carbon nanotubes to the tumor vasculature was tested using human endothelial cells and MCF-7 breast cancer cells in vitro. Single-walled carbon nanotubes were functionalized with the F3 peptide using a polyethylene glycol linker to target nucleolin, a protein found on the surface of endothelial cells in the vasculature of solid tumors. Confocal microscopy and Raman analysis confirmed that the conjugate was internalized by actively dividing endothelial cells. Dividing endothelial cells were used to mimic these cells in the tumor vasculature. Incubation with the conjugate for 8 h or more caused significant cell death in both actively dividing endothelial cells and MCF-7 breast cancer cells, an effect that is hypothesized to be due to the massive uptake of the conjugate. This targeted cell killing was further enhanced when coupled with near-infrared laser treatment. For confluent (non-dividing) endothelial cells, no cytotoxic effect was seen for incubation alone or incubation coupled with laser treatment. These results are promising and warrant further studies using this conjugate for cancer treatment in vivo.

  4. Biodegradation of Single-Walled Carbon Nanotubes in Macrophages through Respiratory Burst Modulation

    Science.gov (United States)

    Hou, Jie; Wan, Bin; Yang, Yu; Ren, Xiao-Min; Guo, Liang-Hong; Liu, Jing-Fu

    2016-01-01

    The biodegradation of carbon nanotubes (CNTs) may be one of major determinants of the toxic outcomes in exposed individuals. In this study, we employed a macrophage/monocyte model, Raw264.7, to investigate the feasibility of regulating the biodegradation of three types of single-walled carbon nanotubes (SWCNTs) (pristine, ox-, and OH-SWCNTs) by respiratory burst modulation. An artificial fluid mimicking the enzymatic reactions of respiratory burst was constituted to reveal the role of respiratory burst played in SWCNT biodegradation. The biodegradation of SWCNTs were characterized by Raman, ultraviolet-visible-near-infrared spectroscopy, and transmission electron microscopy. Our results showed significantly accelerated biodegradation of ox-SWCNTs and OH-SWCNTs in macrophages activated by phorbol myristate acetate (PMA), which could be prevented by N-acetyl-l-cysteine (NAC), whereas p-SWCNTs were resistant to biodegradation. Similar tendencies were observed by using the in vitro enzymatic system, and the degradation rates of these SWCNTs are in the order of OH-SWCNTs > ox-SWCNTs >> p-SWCNTs, suggesting a pivotal role of respiratory burst in accelerating the biodegradation of SWCNTs and that defect sites on SWCNTs might be a prerequisite for the biodegradation to occur. Our findings might provide invaluable clues on the development of intervention measurements for relieving the side effects of SWCNTs and would help to design safer SWCNT products with higher biodegradability and less toxicity. PMID:27011169

  5. Dispersion of dilatation wave propagation in single-wall carbon nanotubes using nonlocal scale effects

    International Nuclear Information System (INIS)

    Nonlocal continuum mechanics allows one to account for the small length scale effect that becomes significant when dealing with micro- or nano-structures. This paper investigates a model of wave propagation in single-wall carbon nanotubes (SWCNTs) with small scale effects are studied. The equation of motion of the dilatation wave is obtained using the nonlocal elastic theory. We show that a dispersive wave equation is obtained from a nonlocal elastic constitutive law, based on a mixture of a local and a nonlocal strain. The SWCNTs structures are treated within the multilayer thin shell approximation with the elastic properties taken to be those of the graphene sheet. The SWCNT was the (40,0) zigzag tube with an effective diameter of 3.13 nm. Nonlinear frequency equations of wave propagation in SWCNTs are described through the effect of small scale. The phase velocity and the group velocity are derived, respectively. The nonlinear dispersion relation is analyzed with different wave numbers versus scale coefficient. It can be observed from the results that the dispersion properties of the dilatation wave are induced by the small scale effects, which will disappear in local continuous models. The dispersion degree can be strengthened by increasing the scale coefficient and the wave number. Furthermore, the characteristics for the group velocity of the dilatation wave in carbon nanotubes can also be tuned by these factors.

  6. Magnetic impurities in single-walled carbon nanotubes and graphene: a review.

    Science.gov (United States)

    Vejpravova, J; Pacakova, B; Kalbac, M

    2016-04-25

    Control over magnetism in single-walled carbon nanotubes (SWCNTs) and graphene is of fundamental importance. Creation and manipulation using the unpaired spins without the need for archetypal magnetic elements results in sp(2)-hybridised nanocarbons being at the forefront of applications in both spintronics and nanoelectronics. The crucial limitation for the experimental observation of the intrinsic carbon magnetism stems from the presence of magnetic impurities, from which a magnetic response usually dominates. Thus, the rigorous identification of such magnetic impurities and their efficient removal is of enormous importance. The present review reports on the current state-of-the-art methodology for the detection and quantification of magnetic impurities in SWCNTs and graphene, reflecting both the preparation and subsequent purification procedures. First, the most common techniques for the preparation of SWCNTs (i.e., arc discharge, laser ablation and chemical vapour deposition) and the corresponding magnetic impurities are reviewed. Then, the available volume, surface and local probes for the identification and quantification of the impurities are discussed, and their efficiency and limitations are evaluated for the given cases. A summary of the current understanding of graphene-related magnetism in the context of the identified impurities is also given. Finally, the key knowledge is reviewed with respect to future prospects in the field. PMID:26938351

  7. Size reduction of 3D-polymer-coated single-walled carbon nanotubes by ultracentrifugation

    Science.gov (United States)

    Tsutsumi, Yusuke; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-11-01

    We describe a novel single-walled carbon nanotube (SWNT) cutting method without introducing any structural defects on the tubes; namely, the finding that simple ultracentrifugation at 600 000g for the SWNTs coated with a cross-linked polymer formed by poly(N-isopropylacrylamide) (PNIPAM) or the polyethylene glycol-carrying PNIPAM copolymer provides shortened (structure and optical properties, such as characteristic absorption and photoluminescence in the near-IR region of the SWNTs, were almost unchanged even after the cutting. The obtained shortened SWNTs were individually solubilized in water and buffer solution due to the remaining cross-linked polymer structures on the SWNTs. The present method is very simple (only ultracentrifugation) and the yield is very high, which are the advantages in the preparation of many shortened isolated SWNTs with specific properties and functions that are applicable in many fields including bioapplications in vivo, such as imaging, NIR-hyperthermic treatment, photodynamic therapy, etc.We describe a novel single-walled carbon nanotube (SWNT) cutting method without introducing any structural defects on the tubes; namely, the finding that simple ultracentrifugation at 600 000g for the SWNTs coated with a cross-linked polymer formed by poly(N-isopropylacrylamide) (PNIPAM) or the polyethylene glycol-carrying PNIPAM copolymer provides shortened (structure and optical properties, such as characteristic absorption and photoluminescence in the near-IR region of the SWNTs, were almost unchanged even after the cutting. The obtained shortened SWNTs were individually solubilized in water and buffer solution due to the remaining cross-linked polymer structures on the SWNTs. The present method is very simple (only ultracentrifugation) and the yield is very high, which are the advantages in the preparation of many shortened isolated SWNTs with specific properties and functions that are applicable in many fields including bioapplications in vivo

  8. Non-covalent conjugates of single-walled carbon nanotubes and folic acid for interaction with cells overexpressing folate receptors

    DEFF Research Database (Denmark)

    Castillo, John J.; Rindzevicius, Tomas; Novoa, Leidy V.;

    2013-01-01

    We here present amethod to form a noncovalent conjugate of single-walled carbon nanotubes and folic acid aimed to interact with cells over-expressing folate receptors. The bonding was obtained without covalent chemical functionalization using a simple, rapid “one pot” synthesis method. The zeta p...

  9. Response of Fe powder, purified and as-produced HiPco single-walled carbon nanotubes to flash exposure

    International Nuclear Information System (INIS)

    The exposure of as-produced HiPCo single-walled carbon nanotubes (SWNTs) to a camera flash causes ignition, (oxidation) and subsequent coalescence of the Fe catalyst particles, while purified SWNTs do not respond to flashing. TEM and electron energy loss spectroscopy (EELS) analysis attribute the phenomena to the pyrophoric oxidation of Fe nanoparticles

  10. Bioaccumulation and Toxicity of Single-Walled Carbon Nanotubes to Benthic Organisms at the Base of the Marine Food Chain

    Science.gov (United States)

    As the use of single-walled carbon nanotubes (SWNTs) increases over time, so does the potential for environmental release. This research aimed to determine the toxicity, bioavailability, and bioaccumulation of SWNTs in marine benthic organisms at the base of the food chain. The t...

  11. Effect of temperature on the selection of semiconducting single walled carbon nanotubes using Poly(3-dodecylthiophene-2,5-diyl)

    NARCIS (Netherlands)

    Gomulya, Widianta; Salazar Rios, Jorge; Derenskyi, Vladimir; Bisri, Satria Zulkarnaen; Jung, Stefan; Fritsch, Martin; Allard, Sybille; Scherf, Ullrich; dos Santos, Maria Cristina; Loi, Maria Antonietta

    2015-01-01

    We report on the investigation of the temperature effect on the selective dispersion of single-walled carbon nanotubes (SWNTs) by Poly(3-dodecylthiophene-2,5-diy1) wrapping. The interaction mechanism between polymer chains and SWNTs is studied by controlling the polymer aggregation via variation of

  12. Tuning the photophysical properties of soluble single-wall carbon nanotube derivatives by co-functionalization with organic molecules

    NARCIS (Netherlands)

    Cordella, Fabrizio; De Nardi, Marco; Menna, Enzo; Hebert, Cecile; Loi, Maria Antonietta

    2009-01-01

    The photophysical characterization of three soluble derivatives of single-wall carbon nanotubes (SWCNTs), functionalized with poly(ethylene glycol) (PEG), co-functionalized with PEG and aminofluorene and co-functionalized with PEG and aminoanthracene is reported. The peculiar excellent solubility of

  13. Nanomaterial release characteristics in a single-walled carbon nanotube manufacturing workplace

    International Nuclear Information System (INIS)

    As carbon nanotubes (CNTs) are widely used in various applications, exposure assessment also increases in importance with other various toxicity tests for CNTs. We conducted 24-h continuous nanoaerosol measurements to identify possible nanomaterial release in a single-walled carbon nanotube (SWCNT) manufacturing workplace. Four real-time aerosol instruments were used to determine the nanosized and microsized particle numbers, particle surface area, and carbonaceous species. Task-based exposure assessment was carried out for SWCNT synthesis using the arc plasma and thermal decomposition processes to remove amorphous carbon components as impurities. During the SWCNT synthesis, the black carbon (BC) concentration was 2–12 μg/m3. The maximum BC mass concentrations occurred when the synthesis chamber was opened for harvesting the SWCNTs. The number concentrations of particles with sizes 10–420 nm were 10,000–40,000 particles/cm3 during the tasks. The maximum number concentration existed when a vacuum pump was operated to remove exhaust air from the SWCNT synthesis chamber due to the penetration of highly concentrated oil mists through the window opened. We analyzed the particle mass size distribution and particle number size distribution for each peak episode. Using real-time aerosol detectors, we distinguished the SWCNT releases from background nanoaerosols such as oil mist and atmospheric photochemical smog particles. SWCNT aggregates with sizes of 1–10 μm were mainly released from the arc plasma synthesis. The harvesting process was the main release route of SWCNTs in the workplace

  14. Nanomaterial release characteristics in a single-walled carbon nanotube manufacturing workplace

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Jun Ho [EcoPictures Co., Ltd (Korea, Republic of); Kim, Jong Bum; Lee, Gwangjae; Bae, Gwi-Nam, E-mail: gnbae@kist.re.kr [Korea Institute of Science and Technology, Center for Environment, Health and Welfare Research (Korea, Republic of)

    2015-02-15

    As carbon nanotubes (CNTs) are widely used in various applications, exposure assessment also increases in importance with other various toxicity tests for CNTs. We conducted 24-h continuous nanoaerosol measurements to identify possible nanomaterial release in a single-walled carbon nanotube (SWCNT) manufacturing workplace. Four real-time aerosol instruments were used to determine the nanosized and microsized particle numbers, particle surface area, and carbonaceous species. Task-based exposure assessment was carried out for SWCNT synthesis using the arc plasma and thermal decomposition processes to remove amorphous carbon components as impurities. During the SWCNT synthesis, the black carbon (BC) concentration was 2–12 μg/m{sup 3}. The maximum BC mass concentrations occurred when the synthesis chamber was opened for harvesting the SWCNTs. The number concentrations of particles with sizes 10–420 nm were 10,000–40,000 particles/cm{sup 3} during the tasks. The maximum number concentration existed when a vacuum pump was operated to remove exhaust air from the SWCNT synthesis chamber due to the penetration of highly concentrated oil mists through the window opened. We analyzed the particle mass size distribution and particle number size distribution for each peak episode. Using real-time aerosol detectors, we distinguished the SWCNT releases from background nanoaerosols such as oil mist and atmospheric photochemical smog particles. SWCNT aggregates with sizes of 1–10 μm were mainly released from the arc plasma synthesis. The harvesting process was the main release route of SWCNTs in the workplace.

  15. Optimization of single-walled carbon nanotube solubility by noncovalent PEGylation using experimental design methods

    Directory of Open Access Journals (Sweden)

    Hadidi N

    2011-04-01

    Full Text Available Naghmeh Hadidi1, Farzad Kobarfard2, Nastaran Nafissi-Varcheh3, Reza Aboofazeli11Department of Pharmaceutics, 2Department of Pharmaceutical Chemistry, 3Department of Pharmaceutical Biotechnology, School of Pharmacy, Shaheed Beheshti University of Medical Sciences, Tehran, IranAbstract: In this study, noncovalent functionalization of single-walled carbon nanotubes (SWCNTs with phospholipid-polyethylene glycols (Pl-PEGs was performed to improve the solubility of SWCNTs in aqueous solution. Two kinds of PEG derivatives, ie, Pl-PEG 2000 and Pl-PEG 5000, were used for the PEGylation process. An experimental design technique (D-optimal design and second-order polynomial equations was applied to investigate the effect of variables on PEGylation and the solubility of SWCNTs. The type of PEG derivative was selected as a qualitative parameter, and the PEG/SWCNT weight ratio and sonication time were applied as quantitative variables for the experimental design. Optimization was performed for two responses, aqueous solubility and loading efficiency. The grafting of PEG to the carbon nanostructure was determined by thermogravimetric analysis, Raman spectroscopy, and scanning electron microscopy. Aqueous solubility and loading efficiency were determined by ultraviolet-visible spectrophotometry and measurement of free amine groups, respectively. Results showed that Pl-PEGs were grafted onto SWCNTs. Aqueous solubility of 0.84 mg/mL and loading efficiency of nearly 98% were achieved for the prepared Pl-PEG 5000-SWCNT conjugates. Evaluation of functionalized SWCNTs showed that our noncovalent functionalization protocol could considerably increase aqueous solubility, which is an essential criterion in the design of a carbon nanotube-based drug delivery system and its biodistribution.Keywords: phospholipid-PEG, D-optimal design, loading efficiency, Raman spectroscopy, scanning electron microscopy, theromogravimetric analysis, carbon nanotubes

  16. 14.7% efficient mesoscopic perovskite solar cells using single walled carbon nanotubes/carbon composite counter electrodes

    Science.gov (United States)

    Li, Hao; Cao, Kun; Cui, Jin; Liu, Shuangshuang; Qiao, Xianfeng; Shen, Yan; Wang, Mingkui

    2016-03-01

    A single walled carbon nanotube (SWCNT) possesses excellent hole conductivity. This work communicates an investigation of perovskite solar cells using a mesoscopic TiO2/Al2O3 structure as a framework in combination with a certain amount of SWCNT-doped graphite/carbon black counter electrode material. The CH3NH3PbI3-based device achieves a power conversion efficiency of 14.7% under AM 1.5G illumination. Detailed investigations show an increased charge collection in this device compared to that without the SWCNT additive.A single walled carbon nanotube (SWCNT) possesses excellent hole conductivity. This work communicates an investigation of perovskite solar cells using a mesoscopic TiO2/Al2O3 structure as a framework in combination with a certain amount of SWCNT-doped graphite/carbon black counter electrode material. The CH3NH3PbI3-based device achieves a power conversion efficiency of 14.7% under AM 1.5G illumination. Detailed investigations show an increased charge collection in this device compared to that without the SWCNT additive. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07347b

  17. Probing nuclear dynamics and architecture using single-walled carbon nanotubes

    Science.gov (United States)

    Jung, Yoon; Li, Junang; Fakhri, Nikta

    Chromatin is a multiscale dynamic architecture that acts as a template for many biochemical processes such as transcription and DNA replication. Recent developments such as Hi-C technology enable an identification of chromatin interactions across an entire genome. However, a single cell dynamic view of chromatin organization is far from understood. We discuss a new live cell imaging technique to probe the dynamics of the nucleus at a single cell level using single-walled carbon nanotubes (SWNTs). SWNTs are non-perturbing rigid rods (diameter of 1 nm and length of roughly 100 nm) that fluoresce in the near infrared region. Due to their high aspect ratio, they can diffuse in tight spaces and report on the architecture and dynamics of the nucleoplasm. We develop 3D imaging and tracking of SWNTs in the volume of the nucleus using double helix point spread function microscopy (DH-PSF) and discuss the capabilities of the DH-PSF for inferring the 3D orientation of nanotubes based on vectorial diffraction theory.

  18. The thermal effect on vibration of single-walled carbon nanotubes using nonlocal Timoshenko beam theory

    International Nuclear Information System (INIS)

    This paper is concerned with the use of the nonlocal Timoshenko beam model for free vibration analysis of single-walled carbon nanotubes (CNTs) including the thermal effect. Unlike the Euler beam model, the Timoshenko beam model allows for the effects of transverse shear deformation and rotary inertia. These effects become significant for CNTs with small length-to-diameter ratios that are normally encountered in applications such as nanoprobes. The elastic Timoshenko beam model is reformulated using the nonlocal differential constitutive relations of Eringen (1972 Int. J. Eng. Sci. 10 1-16). The study focuses on the wave dispersion caused not only by the rotary inertia and the shear deformation in the traditional Timoshenko beam model but also by the nonlocal elasticity characterizing the microstructure of CNTs in a wide frequency range up to terahertz. Numerical results are presented using the nonlocal beam theory to bring out the effect of both the nonlocal parameter and the temperature change on the properties of transverse vibrations of CNTs. The exact nonlocal Timoshenko beam solution presented here should be useful to engineers who are designing microelectromechanical and nanoelectromechanical devices.

  19. The thermal effect on vibration of single-walled carbon nanotubes using nonlocal Timoshenko beam theory

    Energy Technology Data Exchange (ETDEWEB)

    Benzair, A; Tounsi, A; Besseghier, A [Laboratoire des Materiaux et Hydrologie, Universite de Sidi Bel Abbes, BP 89 Cite Ben M' hidi, 22000 Sidi Bel Abbes (Algeria); Heireche, H; Moulay, N; Boumia, L [Universite de Sidi Bel Abbes, Departement de Physique, BP 89 Cite Ben M ' hidi, 22000 Sidi Bel Abbes (Algeria)], E-mail: tou_abdel@yahoo.com

    2008-11-21

    This paper is concerned with the use of the nonlocal Timoshenko beam model for free vibration analysis of single-walled carbon nanotubes (CNTs) including the thermal effect. Unlike the Euler beam model, the Timoshenko beam model allows for the effects of transverse shear deformation and rotary inertia. These effects become significant for CNTs with small length-to-diameter ratios that are normally encountered in applications such as nanoprobes. The elastic Timoshenko beam model is reformulated using the nonlocal differential constitutive relations of Eringen (1972 Int. J. Eng. Sci. 10 1-16). The study focuses on the wave dispersion caused not only by the rotary inertia and the shear deformation in the traditional Timoshenko beam model but also by the nonlocal elasticity characterizing the microstructure of CNTs in a wide frequency range up to terahertz. Numerical results are presented using the nonlocal beam theory to bring out the effect of both the nonlocal parameter and the temperature change on the properties of transverse vibrations of CNTs. The exact nonlocal Timoshenko beam solution presented here should be useful to engineers who are designing microelectromechanical and nanoelectromechanical devices.

  20. Capacitive Spring Softening in Single-Walled Carbon Nanotube Nanoelectromechanical Resonators

    Science.gov (United States)

    Wu, Chung Chiang

    2011-03-01

    Due to their low mass density and high Young's modulus, single-walled carbon nanotubes (SWNTs) offer great promise as nanoelectromechanical (NEM) resonators with applications in ultrasmall mass and force sensing. Nanotube resonators can be actuated and detected simultaneously through electrostatic gate coupling. This gate induced frequency tuning of NEM resonators is known to be governed by two mechanisms: the elastic hardening effect and the capacitive softening effect. Although elastic hardening effect has been widely reported in SWNT resonators, the field-induced capacitive spring softening has rarely been observed. Here we report the capacitive spring softening effect observed in SWNT resonators. The nanotube resonators adopt dual-gate configuration with both bottom-gate and side-gate capable of tuning the resonance frequency through capacitive coupling. Interestingly, downward resonance frequency shifting is observed with increasing side-gate voltage, which can be attributed to the capacitive softening of spring constant. Furthermore, in-plane vibrational modes exhibit much stronger spring softening effect than out-of-plan modes. Our dual-gate design should enable the differentiation between these two types of vibrational modes, and open up new possibility for nonlinear operation of nanotube resonators. Other nonlinear effects in SWNT resonators will also be discussed.