Sample records for metallic single-wall carbon

  1. Proton irradiation of metallic single-walled carbon nanotubes

    Microsoft Academic Search

    Don Walker; Colin J. Mann; John C. Nocerino; Simon H. Liu

    2011-01-01

    Metallic single-walled carbon nanotube (SWNT) films on space qualified solar cell coverglass were irradiated with 100 keV protons at doses of 1 × 1013 and 1 × 1014 protons\\/cm2. The samples were analyzed using UV-vis-NIR spectroscopy, Raman spectroscopy, and four-point probe measurements. The results indicate that defects are not introduced into the metallic carbon nanotubes after irradiation.

  2. The Crystallography of Metal Halides formed within Single Walled Carbon Nanotubes J. Sloan1,2

    E-print Network

    Dunin-Borkowski, Rafal E.

    The Crystallography of Metal Halides formed within Single Walled Carbon Nanotubes J. Sloan1,2 , G Street, Cambridge, CB2 3QZ, U.K. ABSTRACT The crystal growth behaviour and crystallography of a variety

  3. Electronic transport modification of single-walled carbon nanotubes by encapsulating alkali-metal ions

    NASA Astrophysics Data System (ADS)

    Izumida, T.; Jeong, G.-H.; Hirata, T.; Hatakeyama, R.; Neo, Y.; Mimura, H.

    2005-06-01

    We have produced alkali-metal encapsulated single-walled carbon nanotubes using a method of alkali-metal plasma ion irradiation. After plasma ion irradiation, alkali-metal encapsulated single-walled carbon nanotubes are sonicated for several hours in N,N-dimethylformamide to make well dispersed solution, then applied on a field-effect transistor substrate. As a result of measurements, pristine semiconducting single-walled carbon nanotubes show p-type conductivity, but Cs-encapsulated single-walled carbon nanotubes show n-type transport properties. This drastic change can be explained by electron transfer from encapsulated Cs atoms toward the surrounding SWNTs. At 11 K, the Coulomb oscillation is observed, implying that an inhomogeneous encapsulation profile of Cs atoms form several quantum dots. Thus, the electronic properties of SWNTs are found to be successfully controlled by plasma ion irradiation.

  4. Bolometric and nonbolometric radio frequency detection in a metallic single-walled carbon nanotube

    E-print Network

    Kim, Philip

    Bolometric and nonbolometric radio frequency detection in a metallic single-walled carbon nanotube 2011; published online 31 May 2011 We characterize radio frequency detection in a high-quality metallic difficult. The goals of the present work are to study radio frequency rf detec- tion over a range

  5. Reversible Oxidation Effect in Raman Scattering from Metallic Single-Wall Carbon Zhonghua Yu and Louis E. Brus*

    E-print Network

    . More interestingly, in Raman scattering from metallic carbon nano- tubes, the tangential C-C stretchingLETTERS Reversible Oxidation Effect in Raman Scattering from Metallic Single-Wall Carbon NanotubesVed: June 16, 2000; In Final Form: August 23, 2000 Raman scattering from individual single-wall carbon

  6. Bolometric and nonbolometric radio frequency detection in a metallic single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Santavicca, Daniel F.; Chudow, Joel D.; Prober, Daniel E.; Purewal, Meninder S.; Kim, Philip

    2011-05-01

    We characterize radio frequency detection in a high-quality metallic single-walled carbon nanotube. At a bath temperature of 77 K, only bolometric (thermal) detection is seen. At a bath temperature of 4.2 K and low bias current, the response is due instead to the electrical nonlinearity of the non-Ohmic contacts. At higher bias currents, the contacts recover Ohmic behavior and the observed response agrees well with the calculated bolometric responsivity. The bolometric response is expected to operate at terahertz frequencies, and we discuss some of the practical issues associated with developing high frequency detectors based on carbon nanotubes.

  7. Characterizations of Enriched Metallic Single-Walled Carbon Nanotubes in Polymer Composite

    NASA Technical Reports Server (NTRS)

    Chen, Bin; Li, Jing; Lu, Yijiang; Cinke, Martin; Au, Dyng; Harmon, Julie P.; Muisener, Patricia Anne O.; Clayton, LaNetra; D'Angelo, John

    2003-01-01

    Using different processing conditions, we disperse the single-walled carbon nanotube (SWNT) into the polymethyl methacrylate (PMMA) to form composites. In the melt-blended sample, the SWNTs originally semiconducting - became predominantly metallic after dispersion into the melt-blended composite. The interaction of the PMMA and SWNT is investigated by the polarized Raman studies. The structure changes in the PMMA and SWNT shows that the anisotropic interactions are responsible for SWNT electronic density of states (DOS) changes. The increased metallic SWNT percentage is confirmed by the conductivity and dielectric constant measurements .

  8. Nitrogen doping of metallic single-walled carbon nanotubes: n-type conduction and dipole scattering

    E-print Network

    V. Krstic; G. L. J. A. Rikken; P. Bernier; S. Roth; M. Glerup

    2006-01-23

    The charge transport properties of individual, metallic nitrogen doped, single-walled carbon nanotubes are investigated. It is demonstrated that n-type conduction can be achieved by nitrogen doping. Evidence was obtained by appealing to electric-field effect measurements at ambient condition. The observed temperature dependencies of the zero-bias conductance indicate a disordered electron system with electric-dipole scattering, caused mainly by the pyridine-type nitrogen atoms in the honeycomb lattice. These results illustrate the possibility of creating all-metallic molecular devices, in which the charge carrier type can be controlled.

  9. Photogenerated Free Carrier Dynamics in Metal and Semiconductor Single-Walled Carbon Nanotube Films

    SciTech Connect

    Beard, M. C.; Blackburn, J. L.; Heben, M. J.

    2008-01-01

    Time-resolved THz spectroscopy (TRTS) is employed to study the photogenerated charge-carrier dynamics in transparent films of single-walled carbon nanotubes (SWNTs). Two films were investigated: a film with 94% semiconducting-type tubes (s-SWNTs) and a film with only 7% s-SWNT and 93% metal-type tubes (m-SWNTs). We conclude that charge-carriers are generated with >60% yields at low light intensities in both films. Free-carriers are generated by a linear exciton dissociation process that occurs within 1 ps and is independent of excitation wavelength or tube type.

  10. Fast Detection of the Metallic State of Individual Single-Walled Carbon Nanotubes Using a Transient-Absorption Optical Microscope

    E-print Network

    Zhong, Zhaohui

    imaging method holds the potential of serving as a high-speed metallicity-mapping tool to assistFast Detection of the Metallic State of Individual Single-Walled Carbon Nanotubes Using a Transient method for fast, contact-free mapping of metallicity in individual SWNTs. We employ the phase

  11. Assignment of (n,m) Raman and Absorption Spectral Features of Metallic Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Michael S. Strano; Erik H. Haroz; Carter Kittrell; Robert H. Hauge; Richard E. Smalley

    2004-01-01

    The (n,m) spectral features for isolated metallic single walled carbon nanotubes were deduced by examining Raman excitation profiles. Correlation of the radial breathing mode frequency with diameter identifies the (n,m) index of the metallic tube. Observation of the energy of Raman intensity maximum provides experimental values for the optical transitions directly, and allows for model independent estimation of peak splitting

  12. Hydrogen storage properties of catalyst metal-doped single-walled carbon nanotubes

    Microsoft Academic Search

    Yong-Won Lee

    2007-01-01

    In the past decade, hydrogen storage in solid-state materials has been one of the biggest hurdles to meet the storage density, safety, reliability and cost reduction needed for a hydrogen fuel economy. Single-walled carbon nanotubes (SWNTs) are particularly intriguing for hydrogen storage because each carbon atom is a surface site, and calculations have indicated that hydrogen bond strength can be

  13. The effect of single wall carbon nanotube metallicity on genomic DNA-mediated chirality enrichment

    NASA Astrophysics Data System (ADS)

    Kim, Steve S.; Hisey, Colin L.; Kuang, Zhifeng; Comfort, Donald A.; Farmer, Barry L.; Naik, Rajesh R.

    2013-05-01

    Achieving highly enriched single wall carbon nanotubes (SWNTs) is one of the major hurdles today because their chirality-dependent properties must be uniform and predictable for use in nanoscale electronics. Due to the unique wrapping and groove-binding mechanism, DNA has been demonstrated as a highly specific SWNT dispersion and fractionation agent, with its enrichment capabilities depending on the DNA sequence and length as well as the nanotube properties. Salmon genomic DNA (SaDNA) offers an inexpensive and scalable alternative to synthetic DNA. In this study, SaDNA enrichment capabilities were tested on SWNT separation with varying degrees of metallicity that were formulated from mixtures of commercial metallic (met-) and semiconducting (sem-) abundant SWNTs. The results herein demonstrate that the degree of metallicity of the SWNT sample has a significant effect on the SaDNA enrichment capabilities, and this effect is modeled based on deconvolution of the near-infrared (NIR) absorption spectra and verified with photoluminescence emission (PLE) measurements. Using molecular dynamics and circular dichroism, the preferential SaDNA mediated separation of the (6, 5) sem-tube is shown to be largely influenced by the presence of met-SWNTs.Achieving highly enriched single wall carbon nanotubes (SWNTs) is one of the major hurdles today because their chirality-dependent properties must be uniform and predictable for use in nanoscale electronics. Due to the unique wrapping and groove-binding mechanism, DNA has been demonstrated as a highly specific SWNT dispersion and fractionation agent, with its enrichment capabilities depending on the DNA sequence and length as well as the nanotube properties. Salmon genomic DNA (SaDNA) offers an inexpensive and scalable alternative to synthetic DNA. In this study, SaDNA enrichment capabilities were tested on SWNT separation with varying degrees of metallicity that were formulated from mixtures of commercial metallic (met-) and semiconducting (sem-) abundant SWNTs. The results herein demonstrate that the degree of metallicity of the SWNT sample has a significant effect on the SaDNA enrichment capabilities, and this effect is modeled based on deconvolution of the near-infrared (NIR) absorption spectra and verified with photoluminescence emission (PLE) measurements. Using molecular dynamics and circular dichroism, the preferential SaDNA mediated separation of the (6, 5) sem-tube is shown to be largely influenced by the presence of met-SWNTs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00458a

  14. A quantum mechanical formulation of electron transport induced wind forces in metallic single-walled carbon nanotubes

    Microsoft Academic Search

    Tarek Ragab; Cemal Basaran

    2010-01-01

    In this paper the forces induced on the atoms of the lattice due an electric current (electron transport induced wind forces) are calculated based on quantum mechanics. These forces are calculated in metallic single-walled armchair carbon nanotubes (SWCNTs) from the momentum transfer between the charge carriers and the lattice in a quantum mechanical framework. Energy and phonon dispersion relations are

  15. The effect of single wall carbon nanotube metallicity on genomic DNA-mediated chirality enrichment.

    PubMed

    Kim, Steve S; Hisey, Colin L; Kuang, Zhifeng; Comfort, Donald A; Farmer, Barry L; Naik, Rajesh R

    2013-06-01

    Achieving highly enriched single wall carbon nanotubes (SWNTs) is one of the major hurdles today because their chirality-dependent properties must be uniform and predictable for use in nanoscale electronics. Due to the unique wrapping and groove-binding mechanism, DNA has been demonstrated as a highly specific SWNT dispersion and fractionation agent, with its enrichment capabilities depending on the DNA sequence and length as well as the nanotube properties. Salmon genomic DNA (SaDNA) offers an inexpensive and scalable alternative to synthetic DNA. In this study, SaDNA enrichment capabilities were tested on SWNT separation with varying degrees of metallicity that were formulated from mixtures of commercial metallic (met-) and semiconducting (sem-) abundant SWNTs. The results herein demonstrate that the degree of metallicity of the SWNT sample has a significant effect on the SaDNA enrichment capabilities, and this effect is modeled based on deconvolution of the near-infrared (NIR) absorption spectra and verified with photoluminescence emission (PLE) measurements. Using molecular dynamics and circular dichroism, the preferential SaDNA mediated separation of the (6, 5) sem-tube is shown to be largely influenced by the presence of met-SWNTs. PMID:23624632

  16. Valley coupling in finite-length metallic single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Izumida, W.; Okuyama, R.; Saito, R.

    2015-06-01

    Degeneracy of discrete energy levels of finite-length, metallic single-wall carbon nanotubes depends on the type of nanotubes, boundary condition, length of nanotubes, and spin-orbit interaction. Metal-1 nanotubes, in which two nonequivalent valleys in the Brillouin zone have different orbital angular momenta with respect to the tube axis, exhibit nearly fourfold degeneracy and small lift of the degeneracy by the spin-orbit interaction reflecting the decoupling of two valleys in the eigenfunctions. In metal-2 nanotubes, in which the two valleys have the same orbital angular momentum, vernier-scale-like spectra appear for boundaries of orthogonal-shaped edge or cap termination reflecting the strong valley coupling and the asymmetric velocities of the Dirac states. Lift of the fourfold degeneracy by parity splitting overcomes the spin-orbit interaction in shorter nanotubes with a so-called minimal boundary. Slowly decaying evanescent modes appear in the energy gap induced by the curvature of nanotube surface. Effective one-dimensional lattice model reveals the role of boundary on the valley coupling in the eigenfunctions.

  17. Electrical percolation characteristics of metallic single-walled carbon nanotube networks by vacancy evolution.

    PubMed

    Kim, Do-Hyun; Jin, Jun Eon; Piao, Mingxing; Choi, Jun Hee; Kim, Gyu Tae

    2014-09-14

    In the present study, we demonstrate the effect of vacancy evolution on high-pure metallic single-walled carbon nanotube (m-SWCNT) networks by observing the electrical characteristics of the networks on the field-effect transistor (FET). By catalytic oxidation using Co catalyst, vacancy evolution was gradually realized in high-pure m-SWCNT formed as networks between source-drain electrodes of FET. The evolution of vacancy defects in the m-SWCNT networks gradually proceeded by heating FET several times at 250 °C in air. Atomic force microscopic images showed the presence of the Co catalyst nanoparticles, which were evenly formed in the m-SWCNT networks between the electrodes of FET. Vacancy evolution was confirmed by monitoring the D- and G-bands in the Raman spectra measured from the networks after every step of the catalytic oxidation. With vacancy evolution in the networks, the D-band gradually increased, and the transconductance of m-SWCNT networks drastically decreased. In addition, the metallic behaviour of the m-SWCNT networks was converted into a semiconducting one with an on/off ratio of 2.7. PMID:25069594

  18. Metal coated functionalized single-walled carbon nanotubes for composite applications

    NASA Astrophysics Data System (ADS)

    Zeng, Qiang

    This study is considered as a method for producing multifunctional composite materials by using metals coated Single-walled Carbon Nanotubes (SWCNTs). In this research, various metals (Ni, Cu, Ag) were successfully deposited onto the surface of SWCNTs. It has been found that homogenous dispersion and dense nucleation sites are the necessary conditions to form uniform coatings on SWCNTs. Functionalization has been applied to achieve considerable improvement in the dispersion of purified SWCNTs and creates more nucleation sites for subsequent metal deposition. A three-step electroless plating approach was used and the coating mechanism is described in the paper. The samples were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Raman spectroscopy, fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDX). Bulk copper/aluminum-SWNT composites were processed by powder metallurgy with wet mixing techniques. Coated SWCNTs were well dispersed in the metal matrix. Cold pressing followed by sintering was applied to control porosity. The relationships between hardness and SWCNTs addition were discussed. Ni-SWCNTs composite coatings were prepared by electro-composite deposition. SWCNTs were suspended in a Ni deposition electrolyte and deposited together with nickel during electrodeposition. SWCNTs concentrations in the coatings were found to be related to the SWCNTs concentration in the solution, current density and agitation rate. The microstructure of the coatings has been examined by electron microscopy. Ni coated SWCNTs were also incorporated into the high temperature Bismaleimide (BMI)/graphite composite to improve Electromagnetic Interference (EMI) shielding and surface conductivity. The vacuum assisted resin transfer molding (VARTM) was used to process these composites. Surface and volume resistivity and EMI shielding effectiveness of the composites were assessed. A comparison with baseline data of unfilled BMI fiber reinforced composites is presented.

  19. Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Pisharody, Suresh A.; Fisher, John W.; Wignarajah, K.

    2002-01-01

    The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake of gaseous species based on their controlled pore size, high surface area, ordered chemical structure that allows functionalization and their effectiveness also as catalyst support materials for toxic gas conversion. We present results and findings from a preliminary study on the effectiveness of metal impregnated single walled nanotubes as catalyst/catalyst support materials for toxic gas contaminate control. The study included the purification of single walled nanotubes, the catalyst impregnation of the purified nanotubes, the experimental characterization of the surface properties of purified single walled nanotubes and the characterization of physisorption and chemisorption of uptake molecules.

  20. Annealing single-walled metallic carbon nanotube devices in ultra-high vacuum

    NASA Astrophysics Data System (ADS)

    Kane, Alexander Allen

    Single walled carbon nanotube (SWNT) devices were fabricated and annealed in ultra high vacuum (UHV) with simultaneous electrical characterization. As one-dimensional crystals with nanometer scale diameters and up to meter scale lengths, SWNTs offer a unique opportunity to probe 1D transport in mesoscopic electronics. Furthermore, all of the atoms in SWNTs are surface atoms which means that the electronic properties can be examined and tailored using the well-developed tools of surface chemistry. However, electronic resistances and noise for technologically relevant small-diameter SWNT devices are too high for commercial applications. In this work, intrinsic and extrinsic sources of scattering in SWNTs were examined by heating SWNT field effect transistors in UHV with while monitoring changes in the devices' resistance, transconductance, and conductance fluctuations. The effects of the contact interface were studied by varying the electrode metal, including palladium, titanium, and platinum contacts. It was found that metal-SWNT contact interfaces are the primary scatterers in devices as fabricated, but the contact resistance can be greatly reduced by annealing to a limit that depends primarily on the surface chemistry of the electrode metal and the geometry of the interface. Secondary sources of scattering include surface adsorbates on the electrodes and substrate, sub-strate oxide phonons and SWNT phonons. Adsorbates are the primary source of 1/f conductance noise, followed by the electrode interface. Annealing devices in UHV was found to reduce the contact resistance, noise, and device to device inhomogeneity. Graphene, formed through catalysis on the Pt surface during the anneal, was found to make the best contact to SWNTs, rather than the conventional Pd, Ti, and Pt, both in terms of contact resistance and noise.

  1. Structure and dynamics of metallic and carburized catalytic Ni nanoparticles: effects on growth of single-walled carbon nanotubes.

    PubMed

    Gomez-Ballesteros, Jose L; Balbuena, Perla B

    2015-05-27

    Understanding the evolution of the catalyst structure and interactions with the nascent nanotube under typical chemical vapor deposition (CVD) conditions for the synthesis of single-walled carbon nanotubes is an essential step to discover a way to guide growth toward desired chiralities. We use density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations on model metallic and carburized Ni clusters to explore changes in the fundamental features of the nanocatalyst: geometric and electronic structure, dynamics and stability of the carburized nanocatalyst, and interactions with nascent nanotube caps at two different temperatures (750 and 1000 K) and different carbon composition ratios. This allows us to gain insight about the evolution of these aspects during the pre-growth and growth stages of CVD synthesis of single-walled carbon nanotubes and their implications for reactivity and control of the nanotube structure. PMID:25989515

  2. A molecular dynamics study of metal coating on SWNT Abstract Metal coating process on single-walled carbon nanotube (SWNTs) was investigated

    E-print Network

    Maruyama, Shigeo

    SWNT A molecular dynamics study of metal coating on SWNT 1) , 1) , 1) ( 1) ) Abstract Metal coating process on single-walled carbon nanotube (SWNTs) was investigated using molecular dynamics simulations size and temperature highlight the roles of molecular dynamics on the resulting metal morphologies. [1

  3. Metal-oxide-layer-coated single-walled carbon nanotubes as a sensor for trace amounts of oxygen

    NASA Astrophysics Data System (ADS)

    Tabata, Hiroshi; Fukuda, Hiroshi; Matsushita, Kazutoshi; Kubo, Osamu; Kikuchi, Tsutomu; Sato, Tetsuya; Kamimura, Takahiro; Ueda, Tsuyoshi; Shimazaki, Ryotaro; Tanjo, Hiromasa; Horiuchi, Masashi; Katayama, Mitsuhiro

    2014-03-01

    We found that resistive sensors using a single-walled carbon nanotube thin film covered with a SrTiO3 or CeO2 thin layer exhibit excellent responses to trace amounts (˜10-3 Pa) of oxygen. By analysis based on the Langmuir adsorption model, their responses were revealed to be due to O2 adsorption on the metal oxide layer, which involves two adsorption processes. They were assigned to identical adsorptions as superoxide species on the sites at separate locations on the metal oxide surface, i.e., at directly accessible flat areas and at recessed areas that are only accessible via thermally activated surface diffusion.

  4. Hydrogen Storage in Metal-Modified Single-Walled Carbon Nanotubes (start 9/15/01)

    E-print Network

    reflux (Penn State) Carbolex H2O2, HCL reflux (Sony) #12;Accomplishments: Purification, microstructural synthesis routes for graphite and single walled nanotubes KC8 KC24 D. E. Nixon and G. S. Parry, J. Phys. D

  5. Catalytic Routes Towards Single Wall Carbon Nanotubes

    Microsoft Academic Search

    Emmanuel Lamouroux; Philippe Serp; Philippe Kalck

    2007-01-01

    Single wall carbon nanotubes (SWCNT) have become a strategic material in the area of nanotechnologies nowadays, and catalytic chemical vapor deposition seems to be the most promising technique in view of an industrial?scale production. However, the selective catalytic production of single wall carbon nanotubes is still a challenge, since catalytic systems performances both in terms of selectivity and activity are

  6. Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Cinke, Martin; Li, Jing; Chen, Bin; Wignarajah, Kanapathipillai; Pisharody, Suresh A.; Fisher, John W.; Delzeit, Lance; Meyyappan, Meyya; Partridge, Harry; Clark, Kimberlee

    2003-01-01

    The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Highly purified metal-impregnated carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake gaseous species based both on the nanotube s controlled pore size, high surface area, and ordered chemical structure that allows functionalization and on the nanotube s effectiveness as a catalyst support material for toxic contaminants removal. We present results on the purification of single walled carbon nanotubes (SWCNT) and efforts at metal impregnation of the SWCNT's.

  7. Processing of single-walled carbon-nanotube metal matrix composites and a finite element model for the process

    NASA Astrophysics Data System (ADS)

    Wilson, Kenneth

    In the present investigation, single-walled carbon nanotube (SWCNT or SWNT) reinforced titanium (Ti) matrix composites have been produced by powder metallurgy (PM) and induction heating methods. It has been found that a nickel coating and a fast processing time associated with the induction heating method enables carbon nanotubes to survive the high-temperature (above 1950 K) processing conditions. The result has been a Ti-SWCNT metal-matrix composite (MMC) which is three times stronger and harder than Ti alone, a consequence that has never been accomplished before. This is a promising new development in the application of SWCNT technology to materials science. A mathematical model is given to support the experimental findings.

  8. Supramolecular hybrid of metal nanoparticles and semiconducting single-walled carbon nanotubes wrapped by a fluorene-carbazole copolymer.

    PubMed

    Ozawa, Hiroaki; Ide, Natsuko; Fujigaya, Tsuyohiko; Niidome, Yasuro; Nakashima, Naotoshi

    2011-11-25

    The first approach for the preparation of metal nanoparticle/semiconducting single-walled carbon nanotube (SWNT) hybrids with specified chirality is described. For this purpose, a copolymer of a fluorene derivative with two long-chain alkyl substituents and a carbazole derivative carrying a thiol group was used. The copolymer was found to selectively dissolve (7,6)- and (8,7)SWNTs, as determined by UV/Vis/NIR absorption and Raman spectroscopy and 2D photoluminescence mapping. Gold and silver nanoparticles with diameters of about 3.8 and about 3.2 nm, respectively, were readily attached along the SWNTs by means of coordination bonds between the nanoparticles and the thiol moieties on the copolymer, as revealed by atomic force and electron microscopy studies. The study provides a novel way to design and fabricate metal nanoparticle/semiconducting SWNT hybrids with specific nanotube chirality. PMID:22068876

  9. Role of Transition Metal Catalysts in Single-Walled Carbon Nanotube Growth in Chemical Vapor Deposition

    Microsoft Academic Search

    Yoshikazu Homma; Yoshiro Kobayashi; Toshio Ogino; Daisuke Takagi; Roichi Ito; Yung Joon Jung; Pulickel M. Ajayan

    2003-01-01

    We characterize the iron and cobalt catalysts for carbon nanotube growth in chemical vapor deposition (CVD) by using electron microscopy. Nanoparticles of iron and cobalt exhibit a melting point drop in the methane ambient. Nanoparticles after nanotube growth are identified as Fe 3C and Co3C for iron and cobalt, respectively. Those results indicate that a eutectic compound of metal and

  10. Structures, energetics and reaction mechanisms of nitrous oxide on transition-metal-doped and -undoped single-wall carbon nanotubes.

    PubMed

    Pannopard, Panvika; Khongpracha, Pipat; Warakulwit, Chompunuch; Namuangruk, Supawadee; Probst, Michael; Limtrakul, Jumras

    2012-02-01

    The catalytic activity of carbon nanotubes (CNTs) for the removal of greenhouse gases, like nitrous oxide (N(2)O), can be fine-tuned by metal doping. We modify the inert surfaces of CNTs with Sc, Ti and V transition metals in order to investigate their capability of converting N(2)O to N(2). The stable composite catalysts of Sc-, Ti- and V-doped (5,5)single-walled carbon nanotubes (SWCNTs), along with the unmodified one were investigated by periodic DFT calculations. Without metal doping, the N(2) O decomposition on the bare tube proceeds over a high energy barrier (54.3 kcal mol(-1)) which in the presence of active metals is reduced to 3.6, 8.0 and 10.2 kcal mol(-1) for V-, Ti- and Sc-doped (5,5)SWCNTs, respectively. The superior reactivity is a result of the facilitated electron transfer between the tube and N(2)O caused by the overlap between the d orbitals of the metal and the p orbitals of N(2)O. PMID:22241847

  11. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    NASA Technical Reports Server (NTRS)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  12. Noble metal coated single-walled carbon nanotubes for applications in surface enhanced Raman scattering imaging and photothermal therapy.

    PubMed

    Wang, Xiaojing; Wang, Chao; Cheng, Liang; Lee, Shuit-Tong; Liu, Zhuang

    2012-05-01

    Single-walled carbon nanotubes (SWNTs) with various unique optical properties are interesting nanoprobes widely explored in biomedical imaging and phototherapies. Herein, DNA-functionalized SWNTs are modified with noble metal (Ag or Au) nanoparticles via an in situ solution phase synthesis method comprised of seed attachment, seeded growth, and surface modification with polyethylene glycol (PEG), yielding SWNT-Ag-PEG and SWNT-Au-PEG nanocomposites stable in physiological environments. With gold or silver nanoparticles decorated on the surface, the SWNT-metal nanocomposites gain an excellent concentration and excitation-source dependent surface-enhanced Raman scattering (SERS) effect. Using a near-infrared (NIR) laser as the excitation source, targeted Raman imaging of cancer cells labeled with folic acid (FA) conjugated SWNT-Au nanocomposite (SWNT-Au-PEG-FA) is realized, with images acquired in significantly shortened periods of time as compared to that of using nonenhanced SWNT Raman probes. Owing to the strong surface plasmon resonance absorption contributed by the gold shell, the SWNTs-Au-PEG-FA nanocomposite also offers remarkably improved photothermal cancer cell killing efficacy. This work presents a facile approach to synthesize water-soluble noble metal coated SWNTs with a strong SERS effect suitable for labeling and fast Raman spectroscopic imaging of biological samples, which has been rarely realized before. The SWNT-Au-PEG nanocomposite developed here may thus be an interesting optical theranostic probe for cancer imaging and therapy. PMID:22486413

  13. Assembly of single wall carbon nanotube-metal nanohybrids using biomolecular components

    NASA Astrophysics Data System (ADS)

    Kim, Sang Nyon; Slocik, Joseph M.; Naik, Rajesh R.

    2010-08-01

    Biomaterials such as nucleic acids and proteins can be exploited to create higher order structures. The biomolecular components such as DNA and peptides have been used to assemble nanoparticles with high fidelity. Here, we use DNA and peptides, and their preferential interaction with inorganic and carbon nanomaterials to form homogeneous hybrids. The enhanced binding of Pt ions to both DNA and peptide functionalized nanoparticles mediates the assembly of carbon nanotubes functionalized with DNA with peptide coated gold nanoparticles.

  14. Resonance enhancement of first- and second-order coherent phonons in metallic single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Sato, K.; Tahara, K.; Minami, Y.; Katayama, I.; Kitajima, M.; Kawai, H.; Yanagi, K.; Takeda, J.

    2014-12-01

    High-frequency coherent phonons resonantly excited in metallic single-walled carbon nanotubes (M-SWCNTs) were investigated via spectrally resolved pump-probe spectroscopy using 7.5-fs laser pulses. In addition to first-order coherent phonons such as radial breathing mode (RBM) and M and G modes, we clearly observed second-order high-frequency coherent phonons of 2 D and 2 G modes, which can be regarded as squeezed phonons. We found that the amplitudes of the RBM, G and 2 D modes were resonantly enhanced at specific wavelengths: the maximum resides at a wavelength whose energy is smaller than that of the van Hove singularities in M-SWCNTs by an amount corresponding to the phonon energy. Furthermore, the 2 D mode has stronger enhancement than the other first-order Raman modes. These results indicate that the enhancement originates from a Stokes-stimulated Raman-scattering process at van Hove singularities and that efficient resonance enhancement occurs for the 2 D mode, possibly through double resonance due to the trigonal warping effect and strong electron-phonon coupling due to the Kohn anomaly.

  15. Composite films of poly(3-hexylthiophene) grafted single-walled carbon nanotubes for electrochemical detection of metal ions.

    PubMed

    Yang, Shaojun; Meng, Dongli; Sun, Jinhua; Huang, Yan; Huang, Yong; Geng, Jianxin

    2014-05-28

    In this study, we prepared electrochemically active films of poly(3-hexylthiophene) grafted single-walled carbon nanotubes (SWNT-g-P3HT) by using a modified vacuum-assisted deposition approach, in which a SWNT-g-P3HT composite layer of various thicknesses was deposited on the top of a thin SWNT layer. Measurement of the optical and electrical properties of the SWNT-g-P3HT composite films demonstrated that the thickness of the SWNT-g-P3HT composite films was controllable. The data of transmission electron microscope observation and Raman spectroscopy indicated that the covalent grafting of P3HT onto the surfaces of SWNTs resulted in intimate and stable connectivity between the two components in the SWNT-g-P3HT composite. Capitalizing on these unique features, we successfully developed a new class of electrochemical sensors that used the SWNT-g-P3HT composite films deposited on an indium-tin oxide substrate as an electrochemical electrode for detection of metal ions. Significantly, such a SWNT-g-P3HT composite electrode showed advantages in selective, quantitative, and more sensitive detection of Ag(+) ions. PMID:24730434

  16. Electrically Robust Metal Nanowire Network Formation by In-Situ Interconnection with Single-Walled Carbon Nanotubes

    PubMed Central

    Woo, Jong Seok; Han, Joong Tark; Jung, Sunshin; Jang, Jeong In; Kim, Ho Young; Jeong, Hee Jin; Jeong, Seung Yol; Baeg, Kang-Jun; Lee, Geon-Woong

    2014-01-01

    Modulation of the junction resistance between metallic nanowires is a crucial factor for high performance of the network-structured conducting film. Here, we show that under current flow, silver nanowire (AgNW) network films can be stabilised by minimizing the Joule heating at the NW-NW junction assisted by in-situ interconnection with a small amount (less than 3?wt%) of single-walled carbon nanotubes (SWCNTs). This was achieved by direct deposition of AgNW suspension containing SWCNTs functionalised with quadruple hydrogen bonding moieties excluding dispersant molecules. The electrical stabilisation mechanism of AgNW networks involves the modulation of the electrical transportation pathway by the SWCNTs through the SWCNT-AgNW junctions, which results in a relatively lower junction resistance than the NW-NW junction in the network film. In addition, we propose that good contact and Fermi level matching between AgNWs and modified SWCNTs lead to the modulation of the current pathway. The SWCNT-induced stabilisation of the AgNW networks was also demonstrated by irradiating the film with microwaves. The development of the high-throughput fabrication technology provides a robust and scalable strategy for realizing high-performance flexible transparent conductor films. PMID:24763208

  17. Enhanced hydrogen sorption in single walled carbon nanotube incorporated MIL101 composite metal–organic framework

    Microsoft Academic Search

    K. P. Prasanth; Phani Rallapalli; Manoj C. Raj; H. C. Bajaj; Raksh Vir Jasra

    2011-01-01

    Metal–Organic Frameworks (MOFs) have emerged as potential hydrogen storage media due to their high surface area, pore volume and adjustable pore sizes. The large void space generated by cages in MOFs is not completely utilized for hydrogen storage application owing to weak interactions between the walls of MOFs and H2 molecules. These unutilized volumes in MOFs can be effectively utilized

  18. Electron promotion by surface functional groups of single wall carbon nanotubes to overlying metal particles in a fuel-cell catalyst.

    PubMed

    Luksirikul, Patraporn; Tedsree, Karaked; Moloney, Mark G; Green, Malcolm L H; Tsang, Shik Chi Edman

    2012-07-01

    A remarkable promotion: Functional groups added onto single-wall carbon nanotubes (SWNTs) can significantly influence the activity of a noble metal for formic acid oxidation. Phenolate groups on SWNTs under alkaline conditions can double the activity of 20 % w/w Pd compared to unmodified SWNTs. This catalyst has 14 times higher activity than the commercial benchmark catalyst (10 % w/w Pd on Vulcan). PMID:22674641

  19. Mechanism of metal-semiconductor transition in electric properties of single-walled carbon nanotubes induced by low-energy electron irradiation

    SciTech Connect

    Kanzaki, Kenichi; Suzuki, Satoru; Inokawa, Hiroshi; Ono, Yukinori; Vijayaraghavan, Aravind; Kobayashi, Yoshihiro [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2007-02-01

    Low-energy electron irradiation causes damage in single-walled carbon nanotubes and changes the electric behavior of a nanotube field-effect transistor from metallic to semiconducting at low temperature. The irradiation damage was found to form an energy barrier of several 10 meV in the nanotube channel. We show that the transition behavior can be reasonably explained by the barrier formation and gate-induced band bending.

  20. Single-walled carbon nanotubes as excitonic optical wires

    Microsoft Academic Search

    Daniel Y. Joh; Jesse Kinder; Lihong H. Herman; Sang-Yong Ju; Michael A. Segal; Jeffreys N. Johnson; Garnet K.-L. Chan; Jiwoong Park

    2011-01-01

    Although metallic nanostructures are useful for nanoscale optics, all of their key optical properties are determined by their geometry. This makes it difficult to adjust these properties independently, and can restrict applications. Here we use the absolute intensity of Rayleigh scattering to show that single-walled carbon nanotubes can form ideal optical wires. The spatial distribution of the radiation scattered by

  1. Chapter 2 Simulation of Single Walled Carbon Nano Tubes SWNT

    E-print Network

    Goddard III, William A.

    13 Chapter 2 Simulation of Single Walled Carbon Nano Tubes SWNT 2.1 Introduction Carbon nanotubes, mechanical and vibrational properties of single-walled carbon nano tubes SWNT," G. Gao, T. Cagin, and W properties of single-walled carbon nano tubes with di erent radius and chirality armchair n, n, chiral 2n, n

  2. Light Harvesting Single Wall Carbon Nanotube Hybrids

    Microsoft Academic Search

    Benjamin Baker; Tae-Gon Cha; M. Dane Sauffer; Yujun Wu; Jong Hyun Choi

    2010-01-01

    Due to extraordinary electron accepting and conductivity properties, single wall carbon nanotubes (SWNT) are explored as molecular wires in light harvesting cells. Here SWNT are employed as acceptors of photo-excited charge\\/energy in self-assembling aqueous soluble nanohybrids. DNA oligonucleotides and functionalized pyrene moieties are used as surfactants to solubilize an ensemble of individually suspended SWNT. Water-soluble porphyrins, chlorophyll-like molecules with strong

  3. Optical modulation of single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Strano, Michael S.

    2007-03-01

    Recent advances in the spectroscopy of single walled carbon nanotubes have significantly enhanced our ability to understand and control their surface chemistry, both covalently and non-covalently. Our work has focused on modulating the optical properties of semiconducting single walled carbon nanotubes as near infrared photoluminescent sensors for chemical analysis. Molecular detection using near-infrared light between 0.9 and 1.3 eV has important biomedical applications because of greater tissue penetration and reduced auto-fluorescent background in thick tissue or whole-blood media. In one system, the transition of DNA secondary structure modulates the dielectric environment of the single-walled carbon nanotube (SWNT) around which it is adsorbed. The SWNT band-gap fluorescence undergoes a red shift when an encapsulating 30-nucleotide oligomer is exposed to counter ions that screen the charged backbone. We demonstrate the detection of the mercuric ions in whole blood, tissue, and from within living mammalian cells using this technology. Similar results are obtained for DNA hybridization and the detection of single nucleotide polymorphism. We also report the synthesis and successful testing of near-infrared ?-D-glucose sensors2 that utilize a different mechanism: a photoluminescence modulation via charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.

  4. High-density metallic nanogap arrays for the sensitive detection of single-walled carbon nanotube thin films.

    PubMed

    Park, Hyeong-Ryeol; Namgung, Seon; Chen, Xiaoshu; Oh, Sang-Hyun

    2015-01-01

    We have investigated the extraordinary optical transmission of terahertz waves through an array of nanogaps with varying dimensions and periodicities, and used this platform to demonstrate terahertz sensing of a thin film of single-walled carbon nanotubes. We have used atomic layer lithography to fabricate periodic arrays of nanogap loops that have a gap size of 2 nm and a loop length of 100 ?m (aspect ratio of 50?000). These sub-mm-scale loops of nanogaps can sustain terahertz electromagnetic resonances along the contour. We have characterized the transmission of terahertz waves through the nanogap arrays and investigated the influence of inter-gap electromagnetic coupling as the array periodicity shrinks from 100 ?m to 4 ?m. While the gaps occupy only 0.1% of the surface area, we have measured an amplitude (|E|) transmittance of over 50% due to the strong and broadband field enhancement inside the nanogaps. The absolute transmission through the 2 nm gaps along the rectangular loops can be boosted up to 25%, while it is only 1% for annular gaps with the same perimeter. Furthermore, the extremely tight field confinement and strong field enhancement near the 2 nm gap lead to 43% extinction of THz waves in a 10 nm-thick film of single-walled carbon nanotubes over the gaps. On the other hand, THz extinction by the same nanotube film on a bare glass substrate is only 2%. These nanogaps pave the way toward developing sensitive terahertz detectors for biological and chemical targets. PMID:25760454

  5. Is there a Difference in Van Der Waals Interactions between Rare Gas Atoms Adsorbed on Metallic and Semiconducting Single-Walled Carbon Nanotubes?

    SciTech Connect

    Chen, De-Li; Mandeltort, Lynn; Saidi, Wissam A.; Yates, John T Jr, Cole, Milton W Johnson,J Karl

    2013-03-26

    Differences in polarizabilities of metallic (M) and semiconducting (S) single-walled carbon nanotubes (SWNTs) might give rise to differences in adsorption potentials. We show from experiments and van der Waals-corrected density functional theory (DFT) that binding energies of Xe adsorbed on M- and S-SWNTs are nearly identical. Temperature programmed desorption of Xe on purified M- and S-SWNTs give similar peak temperatures, indicating that desorption kinetics and binding energies are independent of the type of SWNT. Binding energies computed from vdW-corrected DFT are in good agreement with experiments.

  6. Single wall carbon nanohorns coated with anatase titanium oxide

    Microsoft Academic Search

    S. Battiston; M. Bolzan; S. Fiameni; R. Gerbasi; M. Meneghetti; E. Miorin; C. Mortalò; C. Pagura

    2009-01-01

    Single wall carbon nanohorns (SWCNHs) were coated with anatase titanium oxide thin films by metal-organic chemical vapour deposition with titanium tetraisopropoxide Ti(OiPr)4 as the precursor. The pristine SWCNHs and the new hybrid material SWCNHs\\/TiO2 were characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction, thermogravimetric thermal analysis and inductively coupled plasma-mass spectrometry, showing that the deposition process does not alter

  7. Diameter- and metallicity-selective enrichment of single-walled carbon nanotubes using polymethacrylates with pendant aromatic functional groups.

    PubMed

    Pan, Xiaoyong; Li, Lain-Jong; Chan-Park, Mary B

    2010-06-21

    Current methods for the synthesis of single-walled nanotubes (SWNTs) produce mixtures of semiconducting (sem-) and metallic (met-) nanotubes. Most approaches to the chemical separation of sem-/met-SWNTs are based on small neutral molecules or conjugated aromatic polymers, which characteristically have low separation/dispersion efficiencies or present difficulties in the postseparation removal of the polymer so that the resulting field-effect transistors (FETs) have poor performance. In this Full Paper, the use of three polymethacrylates with different pendant aromatic functional groups to separate cobalt-molybdenum catalyst (CoMoCAT) SWNTs according to their metallicity and diameters is reported. UV/Vis/NIR spectroscopy indicates that poly(methyl-methacrylate-co-fluorescein-o-acrylate) (PMMAFA) and poly(9-anthracenylmethyl-methacrylate) (PAMMA) preferentially disperse semiconducting SWNTs while poly(2-naphthylmethacrylate) (PNMA) preferentially disperses metallic SWNTs, all in dimethylforamide (DMF). Photoluminescence excitation (PLE) spectroscopy indicates that all three polymers preferentially disperse smaller-diameter SWNTs, particularly those of (6,5) chirality, in DMF. When chloroform is used instead of DMF, the larger-diameter SWNTs (8,4) and (7,6) are instead selected by PNMA. The solvent effects suggest that diameter selectivity and change of polymer conformation is probably responsible. Change of the polymer fluorescence upon interaction with SWNTs indicates that metallicity selectivity presumably results from the photon-induced dipole-dipole interaction between polymeric chromophore and SWNTs. Thin-film FET devices using semiconductor-enriched solution with PMMAFA have been successfully fabricated and the device performance confirms the sem-SWNTs enrichment with a highly reproducible on/off ratio of about 10(3). PMID:20486222

  8. Endohedral Carbon Chains in Single-Wall Carbon Nanotubes R. K. Vadapalli

    E-print Network

    Mintmire, John W.

    Endohedral Carbon Chains in Single-Wall Carbon Nanotubes R. K. Vadapalli and J. W. Mintmire of endohedral linear carbon chains. In these calculations, all-carbon nanowire structures were constructed by inserting cumulenic linear carbon chains inside the semiconducting (7,3) and metallic (7,4) single

  9. Single-walled carbon nanohorns and their applications

    NASA Astrophysics Data System (ADS)

    Zhu, Shuyun; Xu, Guobao

    2010-12-01

    Single-walled carbon nanohorns (SWCNHs) are horn-shaped single-walled tubules with a conical tip. They are generally synthesized by laser ablation of pure graphite without using metal catalyst with high production rate and high yield, and typically form radial aggregates. SWCNHs are essentially metal-free and very pure, which avoids cumbersome purification and makes them user-friendly and environmentally benign. Currently, SWCNHs have been widely studied for various applications, such as gas storage, adsorption, catalyst support, drug delivery system, magnetic resonance analysis, electrochemistry, biosensing application, photovoltaics and photoelectrochemical cells, photodynamic therapy, fuel cells, and so on. This review outlines the research progress on SWCNHs, including their properties, functionalization, applications, and outlook.

  10. Bond-order potential for transition metal carbide cluster for the growth simulation of a single-walled carbon nanotube

    E-print Network

    Maruyama, Shigeo

    as a seed for SWNTs. In these models, carbon atoms precipitate, nucleate the cap structure and form the SWNT-liquid-solid (VLS) model [13], and the carbon-metal alloy phase diagram [14] is often used to explain the VLS model

  11. Single Crystals of Single-Walled Carbon Nanotubes Formed by

    E-print Network

    Gimzewski, James

    -assembly of single crystals of single-walled carbon nano- tubes (SWCNTs) using thermolysis of nano of carbon nanotube fabrication is to form large uniform and ordered nano- and microstructuresSingle Crystals of Single-Walled Carbon Nanotubes Formed by Self-Assembly R. R. Schlittler,1 J. W

  12. Raman study of nanotubesubstrate interaction using single-wall carbon

    E-print Network

    Joselevich, Ernesto

    and vibrational properties of the single-wall carbon nano- tubes (SWNTs) were observed using resonance Raman carbon nanotube, quartz, Raman spectroscopy, tube­substrate interaction * Corresponding author: eRaman study of nanotube­substrate interaction using single-wall carbon nanotubes grown

  13. Enhanced Cellular Activation with Single Walled Carbon Nanotube Bundles

    E-print Network

    Fahmy, Tarek

    focused on new methods of biochemical functionalization of carbon nano- tubes using various proteinsEnhanced Cellular Activation with Single Walled Carbon Nanotube Bundles Presenting Antibody Stimuli the body using single walled carbon nanotube (SWNT) bundles presenting antibody stimuli. Owing to the large

  14. Symmetry of electron diffraction from single-walled carbon nanotubes

    E-print Network

    Qin, Lu-Chang

    Symmetry of electron diffraction from single-walled carbon nanotubes Zejian Liu a , Lu-Chang Qin a-walled carbon nanotube does not have mirror symmetry perpendicular to the tubule axis, the electron diffraction patterns of the single-walled carbon nanotube always possess 2mm symmetry. We have also analyzed

  15. Local opening of a large bandgap in metallic single-walled carbon nanotubes induced by tunnel injection of low-energy electrons

    SciTech Connect

    Yamada, Kenta; Sato, Hiroaki; Komaguchi, Tetsuya; Mera, Yutaka; Maeda, Koji [Department of Applied Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2009-06-22

    Probing with a tip of scanning tunneling microscopy (STM) of metallic single-walled carbon nanotubes (SWCNT) was found to induce defects in the tubes. The primary defect formation by probing was enhanced with a rate proportional to tunnel-injected electron current above a sample-bias threshold of around +4 V. Scanning tunneling spectroscopic measurements of local density of states revealed that the defects imaged by STM, presumably secondary defects stabilized at the test temperature (95 K), are accompanied by a localized bandgap of 0.7 eV, which may account for the reported metal-semiconductor conversion in SWCNT-based field-effect transistor that is induced by low-energy electron irradiation.

  16. Comment on "Single Crystals of Single-Walled Carbon Nanotubes

    E-print Network

    Kono, Junichiro

    et al. (1) reported the production of single crystals of single-walled carbon nano- tubes (SWCNTsComment on "Single Crystals of Single-Walled Carbon Nanotubes Formed by Self-Assembly" Schlittler) by the thermolysis of nano- patterned structures of alternating layers of C60 and nickel. Electron diffraction, high

  17. Single-wall carbon nanotube aerogels

    NASA Astrophysics Data System (ADS)

    Bryning, M. B.; Islam, M. F.; Hough, L. A.; Yodh, A. G.

    2006-03-01

    Aerogels of single-wall carbon nanotubes (SWNTs) were created by freeze drying and critical point drying of aqueous SWNT gels. The resulting aerogels maintain the strongly-connected three-dimensional SWNT network of the original gel and have density less than 0.1 g/cm3. While these pure SWNT aerogels are self-supporting, reinforcement with small amounts of added polyvinylalcohol (PVA) produces much stronger structures that are easy to handle. Electrical conductivity of order 1 S/cm is observed in the self-supporting aerogels, and similar conductivity can be achieved in PVA-reinforced aerogels through additional processing. The aerogels can be backfilled with polymers such as epoxy to create composite materials that retain the high conductivity of the network. Other potential applications for these structures, such as sensors, actuators, and thermoelectric devices, are currently being explored. This work is supported by grants from NSF (MRSEC DMR05-20020 and DMR-0505048) and NASA NAG8-2172.

  18. Improvements in Production of Single-Walled Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    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 modification for conversion from batch to continuous production.

  19. Determination of the metallic/semiconducting ratio in bulk single-wall carbon nanotube samples by cobalt porphyrin probe electron paramagnetic resonance spectroscopy.

    PubMed

    Cambré, Sofie; Wenseleers, Wim; Goovaerts, Etienne; Resasco, Daniel E

    2010-11-23

    A simple and quantitative, self-calibrating spectroscopic technique for the determination of the ratio of metallic to semiconducting single-wall carbon nanotubes (SWCNTs) in a bulk sample is presented. The technique is based on the measurement of the electron paramagnetic resonance (EPR) spectrum of the SWCNT sample to which cobalt(II)octaethylporphyrin (CoOEP) probe molecules have been added. This yields signals from both CoOEP molecules on metallic and on semiconducting tubes, which are easily distinguished and accurately characterized in this work. By applying this technique to a variety of SWCNT samples produced by different synthesis methods, it is shown that these signals for metallic and semiconducting tubes are independent of other factors such as tube length, defect density, and diameter, allowing the intensities of both signals for arbitrary samples to be retrieved by a straightforward least-squares regression. The technique is self-calibrating in that the EPR intensity can be directly related to the number of spins (number of CoOEP probe molecules), and as the adsorption of the CoOEP molecules is itself found to be unbiased toward metallic or semiconducting tubes, the measured intensities can be directly related to the mass percentage of metallic and semiconducting tubes in the bulk SWCNT sample. With the use of this method it was found that for some samples the metallic/semiconducting ratios strongly differed from the usual 1:2 ratio. PMID:20958073

  20. Electrical Transport in Single-Wall Carbon Nanotubes

    Microsoft Academic Search

    Michael J. Biercuk; Shahal Ilani; Charles M. Marcus; Paul L. McEuen

    \\u000a We review recent progress in the measurement and understanding of the electrical\\u000a properties of individual metal and semiconducting single-wall carbon nanotubes. The\\u000a fundamental scattering mechanisms governing the electrical transport in nanotubes\\u000a are discussed, along with the properties of p–n and Schottky-barrier junctions in\\u000a semiconductor tubes. The use of advanced nanotube devices for electronic,\\u000a high-frequency, and electromechanical applications is discussed. We

  1. Single-Walled Carbon Nanotubes: From Discovery to Application

    Microsoft Academic Search

    Ching-Hwa Kiang

    1998-01-01

    Single-walled carbon nanotubes, an all carbon polymer derived from fullerence research, has recently been discovered to be stable and possess useful chemical, electrical, and mechanical properties. These tubular carbon materials are composed of single-layer graphene cylinders and have dimensions on the nanometer scale. The discovery and catalytic synthesis of single-walled carbon nanotubes will be discussed. A growth model, consistent with

  2. Micro-Raman spectroscopy of isolated single wall carbon nanotube

    Microsoft Academic Search

    R. Saito; A. Jorio; A. G. Souza Filho; J. H. Hafner; C. M. Lieber; M. Hunter; T. McClure; M. A. Pimenta; A. M. Rao; G. Dresselhaus; M. S. Dresselhaus

    2001-01-01

    Micro-Raman spectroscopy of an isolated single wall carbon nanotube is overviewed in connection with the recent observation of (1) the chirality-dependent G-band Raman intensity, (2) BWF line analysis and (3) D-band feature of an individual single wall carbon nanotube. The localized phonons appeared around a point defect of carbon nanotube might be relevant to D-band intensity. .

  3. Local Electronic Structure of Single-Walled Carbon Nanotubes from

    E-print Network

    Bockrath, Marc

    reflects its fundamental properties. Measurements of electronic com- pressibility, which is determinedLocal Electronic Structure of Single-Walled Carbon Nanotubes from Electrostatic Force Microscopy, thereby coupling the cantilever's mechanical oscillations to the nanotube's local electronic properties

  4. Computational Study of Catalyzed Growth of Single Wall Carbon Nanotubes 

    E-print Network

    Zhao, Jin

    2010-01-14

    A recently developed chemical vapor deposition (CVD) synthesis process called CoMoCAT yields single-wall carbon nanotubes (SWCNT)s of controlled diameter and chirality, making them extremely attractive for technological ...

  5. Center for Applications of Single-Walled Carbon Nanotubes

    SciTech Connect

    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. Determination and mapping of diameter and helicity for single-walled carbon nanotubes using nanobeam electron diffraction

    E-print Network

    Qin, Lu-Chang

    the diameter is extremely small where all nano- tubes appear metallic.3 Of all possible carbon nanotube speDetermination and mapping of diameter and helicity for single-walled carbon nanotubes using June 2005 The atomic structures of 124 single-walled carbon nanotubes, described by their diameter

  7. Electronic structure of single-wall, multiwall, and filled carbon nanotubes D. O stling, D. Tomanek,* and A. Rosen

    E-print Network

    was enriched by traces of transition metals such as Co or Ni, acting as a catalyst. Single-wall nanotubes have of endohedral fullerenes by encapsulating metal atoms in carbon cages,11 was a synthesis of metal

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

    PubMed

    Arepalli, Sivaram

    2004-04-01

    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. PMID:15296222

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Single walled carbon nanotube network electrodes for dye solar cells

    Microsoft Academic Search

    Daniel D. Tune; Benjamin S. Flavel; Jamie S. Quinton; Amanda V. Ellis; Joseph G. Shapter

    2010-01-01

    The photovoltaic properties of a new working electrode for dye sensitised solar cells, consisting of networks of covalently bound single walled carbon nanotubes on indium tin oxide, have been investigated. Following covalent sensitisation of the carbon nanotube networks with a ruthenium dye an appreciable cathodic photocurrent is measured upon illumination with simulated sunlight. Significant increases in photocurrent density are observed

  11. Single-walled Carbon Nanotube Growth in a Wide Temperature Range

    E-print Network

    Maruyama, Shigeo

    Single-walled Carbon Nanotube Growth in a Wide Temperature Range Shohei Chiashi1, Taiki Inoue1 range. Ethanol and dimethyl ether (DME) were used as the carbon source and Co/Mo metal particles deposited on silicon substrates were used as the catalyst. The CVD temperature ranged from 400 to 900 degree

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Electronic transport in single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Antonov, Radoslav Dimitrov

    1999-12-01

    We have studied the electronic properties of single-wall carbon nanotubes (SWNTs) from room temperature down to 10mK by performing electronic transport spectroscopy measurements on individual single-wall nanotubes, nanotube ropes and untreated bulk SWNT material. Transport in metallic single-wall nanotubes at dilution refrigerator temperatures occurs via the resonant tunneling of electrons through discrete molecular orbitals of the tubes. The discrete energy level splitting in a 0.8mum long nanotube was roughly 1.2meV, which agrees with the 1meV estimate for the energy level splitting. Zeeman splitting of a single particle level was observed when a magnetic field was applied perpendicular to the tube, which yielded g = 1.8 for the electronic g-factor in a nanotube. Due to the small capacitance of the nanotube, the conductance at low bias voltages is suppressed by the Coulomb blockade. Surprisingly, the differential conductance of the tube shows a pattern of single electron charging that suggests the tube behaves as a couple of quantum dots in series. A numerical simulation, based on a model of a tube with three levels, reproduces some prominent features of the data. Electrons in a nanotube occupy 1D subbands. Sharp van Hove singularities in the density of states are expected at the band edges of the 1D modes and were observed as steps in the current-voltage characteristics of a semiconducting nanotube at 77K. By varying an external gate voltage we electrostatically doped the tube and controllably populated its subbands. The IV characteristics of a segment of the nanotube covered in part by an impurity were highly asymmetric. This was in sharp contrast to the symmetric IVs observed for a clean segment of the same tube. A simple band model, in which the impurity acts as a local charge dopant, can account for the diodic behavior of the tube. Early experiments on "mats" of bulk SWNT material revealed that low temperature transport in the bulk occurs via three dimensional (3D) variable range hopping of electrons between localized states. A typical characteristic temperature T0 for the material is 110 K. The bulk samples also exhibited a negative magneto-resistance, which indicates that transport in the mats is partly phase coherent. We used 3D weak localization theory to fit the data and obtained l ? = 1500A for the phase coherence length at 100mK .

  14. Chemical Sensing with Polyaniline Coated Single-Walled Carbon Nanotubes

    SciTech Connect

    Ding, Mengning; Tang, Yifan; Gou, Pingping; Reber, Michael J; Star, Alexander

    2011-01-25

    Single-walled carbon nanotube/polyaniline (SWNT/PAni) nanocomposite with controlled core/shell morphology was synthesized by a noncovalent functionalization approach. Unique electron interactions between the SWNT core and the PAni shell were studied electrochemically and spectroscopically, and superior sensor performance to chemical gases and vapors was demonstrated.

  15. Gas Separation by Kinked Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Z. Q. Zhang; H. W. Zhang

    2010-01-01

    A kink model for gas separation is presented. Transport of pure nitrogen, oxygen and their mixture in single walled carbon nanotubes (SWCNTs) with a kink formed by bending is studied using molecular dynamics simulations. The results show that a kinked SWCNT results in transport resistance to nitrogen while allowing oxygen to pass even though the two gases have very similar

  16. Electro-optical properties of single-walled carbon nanotubes

    Microsoft Academic Search

    I. Miloševi?; T. Vukovic; S. Dmitrovic; M. Damnjanovic

    2002-01-01

    Optical conductivity tensor and electron energy loss function for individual single-wall carbon nanotubes (SWCNT) of arbitrary chirality are found. The reported two types of results obtained in the TEM measurements on the isolated SWCNT of the same diameter are interpreted. The difference in plasmon excitation probabilities is shown to be related to the different numbers of allowed interband transitions in

  17. Fully integrated single-walled carbon nanotube thermoplastic composites

    Microsoft Academic Search

    Fernando J. Rodriguez-Macias

    2004-01-01

    The development of composites of single-walled carbon nanotubes (SWNTs) with thermoplastics requires methods for good dispersion and achieving good interaction between SWNTs and the matrix. This thesis presents a new method to achieve good dispersion by a preliminary treatment called incipient wetting. The SWNTs dispersed in a solvent are mixed with polymer particles and deposited over them as the solvent

  18. Elastic properties of single-walled carbon nanotubes

    Microsoft Academic Search

    V. N. Popov; V. E. Van Doren; M. Balkanski

    2000-01-01

    Analytical expressions for the velocities of the longitudinal and the torsional sound waves in single-walled carbon nanotubes are derived using Born's perturbation technique within a lattice-dynamical model. These expressions are compared to the formulas for the velocities of the sound waves in an elastic hollow cylinder from the theory of elasticity to obtain analytical expressions for the Young's and shear

  19. A Computational Experiment on Single-Walled Carbon Nanotubes

    ERIC Educational Resources Information Center

    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…

  20. Graphite fiber composites interlayered with single-walled carbon nanotubes

    Microsoft Academic Search

    H. S. Kim; H. T. Hahn

    2011-01-01

    A scalable processing method was used to fabricate graphite fiber composites with single-walled carbon nanotubes (SWCNTs) and the microstructures and properties of the fabricated laminates were investigated. SWCNTs were sprayed onto the surface of graphite\\/epoxy prepreg using an air spray. Interlaminar shear strength (ILSS) tests showed that the air spray processing had minimal effect on the quality of the laminates.

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

    PubMed

    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

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

    PubMed

    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

  3. Single-wall carbon nanotubes for optical limiting

    Microsoft Academic Search

    L. Vivien; E. Anglaret; D. Riehl; F. Bacou; C. Journet; C. Goze; M. Andrieux; M. Brunet; F. Lafonta; P. Bernier; F. Hache

    1999-01-01

    We report on the non-linear optical transmittance of single-wall carbon nanotubes (SWNT) in a water\\/surfactant suspension. Optical limiting is observed at low-energy thresholds both in the visible and near-infrared. We find small non-linear thresholds and large optical densities that match or overpass the performances of other good optical limiters (C60 and carbon black) both in the visible and in the

  4. Production of single-walled carbon nanotube grids

    DOEpatents

    Hauge, Robert H; Xu, Ya-Qiong; Pheasant, Sean

    2013-12-03

    A method of forming a nanotube grid includes placing a plurality of catalyst nanoparticles on a grid framework, contacting the catalyst nanoparticles with a gas mixture that includes hydrogen and a carbon source in a reaction chamber, forming an activated gas from the gas mixture, heating the grid framework and activated gas, and controlling a growth time to generate a single-wall carbon nanotube array radially about the grid framework. A filter membrane may be produced by this method.

  5. Single Wall Carbon Nano Tube Films and Coatings

    Microsoft Academic Search

    T. V. Sreekumar; Satish Kumar; Lars M. Ericson; Richard E. Smalley

    2002-01-01

    Purified single wall carbon nano tubes (SWNTs) produced from the high-pressure carbon monoxide (HiPCO) process have been dissolved \\/dispersed in oleum. These solutions \\/dispersions were optically homogeneous and have been used to form stand-alone SWNT films. The washed, dried, and heat-treated films are isotropic. The scanning electron micrographs of the film surface shows that the nanotube ropes (or fibrils) of

  6. Mechanically interlocked single-wall carbon nanotubes.

    PubMed

    de Juan, Alberto; Pouillon, Yann; Ruiz-González, Luisa; Torres-Pardo, Almudena; Casado, Santiago; Martín, Nazario; Rubio, Ángel; Pérez, Emilio M

    2014-05-19

    Extensive research has been devoted to the chemical manipulation of carbon nanotubes. The attachment of molecular fragments through covalent-bond formation produces kinetically stable products, but implies the saturation of some of the C-C double bonds of the nanotubes. Supramolecular modification maintains the structure of the SWNTs but yields labile species. Herein, we present a strategy for the synthesis of mechanically interlocked derivatives of SWNTs (MINTs). In the key rotaxane-forming step, we employed macrocycle precursors equipped with two ?-extended tetrathiafulvalene SWNT recognition units and terminated with bisalkenes that were closed around the nanotubes through ring-closing metathesis (RCM). The mechanically interlocked nature of the derivatives was probed by analytical, spectroscopic, and microscopic techniques, as well as by appropriate control experiments. Individual macrocycles were observed by HR?STEM to circumscribe the nanotubes. PMID:24729452

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

    SciTech Connect

    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.

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

    SciTech Connect

    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.

  9. Role of pH controlled DNA secondary structures in the reversible dispersion/precipitation and separation of metallic and semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Maji, Basudeb; Samanta, Suman K.; Bhattacharya, Santanu

    2014-03-01

    Single-stranded DNA (ss-DNA) oligomers (dA20, d[(C3TA2)3C3] or dT20) are able to disperse single-walled carbon nanotubes (SWNTs) in water at pH 7 through non-covalent wrapping on the nanotube surface. At lower pH, an alteration of the DNA secondary structure leads to precipitation of the SWNTs from the dispersion. The structural change of dA20 takes place from the single-stranded to the A-motif form at pH 3.5 while in case of d[(C3TA2)3C3] the change occurs from the single-stranded to the i-motif form at pH 5. Due to this structural change, the DNA is no longer able to bind the nanotube and hence the SWNT precipitates from its well-dispersed state. However, this could be reversed on restoring the pH to 7, where the DNA again relaxes in the single-stranded form. In this way the dispersion and precipitation process could be repeated over and over again. Variable temperature UV-Vis-NIR and CD spectroscopy studies showed that the DNA-SWNT complexes were thermally stable even at ~90 °C at pH 7. Broadband NIR laser (1064 nm) irradiation also demonstrated the stability of the DNA-SWNT complex against local heating introduced through excitation of the carbon nanotubes. Electrophoretic mobility shift assay confirmed the formation of a stable DNA-SWNT complex at pH 7 and also the generation of DNA secondary structures (A/i-motif) upon acidification. The interactions of ss-DNA with SWNTs cause debundling of the nanotubes from its assembly. Selective affinity of the semiconducting SWNTs towards DNA than the metallic ones enables separation of the two as evident from spectroscopic as well as electrical conductivity studies.Single-stranded DNA (ss-DNA) oligomers (dA20, d[(C3TA2)3C3] or dT20) are able to disperse single-walled carbon nanotubes (SWNTs) in water at pH 7 through non-covalent wrapping on the nanotube surface. At lower pH, an alteration of the DNA secondary structure leads to precipitation of the SWNTs from the dispersion. The structural change of dA20 takes place from the single-stranded to the A-motif form at pH 3.5 while in case of d[(C3TA2)3C3] the change occurs from the single-stranded to the i-motif form at pH 5. Due to this structural change, the DNA is no longer able to bind the nanotube and hence the SWNT precipitates from its well-dispersed state. However, this could be reversed on restoring the pH to 7, where the DNA again relaxes in the single-stranded form. In this way the dispersion and precipitation process could be repeated over and over again. Variable temperature UV-Vis-NIR and CD spectroscopy studies showed that the DNA-SWNT complexes were thermally stable even at ~90 °C at pH 7. Broadband NIR laser (1064 nm) irradiation also demonstrated the stability of the DNA-SWNT complex against local heating introduced through excitation of the carbon nanotubes. Electrophoretic mobility shift assay confirmed the formation of a stable DNA-SWNT complex at pH 7 and also the generation of DNA secondary structures (A/i-motif) upon acidification. The interactions of ss-DNA with SWNTs cause debundling of the nanotubes from its assembly. Selective affinity of the semiconducting SWNTs towards DNA than the metallic ones enables separation of the two as evident from spectroscopic as well as electrical conductivity studies. Electronic supplementary information (ESI) available: Additional UV-Vis-NIR absorption, CD and Raman spectra, zeta potential, AFM, laser irradiation and electrical conductivity data (S1-S15). See DOI: 10.1039/c3nr05045a

  10. Single-Walled Carbon Nanotube/Metalloporphyrin Composites for the Chemiresistive Detection of Amines and Meat Spoilage

    E-print Network

    Petty, Alexander R.

    Chemiresistive detectors for amine vapors were made from single-walled carbon nanotubes by noncovalent modification with cobalt meso-arylporphyrin complexes. We show that through changes in the oxidation state of the metal, ...

  11. Covalently Bridging Gaps in Single-Walled Carbon Nanotubes with Conducting Molecules

    Microsoft Academic Search

    Xuefeng Guo; Joshua P. Small; Jennifer E. Klare; Yiliang Wang; Meninder S. Purewal; Iris W. Tam; Byung Hee Hong; Robert Caldwell; Limin Huang; Stephen O'Brien; Jiaming Yan; Ronald Breslow; Shalom J. Wind; James Hone; Philip Kim; Colin Nuckolls

    2006-01-01

    Molecular electronics is often limited by the poorly defined nature of the contact between the molecules and the metal surface. We describe a method to wire molecules into gaps in single-walled carbon nanotubes (SWNTs). Precise oxidative cutting of a SWNT produces carboxylic acid-terminated electrodes separated by gaps of <=10 nanometers. These point contacts react with molecules derivatized with amines to

  12. High temperature electrical resistance of substrate-supported single walled carbon nanotubes

    Microsoft Academic Search

    C. Thomas Avedisian; Richard E. Cavicchi; Paul M. McEuen; Xinjian Zhou; Wilbur S. Hurst; Joseph T. Hodges

    2008-01-01

    We report the electrical characteristics of substrate-supported metallic single walled carbon nanotubes at temperatures up to 573 K over a range of bias voltages (Vb) for zero gate voltage in air under atmospheric pressure. Our results show a monotonic increase in resistance with temperature, with an I-Vb characteristic that is linear at high temperature but nonlinear at low temperature. A

  13. Cesium-Filled Single Wall Carbon Nanotubes as Conducting Nanowires: Scanning Tunneling Spectroscopy Study

    Microsoft Academic Search

    S. H. Kim; W. I. Choi; G. Kim; Y. J. Song; G.-H. Jeong; R. Hatakeyama; J. Ihm; Y. Kuk

    2007-01-01

    Metal-filled single wall carbon nanotubes (SWCNTs) are examined for possible application to conducting wires in nanoelectronics architecture. The local electronic structure of SWCNTs partially filled with cesium atoms is studied with scanning tunneling spectroscopy. The conduction and valence bands are shifted downward with two localized states in the gap at the location where the Cs atoms are filled. From a

  14. Sensitivity of single wall carbon nanotubes to oxidative processing: structural modification, intercalation and functionalisation

    Microsoft Academic Search

    M. T. Mart??nez; M. A. Callejas; A. M. Benito; M. Cochet; T. Seeger; A. Ansón; J. Schreiber; C. Gordon; C. Marhic; O. Chauvet; J. L. G. Fierro; W. K. Maser

    2003-01-01

    The effect of oxidation on modification of single wall carbon nanotubes (SWCNTs) through successive purification steps has been studied. The efficient elimination of metal impurities has been followed by induced coupled plasma spectroscopy. Upon acid treatment, Raman spectroscopy clearly proofed that HNO3 molecules were intercalated into the bundles of SWCNTs. At the same time, SWCNTs also have suffered a high

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

    Microsoft Academic Search

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

    2011-01-01

    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,

  16. Electrically driven thermal light emission from individual single-walled carbon nanotubes

    Microsoft Academic Search

    David Mann; Y. K. Kato; Anika Kinkhabwala; Eric Pop; Jien Cao; Xinran Wang; Li Zhang; Qian Wang; Jing Guo; Hongjie Dai

    2007-01-01

    Light emission from nanostructures exhibits rich quantum effects and has broad applications. Single-walled carbon nanotubes (SWNTs) are one-dimensional metals or semiconductors in which large numbers of electronic states in narrow energy ranges, known as van Hove singularities, can lead to strong spectral transitions. Photoluminescence and electroluminescence involving interband transitions and excitons have been observed in semiconducting SWNTs, but are not

  17. Lithography-Free in Situ Pd Contacts to Templated Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Matthew R. Maschmann; Aaron D. Franklin; Adina Scott; Timothy D Sands; Timothy Fisher

    2006-01-01

    We report a metalization technique for electrically addressing templated vertical single-walled carbon nanotubes (SWNTs) using in situ palladium (Pd) nanowires. SWNTs are synthesized from an embedded catalyst in a modified porous anodic alumina (PAA) template. Pd is electrodeposited into the template to form nanowires that grow from an underlying conductive layer beneath the PAA and extend to the initiation sites

  18. Fabrication of stretchable single-walled carbon nanotube logic devices.

    PubMed

    Yoon, Jangyeol; Shin, Gunchul; Kim, Joonsung; Moon, Young Sun; Lee, Seung-Jung; Zi, Goangseup; Ha, Jeong Sook

    2014-07-23

    The fabrication of a stretchable single-walled carbon nanotube (SWCNT) complementary metal oxide semiconductor (CMOS) inverter array and ring oscillators is reported. The SWCNT CMOS inverter exhibits static voltage transfer characteristics with a maximum gain of 8.9 at a supply voltage of 5 V. The fabricated devices show stable electrical performance under the maximum strain of 30% via forming wavy configurations. In addition, the 3-stage ring oscillator demonstrates a stable oscillator frequency of ?3.5 kHz at a supply voltage of 10 V and the oscillating waveforms are maintained without any distortion under cycles of pre-strain and release. The strains applied to the device upon deformation are also analyzed by using the classical lamination theory, estimating the local strain of less than 0.6% in the SWCNT channel and Pd electrode regions which is small enough to keep the device performance stable under the pre-strain up to 30%. This work demonstrates the potential application of stretchable SWCNT logic circuit devices in future wearable electronics. PMID:24700788

  19. Flexible vapour sensors using single walled carbon nanotubes

    Microsoft Academic Search

    Kunjal Parikh; Kyle Cattanach; Rashmi Rao; Dong-Seok Suh; Aimei Wu; Sanjeev K. Manohar

    2006-01-01

    Thin, strongly adhering films of single-walled carbon nanotube bundles (SWNT) on flexible substrates such as poly(ethyleneterephthalate) (PET) were used for vapour sensing (hexane, toluene, acetone, chloroform, acetonitrile, methanol, water, etc.). These sensors are extremely easy to fabricate using the line patterning method. For example, ‘4-probe’ sensor patterns are drawn on a computer and then printed on overhead transparency (PET) sheets.

  20. Reversible separation of single-walled carbon nanotubes in bundles

    SciTech Connect

    Sahoo, Sangeeta; Lastella, Sarah [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590 (United States); Maranganti, Ravi; Sharma, Pradeep [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States); Mallick, Govind; Karna, Shashi [AMSRD-ARL-WM-BD, Weapons and Materials Directorate, US Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005-5069 (United States); Ajayan, Pulickel M. [Department of Mechanical Engineering and Materials Science, Rice University, 6100 Main Street, Houston, Texas 77005 (United States)

    2008-08-25

    We show that electrostatic charging of nanotubes and the consequent repulsion can lead to reversible separation of individual single-walled carbon nanotubes in bundles. Low-energy electron beam irradiation leads to this completely reversible phenomenon. A simple semianalytical model is used to explain the observed separation mechanism. The reversibility of the separation process is attributed to discharging and thermal-fluctuation induced motion of the nanotubes in ambient air. Further, the separation impacts the electrical conductance of small nanotube bundled devices.

  1. Hydrogen adsorption studies on single wall carbon nanotubes

    Microsoft Academic Search

    A. Ansón; M. A. Callejas; A. M. Benito; W. K. Maser; M. T. Izquierdo; B. Rubio; J. Jagiello; M. Thommes; J. B. Parra; M. T. Mart??nez

    2004-01-01

    Hydrogen adsorption data on as-grown and heat-treated single walled carbon nanotubes (SWNTs) obtained by a volumetric procedure using a Quantachrome Autosorb-1 equipment are presented. The amounts of hydrogen adsorbed at atmospheric pressure reach approximately 0.01 wt.% at 298 K and 1 wt.% at 77 K. The isosteric heat of adsorption has been calculated for both samples from H2 equilibrium adsorption

  2. Supramolecularly knitted tethered oligopeptide/single-walled carbon nanotube organogels.

    PubMed

    Zou, Jiong; He, Xun; Fan, Jingwei; Raymond, Jeffery E; Wooley, Karen L

    2014-07-14

    A facile polymerization of an allyl-functionalized N-carboxyanhydride (NCA) monomer is utilized to construct an A-B-A-type triblock structure containing ?-sheet-rich oligomeric peptide segments tethered by a poly(ethylene oxide) chain, which are capable of dispersing and gelating single-walled carbon nanotubes (SWCNTs) noncovalently in organic solvents, resulting in significant enhancement of the mechanical properties of polypeptide-based organogels. PMID:24961389

  3. A novel aerosol method for single walled carbon nanotube synthesis

    Microsoft Academic Search

    Albert G. Nasibulin; Anna Moisala; David P. Brown; Hua Jiang; Esko I. Kauppinen

    2005-01-01

    Single walled carbon nanotubes (CNTs) were produced by a novel aerosol method. Catalyst particles were formed by a hot wire generator and introduced into a laminar flow reactor. The size of catalyst particles was approximately 1–3nm, while the diameter of formed CNTs was 0.6–2nm. The average length of CNTs was about 50nm. The important role of hydrogen in the process

  4. Single-Wall Carbon Nanotubes as Transparent Electrodes for Photovoltaics

    Microsoft Academic Search

    Jorma Peltola; Igor Levitsky; Paul Glatkowski; Jao van de Lagemaat; Garry Rumbles; Teresa Barnes; Tim Coutts

    2006-01-01

    Transparent and electrically conductive coatings and films have a variety of uses in the fast-growing field of optoelectronic applications. Transparent electrodes typically include semiconductive metal oxides such as indium tin oxide (ITO), and conducting polymers such as poly(3,4-ethylenedioxythiophene), doped and stabilized with poly(styrenesulfonate) (PEDOT\\/PSS). In recent years, Eikos, Inc. has conceived and developed technologies to deliver novel alternatives using single-wall

  5. Measurements of Electronic Transport Properties of Single-Walled Carbon Nanotubes Encapsulating Alkali-Metals and C60 Fullerenes via Plasma Ion Irradiation

    NASA Astrophysics Data System (ADS)

    Izumida, Takeshi; Jeong, Goo-Hwan; Neo, Yoichiro; Hirata, Takamichi; Hatakeyama, Rikizo; Mimura, Hidenori; Omote, Kenji; Kasama, Yasuhiko

    2005-04-01

    We report on the measurements of the electronic transport properties of Cs-encapsulated single-walled carbon nanotubes (SWNTs), Li-encapsulated SWNTs, and C60-encapsulated SWNTs synthesized by plasma ion irradiation method. After fabricating field-effect transistor (FET) configurations using pristine and plasma-ion-irradiated SWNTs, the electronic transport properties of these devices are investigated in vacuum at room temperature. As a result, C60-encapsulated SWNTs give rise to a p-type semiconducting property as pristine SWNTs do. On the other hand, it is clearly observed that Cs-encapsulated SWNTs exhibit n-type transport behavior. Moreover, Li-encapsulated SWNTs show an ambipolar transport property with both n-type and p-type characteristics. Thus, the electronic properties of SWNTs are found to be successfully controlled by plasma ion irradiation.

  6. Millimeter-Thick Single-Walled Carbon Nanotube Forests: Hidden Role of Catalyst Support

    E-print Network

    Maruyama, Shigeo

    Millimeter-Thick Single-Walled Carbon Nanotube Forests: Hidden Role of Catalyst Support Suguru Noda the realizations of the vertically-aligned single-walled carbon nanotube (VA-SWNT) forests1) by alcohol chemical-called "super growth" of single-walled carbon nanotubes (SWNTs) was done by using combinatorial libraries

  7. Thermal conductivity enhancement of liquid and solid with single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    Thermal conductivity enhancement of liquid and solid with single-walled carbon nanotubes (CNT) #12;#12;Thermal conductivity enhancement of liquid and solid with single-walled carbon nanotubes (CNT in the thesis entitled "Thermal conductivity enhancement of liquid and solid with single-walled carbon nanotubes

  8. Controlled growth and assembly of single-walled carbon nanotubes for nanoelectronics

    NASA Astrophysics Data System (ADS)

    Omrane, Badr

    Carbon nanotubes are promising candidates for enhancing electronic devices in the future at the nanoscale level. Their integration into today's electronics has however been challenging due to the difficulties in controlling their orientation, location, chirality and diameter during formation. This thesis investigates and develops new techniques for the controlled growth and assembly of carbon nanotubes as a way to address some of these challenges. Colloidal lithography using nanospheres of 450 nm in diameter, acting as a shadow mask during metal evaporation, has been used to pattern thin films of single-walled carbon nanotube multilayer catalysts on Si and Si/SiO2 substrates. Large areas of periodic hexagonal catalyst islands were formed and chemical vapor deposition resulted in aligned single-walled carbon nanotubes on Si substrates within the hexagonal array of catalyst islands. On silicon dioxide, single-walled carbon nanotubes connecting the hexagonal catalyst islands were observed. To help explain these observations, a growth model based on experimental data has been used. Electrostatic interaction, van der Waals interaction and gas flow appear to be the main forces contributing to single-walled carbon nanotube alignment on Si/SiO2. Although the alignment of single-walled carbon nanotubes on Si substrates is still not fully understood, it may be due to a combination of the above factors, in addition to silicide-nanotube interaction. Atomic force microscopy and Raman spectroscopy of the post-growth samples show single-walled carbon nanotubes of 1-2 nm in diameter. Based on the atomic force microscopy data and Raman spectra, a mixture of individual and bundles of metallic and semiconducting nanotubes were inferred to be present. A novel technique based on direct nanowriting of carbon nanotube catalysts in liquid form has also been developed. The reliability of this method to produce nanoscale catalyst geometries in a highly controlled manner, as required for carbon nanotube growth and applications, was demonstrated. Chemical vapor deposition growth of the patterned regions shows individual and bundles of single-walled carbon nanotubes. This was confirmed by Raman spectroscopy of the samples, giving single-walled carbon nanotubes ˜1-2 nm in diameter. The capabilities of the nanowriting process were also explored for direct-writing of carbon based nanomaterials such as single-walled carbon nanotubes and C 60 molecules. Finally, a brief survey on carbon nanotube field-effect transistor modeling tools has been presented, followed by two-terminal current-voltage measurements on colloidal lithography and nanowriting samples. Results show primarily ohmic behavior with conductances of ˜0.86-16.5 muS for the hexagonal catalyst array patterned samples for various geometries and ˜0.27-1 muS for the nanowriting samples. In addition, compact models have been used to gain insights into the device performance and the unique advantages of the hexagonal array approach over devices fabricated using parallel or randomly distributed SWCNTs. Device performance appears to be determined primarily by the contact resistance which includes both Schottky barrier resistances and an interface resistance. In summary, colloidal lithography and direct-writing of single-walled carbon nanotube catalyst have been used to achieve the controlled growth and assembly of carbon nanotubes. Electronic transport of carbon nanotube devices fabricated using these two methods showed near ohmic behavior with device performance modeled primarily by the contact resistance. The approaches developed in this thesis allow nanoscale control over catalyst deposition and nanotube growth which makes them promising for the fabrication of future carbon nanotube electronic devices.

  9. Electron-phonon coupling in single-walled carbon nanotubes determined by shot noise

    E-print Network

    Plaçais, Bernard

    -voltage characteristics of single-walled carbon nano- tubes SWNTs , and they indicate optical phonon generation with high temperature has not been de- termined. We have studied shot noise in single-walled nano- tubes at high biasElectron-phonon coupling in single-walled carbon nanotubes determined by shot noise F. Wu,1 P

  10. Imaging as-grown single-walled carbon nanotubes originated from isolated catalytic nanoparticles

    Microsoft Academic Search

    Y. Zhang; Y. Li; W. Kim; D. Wang; H. Dai

    2002-01-01

    .   Discrete catalytic nanoparticles with diameters in the range of 1–3 nm are obtained by placing controllable numbers of metal\\u000a atoms into the cores of apoferritin. With nanoparticles placed on transmission electron microscope (TEM) grids coated with\\u000a ultra-thin alumina membranes, isolated single-walled carbon nanotubes are grown by chemical vapor deposition and directly\\u000a examined by TEM. The characterizations, carried out at single-tube

  11. Three dimensional solid-state supercapacitors from aligned single-walled carbon nanotube array templates

    Microsoft Academic Search

    Cary L. Pint; Nolan W. Nicholas; Sheng Xu; Zhengzong Sun; James M. Tour; Howard K. Schmidt; Roy G. Gordon; Robert H. Hauge

    2011-01-01

    We demonstrate the fabrication of solid-state dielectric energy storage materials from self-assembled, aligned single-walled carbon nanotube arrays (VA-SWNTs). The arrays are transferred as intact structures to a conductive substrate and the nanotubes are conformally coated with a thin metal-oxide dielectric and a conductive counter-electrode layer using atomic layer deposition. Experimental results yield values in agreement with those obtained through capacitive

  12. Field-effect transistor biosensor fabricated With selective enrichment of semiconducting Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Xiaoxian Zhang; Dongwei Wang; Danna Yang; Sai Li; Yi He

    2012-01-01

    Single-Walled Carbon Nanotubes(SWNTs) have excellent electrical properties to fabricate field-effect transistor (FET) biosensor, microelectrodes, microelectric unit etc. At present, biosensors based on CNTFET are required in various applications, including clinical diagnostics, environmental testing, food analysis, and bioterrorism detection technologies. But nowadays SWNTs are typically grown as mixtures of metallic-SWNTs and semiconducting-SWNTs, which limited their further application. In this paper, we

  13. Translocation events in a single walled carbon nanotube

    PubMed Central

    He, Jin; Liu, Hao; Pang, Pei; Cao, Di; Lindsay, Stuart

    2010-01-01

    Translocation of DNA oligomers through a single walled carbon nanotube was demonstrated recently. Translocation events are accompanied by giant current pulses, the origin of which remains obscure. Here, we show that introduction of a nucleotide alone, guanosine triphosphate into the input reservoir of a carbon nanotube nanofluidic also gives giant current pulses. Taken together with data on oligomer translocation, theses new results suggest that pulse width has a non-linear, power-law dependence on the number of nucleotides in a DNA molecule. We have also measured the time for the onset of DNA translocation pulses after bias reversal, finding that the time for the onset of translocation is directly proportional to the period of bias reversal. PMID:21179393

  14. Single Wall Carbon Nano Tube Films and Coatings

    NASA Astrophysics Data System (ADS)

    Sreekumar, T. V.; Kumar, Satish; Ericson, Lars M.; Smalley, Richard E.

    2002-03-01

    Purified single wall carbon nano tubes (SWNTs) produced from the high-pressure carbon monoxide (HiPCO) process have been dissolved /dispersed in oleum. These solutions /dispersions were optically homogeneous and have been used to form stand-alone SWNT films. The washed, dried, and heat-treated films are isotropic. The scanning electron micrographs of the film surface shows that the nanotube ropes (or fibrils) of about 20 nm diameters are arranged just like macroscopic fibers in a non-woven fabric. Polarized Raman spectroscopy of the SWNT film confirms the isotropic nature of these films. The films are being characterized for their thermal, mechanical as well electrical properties. Thin nano tube coatings, including optically transparent coatings, have also been made on a variety of substrates such as glass, polyethylene, polystyrene, polypropylene, silicon wafer, as well as stainless steel.

  15. Production of thick single-walled carbon nanotubes by arc discharge in hydrogen ambience

    NASA Astrophysics Data System (ADS)

    Ando, Yoshinori; Zhao, Xinluo; Hirahara, Kaori; Iijima, Sumio

    2001-10-01

    High-quality single-walled carbon nanotubes (SWNTs) have been produced by DC arc discharge in hydrogen ambience. By using Fe 1% catalyst a large amount of SWNTs are produced in pure H2 gas. Other transition metals of iron group and its combination are also used as catalyst for preparing SWNTs by adding 1% H2S gas in H2. Tri-metal catalyst, Fe(0.25%)-Ni(0.9%)-Co(0.9%), is found to be most effective for high yield of SWNTs. The SWNTs diameters are fairly thick ˜1.4-4 nm, and some double-walled carbon nanotubes also exist with them.

  16. A Shell Theory for Chiral Single-Wall Carbon Nanotubes

    E-print Network

    Antonino Favata; Paolo Podio-Guidugli

    2013-06-28

    In this paper, we propose a characterization of the mechanical response of the linearly elastic shell we associate to a single-wall carbon nanotube of arbitrary chirality. In Bajaj et al. 2013, we gave such a characterization in the case of zigzag and armchair nanotubes; in particular, we showed that the orthotropic response we postulated for the associated shells is to become isotropic in the graphene-limit, that is, when the shell radius grows bigger and bigger. Here we give an explicit recipe to construct the generally anisotropic response of the shell associated to a nanotube of any chirality in terms of the response of the shell associated to a related zigzag or armchair nanotube. The expected coupling of mechanical effects that anisotropy entrains is demonstrated in the case of a torsion problem, where the axial extension accompanying twist is determined analytically and found in good agreement with the available experimental data.

  17. Multifunctional free-standing single-walled carbon nanotube films.

    PubMed

    Nasibulin, Albert G; Kaskela, Antti; Mustonen, Kimmo; Anisimov, Anton S; Ruiz, Virginia; Kivistö, Samuli; Rackauskas, Simas; Timmermans, Marina Y; Pudas, Marko; Aitchison, Brad; Kauppinen, Marko; Brown, David P; Okhotnikov, Oleg G; Kauppinen, Esko I

    2011-04-26

    We report a simple and rapid method to prepare multifunctional free-standing single-walled carbon nanotube (SWCNT) films with variable thicknesses ranging from a submonolayer to a few micrometers having outstanding properties for a broad range of exceptionally performing devices. We have fabricated state-of-the-art key components from the same single component multifunctional SWCNT material for several high-impact application areas: high efficiency nanoparticle filters with a figure of merit of 147 Pa(-1), transparent and conductive electrodes with a sheet resistance of 84 ?/? and a transmittance of 90%, electrochemical sensors with extremely low detection limits below 100 nM, and polymer-free saturable absorbers for ultrafast femtosecond lasers. Furthermore, the films are demonstrated as the main components in gas flowmeters, gas heaters, and transparent thermoacoustic loudspeakers. PMID:21361334

  18. CVD Synthesis of Single Wall Carbon Nanotubes under ``soft" Conditions

    NASA Astrophysics Data System (ADS)

    Harutyunyan, A. R.; Pradhan, B. K.; Kim, J.; Chen, G.; Eklund, P. C.

    2002-03-01

    Single wall carbon nanotubes (SWNT) were synthesized using chemical vapor deposition (CVD) in flowing methane gas at temperatures as low as T=680^circC using an alumina supported Fe/Mo-oxide catalyst. Iron oxide (without Mo) supported on alumina was not observed to produce SWNTs at this temperature. However, reduction of the Fe-oxide catalyst in flowing H_2/He gases produced SWNT growth at T=680^circC as well. Electron microscopy revealed that small bundles of tubes were produced in most cases. However, Fe-Mo oxide produced primarily individual tubes and a small number of double-walled tubes. Raman spectra were used to estimate the relative yield and survey the tube diameters present in the material. Work supported by Honda R&D Japan.

  19. A fully tunable single-walled carbon nanotube diode.

    PubMed

    Liu, Chang-Hua; Wu, Chung-Chiang; Zhong, Zhaohui

    2011-04-13

    We demonstrate a fully tunable diode structure utilizing a fully suspended single-walled carbon nanotube. The diode's turn-on voltage under forward bias can be continuously tuned up to 4.3 V by controlling gate voltages, which is ?6 times the nanotube band gap energy. Furthermore, the same device design can be configured into a backward diode by tuning the band-to-band tunneling current with gate voltages. A nanotube backward diode is demonstrated for the first time with nonlinearity exceeding the ideal diode. These results suggest that a tunable nanotube diode can be a unique building block for developing next generation programmable nanoelectronic logic and integrated circuits. PMID:21413780

  20. Single-walled carbon nanotube fibers, films and balls

    NASA Astrophysics Data System (ADS)

    Guan, Lunhui; Li, Huanjun; Shi, Zujin; Gu, Zhennan

    2007-02-01

    Well-defined fibers and films of single-walled carbon nanotubes (SWNTs) with high purity and narrow diameter distributions were obtained from the strand-like raw soot produced by a dc arc-discharge method. These architectures made up of SWNTs have very uniform smooth surfaces. When the strand-like product was placed on a silicon substrate, dipped into water, treated ultrasonically, and then dried in air, another interesting architecture, an SWNT ball, was obtained. This ball-like structure could also be found on the surface of purified SWNTs. We propose that the surface tension of water and the interaction between SWNTs and silica sphere played the key role in the ball (SWNTs outside and silica sphere inside) formation process.

  1. Single Wall Carbon Nanotube-polymer Solar Cells

    NASA Technical Reports Server (NTRS)

    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.

  2. Single-walled carbon nanotubes for high-performance electronics

    NASA Astrophysics Data System (ADS)

    Cao, Qing; Han, Shu-Jen

    2013-09-01

    Single-walled carbon nanotubes (SWNT) could replace silicon in high-performance electronics with their exceptional electrical properties and intrinsic ultra-thin body. During the past five years, the major focus of this field is gradually shifting from proof-of-concept prototyping in academia to technology development in industry with emphasis on manufacturability and integration issues. This article reviews recent advances, starting with experimental and modeling works that evaluate the potential of adopting SWNTs in ultimately scaled transistors. Techniques to separate nanotubes according to their electronic types and assemble them into aligned arrays are then discussed, followed by a description of the engineering aspects in their implementation in integrated circuits and systems. A concluding discussion provides some perspectives on future challenges and research opportunities.

  3. Functionalization of single-walled carbon nanotubes with ribonucleic acids

    NASA Astrophysics Data System (ADS)

    Park, June; Kim, Sejin; Seong, Maeng-Je; Kim, Yu Jin; Go, Hayoung; Lee, Kangseok

    2013-12-01

    The optical properties of single-walled carbon nanotubes (SWCNTs) dispersed in aqueous solutions of ribonucleic acids (RNA) purified from Escherichia coli were studied using photoluminescence (PL), Raman, and absorption spectroscopy. SWCNT-RNA complexes, down to a single isolated nanotube level, were successfully synthesized. SWCNT signatures in Raman, PL, and absorption spectroscopy were observed from the SWCNT-RNA complexes. Observation of two distinct PL peaks, one at 1.248 eV and the other at 1.392 eV, confirmed the existence of isolated (6,5) and (6,4) SWCNTs, respectively. Atomic force microscope images and height profiles also showed evidence of isolated SWCNT-RNA complex.

  4. Single-walled carbon nanotube thermopile for broadband light detection.

    PubMed

    St-Antoine, Benoit C; Ménard, David; Martel, Richard

    2011-02-01

    We designed a thermopile based on a PN doping profile engineered in a suspended film of single-walled carbon nanotubes (SWNTs). Using estimates of the film local Seebeck coefficients, the SWNT thermopile was optimized in situ through depositions of potassium dopants. The overall performances of the thermopile were found to be comparable to state-of-the-art SWNT bolometers. The device is characterized at room temperature by a time response of 36 ms, typical of thermal detectors, and an optimum spectral detectivity of 2 × 10(6) cm Hz(1/2)/W in the visible and near-infrared. This paper presents the first thermopile made of a suspended SWNT film and paves the way to new applications such as broadband light (including THz) detection and thermoelectric power generation. PMID:21189022

  5. Determination of moisture content of single-wall carbon nanotubes.

    PubMed

    Sturgeon, Ralph E; Lam, Joseph W; Windust, Anthony; Grinberg, Patricia; Zeisler, Rolf; Oflaz, Rabia; Paul, Rick L; Lang, Brian E; Fagan, Jeffrey A; Simard, Benoit; Kingston, Christopher T

    2012-01-01

    Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides a direct measure of the water content and was used for benchmarking against results obtained by conventional oven drying, desiccation over anhydrous magnesium perchlorate as well as by thermogravimetry and prompt gamma-ray activation analysis. Agreement amongst results was satisfactory with the exception of thermogravimetry, although care must be taken with oven drying as it is possible to register mass gain after an initial moisture loss if prolonged drying time or elevated temperatures (120 °C) are used. Thermogravimetric data were precise but a bias was evident that could be accounted for by considering the non-selective loss of mass as volatile carbonaceous components. Simple drying over anhydrous magnesium perchlorate for a minimum period of 8-10 days is recommended if KF is not available for this measurement. PMID:22124752

  6. Single-walled carbon nanotubes as optical materials for biosensing

    NASA Astrophysics Data System (ADS)

    Chen, Zhuo; Zhang, Xiaobing; Yang, Ronghua; Zhu, Zhi; Chen, Yan; Tan, Weihong

    2011-05-01

    In this review, we summarize recent progress in the development of single-walled carbon nanotubes (SWNTs) as optical materials for biosensing applications. First, as optical labels, we discuss the use of SWNTs in Raman-based protein detection. Strong and simple resonance Raman spectroscopy of SWNTs opens up a method of protein microarray with detection sensitivity down to femtomolar range. Also, tunable isotopic SWNT-Raman signature enables the simultaneous detection of multiple analytes in complex fluids. Second, the photoluminescence properties of SWNTs are also explored. We examine fluorescence biosensors that integrate the quenching property of SWNTs and the recognition property of functional nucleic acids. Particularly, SWNTs are established as an efficient signal transduction substrate in different biosensing systems, including the detection of specific proteins and DNA sequences, regulation of singlet oxygen generation and label-free fluorescence assays, and all have exhibited very high selectivity and sensitivity.

  7. Selective bundling of zigzag single-walled carbon nanotubes.

    PubMed

    Blum, Carolin; Stürzl, Ninette; Hennrich, Frank; Lebedkin, Sergei; Heeg, Sebastian; Dumlich, Heiko; Reich, Stephanie; Kappes, Manfred M

    2011-04-26

    A simple, high throughput fractionation procedure for aqueous/SDS (sodium dodecyl sulfate) suspensions of single-walled carbon nanotubes (SWNTs) is presented, which yields thin bundles of semiconducting-SWNTs with small chiral angles. To demonstrate this we show the photoluminescence signatures of nanotube suspensions that contain almost exclusively zigzag and near-zigzag tubes. Starting suspensions and resulting fractions were characterized using optical absorption, resonance Raman and photoluminescence spectroscopies as well as scanning force microscopy. Taken together with literature observations, our findings suggest that near zigzag edge tubes of similar diameters in a bundle are harder to separate from each other than for other chiral index combinations. We discuss the implications of these observations for SWNT growth and dispersion. PMID:21410134

  8. Thermal oscillations of structurally distinct single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Pine, Polina; Yaish, Yuval E.; Adler, Joan

    2011-12-01

    Zigzag, armchair, and different types of chiral single-walled carbon nanotubes (SWCNTs) have distinct structures, due to different wrapping vectors of the underlying graphene sheets. The electronic properties depend on their structure, but this is less clear with regard to their mechanical properties. We modeled the first four flexural thermal vibrational modes of all three types with clamped ends, as a function of length. We applied a carefully equilibrated molecular dynamics procedure that was previously validated by comparison with the Timoshenko beam model in suitable limits. This analytic model allows for both rotary inertia and shearing deformation, but it cannot differentiate among the three atomistic structures. Comparison between the vibrational behavior of the three types of nanotubes clearly shows that the SWCNT structure does not affect the vibrational frequencies under clamped conditions.

  9. Single-Wall Carbon Nanotube Anodes for Lithium Cells

    NASA Technical Reports Server (NTRS)

    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.

  10. Temperature dependence of Raman spectra in single-walled carbon nanotube rings

    E-print Network

    Ludwig-Maximilians-Universität, München

    Temperature dependence of Raman spectra in single-walled carbon nanotube rings Li Song,1,a ,b The temperature-dependent Raman frequency shift in single-walled carbon nanotube SWCNT rings in the range of 80. © 2008 American Institute of Physics. DOI: 10.1063/1.2891870 Since their discovery, carbon nanotubes CNTs

  11. Charge Noise in Liquid-Gated Single-Wall Carbon Nanotube

    E-print Network

    Dekker, Cees

    Charge Noise in Liquid-Gated Single-Wall Carbon Nanotube Transistors Jaan Ma1nnik, Iddo Heller properties of single-walled carbon nanotube transistors (SWNT-FETs) are essential for the performance of the surrounding electrolyte has a minimal effect on the noise magnitude in SWNT-FETs. Carbon nanotube

  12. Localized modes in capped single-walled carbon nanotubes Alexander V. Savin1,2,a

    E-print Network

    experimentally.9 The growing interest in carbon nano- tubes can be explained by their unique physical properties consider four types of single-walled carbon nano- tubes SWCNs , which are known to have the smallestLocalized modes in capped single-walled carbon nanotubes Alexander V. Savin1,2,a and Yuri S

  13. Studies of Mechanically Deformed Single Wall Carbon Nanotubes and Graphene by Optical Spectroscopy

    E-print Network

    Hone, James

    Studies of Mechanically Deformed Single Wall Carbon Nanotubes and Graphene by Optical Spectroscopy single wall carbon nanotubes (SWNTs). For the mechanical properties, we have combined optical Carbon Nanotubes and Graphene by Optical Spectroscopy Mingyuan Huang Due to the extremely low density

  14. Thermal expansion in single-walled carbon nanotubes and graphene: Nonequilibrium Green's function approach

    E-print Network

    Li, Baowen

    Thermal expansion in single-walled carbon nanotubes and graphene: Nonequilibrium Green's function.70. a, 61.46. w, 62.23.Kn I. INTRODUCTION Single-walled carbon nanotubes SWCNT and graphene are two kinds of novel carbon-based materials with lots of intriguing electronic and mechanical properties.1

  15. Structure Controlled Synthesis of Single-Walled Carbon Nanotubes Using Solution Based Catalyst Deposition

    E-print Network

    Mellor-Crummey, John

    and physical properties, single-walled carbon nanotube (SWCNT) has been considered for many applications. We, mechanical application, etc. #12;Structure Controlled Synthesis of Carbon Nanotubes Theerapol Thurakitseree1Structure Controlled Synthesis of Single-Walled Carbon Nanotubes Using Solution Based Catalyst

  16. CVD growth mechanism of single-walled carbon nanotubes from alcohol

    E-print Network

    Maruyama, Shigeo

    CVD growth mechanism of single-walled carbon nanotubes from alcohol Shigeo Maruyama, Yuhei Miyauchi@photon.t.u-tokyo.ac.jp By using alcohol as carbon source, high-purity single-walled carbon nanotubes (SWNTs) can be generated at relatively low CVD temperatures. Based on these findings, we have proposed the alcohol catalytic CVD (ACCVD

  17. Improved cellular uptake of functionalized single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Antonelli, A.; Serafini, S.; Menotta, M.; Sfara, C.; Pierigé, F.; Giorgi, L.; Ambrosi, G.; Rossi, L.; Magnani, M.

    2010-10-01

    Single-walled carbon nanotubes (SWNTs) due to their unique structural and physicochemical properties, have been proposed as delivery systems for a variety of diagnostic and therapeutic agents. However, SWNTs have proven difficult to solubilize in aqueous solution, limiting their use in biological applications. In an attempt to improve SWNTs' solubility, biocompatibility, and to increase cell penetration we have thoroughly investigated the construction of carbon scaffolds coated with aliphatic carbon chains and phospholipids to obtain micelle-like structures. At first, oxidized SWNTs (2370 ± 30 nmol mg - 1 of SWNTs) were covalently coupled with an alcoholic chain (stearyl alcohol, C18H37OH; 816 nmol mg - 1 of SWNTs). Subsequently, SWNTs-COOC18H37 derivatives were coated with phosphatidylethanolamine (PE) or -serine (PS) phospholipids obtaining micelle-like structures. We found that cellular uptake of these constructs by phagocytic cells occurs via an endocytotic mechanism for constructs larger than 400 nm while occurs via diffusion through the cell membrane for constructs up to 400 nm. The material that enters the cell by phagocytosis is actively internalized by macrophages and localizes inside endocytotic vesicles. In contrast the material that enters the cells by diffusion is found in the cell cytosol. In conclusion, we have realized new biomimetic constructs based on alkylated SWNTs coated with phospholipids that are efficiently internalized by different cell types only if their size is lower than 400 nm. These constructs are not toxic to the cells and could now be explored as delivery systems for non-permeant cargoes.

  18. Phonon-phonon interactions in single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hepplestone, S. P.; Srivastava, G. P.

    2006-10-01

    The lifetime of phonon modes undergoing three-phonon interactions in single-wall carbon nanotubes has been calculated. The calculations are based upon an approach using Fermi’s golden rule and a quasielastic continuum model for the anharmonic potential. In deriving the relaxation-rate equation, the effects of both normal and umklapp processes have been included, and a clear distinction between class 1 and class 2 events is made. Dispersion relations for the phonon modes of a carbon nanotube were obtained from analytic expressions developed by Zhang The lifetime of the lowest two optical modes is found to be comparable to the lifetime of the acoustic modes. The results show that the relaxation rate is dominated by normal processes at low temperatures and umklapp processes at room temperature and above. A linear relationship between the relaxation rate and temperature is obtained for temperatures greater than 200K . The relaxation-rate contribution decreases (increases) with an increase in the tube radius for normal (umklapp) processes. These results are suggested to have interesting implications for mean-free-path and thermal-conductivity calculations.

  19. Growth mechanism and internal structure of vertically aligned single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    Growth mechanism and internal structure of vertically aligned single-walled carbon nanotubes Erik the growth of verti- cally aligned single-walled carbon nanotubes (VA-SWNTs) at various temperatures and pressures. This yielded a profile of the VA-SWNT thickness vs growth time, which was analyzed using a growth

  20. Water transport inside a single-walled carbon nanotube driven by temperature gradient

    E-print Network

    Maruyama, Shigeo

    Water transport inside a single-walled carbon nanotube driven by temperature gradient J. Shiomi mass transport of a water cluster inside a single-walled carbon nanotube (SWNT) with the diameter of about 1.4 nm. The influence of the non-equilibrium thermal environment on the confined water cluster has

  1. The Prediction of thermal properties of single walled carbon nanotube suspensions

    E-print Network

    Maruyama, Shigeo

    1 The Prediction of thermal properties of single walled carbon nanotube suspensions Hai M. Duong1 The present work is a systematic numerical study of the thermal properties of single walled carbon nanotubes thermal properties. The dependence of the effective thermal conductivity on the temperature for aqueous

  2. Isotope-induced elastic scattering of optical phonons in individual suspended single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    of optical phonons into acoustic phonons [3, 4]. We propose that this process is allowed because of soIsotope-induced elastic scattering of optical phonons in individual suspended single-walled carbon 10, 2011) Isotope-induced scattering of optical phonons in individual single-walled carbon nanotubes

  3. Single-walled carbon nanotubes as a multimodal-thermoacoustic and photoacoustic-contrast agent

    E-print Network

    Wang, Lihong

    Single-walled carbon nanotubes as a multimodal- thermoacoustic and photoacoustic-contrast agent thermoacoustic and photoacoustic tomography. In comparison to deionized water, single-walled carbon nanotubes ex- hibited more than twofold signal enhancement for thermoacoustic to- mography at 3 GHz. In comparison

  4. Adsorption of Glucose Oxidase onto Single-Walled Carbon Nanotubes and Its Application in

    E-print Network

    Resasco, Daniel

    Adsorption of Glucose Oxidase onto Single-Walled Carbon Nanotubes and Its Application in Layer suspension-dialysis method to adsorb the redox enzyme glucose oxidase (GOX) onto single-walled carbon nano. To test this we used the enzyme glucose oxidase (GOX), which is * To whom correspondence should

  5. Growth Window and Possible Mechanism of Millimeter-Thick Single-Walled Carbon Nanotube Forests

    E-print Network

    Maruyama, Shigeo

    Growth Window and Possible Mechanism of Millimeter-Thick Single-Walled Carbon Nanotube Forests Kei-called "supergrowth", has an outstanding growth rate of single-walled carbon nanotubes (SWNTs) [1]. However, few 4 nm as shown in Fig. 1(b), and thicker Fe grew thicker nanotubes. Nanotube forests grew up

  6. Reversible thermal conductivity enhancement of phase change composites with single walled carbon nanotube inclusions

    E-print Network

    Maruyama, Shigeo

    Reversible thermal conductivity enhancement of phase change composites with single walled carbon report the thermal conductivity enhancement of phase change alkanes with single walled carbon nanotube and thermogravimetric analysis. Thermal conductivity measurements in solid and liquid state were carried out using

  7. Thermal conductivity measurement of vertically-aligned single-walled carbon

    E-print Network

    Maruyama, Shigeo

    Thermal conductivity measurement of vertically-aligned single-walled carbon nanotubes by 3 omega@photon.t.u-tokyo.ac.jp Thermal conductivity of single-walled carbon nanotubes expected from molecular dynamics simulations va conductivity can be possible. The 3 omega method commonly used for thin film thermal conductivity measurements

  8. Thermal conductivity characterization of vertically-aligned single-walled carbon nanotube films

    E-print Network

    Maruyama, Shigeo

    Thermal conductivity characterization of vertically-aligned single-walled carbon nanotube films Kei, the expectation on single-walled carbon nanotubes (SWNTs) to possess high thermal conductivity has attracted of the thermal conductivity characteristics, the number of experimental works has been limited mainly due

  9. In situ imaging and spectroscopy of single-wall carbon nanotube synthesis by laser vaporization

    E-print Network

    Geohegan, David B.

    In situ imaging and spectroscopy of single-wall carbon nanotube synthesis by laser vaporization A is investigated by laser-induced luminescence imaging and spectroscopy of Co atoms, C2 and C3 molecules The synthesis of single-wall carbon nanotubes by Nd:YAG laser vaporization of a graphite/ Ni, Co target

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

    ERIC Educational Resources Information Center

    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…

  11. Coulomb blockade in suspended Si3N4-coated single-walled carbon nanotubes

    E-print Network

    Golovchenko, Jene A.

    materials,2­4 and also because the physical properties of exposed nano- tubes are sensitiveCoulomb blockade in suspended Si3N4-coated single-walled carbon nanotubes H. B. Peng and J. A of suspended single-walled carbon nanotubes with high-quality dielectric silicon nitride has been obtained

  12. Novel Nanotube-on-Insulator (NOI) Approach toward Single-Walled Carbon

    E-print Network

    Zhou, Chongwu

    -on-insulator (NOI) approach for fabricating nano- tube devices based on aligned single-walled carbon nanotubes grown include dispersing nanotubes onto prefabricated electrodes, or locating the predispersed nano- tubes usingNovel Nanotube-on-Insulator (NOI) Approach toward Single-Walled Carbon Nanotube Devices Xiaolei Liu

  13. Valence excitations in individual single-wall carbon nanotubes Thomas Stockli,a),b)

    E-print Network

    Wang, Zhong L.

    single-wall carbon nano- tubes are sensitive to electron irradiation we have operated the microscope. In Fig. 2 c the zero loss peak recorded on a zone just beside the nano- tube is shown. This illustratesValence excitations in individual single-wall carbon nanotubes Thomas Sto¨ckli,a),b) Jean

  14. Patterned growth of single-walled carbon nanotube arrays from a vapor-deposited Fe catalyst

    E-print Network

    Golovchenko, Jene A.

    of nano- tubes on patterned Si3N4 membranes as observed with a SEM operated at 1 keV. Using such a lowPatterned growth of single-walled carbon nanotube arrays from a vapor-deposited Fe catalyst H. B September 2003 Single-walled carbon nanotubes have been grown on a variety of substrates by chemical vapor

  15. Diameter Controlled CVD Synthesis of Single-Walled Carbon Theerapol Thurakitseree1

    E-print Network

    Maruyama, Shigeo

    diameter SWNTs. The morphology of the SWNTs also changed from vertically aligned to randomly oriented when1 Diameter Controlled CVD Synthesis of Single-Walled Carbon Nanotubes Theerapol Thurakitseree1 on the mean diameter of single-walled carbon nanotubes (SWNTs) synthesized by the alcohol catalytic chemical

  16. Fluorescence spectroscopy of single-walled carbon nanotubes synthesized from alcohol

    E-print Network

    Maruyama, Shigeo

    I&EC 221 Fluorescence spectroscopy of single-walled carbon nanotubes synthesized from alcohol fluorescence measurements of single-walled carbon nanotubes (SWNTs) catalytically synthesized from alcohol (Alcohol catalytic CVD method, ACCVD) in various experimental conditions were performed. The chirality

  17. Potassium-Decorated, Single-Wall Carbon Nanotubes.

    NASA Astrophysics Data System (ADS)

    Rao, A. M.; Richter, E.; Menon, M.; Subbaswamy, K. R.; Eklund, P. C.; Thess, A.; Smalley, R. E.

    1997-03-01

    Crystalline ropes of single-wall carbon nanotubes have been reacted in sealed glass tubes with potassium vapor and Raman scattering has been used to monitor the vibrational modes as a function of reaction time. An overall broadening and downshifting of the Raman bands is observed. For example, huge downshifts (40 cm-1) in the high frequency tangential modes observed near 1593 cm-1 in the pristine tubes are detected. These downshifts are attributed to significant charge transfer of K 4s electrons into antibonding pz states of the nanotube which should expand the tube diameter and soften the lattice. Presumably, the potassium ions are chemisorbed onto the walls of the nanotubes, rather than inside the nanotube, although no structural information to support this model has yet been collected. Theoretical results on electron doped armchair symmetry nanotubes using the Generalized Tight Binding Molecular Dynamics model will also be presented to help explain experimental results. The Kentucky group was supported by the University of Kentucky Center for Applied Energy Research and NSF Grant No. OSR-94-52895 and DOE Contract No. DE-F22-90PC90029. The work at Rice was supported by the Office of Naval Research Contract N0014-91-J1794.

  18. Single-walled carbon nanotubes alter soil microbial community composition.

    PubMed

    Jin, Lixia; Son, Yowhan; DeForest, Jared L; Kang, Yu Jin; Kim, Woong; Chung, Haegeun

    2014-01-01

    Recent developments in nanotechnology may lead to the release of nanomaterials into the natural environment, such as soils, with largely unknown consequences. We investigated the effects of single-walled carbon nanotubes (SWCNTs), one of the most widely used nanomaterials, on soil microbial communities by incubation of soils to which powder or suspended forms of SWCNTs were added (0.03 to 1 mg g(-1) soil). To determine changes in soil microbial community composition, phospholipid fatty acid (PLFA) profiles were analyzed at 25th day of the incubation experiment. The biomass of major microbial groups including Gram-positive and Gram-negative bacteria, and fungi showed a significant negative relationship with SWCNT concentration, while the relative abundance of bacteria showed a positive relationship with SWCNT concentration. Furthermore, soils under distinct concentrations of SWCNT treatments had PLFA profiles that were significantly different from one another. Our results indicate that the biomass of a broad range of soil microbial groups is negatively related with SWCNT concentration and upon entry into soils, SWCNTs may alter microbial community composition. Our results may serve as foundation for scientific guideline on regulating the discharge of nanomaterials such as SWCNTs to the soil ecosystem. PMID:23933455

  19. Single walled carbon nanotube composites for bone tissue engineering.

    PubMed

    Gupta, Ashim; Woods, Mia D; Illingworth, Kenneth David; Niemeier, Ryan; Schafer, Isaac; Cady, Craig; Filip, Peter; El-Amin, Saadiq F

    2013-09-01

    The purpose of this study was to develop single walled carbon nanotubes (SWCNT) and poly lactic-co-glycolic acid (PLAGA) composites for orthopedic applications and to evaluate the interaction of human stem cells (hBMSCs) and osteoblasts (MC3T3-E1 cells) via cell growth, proliferation, gene expression, extracellular matrix production and mineralization. PLAGA and SWCNT/PLAGA composites were fabricated with various amounts of SWCNT (5, 10, 20, 40, and 100 mg), characterized and degradation studies were performed. Cells were seeded and cell adhesion/morphology, growth/survival, proliferation and gene expression analysis were performed to evaluate biocompatibility. Imaging studies demonstrated uniform incorporation of SWCNT into the PLAGA matrix and addition of SWCNT did not affect the degradation rate. Imaging studies revealed that MC3T3-E1 and hBMSCs cells exhibited normal, non-stressed morphology on the composites and all were biocompatible. Composites with 10 mg SWCNT resulted in highest rate of cell proliferation (p < 0.05) among all composites. Gene expression of alkaline phosphatase, collagen I, osteocalcin, osteopontin, Runx-2, and Bone Sialoprotein was observed on all composites. In conclusion, SWCNT/PLAGA composites imparted beneficial cellular growth capabilities and gene expression, and mineralization abilities were well established. These results demonstrate the potential of SWCNT/PLAGA composites for musculoskeletal regeneration and bone tissue engineering (BTE) and are promising for orthopedic applications. PMID:23629922

  20. Gas Separation by Kinked Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Zhang, Z. Q.; Zhang, H. W.

    2010-05-01

    A kink model for gas separation is presented. Transport of pure nitrogen, oxygen and their mixture in single walled carbon nanotubes (SWCNTs) with a kink formed by bending is studied using molecular dynamics simulations. The results show that a kinked SWCNT results in transport resistance to nitrogen while allowing oxygen to pass even though the two gases have very similar molecular sizes. The permeability decreases while the selectivity increases with increasing the bending angle of SWCNTs. The tradeoff between permeability and selectivity is evaluated by linear weighting method to attain an optimum bending angle for gas separation. It is also found that the kink model can be used to improve the permeability by changing the diameter of the SWCNTs while keeping a high selectivity in the gas separation process. Both the permeability and purity of oxygen increase with increasing the gas pressure. Interestingly, it is very convenient to obtain the required purity and permeability of the oxygen by adjusting the bending angle of SWCNTs.

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

    PubMed Central

    Andón, Fernando T.; Kapralov, Alexandr A.; Yanamala, Naveena; Feng, Weihong; Baygan, Arjang; Chambers, Benedict J.; Hultenby, Kjell; Ye, Fei; Toprak, Muhammet S.; Brandner, Birgit D.; Fornara, Andrea; Klein-Seetharaman, Judith; Kotchey, Gregg P.; Star, Alexander; Shvedova, Anna A.

    2014-01-01

    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 H2O2 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) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials. PMID:23447468

  2. "Smart Skin" optical strain sensor using single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Sun, Peng; Kim, Ji-Hoon; Bachilo, Sergei M.; Weisman, R. Bruce; Nagarajaiah, Satish

    2014-04-01

    Strain measurements are essential in structural health monitoring. Traditional strain gages require physical contact between the sensor and read-out device, perturb the surface being monitored, and allow measurement only at the specific location and orientation axis of the sensor. We demonstrate a novel non-contact, multi- point, multi-directional strain sensing approach that overcomes these limitations. In our method, the surface is coated with a thin film of "smart skin" containing individualized single-walled carbon nanotubes in a polymeric host. After curing, substrate strains are transmitted through the polymer film to embedded nanotubes. This induces axial strains in the nanotubes, systematically shifting the wavelengths of their characteristic near-infrared fluorescence peaks. To measure strain, a visible laser excites nanotubes at points of interest on the surface, and the near-infrared emission is collected and spectrally analyzed. Observed spectral shifts reveal quantitative strain values. Laboratory tests show sensitivity down to ~400µm, limited by mechanical properties of the polymeric host film. We also vary excitation beam polarization to find the axis of substrate strain. Our method provides spatial resolution down to its gage length of ~100µm. Because the entire substrate is coated with nanoscale strain sensors, measurements can be made at arbitrary locations to construct a full strain map. We will describe recent smart skin refinements involving selection of polymer host, nanotube surfactant, nanotube dispersion method, and preparation protocol. Finally, we characterize the orientational distribution of nanotubes using a probabilistic model.

  3. Flame synthesis of Fe catalyzed single-walled carbon nanotubes and Ni catalyzed nanofibers: growth mechanisms and consequences

    NASA Astrophysics Data System (ADS)

    Vander Wal, Randall L.; Hall, Lee J.

    2001-11-01

    Flame synthesis of single-walled carbon nanotubes and nanofibers is demonstrated using a pyrolysis flame configuration. Fe reacts preferentially with CO/H 2/He mixtures to produce single-walled nanotubes (SWNTs). In contrast, Ni reacts preferentially with C 2H 2/H 2/He mixtures to yield nanofibers. Both catalyst metals exhibit a marked size dependent reactivity towards these reactant gas mixtures. The yarmulke mechanism and a carbon solvation/diffusion/precipitation account for the different catalyzed products; SWNTs and nanofibers, respectively. Consequences of the size dependent reactivities of Fe and Ni nanoparticles and the respective growth mechanisms for the SWNTs and nanofibers are discussed.

  4. Octopus and VLS mode growth of single-walled carbon nanotubes by molecular dynamics method

    E-print Network

    Maruyama, Shigeo

    67 P36 P37 NT13 Octopus and VLS mode growth of single-walled carbon nanotubes by molecular dynamics modes of SWNTs. A preferred structure at lower temperature is `Octopus' mode where several carbon chains

  5. CVD Synthesis of Single-Walled Carbon Nanotubes from Catalylsts Supported on Zeolite and Layered Silicate Surfaces

    E-print Network

    Maruyama, Shigeo

    this by employing zeolites and layered silicates as catalyst support materials. Since the dimensions CVD Synthesis of Single-Walled Carbon Nanotubes from Catalylsts Supported on Zeolite and Layered, the diameter of catalyst metal particles is known to have a close correlation with that of grown SWNTs

  6. Fine Patterning of Inkjet-Printed Single-Walled Carbon-Nanotube Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Nobusa, Yuki; Takagi, Yuki; Gocho, Shota; Matsuzaki, Satoki; Yanagi, Kazuhiro; Takenobu, Taishi

    2012-06-01

    We fabricated single-walled carbon nanotube (SWCNT) thin-films via the combination of inkjet printing and site-selective deposition based on the patterning of self-assembled monolayers (SAMs) through an optical lithography mask. Previously, we patterned SWCNT films by ultraviolet light irradiation onto SAMs through metal masks, and the minimum film size achieved was 90 µm wide. In this study, we succeeded in achieving a width of 13 µm using SAMs and optical lithography masks, thus improving the performance limit of SWCNT printed electronics.

  7. Growth of semiconducting single-walled carbon nanotubes by using ceria as catalyst supports.

    PubMed

    Qin, Xiaojun; Peng, Fei; Yang, Feng; He, Xiaohui; Huang, Huixin; Luo, Da; Yang, Juan; Wang, Sheng; Liu, Haichao; Peng, Lianmao; Li, Yan

    2014-02-12

    The growth of semiconducting single-walled carbon nanotubes (s-SWNTs) on flat substrates is essential for the application of SWNTs in electronic and optoelectronic devices. We developed a flexible strategy to selectively grow s-SWNTs on silicon substrates using a ceria-supported iron or cobalt catalysts. Ceria, which stores active oxygen, plays a crucial role in the selective growth process by inhibiting the formation of metallic SWNTs via oxidation. The so-produced ultralong s-SWNT arrays are immediately ready for building field effect transistors. PMID:24392872

  8. Controlling the doping of single-walled carbon nanotube networks by proton irradiation

    SciTech Connect

    Walker, D.; Mann, C. J.; Panetta, C. J.; Alaan, D. R.; Hopkins, A. R.; Liu, S. H. [Physical Sciences Laboratories, Aerospace Corporation, P. O. Box 92957 M2/275, Los Angeles, California 90009-2957 (United States)

    2012-09-03

    We demonstrate the controlled desorption of adventitious dopants on networks of single-walled carbon nanotubes (SWNTs) with 100 keV proton irradiation. Networks of sorted metallic, semiconducting SWNTs, and unsorted SWNTs were investigated. The removal of dopants was indicated by an increase in sheet resistances along with an increase in the absorption of the low energy absorption band of semiconducting SWNTs. Semiconducting and unsorted SWNT networks exhibited the largest change in their sheet resistance, which indicates the conductivity of unsorted SWNT networks is dominated by the tube-tube junctions of semiconducting SWNTs.

  9. Chirality distribution in single walled carbon nanotube films by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Battie, Y.; Jamon, D.; En Naciri, A.; Lauret, J.-S.; Loiseau, A.

    2013-03-01

    We report an experimental technique that determines the chirality distribution in single wall carbon nanotube (SWCNT) films. Films of CoMoCat SWCNTs and SWCNTs enriched in (6,5) chirality are considered. Classical methods like photoluminescence spectroscopy frequently give incomplete distribution. In this way, spectroscopic ellipsometry is used to determine the dielectric function of SWCNT film. The chirality abundance obtained by analysing the ellipsometric data with a tight binding model is compared with that deduced from photoluminescence excitation spectroscopy. We demonstrate that ellipsometry is an efficient tool for a complete and quantitative determination of the chirality distribution and the metallic/semiconducting ratio.

  10. State of the art of single-walled carbon nanotube synthesis on surfaces.

    PubMed

    Chen, Yabin; Zhang, Yingying; Hu, Yue; Kang, Lixing; Zhang, Shuchen; Xie, Huanhuan; Liu, Dan; Zhao, Qiuchen; Li, Qingwen; Zhang, Jin

    2014-09-10

    Single-walled carbon nanotubes (SWNTs) directly synthesized on surfaces are promising building blocks for nanoelectronics. The structures and the arrangement of the SWNTs on surfaces determine the quality and density of the fabricated nanoelectronics, implying the importance of structure controlled growth of SWNTs on surfaces. This review summarizes the recent research status in controlling the orientation, length, density, diameter, metallicity, and chirality of SWNTs directly synthesized on surfaces by chemical vapor deposition, together with a session presenting the characterization method of the chirality of SWNTs. Finally, the remaining major challenges are discussed and future research directions are proposed. PMID:25042346

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

    NASA Astrophysics Data System (ADS)

    Zaumseil, Jana

    2015-07-01

    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.

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

    PubMed

    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

  13. Single walled carbon nanotube networks as substrates for bone cells

    NASA Astrophysics Data System (ADS)

    Tutak, Wojtek

    A central effort in biomedical research concerns the development of materials for sustaining and controlling cell growth. Carbon nanotube based substrates have been shown to support the growth of different kinds of cells. However the underlying molecular mechanisms remain poorly defined. To address the fundamental question of mechanisms by which nanotubes promote bone mitosis and histogenesis, primary calvariae osteoblastic cells were grown on single walled carbon nanotube (SWNT) network substrates. Using a combination of biochemical and optical techniques, we demonstrate here that SWNT networks promote cell development through two distinct steps. Initially, SWNTs are absorbed in a process that resembles endocytosis, inducing acute toxicity. Nanotube mediated cell destruction, however, induces a release of endogenous factors that act to boost the activity of the surviving cells by stimulating the synthesis of extracellular matrix. In the second part of the research, minimally invasive SWNT matrices were used to further investigate network properties for biomedical applications without extensive presence of cytotoxicity. In the literature, carbon nanotube based substrates have been shown to support the growth of different cell types and, as such, have raised considerable interest in their possible use in biomedical applications. Nanotube matrices that are embedded in polymers cause inherent changes in nanotube chemical and physical film properties. Thus, it is critical to understand how the physical properties of the pristine networks affect the biology of the host tissue. Here, we investigated how the physical and chemical properties of SWNT networks impact the response of MC3T3-E1 bone osteoblasts. We found that two fundamental steps in cell growth: initial attachment to the substrate and proliferation, are strongly dependent on the energy and roughness of the surface, respectively. Thus, fine-tuning the properties of the film may represent a strategy to optimize the response of the biological host. Above results guided the next set of experiments in which in-situ, real time cell interactions with SWNT films were investigated. Direct electrical measurements on SWNT films during osteoblastic cell growth were conducted. The experiments indicated that the nanotube networks may provide some interesting insight into the initial cell/material interactions.

  14. Sequestration of Single-Walled Carbon Nanotubes in a Polymer

    NASA Technical Reports Server (NTRS)

    Bley, Richard A.

    2007-01-01

    Sequestration of single-walled carbon nanotubes (SWCNs) in a suitably chosen polymer is under investigation as a means of promoting the dissolution of the nanotubes into epoxies. The purpose of this investigation is to make it possible to utilize SWCNs as the reinforcing fibers in strong, lightweight epoxy-matrix/carbon-fiber composite materials. SWCNs are especially attractive for use as reinforcing fibers because of their stiffness and strength-to-weight ratio: Their Young s modulus has been calculated to be 1.2 TPa, their strength has been calculated to be as much as 100 times that of steel, and their mass density is only one-sixth that of steel. Bare SWCNs cannot be incorporated directly into composite materials of the types envisioned because they are not soluble in epoxies. Heretofore, SWCNS have been rendered soluble by chemically attaching various molecular chains to them, but such chemical attachments compromise their structural integrity. In the method now under investigation, carbon nanotubes are sequestered in molecules of poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene) [PmPV]. The strength of the carbon nanotubes is preserved because they are not chemically bonded to the PmPV. This method exploits the tendency of PmPV molecules to wrap themselves around carbon nanotubes: the wrapping occurs partly because there exists a favorable interface between the conjugated face of a nanotube and the conjugated backbone of the polymer and partly because of the helical molecular structure of PmPV. The constituents attached to the polymer backbones (the side chains) render the PmPV-wrapped carbon nanotubes PmPV soluble in organic materials that, in turn, could be used to suspend the carbon nanotubes in epoxy precursors. At present, this method is being optimized: The side chains on the currently available form of PmPV are very nonpolar and unable to react with the epoxy resins and/or hardeners; as a consequence, SWCN/PmPV composites have been observed to precipitate out of epoxies while the epoxies were being cured. If the side chains of the PmPV molecules were functionalized to make them capable of reacting with the epoxy matrices, it might be possible to make progress toward practical applications. By bonding the side chains of the PmPV molecules to an epoxy matrix, one would form an PmPV conduit between the epoxy matrix and the carbon nanotubes sequestered in the PmPV. This conduit would transfer stresses from the epoxy matrix to the nanotubes. This proposed load-transfer mode is similar to that of the current practice in which silane groups are chemically bonded to both the epoxy matrices and the fibers (often glass fibers) in epoxymatrix/fiber composites.

  15. Single-walled carbon nanotubes as a multimodal-thermoacoustic and photoacoustic-contrast agent.

    PubMed

    Pramanik, Manojit; Swierczewska, Magdalena; Green, Danielle; Sitharaman, Balaji; Wang, Lihong V

    2009-01-01

    We have developed a novel carbon nanotube-based contrast agent for both thermoacoustic and photoacoustic tomography. In comparison to deionized water, single-walled carbon nanotubes exhibited more than twofold signal enhancement for thermoacoustic tomography at 3 GHz. In comparison to blood, they exhibited more than sixfold signal enhancement for photoacoustic tomography at 1064 nm wavelength. The large contrast enhancement of single-walled carbon nanotubes was further corroborated by tissue phantom imaging studies. PMID:19566311

  16. Single-walled carbon nanotubes as a multimodal — thermoacoustic and photoacoustic — contrast agent

    PubMed Central

    Pramanik, Manojit; Swierczewska, Magdalena; Green, Danielle; Sitharaman, Balaji; Wang, Lihong V.

    2009-01-01

    We have developed a novel carbon nanotube-based contrast agent for both thermoacoustic and photoacoustic tomography. In comparison with de-ionized water, single-walled carbon nanotubes exhibited more than two-fold signal enhancement for thermoacoustic tomography at 3 GHz. In comparison with blood, they exhibited more than six-fold signal enhancement for photoacoustic tomography at 1064 nm wavelength. The large contrast enhancement of single-walled carbon nanotubes was further corroborated by tissue phantom imaging studies. PMID:19566311

  17. Solution-processed single-walled carbon nanotube field effect transistors and bootstrapped inverters for disintegratable, transient electronics

    E-print Network

    Rogers, John A.

    Solution-processed single-walled carbon nanotube field effect transistors and bootstrapped field effect transistors based on single-walled carbon nanotube network and formed on a gold transistors with single­walled­carbon nanotube network on flexible substrate J. Appl. Phys. 114, 214504 (2013

  18. Different techniques for characterizing single-walled carbon nanotube purity

    NASA Astrophysics Data System (ADS)

    Yuca, Neslihan; Camtakan, Zeyneb; Karatepe, Nilgün

    2013-09-01

    Transition-metal catalysts, fullerenes, graphitic carbon, amorphous carbon, and graphite flakes are the main impurities in carbon nanotubes. In this study, we demonstrate an easy and optimum method of cleaning SWCNTs and evaluating their purity. The purification method, which employed oxidative heat treatment followed by 6M HNO3, H2SO4, HNO3:H2SO4 and HCl acid reflux for 6h at 120°C and microwave digestion with 1.5M HNO3 for 0.5h at 210°C which was straightforward, inexpensive, and fairly effective. The purified materials were characterized by thermogravimetric analysis and nuclear techniques such as INAA, XRF and XRD.

  19. Structural modification of nanoporous carbon with single wall carbon nanotube

    Microsoft Academic Search

    Bo Yi

    2007-01-01

    A novel CC nanocomposite was synthesized by pyrolysis of well dispersed individual functionalized SWNTs in a thermosetting resin, poly(furfuryl alcohol) (PFA). Strong interaction between SWNT and nanoporous carbon derived from PFA (PFA-NPC) was obtained with this strategy and the integrity of SWNTs was maintained after heat treatment. Usually, it is challenging to separate SWNT bundles and disperse them in preparation

  20. Thermal conductivity of single-walled carbon nanotubes

    Microsoft Academic Search

    J. Hone; M. Whitney; A. Zettl

    1999-01-01

    We have measured the thermal conductivity (?) of bulk samples of single-walled nanotube (SWNT) bundles. The thermal conductivity of SWNT's is found to be large, and dominated by phonons at all temperatures. ?(T) of SWNT's is linear in temperature from 7 K to 25 K, increases slope between 25 K and 40 K, and rises monotonically with temperature to above

  1. Preparation and characterization of transparent and conductive thin films of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Maeda, Yutaka; Komoriya, Kazuki; Sode, Katsuya; Higo, Junki; Nakamura, Takayuki; Yamada, Michio; Hasegawa, Tadashi; Akasaka, Takeshi; Saito, Takeshi; Lu, Jing; Nagase, Shigeru

    2011-04-01

    Single-walled carbon nanotubes (SWNTs), synthesized using the arc-discharge method and the direct-injection-pyrolytic synthesis (DIPS) method, were dispersed in a tetrahydrofuran solution containing propylamine and used to prepare transparent and conductive thin films on PET films using an airbrush technique. The SWNTs were analyzed using vis-near infrared absorption spectroscopy, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. The surface resistivity of the SWNT films on the substrates was measured using a four-point probe conductivity measurement. The results revealed that the purity, length, and proportion of the metallic SWNTs are important factors in decreasing the sheet resistance.Single-walled carbon nanotubes (SWNTs), synthesized using the arc-discharge method and the direct-injection-pyrolytic synthesis (DIPS) method, were dispersed in a tetrahydrofuran solution containing propylamine and used to prepare transparent and conductive thin films on PET films using an airbrush technique. The SWNTs were analyzed using vis-near infrared absorption spectroscopy, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. The surface resistivity of the SWNT films on the substrates was measured using a four-point probe conductivity measurement. The results revealed that the purity, length, and proportion of the metallic SWNTs are important factors in decreasing the sheet resistance. Electronic supplementary information (ESI) available: SEM images and absorption spectra of SWNT films. See DOI: 10.1039/c0nr00940g

  2. Fully integrated single-walled carbon nanotube thermoplastic composites

    NASA Astrophysics Data System (ADS)

    Rodriguez-Macias, Fernando J.

    The development of composites of single-walled carbon nanotubes (SWNTs) with thermoplastics requires methods for good dispersion and achieving good interaction between SWNTs and the matrix. This thesis presents a new method to achieve good dispersion by a preliminary treatment called incipient wetting. The SWNTs dispersed in a solvent are mixed with polymer particles and deposited over them as the solvent is evaporated to give an initial dispersion. Factors that make this more effective are: good wetting of the polymer by the solvent, swelling of the polymer, high surface area of the polymer. Swelling enhances the initial dispersion with some initial mixing. A high surface area is achieved using polymer powder. High shear mixing alone does not achieve the same uniform and repeatable level of dispersion that the combination with incipient wetting allows. The incipient wetting method was studied and applied to different polymers. The possibility of recovering SWNTs from thermoplastics by dissolving or burning away the matrix is an extension of this study. A new comprehensive approach to control the interface of thermoplastics with SWNTs is studied. This is based on achieving direct chemical bonding between polymer molecules and functional groups on oxidized open ends, sidewalls, or both, in the SWNTs. Different concepts and approaches to these "fully integrated nanotube composites" are discussed. The concepts have been applied to epoxies elsewhere and are tested here with nylon-6,6 as a model system. Nylon was synthesized by interfacial polymerization in the presence of SWNTs resulting in excellent dispersion in the composite without further processing. The essential requirement for good dispersion is that the SWNTs are well dispersed in the solvent. Interfacial polymerization opens the way to many types of polymer-SWNT composites. Tests of full integration of SWNTs with open ended nanotubes showed promising results and hints of integration but were limited by dispersion in the solvent. Fluorinated SWNTs were dispersed effectively with dichlorobenzene, another solvent may be better. There is no conclusive evidence of integration with F-SWNTs but they may react with the polymer chain with thermal post-processing.

  3. Epoxy/Single Walled Carbon Nanotube Nanocomposite Thin Films for Composites Reinforcement 

    E-print Network

    Warren, Graham

    2010-07-14

    containing SWCNTs were successfully cast into thin films by manipulating degree of cure and viscosity of epoxy. The first section of this study focuses on the covalent oxidation and functionalization of single-walled carbon nanotubes (SWCNTs), which...

  4. Scanning tunneling microscopy and spectroscopy studies of single wall carbon nanotubes

    E-print Network

    Odom, Teri W.

    single wall carbon nanotubes (SWNT's) and ropes containing many SWNT's. Analysis of atomically resolved a striking elastic buckling deformation, and are exceedingly tough materials.5 It is, however, the remarkable

  5. Unusually Large Franz-Keldysh Oscillations at Ultraviolet Wavelengths in Single-Walled Carbon Nanotubes

    E-print Network

    Ham, Moo-Ho

    We report large electroabsorption susceptibilities in the ultraviolet region for single-walled carbon nanotubes (SWNT) supported on quartz that are approximately 10[superscript 3] larger than the highest values reported ...

  6. Controlling the crystalline three-dimensional order in bulk materials by single-wall carbon nanotubes.

    PubMed

    López-Andarias, Javier; López, Juan Luis; Atienza, Carmen; Brunetti, Fulvio G; Romero-Nieto, Carlos; Guldi, Dirk M; Martín, Nazario

    2014-01-01

    The construction of ordered single-wall carbon nanotube soft-materials at the nanoscale is currently an important challenge in science. Here we use single-wall carbon nanotubes as a tool to gain control over the crystalline ordering of three-dimensional bulk materials composed of suitably functionalized molecular building blocks. We prepare p-type nanofibres from tripeptide and pentapeptide-containing small molecules, which are covalently connected to both carboxylic and electron-donating 9,10-di(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene termini. Adding small amounts of single-wall carbon nanotubes to the so-prepared p-nanofibres together with the externally controlled self assembly by charge screening by means of Ca(2+) results in new and stable single-wall carbon nanotube-based supramolecular gels featuring remarkably long-range internal order. PMID:24777055

  7. Peptide Secondary Structure Modulates Single-Walled Carbon Nanotube Fluorescence as a Chaperone Sensor for Nitroaromatics

    E-print Network

    Heller, Daniel Alan

    A class of peptides from the bombolitin family, not previously identified for nitroaromatic recognition, allows near-infrared fluorescent single-walled carbon nanotubes to transduce specific changes in their conformation. ...

  8. Theoretical and simulation tools for electron transfer and chain reactions in single walled carbon nanotubes

    E-print Network

    Nair, Nitish

    2009-01-01

    Single walled carbon nanotubes (SWNT) are cylindrical sheets of graphene whose electronic structures and diameters are determined by their chiralities. Current synthetic methods produce batches of nanotubes containing a ...

  9. Evidence for substitutional boron in doped single-walled carbon nanotubes

    SciTech Connect

    Ayala, P.; Pichler, T. [Faculty of Physics, University of Vienna, 1090 Wien (Austria); Reppert, J.; Rao, A. M. [Department of Physics and Astronomy and COMSET, Clemson University (United States); Grobosch, M.; Knupfer, M. [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

    2010-05-03

    Precise determination of acceptors in the laser ablation grown B doped single-walled carbon nanotubes (SWCNTs) has been elusive. Photoemission spectroscopy finds evidence for subpercent substitutional B in this material, which leads to superconductivity in thin film SWNT samples.

  10. Catalytic CVD Synthesis of Single-Walled Carbon Nanotubes from Alcohol

    E-print Network

    Maruyama, Shigeo

    Catalytic CVD Synthesis of Single-Walled Carbon Nanotubes from Alcohol S. Maruyama Department-temperature feature of alcohol CCVD method. With a simple dip-coat method, this technique first produced SWNTs

  11. High Weight Fraction Surfactant Solubilization of Single-Wall Carbon Nanotubes in Water

    Microsoft Academic Search

    M. F. Islam; E. Rojas; D. M. Bergey; A. T. Johnson; A. G. Yodh

    2003-01-01

    We report a simple process to solubilize high weight fraction single-wall carbon nanotubes in water by the nonspecific physical adsorption of sodium dodecylbenzene sulfonate. The diameter distribution of nanotubes in the dispersion, measured by atomic force microscopy, showed that even at 20 mg\\/mL 63 ± 5% of single-wall carbon nanotube bundles exfoliated into single tubes. A measure of the length

  12. Synthesis and Electronic Transport in Single-Walled Carbon Nanotubes of Known Chirality

    NASA Astrophysics Data System (ADS)

    Caldwell, Robert Victor

    Since their discovery in 1991, carbon nanotubes have proven to be a very interesting material for its physical strength, originating from the pure carbon lattice and strong covalent sp2 orbital bonds, and electronic properties which are derived from the lattice structure lending itself to either a metallic or semiconducting nature among its other properties. Carbon nanotubes have been researched with an eye towards industry applications ranging from use as an alloy in metals and plastics to improve physical strength of the resulting materials to uses in the semiconductor industry as either an interconnect or device layer for computer chips to chemical or biological sensors. This thesis focuses on both the synthesis of individual single-walled carbon nanotubes as well as the electrical properties of those tubes. What makes the work herein different from that of other thesis is that the research has been performed on carbon nanotubes of known chirality. Having first grown carbon nanotubes with a chemical vapor deposition growth in a quartz tube using ethanol vapor as a feedstock to grow long individual single-walled carbon nanotubes on a silicon chip that is also compatible with Rayleigh scattering spectroscopy to identify the chiral indices of the carbon nanotubes in question, those tubes were then transferred with a mechanical transfer process specially designed in our research lab onto a substrate of our choosing before an electrical device was made out of those tubes using standard electron beam lithography. The focus in this thesis is on the work that went into designing and testing this process as well as the initial results of the electronic properties of those carbon nanotubes of known chirality, such as the first known electrical measurements on single individual armchair carbon nanotubes as well as the first known electrical measurements of a single semiconducting carbon nanotube on thin hexagonal boron nitride to study the effects of the surface optical phonons from the boron nitride on the electrical properties of the carbon nanotube. Finally a few research projects are discussed in which carbon nanotubes of known chirality were used in conjunction with first electrical tests on molecules, secondly on a prefabricated complementary metal-oxide-semiconductor integrated circuit as an inverter and lastly to study the photoconductivity generated by a synchrotron laser source to identify the values for the low energy excitonic peak.

  13. Structural modification of nanoporous carbon with single wall carbon nanotube

    NASA Astrophysics Data System (ADS)

    Yi, Bo

    A novel CC nanocomposite was synthesized by pyrolysis of well dispersed individual functionalized SWNTs in a thermosetting resin, poly(furfuryl alcohol) (PFA). Strong interaction between SWNT and nanoporous carbon derived from PFA (PFA-NPC) was obtained with this strategy and the integrity of SWNTs was maintained after heat treatment. Usually, it is challenging to separate SWNT bundles and disperse them in preparation of composites. 50 wt% SWNT/NPC composites prepared with solution blending showed mass transfer rate of ˜140% higher than the original NPC. The improvement was not significant due to poor dispersion and the bundle structure of SWNTs. Functionalization of SWNTs successfully separated the SWNT bundles and solved the problems of dispersion. In this process, the SWNTs were first functionalized with sulfonic acid groups (SA-SWNT) on sidewall. Then they were converted to PFA-grafted SWNT (PFA-SWNT) by in situ polymerization of furfuryl alcohol (FA). NPC/SWNT nanocomposite was generated by pyrolysis of PFA-SWNT at 600°C. The structural transformation of NPC/SWNT at high temperature was studied by heating it at temperatures from 1200 to 2000°C in vacuum and characterized with HRTEM and Raman spectra. It was found that NPC and SWNT coalesce upon heat treatment and NPC tended to graphitize along the axis of neighboring nanotubes at temperature higher than 1400°C. Complete graphitization of NPC and SWNTs was obtained at 2000°C, when the NPC transformed to graphitic nanoribbons (GNRs) and SWNT or DWNT collapsed within the confines of the GNR. The mass transfer rate in 0.05 wt% SWNT/NPC nanocomposite was ˜2 times higher than that in the pure NPC. Similar improvement required SWNT concentration of ˜60 wt% in the SWNT/NPC composites prepared by solution blending. SWNT/NPC nanocomposite fibers prepared from 0.1 wt% SA-SWNT/FA had ˜13% increase of Young's modulus over the pure NPC fibers when they were pyrolyzed at 400 -- 1600ºC. The augment was slightly higher than Halpin-Tsai's model prediction for composites with randomly dispersed fibers, indicating that the strong interaction between NPC and SWNT strengthened the material.

  14. Oxidative enzymatic response of white-rot fungi to single-walled carbon nanotubes.

    PubMed

    Berry, Timothy D; Filley, Timothy R; Blanchette, Robert A

    2014-10-01

    Although carbon nanomaterials such as single-walled carbon nanotubes (SWCNT) are becoming increasingly prevalent in manufacturing, there is little knowledge on the environmental fate of these materials. Environmental degradation of SWCNT is hindered by their highly condensed aromatic structure as well as the size and aspect ratio, which prevents intracellular degradation and limits microbial decomposition to extracellular processes such as those catalyzed by oxidative enzymes. This study investigates the peroxidase and laccase enzymatic response of the saprotrophic white-rot fungi Trametes versicolor and Phlebia tremellosa when exposed to SWCNTs of different purity and surface chemistry under different growth conditions. Both unpurified, metal catalyst-rich SWCNT and purified, carboxylated SWCNTs promoted significant changes in the oxidative enzyme activity of the fungi while pristine SWCNT did not. These results suggest that functionalization of purified SWCNT is essential to up regulate enzymes that may be capable of decomposing CNT in the environment. PMID:25047356

  15. Growth of single-walled carbon nanotubes from the condensed phase

    NASA Astrophysics Data System (ADS)

    Sen, Rahul; Suzuki, S.; Kataura, H.; Achiba, Y.

    2001-12-01

    Single-walled carbon nanotubes (SWNTs) were grown from the condensed phase by thermally post-annealing of a soot-like material, possibly containing precursors for SWNT growth. The soot-like material was obtained by laser ablation of Ni-Co-graphite composite targets at 550-700 °C. This initial material did not contain any SWNTs but post-annealing treatment inside an electric furnace at 1200 °C under argon flow resulted in SWNTs. The soot-like material prepared at lower temperatures (room temperature to 400 °C did not yield SWNTs even after post-annealing. These results indicate that the precursors for the growth of SWNTs can form only above a certain threshold temperature, about 550 °C. Once these precursors are present, SWNTs can grow by annealing of the metal-carbon mixture. A growth model is proposed based on these results.

  16. Electronic performance of flexible single-wall carbon nanotube films: The role of electronic type

    NASA Astrophysics Data System (ADS)

    Harris, John M.; Hudson, Steven D.; Fagan, Jeffrey A.; Hobbie, Erik K.

    2012-02-01

    Recent advances in the separation of single-wall carbon nanotubes (SWCNTs) by length and electronic type have made highly monodisperse SWCNT membranes a reality, opening up new realms of potential application in flexible electronics. By measuring the coupling between mechanical flexibility and electronic performance for thin transparent films of metallic and semiconducting SWCNTs assembled on elastic polymer substrates, we demonstrate a marked difference in the electronic manifestations of thin-film deformation for the two electronic SWCNT types. We relate these differences to mechanical and interfacial phenomena that stem from the distinct optical resonances characteristic of metallic or semiconducting nanotubes, and we evaluate the durability of each film type in response to repeated mechanical strain.

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

    NASA Astrophysics Data System (ADS)

    Iyer, Ajai; Kaskela, Antti; Johansson, Leena-Sisko; Liu, Xuwen; Kauppinen, Esko I.; Koskinen, Jari

    2015-06-01

    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.

  18. An efficient numerical model for vibration analysis of single-walled carbon nanotubes

    Microsoft Academic Search

    S. K. Georgantzinos; G. I. Giannopoulos; N. K. Anifantis

    2009-01-01

    This paper presents a linear spring-based element formulation for computation of vibrational characteristics of single-walled\\u000a carbon nanotubes (CNTs). Three-dimensional nanoscale elements and corresponding elemental equations are developed for the\\u000a numerical treatment of the dynamic behaviour of single-walled CNTs, including appropriate stiffness and mass characteristics.\\u000a The atomistic microstructure of nanotubes is used to assemble the elemental equations and construct the dynamic

  19. Excited-state carrier lifetime in single-walled carbon nanotubes Department of Engineering, University of Cambridge, Cambridge CB2 IPZ, United Kingdom

    E-print Network

    Nabben, Reinhard

    - served in carbon nanotubes if the originally bundled tubes were isolated in micelles.3­5 While spectroscopy to probe metallic nano- tubes. They found that the carriers in metallic tubes first relaxExcited-state carrier lifetime in single-walled carbon nanotubes S. Reich* Department

  20. Importance of carbon solubility and wetting properties of nickel nanoparticles for single wall nanotube growth

    E-print Network

    Paris-Sud XI, Université de

    Importance of carbon solubility and wetting properties of nickel nanoparticles for single wall, a typical catalyst, and show that carbon solubility increases for smaller nanoparticles that are either that wetting properties of the nanoparticles, controlled by carbon solubility, are of fundamental importance

  1. Patterning of single walled carbon nanotubes using a low-fluence excimer laser photoablation process

    E-print Network

    Rogers, John A.

    , as the ablation assistor and it was coated on the carbon nano- tube layer, as shown in Fig. 1 b . The photoresist deposition process causes the resist to be placed under the carbon nano- tubes as well as on topPatterning of single walled carbon nanotubes using a low-fluence excimer laser photoablation

  2. Chirality-Dependent Vapor-Phase Epitaxial Growth and Termination of Single-Wall Carbon Nanotubes

    E-print Network

    Zhou, Chongwu

    -wall carbon nano- tubes are highly desired for both fundamental study and many of their technologicalChirality-Dependent Vapor-Phase Epitaxial Growth and Termination of Single-Wall Carbon Nanotubes-controlled carbon nanotube synthesis. Nevertheless, the yield of vapor-phase epitaxial growth is rather limited

  3. Polarization State Control of Light by Single-Walled Carbon Nanotubes

    E-print Network

    Maruyama, Shigeo

    components I. Introduction Single-walled carbon nano-tubes (SWCNTs) have been the subject of focused multi of carbon nano tube (CNT) growth direction has been recently achieved and polarization dependent optical and anisotropic carbon nano tube films would serve the purpose. In this paper we report the optical activity

  4. Amphoteric doping of single-wall carbon-nanotube thin films as probed by optical absorption spectroscopy

    Microsoft Academic Search

    S. Kazaoui; N. Minami; R. Jacquemin; H. Kataura; Y. Achiba

    1999-01-01

    We have separately probed the doping behavior of semiconducting (S) and metallic (M) single-wall carbon-nanotube (SWNT) films, by optical absorption and dc resistance (R) measurements. Either electron acceptors (Br2, I2) or donors (K, Cs) were used as dopants with controlled stoichiometry. Disappearance of absorption bands at 0.68, 1.2, and 1.8 eV, and concomitant decrease of R by doping have been

  5. Lithium Doping of Single-Walled Carbon Nanotubes for Battery and Semiconductor Applications Kevin Donaher, Columbia University, Georgia Institute of Technology SURF 2010 Fellow

    E-print Network

    Li, Mo

    Lithium Doping of Single-Walled Carbon Nanotubes for Battery and Semiconductor Applications Kevin Jang, Mentor: Wonsang Koh Abstract The properties of lithium doped (5,5) metallic and (8 lithium binds to carbon nanotubes and how this affects the band structure of the semiconducting carbon

  6. Position of K Atoms in Doped Single-Walled Carbon Nanotube Crystals

    NASA Astrophysics Data System (ADS)

    Gao, Guanghua; Ça?in, Tahir; Goddard, William A.

    1998-06-01

    Recent experiments by Lee et al. [Nature (London) 363, 255 (1997)] show that doping carbon single-wall nanotube (SWNT) ropes with K, Rb, or Br2 leads to metallic conductivity, but the structure and properties are not known. We used molecular dynamics to predict structures and properties which should help motivate and interpret experiments on SWNT/K. We find the optimum stoichiometry to be KC16 if the K cannot penetrate the tubes and K1C10 ( Kexo5Kendo3C80, 3 within the tube) if they can. We predict the optimum structure and the associated powder-diffraction x-ray pattern expected for KnC80 from n = 0-10 (optimum is n = 5). The Young's modulus per tube along the tube axis varies from 640 to 525 GPa for n = 0 to 5.

  7. Heteroepitaxial Growth of Single-Walled Carbon Nanotubes from Boron Nitride

    PubMed Central

    Tang, Dai-Ming; Zhang, Li-Li; Liu, Chang; Yin, Li-Chang; Hou, Peng-Xiang; Jiang, Hua; Zhu, Zhen; Li, Feng; Liu, Bilu; Kauppinen, Esko I.; Cheng, Hui-Ming

    2012-01-01

    The growth of single-walled carbon nanotubes (SWCNTs) with predefined structure is of great importance for both fundamental research and their practical applications. Traditionally, SWCNTs are grown from a metal catalyst with a vapor-liquid-solid mechanism, where the catalyst is in liquid state with fluctuating structures, and it is intrinsically unfavorable for the structure control of SWCNTs. Here we report the heteroepitaxial growth of SWCNTs from a platelet boron nitride nanofiber (BNNF), which is composed of stacked (002) planes and is stable at high temperatures. SWCNTs are found to grow epitaxially from the open (002) edges of the BNNFs, and the diameters of the SWCNTs are multiples of the BN (002) interplanar distance. In situ transmission electron microscopy observations coupled with first principles calculations reveal that the growth of SWCNTs from the BNNFs follows a vapor-solid-solid mechanism. Our work opens opportunities for the control over the structure of SWCNTs by hetero-crystallographic epitaxy. PMID:23240076

  8. Golden single-walled carbon nanotubes prepared using double layer polysaccharides bridge for photothermal therapy.

    PubMed

    Meng, Lingjie; Xia, Wenjian; Liu, Li; Niu, Lvye; Lu, Qinghua

    2014-04-01

    Golden single-walled carbon nanotubes (SWNTs) were prepared by growing gold nanoparticles onto the bilayer polysaccharide functionalized SWNTs. The layer-by-layer self-assembly of sodium alginate and chitosan on SWNTs provided an ideal surface with high density of active metal-binding groups such as amino and carboxylic acid groups, and then an approach of seed growth was adopted to facilitate the formation of gold nanoparticles coated SWNTs. The resulting golden SWNT hybrids have good water dispersibility and biocompatibility and tend to enter cancer cells. Interestingly, they have an enhanced NIR absorption and effectively transfer NIR laser into heat. The material can quickly cause localized hyperthermia, resulting in rapid cell death, and therefore appears to act as a highly effective photothermal converter for cancer ablation. PMID:24606763

  9. Electrical properties of nanoceramics reinforced with ropes of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhan, Guo-Dong; Kuntz, Joshua D.; Garay, Javier E.; Mukherjee, Amiya K.

    2003-08-01

    Single-walled carbon nanotubes (SWCNTs) were used to convert insulating nanoceramics to metallically conductive composites. Dense SWCNT/Al2O3 nanocomposites with CNT contents ranging from 5.7 to 15 vol % and with nanocrystalline alumina matrices have been fabricated by spark-plasma-sintering that retains the integrity of SWCNT in the matrix. The conductivity of these composites increases with increasing content of CNTs. The conductivity has been increased to 3345 S/m in the 15 vol % SWCNT/Al2O3 nanocomposite at room temperature. This is an increase of 13 orders of magnitude over pure alumina and of more than 735% over previously reported results in CNT-ceramic composites.

  10. How catalysts affect the growth of single-walled carbon nanotubes on substrates.

    PubMed

    Li, Yan; Cui, Rongli; Ding, Lei; Liu, Yu; Zhou, Weiwei; Zhang, Yan; Jin, Zhong; Peng, Fei; Liu, Jie

    2010-04-01

    Direct growth of single-walled carbon nanotubes (SWNTs) on flat substrates by chemical vapor deposition (CVD) is very important for the application of SWNTs in nanodevices. In the growth process, catalysts play an important role in controlling the structure of SWNTs. Over the years, we have systematically studied the size-controlled synthesis of Fe-based nanoparticles and the CVD growth of SWNTs, especially the horizontally aligned SWNTs, catalyzed by these produced nanoparticles. Some new catalysts were also developed. Among them, Cu is shown to be a superior catalyst for growing SWNT arrays on both silicon and quartz substrates and Pb is a unique catalyst from which one can obtain SWNTs without any metallic contaminant. SWNTs prepared with both Cu and Pb are very suitable for building high-performance nanodevices. These studies are also very helpful for further understanding the growth mechanism of SWNTs. PMID:20437500

  11. The controlled growth of single walled carbon nanotubes from ordered substrates

    NASA Astrophysics Data System (ADS)

    Wang, Yuhuang; Kittrell, Carter; Kim, Myung Jong; Brinson, Bruce E.; Ripley, Steve; Ramesh, Sivarajan; Hauge, Robert H.; Smalley, Richard E.

    2003-03-01

    We explore a single walled carbon nanotube (SWNT) growth process starting with an ordered substrate similar to a "bed-of-nails" membrane of SWNTs. The membrane consists of closely packed SWNTs aligned along the normal of the substrate. Each nanotube end is etched open such that a nanometer sized metal particle can be docked to the open end to serve as the catalyst. We have successfully grown SWNTs following this general scheme. The conditions will be optimized to enhance the possibility of growing a continuous fiber with the aid of the van der Waals force between SWNTs. If successful this may present a first step toward the synthesis of continuous fibers of crystalline nanotube materials comprising long, parallel nanotubes in an ordered array that have all the same extraordinary mechanical, chemical, thermal, and electrical properties that SWNT exhibits on the nanometer scale.

  12. Ethanol sensor development using three-dimensional single-walled carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Chao, Wan-Jung

    2011-12-01

    A novel ethanol sensor using three-dimensional single-walled carbon nanotube networks (3D-SWNTs) with an alkaline electrolyte solution has been developed. A cyclic voltammetry was used to examine the electrochemical response of the sensor. The relationship between response currents and ethanol concentrations was found to be linear for the ethanol concentrations' range from 1 to 5%. The CV performance test showed the best sensitivity was 0.0024 mAmM -1cm-2 with the 3D-SWNT electrode having no Pt particle loading. The Pt-free electrode gave better performance than platinum-coated 3D-SWNTs electrodes did. Since the 3D-SWNTs electrode without using Pt metal loading detects ethanol concentrations (1--5%) with high sensitivity and accuracy, it can lower the fabrication cost for potential commercial application.

  13. Light-induced selective deposition of Au nanoparticles on single-wall carbon nanotubes.

    PubMed

    Quintana, Mildred; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Meneghetti, Moreno; Bittencourt, Carla; Prato, Maurizio

    2010-10-26

    Novel applications of single-walled carbon nanotubes (SWNT) rely on the development of new strategies to make them easier to handle without affecting their structural properties. In this work, we have selectively deposited Au nanoparticles (Au NP) on SWNT assisted by UV light irradiation. XPS analysis and UV-vis spectroscopy indicate that the deposition occurs at the defects generated after oxidation of the SWNT. By addition of n-dodecylthiol, the separation of oxidized tubes with Au NP (Au-ox-SWNT) from tubes devoid of Au NP (bare tubes, b-SWNT) was achieved. Raman and UV-vis-NIR spectra indicate that UV irradiation induces a faster nucleation of Au NP on metallic SWNT. This new technique can be useful for the preparation of nanohybrid composites with enhanced properties, as increased thermal stability, and to obtain purified SWNT. PMID:20866064

  14. Towards carbon-nanotube integrated devices: optically controlled parallel integration of single-walled carbon nanotubes

    Microsoft Academic Search

    Y. S. Zhou; W. Xiong; Y. Gao; M. Mahjouri-Samani; M. Mitchell; L. Jiang; Y. F. Lu

    2010-01-01

    Where it starts and where it goes? Controlled integration of single-walled carbon nanotubes (SWNTs) into pre-designed nano-architectures is one of the major challenges to be overcome for extensive scientific research and technological applications. Various serial assembly techniques have been proposed and developed. However, they are still a long way from practical applications due to the drawbacks on reliability, yield and

  15. Systematic Conversion of Single Walled Carbon Nanotubes into n-type Thermoelectric Materials by Molecular Dopants

    NASA Astrophysics Data System (ADS)

    Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

    2013-11-01

    Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. -4.4 eV and ca. -5.6 eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules.

  16. Systematic conversion of single walled carbon nanotubes into n-type thermoelectric materials by molecular dopants.

    PubMed

    Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

    2013-01-01

    Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. -4.4 eV and ca. -5.6 eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules. PMID:24276090

  17. Systematic Conversion of Single Walled Carbon Nanotubes into n-type Thermoelectric Materials by Molecular Dopants

    PubMed Central

    Nonoguchi, Yoshiyuki; Ohashi, Kenji; Kanazawa, Rui; Ashiba, Koji; Hata, Kenji; Nakagawa, Tetsuya; Adachi, Chihaya; Tanase, Tomoaki; Kawai, Tsuyoshi

    2013-01-01

    Thermoelectrics is a challenging issue for modern and future energy conversion and recovery technology. Carbon nanotubes are promising active thermoelectic materials owing to their narrow bandgap energy and high charge carrier mobility, and they can be integrated into flexible thermoelectrics that can recover any waste heat. We here report air-stable n-type single walled carbon nanotubes with a variety of weak electron donors in the range of HOMO level between ca. ?4.4?eV and ca. ?5.6?eV, in which partial uphill electron injection from the dopant to the conduction band of single walled carbon nanotubes is dominant. We display flexible films of the doped single walled carbon nanotubes possessing significantly large thermoelectric effect, which is applicable to flexible ambient thermoelectric modules. PMID:24276090

  18. Linear Plasmon Dispersion in Single-Wall Carbon Nanotubes and the Collective Excitation Spectrum of Graphene

    NASA Astrophysics Data System (ADS)

    Kramberger, C.; Hambach, R.; Giorgetti, C.; Rümmeli, M. H.; Knupfer, M.; Fink, J.; Büchner, B.; Reining, Lucia; Einarsson, E.; Maruyama, S.; Sottile, F.; Hannewald, K.; Olevano, V.; Marinopoulos, A. G.; Pichler, T.

    2008-05-01

    We have measured a strictly linear ? plasmon dispersion along the axis of individualized single-wall carbon nanotubes, which is completely different from plasmon dispersions of graphite or bundled single-wall carbon nanotubes. Comparative ab initio studies on graphene-based systems allow us to reproduce the different dispersions. This suggests that individualized nanotubes provide viable experimental access to collective electronic excitations of graphene, and it validates the use of graphene to understand electronic excitations of carbon nanotubes. In particular, the calculations reveal that local field effects cause a mixing of electronic transitions, including the “Dirac cone,” resulting in the observed linear dispersion.

  19. Electrical properties of Poly(ethylene glycol dimethacrylate-n-vinyl imidazole)\\/Single Walled Carbon Nanotubes\\/n-Si Schottky diodes formed by surface polymerization of Single Walled Carbon Nanotubes

    Microsoft Academic Search

    Ali Kara; Nalan Tekin; Saadet Beyaz; Hakan Köçkar

    In this paper we report the electrical characteristics of the Schottky diodes formed by surface polymerization of the Poly(ethylene glycol dimethacrylate-n-vinyl imidazole)\\/Single Walled Carbon Nanotubes on n-Si. The Single Walled Carbon Nanotubes were synthesized by CVD method. The main electrical properties of the Poly(ethylene glycol dimethacrylate-n-vinyl imidazole)\\/Single Walled Carbon Nanotubes\\/n-Si have been investigated through the barrier heights, the ideality factors

  20. Van der Waals interaction between a microparticle and a single-wall carbon nanotube

    E-print Network

    E. V. Blagov; G. L. Klimchitskaya; V. M. Mostepanenko

    2007-04-13

    The Lifshitz-type formulas describing the free energy and the force of the van der Waals interaction between an atom (molecule) and a single-wall carbon nanotube are obtained. The single-wall nanotube is considered as a cylindrical sheet carrying a two-dimensional free electron gas with appropriate boundary conditions on the electromagnetic field. The obtained formulas are used to calculate the van der Waals free energy and force between a hydrogen atom (molecule) and single-wall carbon nanotubes of different radia. Comparison studies of the van der Waals interaction of hydrogen atoms with single- and multi-wall carbon nanotubes show that depending on atom-nanotube separation distance the idealization of graphite dielectric permittivity is already applicable to nanotubes with only two or three walls.

  1. Hybrid Devices from Single Wall Carbon Nanotubes Epitaxially Grown into a

    E-print Network

    Nygård, Jesper

    carbon nanotubes encapsulated in epitaxially grown semiconductor heterostructures of GaAs/AlAs and (GaHybrid Devices from Single Wall Carbon Nanotubes Epitaxially Grown into a Semiconductor Heterostructure Ane Jensen,*, Jonas Rahlf Hauptmann, Jesper Nygård, Janusz Sadowski, and Poul Erik Lindelof Nano

  2. Ion desorption from single-walled carbon nanotubes induced by soft X-ray illumination

    E-print Network

    Maruyama, Shigeo

    1 Ion desorption from single-walled carbon nanotubes induced by soft X-ray illumination Y. Mera1 by soft X-ray illumination in the C 1s core-excitation energy range in order to have insight for illumination. Experimental results exclude the simple detachment of carbon atoms constituting the nanotubes

  3. Suppressed Conductance of Individual Single Walled Carbon Nanotube\\/Polypyrole Composite Nanowires and Their Sensing Applications

    Microsoft Academic Search

    Xiaolei Liu

    2005-01-01

    We present synthesis of individual single walled carbon nanotube\\/polypyrrole composite nanowire by chemical vapor deposition followed by electrochemical deposition for the first time. The transport properties of the composite nanowire were studied and suppression in conduction through carbon nanotube channels was discovered and discussed. Moreover, we also demonstrated the composite nanowire devices can serve as chemical sensors, which responses to

  4. Composites of Single-Walled Carbon Nanotubes and Styrene-Isoprene

    E-print Network

    Resasco, Daniel

    /polymer composites involve both polymer and nano- tubes. M. L. P. Ha, B. P. Grady, G. Lolli, D. E. Resasco SchoolComposites of Single-Walled Carbon Nanotubes and Styrene-Isoprene Copolymer Latices Mai L. P. Ha the date Iijima reported about the existence of carbon nanotubes[1] (CNTs), enormous pro- gress has been

  5. Alignment Dynamics of Single-Walled Carbon Nanotubes in Pulsed Ultrahigh

    E-print Network

    Kono, Junichiro

    ), rolled up tubes of graphene sheets, are unique nano-objects with extreme aspect ratios, which leadAlignment Dynamics of Single-Walled Carbon Nanotubes in Pulsed Ultrahigh Magnetic Fields Jonah and CNRS, 351 cours de la Libe´ration, Talence, F-33405, France. S ingle-walled carbon nanotubes (SWNTs

  6. Packing-induced electronic structure changes in bundled single-wall carbon nanotubes

    E-print Network

    of carbon hexagons and their matching around the tube's circumference,12­15 the distortion of the straight of parallel and braided nano- tubes. These observations unambiguousPacking-induced electronic structure changes in bundled single-wall carbon nanotubes P. Castrucci

  7. VERTICALLY ALIGNED CARPET OF SINGLE-WALLED CARBON NANOTUBES CATALYTICALLY GROWN FROM ALCOHOL

    E-print Network

    Maruyama, Shigeo

    VERTICALLY ALIGNED CARPET OF SINGLE-WALLED CARBON NANOTUBES CATALYTICALLY GROWN FROM ALCOHOL Shigeo alcohol as the carbon source are discussed. High-purity SWNTs can be generated at relatively low CVD ethanol (alcohol catalytic chemical vapor deposition, ACCVD) is performed by using densely mono

  8. Floated Catalyst CVD Generation of Single-Walled Carbon Nanotubes from Alcohol

    E-print Network

    Maruyama, Shigeo

    Floated Catalyst CVD Generation of Single-Walled Carbon Nanotubes from Alcohol Shigeo Maruyama technique of SWNTs from alcohol. By using alcohol as a carbon source, high-purity SWNTs were produced at relatively low temperature (550-900 $^o$C), probably because oxygen atoms contained in alcohol molecules

  9. High-Purity Catalytic CVD Generation of Single-Walled Carbon Nanotubes from Alcohol

    E-print Network

    Maruyama, Shigeo

    High-Purity Catalytic CVD Generation of Single-Walled Carbon Nanotubes from Alcohol Shigeo Maruyama alcohols are much better carbon sources for SWNTs than hydrocarbons is explained by the role of decomposed OH radicals as follows. Since an OH radical is decomposed on the catalyst surface from an alcohol

  10. NASA-JSC Protocol for the Characterization of Single Wall Carbon Nanotube Material Quality

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram; Nikolaev, Pasha; Gorelik, Olga; Hadjiev, Victor; Holmes, William; Devivar, Rodrigo; Files, Bradley; Yowell, Leonard

    2010-01-01

    It is well known that the raw as well as purified single wall carbon nanotube (SWCNT) material always contain certain amount of impurities of varying composition (mostly metal catalyst and non-tubular carbon). Particular purification method also creates defects and/or functional groups in the SWCNT material and therefore affects the its dispersability in solvents (important to subsequent application development). A number of analytical characterization tools have been used successfully in the past years to assess various properties of nanotube materials, but lack of standards makes it difficult to compare these measurements across the board. In this work we report the protocol developed at NASA-JSC which standardizes measurements using TEM, SEM, TGA, Raman and UV-Vis-NIR absorption techniques. Numerical measures are established for parameters such as metal content, homogeneity, thermal stability and dispersability, to allow easy comparison of SWCNT materials. We will also report on the recent progress in quantitative measurement of non-tubular carbon impurities and a possible purity standard for SWCNT materials.

  11. Optical Signatures of the Aharonov-Bohm Phase in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Zaric, Sasa; Ostojic, Gordana N.; Kono, Junichiro; Shaver, Jonah; Moore, Valerie C.; Strano, Michael S.; Hauge, Robert H.; Smalley, Richard E.; Wei, Xing

    2004-05-01

    We report interband magneto-optical spectra for single-walled carbon nanotubes in high magnetic fields up to 45 tesla, confirming theoretical predictions that the band structure of a single-walled carbon nanotube is dependent on the magnetic flux ? threading the tube. We have observed field-induced optical anisotropy as well as red shifts and splittings of absorption and photoluminescence peaks. The amounts of shifts and splittings depend on the value of ?/?0 and are quantitatively consistent with theories based on the Aharonov-Bohm effect. These results represent evidence of the influence of the Aharonov-Bohm phase on the band gap of a solid.

  12. Hydrogen peroxide adsorption on Fe-filled single-walled carbon nanotubes: a theoretical study.

    PubMed

    Moreno, J; Kasai, K; David, M; Nakanishi, H; Kasai, H

    2009-02-11

    We investigated the adsorption of hydrogen peroxide molecules on Fe-filled single-walled carbon nanotubes (SWNTs) based on density functional theory (DFT) calculations. The adsorption possibilities for the hydrogen peroxide molecule were tested by finding the minimum energy as a function of distance of the molecule from the Fe-filled SWNT. Stable structures were obtained by optimizing the hydrogen peroxide (H(2)O(2)) as it was adsorbed on to the Fe-filled SWNT. This study may serve as an initial investigation into the possibility of Fe-filled single-walled carbon nanotubes (SWNTs) as catalyst material for the proton exchange membrane fuel cell (PEMFC). PMID:21715921

  13. Growth of Horizontally-Aligned Single-Walled Carbon Nanotubes on Sapphire Surface by Needle-Scratching Method

    NASA Astrophysics Data System (ADS)

    Ago, Hiroki; Kayo, Yasumichi; Tsuji, Masaharu

    2012-04-01

    We report the growth of single-walled carbon nanotubes (SWNTs) over metal nanoparticles which are formed by scratching sapphire surface with metal wires. The chemical vapor deposition over sapphire substrate scratched with Fe and Co metal wires gives horizontally aligned SWNTs, while no nanotube growth is observed for Au, Mo, and Ni wires. This result suggests that the nanoparticles scattered from Fe and Co wires act as the catalyst for SWNT growth, being different from the previously proposed substrate-catalyzed reaction mechanism. Further, we study the effects of the flow rates of CH4-H2 gases during the SWNT growth on the nanotube density and diameter.

  14. Carbon Single-Wall Nanatube Growth in a Volumetrically Confined Arc Discharge System

    SciTech Connect

    Franz, K.J.; Alleman, J.L.; Jones, K.M.; Dillon, A.C.; Heben, M.J.

    2004-01-01

    Carbon nanotubes hold significant promise for a vast number of materials applications due to their unique mechanical, electrical, and gas storage properties. Although carbon single-wall nanotubes (SWNTs) have been synthesized since 1993 by the arc discharge method, and numerous other synthesis methods have since been developed, no method has yet produced 100% pure carbon nanotubes. Instead, a significant amount of impurities—various carbon structures and metal catalysts—are present in the raw soot. While arc discharge was the first method for SWNT synthesis, it also produces more impure raw soot in comparison to the more recently developed laser vaporization, which has produced the purest raw soot to date but is much slower. Geometry and thermal gradient are appreciably different between traditional arc discharge systems and laser vaporization systems. We report that, by incorporating some characteristics inherent to a laser vaporization system into an arc discharge system, improvement in the yield of SWNT raw soot may be achieved. This is accomplished by confining the arc within a 50 mm diameter quartz tube, similar to laser vaporization. We find through transmission electron microscopy and Raman spectroscopy that SWNTs are made in significant numbers in this confined arc discharge system, comparable to laser vaporization synthesized material. Further study is, however, required to prove reproducibility and attain an exact value for the purity of the produced raw soot.

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

    NASA Technical Reports Server (NTRS)

    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.

  16. Resonance Raman Spectroscopy of Single-Wall Carbon Nanotubes Separated via Aqueous Two-Phase Extraction

    NASA Astrophysics Data System (ADS)

    Simpson, J. R.; Fagan, J. A.; Hight Walker, A. R.

    2014-03-01

    We report Resonance Raman Spectroscopy (RRS) measurements of single-wall carbon nanotube (SWCNT) samples dispersed in aqueous solutions via surfactant wrapping and separated using aqueous two-phase extraction (ATPE) into chirality-enriched semiconducting and metallic SWCNT species. ATPE provides a rapid, robust, and remarkably tunable separation technique that allows isolation of high-purity, individual SWCNT chiralities via modification of the surfactant environment. We report RRS measurements of individual SWCNT species of various chiral index including, armchair and zigzag metals. Raman provides a powerful technique to quantify the metallic SWCNTs in ATPE fractions separated for metallicity. We measure Raman spectra over a wide range of excitation wavelengths from 457 nm to 850 nm using a series of discrete and continuously tunable laser sources coupled to a triple-grating spectrometer with a liquid-nitrogen-cooled detector. The spectra reveal Raman-active vibrational modes, including the low-frequency radial breathing mode (RBM) and higher-order modes. SWCNT chiral vectors are determined from the Raman spectra, specifically the RBM frequencies and corresponding energy excitation profiles, together with input from theoretical models.

  17. Thermal Properties of Metal-Coated Vertically Aligned Single-Wall Nanotube Arrays

    Microsoft Academic Search

    M. A. Panzer; G. Zhang; D. Mann; X. Hu; E. Pop; H. Dai; K. E. Goodson

    2008-01-01

    Owing to their high thermal conductivities, carbon nanotubes (CNTs) are promising for use in advanced thermal interface materials. While there has been much previous re- search on the properties of isolated CNTs, there are few thermal data for aligned films of single wall nanotubes. Furthermore, such data for nanotube films do not separate volume from interface thermal resistances. This paper

  18. Carbene-functionalized single-walled carbon nanotubes and their electrical properties.

    PubMed

    Liu, Chao; Zhang, Qing; Stellacci, Francesco; Marzari, Nicola; Zheng, Lianxi; Zhan, Zhaoyao

    2011-05-01

    Pure metallic single-walled carbon nanotubes (m-SWCNTs) are very desirable for many electrode and interconnecting applications. However, the lack of reliable processing techniques to sort m-SWCNTs from the as-synthesized SWCNT samples is an obstacle to these applications. The effects of carbene-based covalent functionalization on the electrical properties of an isolated m-SWCNT, a semiconducting (s)-SWCNT, and a mixture network of both m- and s-SWCNTs are reported. For the first time, a semiconducting-to-metallic SWCNT transition upon dichlorocarbene functionalization is observed. Interestingly, the transition is reversible upon thermal annealing under ambient conditions. The electrical properties of m-SWCNTs remain largely unaffected whereas the on-state conductivity of s-SWCNTs is greatly reduced by this process, in agreement with the relevant theoretical predictions. These findings could pave the way for fabricating large-scale SWCNT-based interconnects and electrodes in full-carbon integrated circuits. PMID:21485006

  19. Carbon atoms in ethanol do not contribute equally to formation of single-walled carbon nanotubes during CVD

    E-print Network

    Maruyama, Shigeo

    Carbon atoms in ethanol do not contribute equally to formation of single-walled carbon nanotubes in which isotopically labeled ethanol, e.g., 12CH3-13CH2-OH, is used to trace the carbon atoms during of ethanol's two different carbon atoms to SWNT formation. Surprisingly, the carbon away from the hydroxyl

  20. Electromagnetic Interference (EMI) Shielding of Single-Walled Carbon

    E-print Network

    Gao, Hongjun

    ) of a composite material depends on many factors, including the filler's intrinsic conductivity, dielectric strength of carbon nanotubes (CNTs), including SWNTs and MWNTs, make them an excellent option for creating

  1. Chirality-Selective Optical Scattering Force on Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Skelton Spesyvtseva, Susan E.; Shoji, Satoru; Kawata, Satoshi

    2015-04-01

    We show that optical forces acting on carbon nanotubes are substantially enhanced when the optical wavelength is tuned to resonances in the electronic band structure. Using a tunable laser source, we experimentally demonstrate a resonant optical scattering force on single-walled carbon nanotubes and, by tuning the wavelength, exploit this force to achieve chirality enrichment of four chiralities of nanotubes. Our results represent a significant step towards optical manipulation and sorting of carbon nanotubes based on their chiral vector.

  2. Hybrid Devices from Single Wall Carbon Nanotubes Epitaxially Grown into a Semiconductor Heterostructure

    Microsoft Academic Search

    Ane Jensen; Jonas Rahlf Hauptmann; Jesper Nygård; Janusz Sadowski; Poul Erik Lindelof

    2004-01-01

    To take advantage of nanoscale molecular electronic components in semiconductor technology, there will be a desire to integrate new elements such as one-dimensional (1D) carbon nanotubes in conventional 2D or 3D semiconductor systems. We report on hybrid devices based on single wall carbon nanotubes encapsulated in epitaxially grown semiconductor heterostructures of GaAs\\/AlAs and (Ga,Mn)As below and above the carbon nanotube.

  3. Conductivities of graphite fiber composites with single-walled carbon nanotube layers

    Microsoft Academic Search

    Lawrence Yoo; Hansang Kim

    2011-01-01

    The present study investigates the potential of air-spraying method in enhancement of electrical and thermal conductivities.\\u000a Single-walled carbon nanotubes (SWCNTs) functionalized with carboxylic acid groups were air-sprayed on the surface of carbon\\u000a fiber prepreg. The prepregs were stacked up and processed to carbon fiber laminates with SWCNTs layered between plies. From\\u000a scanning electron microscopy, it was discovered that SWCNTs formed

  4. Dynamics of Surfactant-Suspended Single-Walled Carbon Nanotubes in a Centrifugal Field

    E-print Network

    Braatz, Richard D.

    Dynamics of Surfactant-Suspended Single-Walled Carbon Nanotubes in a Centrifugal Field Nitish Nair,,§ Woo-Jae Kim,,§ Richard D. Braatz, and Michael S. Strano*, Department of Chemical Engineering and Biomolecular Engineering, UniVersity of Illinois at Urbana-Champaign, Urbana, Illinois 61801 ReceiVed August 14

  5. Growth window and possible mechanism of millimeter-thick single-walled carbon nanotube forests

    E-print Network

    Maruyama, Shigeo

    1 Growth window and possible mechanism of millimeter-thick single-walled carbon nanotube forests@chemsys.t.u-tokyo.ac.jp Our group recently reproduced the water-assisted growth method, so-called "super growth and catalyst conditions. Results revealed that a thin Fe catalyst layer (about 0.5 nm) yielded rapid growth

  6. Single Wall Carbon Nanotubes Filled With Metallocenes: a First Example of Non-Fullerene Peapods

    Microsoft Academic Search

    F. Stercel; N. M. Nemes; J. E. Fischer; D. E. Luzzi

    We report the synthesis and analysis of metallocenes (ferrocene, chromocene, ruthenocene, vanadocene, tungstenocene-dihydride) encapsulated in single wall carbon nanotubes (SWNTs). In the case of ferrocene, efficient filling of the SWNTs was accomplished from both the liquid and the vapor phase. The other two metallocenes were filled from the vapor phase. High resolution transmission electron microscopy reveals single molecular chains of

  7. Wrinkling and Strain Softening in Single-Wall Carbon Nanotube Membranes

    Microsoft Academic Search

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

    2010-01-01

    The nonlinear elasticity of thin supported membranes assembled from length purified single-wall carbon nanotubes is analyzed through the wrinkling instability that develops under uniaxial compression. In contrast with thin polymer films, pristine nanotube membranes exhibit strong softening under finite strain associated with bond slip and network fracture. We model the response as a shift in percolation threshold generated by strain-induced

  8. Interaction of Acetone with Single Wall Carbon Nanotubes at Cryogenic Temperatures: A Combined Temperature Programmed

    E-print Network

    Borguet, Eric

    Interaction of Acetone with Single Wall Carbon Nanotubes at Cryogenic Temperatures: A CombinedVersity, Philadelphia, PennsylVania 19122, Department of Chemical Engineering, UniVersity of Pittsburgh, Pittsburgh, PennsylVania 15261, Department of Chemistry and Institute for AdVanced Research, Nagoya UniVersity, Nagoya

  9. Single walled carbon nanotube array as working electrode for dye solar cells

    Microsoft Academic Search

    Daniel D. Tune; Christopher T. Gibson; Jamie S. Quinton; Amanda V. Ellis; Joseph G. Shapter

    2010-01-01

    A new working electrode for dye solar cells has been fabricated incorporating an array of dye sensitised single walled carbon nanotubes on an indium tin oxide coated glass substrate as a replacement for the titania used in conventional dye solar cells.

  10. Raman probing of uniaxial strain in individual single-wall carbon nanotubes in a composite

    E-print Network

    Paris-Sud XI, Université de

    Raman probing of uniaxial strain in individual single-wall carbon nanotubes in a composite material temperature range. These results are well understood by considering a uniaxial strain on the nanotube induced embedded in gelatin showed a broadening and a global red shift of the PL lines with respect to PL

  11. Unexpected Hole Transfer Leads to High Efficiency Single-Walled Carbon Nanotube

    E-print Network

    Zhong, Zhaohui

    external quantum efficiency (EQE) after taking into account the exciton diffusion length is measured. Importantly, the devices exhibit greater than 90% effective external quantum efficiency. These key findingsUnexpected Hole Transfer Leads to High Efficiency Single-Walled Carbon Nanotube Hybrid Photovoltaic

  12. Single-Walled Carbon Nanotubes for High-Energy Optical Pulse Formation Yong-Won Song

    E-print Network

    Maruyama, Shigeo

    - 1 - Single-Walled Carbon Nanotubes for High-Energy Optical Pulse Formation Yong-Won Song Center@kist.re.kr Shinji Yamashita Department of Electronic Engineering, University of Tokyo, Tokyo 113-8656, Japan Shigeo Maruyama Department of Mechanical Engineering, University of Tokyo, Tokyo 113-8656, Japan (Received

  13. Extinction and orientational dependence of electron diffraction from single-walled carbon nanotubes

    E-print Network

    Qin, Lu-Chang

    Extinction and orientational dependence of electron diffraction from single-walled carbon nanotubes; in final form 27 June 2005 Available online 1 August 2005 Abstract The extinction and orientational dependence and extinction of certain layer lines in experiment due to the interference of two primary Bessel

  14. High-performance electronics using dense, perfectly aligned arrays of single-walled carbon nanotubes

    Microsoft Academic Search

    Seong Jun Kang; Coskun Kocabas; Taner Ozel; Moonsub Shim; Ninad Pimparkar; Muhammad A. Alam; Slava V. Rotkin; John A. Rogers

    2007-01-01

    Single-walled carbon nanotubes (SWNTs) have many exceptional electronic properties. Realizing the full potential of SWNTs in realistic electronic systems requires a scalable approach to device and circuit integration. We report the use of dense, perfectly aligned arrays of long, perfectly linear SWNTs as an effective thin-film semiconductor suitable for integration into transistors and other classes of electronic devices. The large

  15. Growth transition from single wall- to double walled carbon nanotubes by using acetylene gas

    Microsoft Academic Search

    Vijaya Kayastha; Yoke Khin Yap

    2006-01-01

    Based on a growth model that we have proposed for multiwalled carbon nanotubes (CNTs) [1, 2], we found that similar mechanism is applied for the growth of single wall- and double walled- CNTs by acetylene gas. This model combines disociative adsorption of acetylene molecules on Fe catalyst and the vapor-liquid-solid mechanism. Basically, the growth is the consequence of optimization of

  16. Optical Properties of Empty and Water-Filled Single-Wall Carbon Nanotubes

    Microsoft Academic Search

    J. R. Simpson; J. A. Fagan; J. Y. Huh; A. R. Hight Walker; J. L. Blackburn; B. A. Larsen; J. Holt

    2011-01-01

    The necessity for separation of single-wall carbon nanotube (SWCNT) populations to achieve desired properties presents a major technical barrier for the development of SWCNT-based applications, and has been the focus of significant academic and industrial research. Recent advances include the separation of SWCNT populations by diameter through buoyancy differences. Here we report on the optical spectroscopic properties of large diameter

  17. Transport of Single-Walled Carbon Nanotubes in Porous Media: Filtration Mechanisms and Reversibility

    Microsoft Academic Search

    DEB P. J AISI; NAVID B. S ALEH; RUTH E. B LAKE; MENACHEM E LIMELECH

    Deposition of nanomaterials onto surfaces is a key process governing their transport, fate, and reactivity in aquatic systems. We evaluated the transport and deposition behavior of carboxyl functionalized single-walled carbon nanotubes (SWNTs) in a well-defined porous medium composed of clean quartz sand over a range of solution chemistries. Our results showthatincreasingsolutionionicstrengthoradditionofcalcium ions result in increased SWNT deposition (filtration). This observation

  18. Three dimensional solid-state supercapacitors from aligned single-walled carbon nanotube array templates

    E-print Network

    Three dimensional solid-state supercapacitors from aligned single-walled carbon nanotube array- thermore, modeling of supercapacitor architectures utilizing other dielectric layers suggests the ability, and supercapacitor technologies, are being adapted and optimized with nanostructured compo- nents [1­5]. The promise

  19. Compact-designed supercapacitors using free-standing single-walled carbon nanotube films

    E-print Network

    Wang, Wei Hua

    Compact-designed supercapacitors using free-standing single-walled carbon nanotube films Zhiqiang0ee00261e We reported the realization of assembling compact-designed supercapacitors using large) were achieved from the prepared SWCNT film-based compact-designed supercapacitors with small equivalent

  20. Production of vertical arrays of small diameter single-walled carbon nanotubes

    SciTech Connect

    Hauge, Robert H; Xu, Ya-Qiong

    2013-08-13

    A hot filament chemical vapor deposition method has been developed to grow at least one vertical single-walled carbon nanotube (SWNT). In general, various embodiments of the present invention disclose novel processes for growing and/or producing enhanced nanotube carpets with decreased diameters as compared to the prior art.

  1. 43 (2006-5) Thermal Conductivity of Vertically-Aligned Single-Walled Carbon Nanotubes by

    E-print Network

    Maruyama, Shigeo

    Vacuum chamber Constant AC Current Keithley 6221 Lock-in Amplifier Stanford Research Systems SR850 cos3t 43 (2006-5) Thermal Conductivity of Vertically-Aligned Single-Walled Carbon Nanotubes by 3omega thermal conductivity than diamonds. Thermal conductivity measurement of Vertically-Aligned Single

  2. Multicomponent ballistic transport in narrow single wall carbon nanotubes: Analytic model and molecular dynamics simulations

    E-print Network

    Adler, Joan

    and molecular dynamics simulations T. Mutat, J. Adler, and M. Sheintuch Citation: J. Chem. Phys. 134, 044908 single wall carbon nanotubes: Analytic model and molecular dynamics simulations T. Mutat,1 J. Adler,1,a predic- tions. Our model, based on extensive molecular dynamics simulations, proposes that ballistic

  3. Photoconductivity of single-wall carbon nanotubes under continuous-wave near-infrared illumination

    E-print Network

    Euler, William B.

    Photoconductivity of single-wall carbon nanotubes under continuous-wave near-infrared illumination studied under continuous-wave near-infrared illumination. The photocurrent exhibits a linear response with the light intensity and with bias voltage up to 5 V. The temporal photoresponse of on/off step illumination

  4. Gas separation by kinked single-walled carbon nanotubes: Molecular dynamics simulations

    Microsoft Academic Search

    Zhongqiang Zhang; Hongwu Zhang; Yonggang Zheng; Lei Wang; Jinbao Wang

    2008-01-01

    In this paper, a kink model for gas separation is presented. Transport of pure nitrogen, oxygen, and their mixture in single-walled carbon nanotubes (SWCNTs) with a kink formed by bending is studied using molecular dynamics simulations. The results show that a nanotube with a specified kink results in transport resistance to nitrogen, while allowing oxygen to pass even though the

  5. Single-wall carbon nanotubes phonon spectra: Symmetry-based calculations

    Microsoft Academic Search

    E. Dobardzic; I. Milosevic; B. Nikolic; T. Vukovic; M. Damnjanovic

    2003-01-01

    The phonon dispersions and atomic displacements for single-wall carbon nanotubes of arbitrary chirality are calculated. The full symmetry is implemented. The approach is based on the force constants of graphene, with the symmetry imposed modifications providing the twisting acoustic mode exactly. The functional dependence of frequencies of the Raman and infrared active modes on the wrapping angle and on the

  6. Impedimetric microbial biosensor based on single wall carbon nanotube modified microelectrodes for trichloroethylene detection

    Microsoft Academic Search

    M. Hnaien; S. Bourigua; F. Bessueille; J. Bausells; A. Errachid; F. Lagarde; N. Jaffrezic-Renault

    Contamination of soils and groundwaters with persistent organic pollutants is a matter of increasing concern. The most common organic pollutants are chlorinated hydrocarbons such as perchloroethylene and trichloroethylene (TCE). In this study, we developed a bacterial impedimetric biosensor for TCE detection, based on the immobilization of Pseudomonas putida F1 strain on gold microelectrodes functionalized with single wall carbon nanotubes covalently

  7. Polymer-assisted dispersion of single-wall carbon nanotubes for transparent conducting film fabrication

    Microsoft Academic Search

    Wei-Chao Chen; Hsiang-Ting Lien; Tzu-Wei Cheng; Kuei-Hsien Chen; Li-Chyong Chen

    2010-01-01

    Transparent electrodes, for instance ITO (indium tin oxide), are used in electronic devices such as touch screen, flat panel display, and solar cell technologies. It is costly to pattern and has a tendency to crack when used due to its brittle nature. The development of technologies to deliver low cost flexible alternatives using single walled carbon nanotubes (CNTs) are fledgling

  8. Adsorption Equilibrium and Kinetics of Microorganisms on Single-Wall Carbon Nanotubes

    Microsoft Academic Search

    Shuguang Deng; Venkata K. K. Upadhyayula; Geoffrey B. Smith; Martha C. Mitchell

    2008-01-01

    Adsorption equilibrium and kinetics of pure and mixed cultures of Escherichia coli and Staphylococcus aureus on single-walled carbon nanotubes (CNT) aggregates were studied in an effort to develop CNT-based biosensors for quick detection of these bacteria in water. Batch experiments were carried out to measure the adsorption kinetics and equilibrium of pure and mixed culture of E. coli and S.

  9. Effective Elastic Moduli Evaluation of Single Walled Carbon Nanotubes Using Flexural Vibrations

    Microsoft Academic Search

    J. V. Araújo dos Santos

    2011-01-01

    Two new methods for effective elastic moduli evaluation of single walled carbon nanotubes (SWCNT) are presented. These methods rely on the Euler-Bernoulli and the Timoshenko beam theories, the modification of finite elements based on these theories, and an optimization technique. The proposed modification of the standard Euler-Bernoulli and Timoshenko finite elements assumes that the SWCNT diameter is much larger than

  10. Correlating AFM Probe Morphology to Image Resolution for Single-Wall Carbon

    E-print Network

    Quake, Stephen R.

    Correlating AFM Probe Morphology to Image Resolution for Single-Wall Carbon Nanotube Tips Lawrence and to correlate probe morphology with AFM image resolution. Several methods for fabricating such probes were compatible with their routine use. Surprisingly, about one-third of the tips image with resolution better

  11. Aggregation Kinetics and Transport of Single-Walled CarbonNanotubes at Low Surfactant Concentrations

    EPA Science Inventory

    Little is known about how low levels of surfactants can affect the colloidal stability of single-walled carbon nanotubes (SWNTs) and how surfactant-wrapping of SWNTs can impact ecological exposures in aqueous systems. In this study, SWNTs were suspended in water with sodium ...

  12. Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated

    E-print Network

    Wang, Howard "Hao"

    Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated online: Abstract We report small angle neutron scattering (SANS) from dilute suspensions of purified University, Houghton, MI 49931, USA e NIST Center for Neutron Research, National Institute of Standards

  13. Separation of single-walled carbon nanotubes by 1-dodecanol-mediated size-exclusion chromatography.

    PubMed

    Flavel, Benjamin S; Kappes, Manfred M; Krupke, Ralph; Hennrich, Frank

    2013-04-23

    A simple, single-column, high-throughput fractionation procedure based on size-exclusion chromatography of aqueous sodium dodecyl sulfate suspensions of single-walled carbon nanotubes (SWCNTs) is presented. This procedure is found to yield monochiral or near monochiral SWCNT fractions of semiconducting SWCNTs. Unsorted and resulting monochiral suspensions are characterized using optical absorption and photoluminescence spectroscopy. PMID:23540203

  14. Separation of single-walled carbon nanotubes with a gel permeation chromatography system.

    PubMed

    Flavel, Benjamin S; Moore, Katherine E; Pfohl, Moritz; Kappes, Manfred M; Hennrich, Frank

    2014-02-25

    A gel permeation chromatography system is used to separate aqueous sodium dodecyl sulfate suspensions of single-walled carbon nanotubes (SWCNTs). This automated procedure requires no precentrifugation, is scalable, and is found to yield monochiral SWCNT fractions of semiconducting SWCNTs with a purity of 61-95%. Unsorted and resulting monochiral fractions are characterized using optical absorption and photoluminescence spectroscopy. PMID:24460395

  15. Engineered Carbohydrate-Binding Module (CBM) Protein-Suspended Single-Walled Carbon Nanotubes in Water

    SciTech Connect

    Xu,Q.; Song, Q.; Ai, X.; McDonald, T. J.; Long, H.; Ding. S. Y.; Himmel, M. E.; Rumbles, G.

    2009-01-01

    Engineered protein, CtCBM4, the first carbohydrate-binding module (CBM) protein is successfully used to debundle and suspend single-walled carbon nanotubes (SWNTs) effectively in aqueous solution, which opens up a new avenue in further functionalizing and potential selectively fractionating SWNTs for diverse biology- and/or energy-related applications.

  16. Single-walled Carbon Nanotubes Are a New Class of Ion Channel Blockers

    Microsoft Academic Search

    Ki Ho Park; Manish Chhowalla; Zafar Iqbal; Federico Sesti

    2003-01-01

    Here we identify a novel class of biological membrane ion channel blockers called single-walled carbon nano- tubes (SWNTs). SWNTs with diameter distributions peaked at 0.9 and 1.3 nm, C60 fullerenes, multi wall nanotubes (MWNTs), and hyperfullerenes (nano-\\

  17. A comparative study of single-walled carbon nanotube purification techniques using Raman spectroscopy

    Microsoft Academic Search

    Anthony W. Musumeci; Eric R. Waclawik; Ray L. Frost

    2008-01-01

    Raman spectroscopy has been utilized to show the increase of single-walled carbon nanotubes (SWCNTs) content in commercial grade samples synthesized by the chemical vapour deposition (CVD) technique with a minimization of impurities using both hydrochloric acid treatment and surfactant purification. Surfactant purification methods proved to be the most effective, resulting in a three-fold increase in the percentage of SWCNTs present

  18. Range Analysis on the Wave Propagation Properties of a Single Wall Carbon Nano Tube

    Microsoft Academic Search

    B. de Vivo; L. Egiziano; P. Lamberti; V. Tucci

    2008-01-01

    In this paper consistent bounds of the wave propagation properties concerning a Single Wall Carbon NanoTube (SWCNT) modeled as a Transmission Line are assessed. The monotonic inclusion property of the Interval Analysis leads to guaranteed limits for the given characteristics when the model parameters are uncertain. The common mode wave propagation in a SWCNT is considered and the variability range

  19. Single walled carbon nano-tube, ferroelectric liquid crystal composites: Excellent diffractive tool

    Microsoft Academic Search

    A. K. Srivastava; E. P. Pozhidaev; V. G. Chigrinov; R. Manohar

    2011-01-01

    We present a switchable grating based on chiral single walled carbon nano-tube (SWCNT) doped ferroelectric liquid crystals (FLCs). The presence of SWCNTs improves the diffraction profile of the pure FLC. The diffraction efficiency, i.e., the ratio of intensities of first order and zero order maxima is more than 100% for the higher concentration of SWCNTs in pure FLC. This phenomenon

  20. From isotope labeled CH3CN to N2 inside single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    From isotope labeled CH3CN to N2 inside single-walled carbon nanotubes Christian Kramberger to this peculiar place? We have used N15 and C13 isotope labeled acetonitrile during the synthesis of single- cation of the reaction pathway by isotope labeling has not yet been achieved. Moreover, it remains

  1. Mechanical Purification of Single-Walled Carbon Nanotube Bundles from Catalytic Particles

    Microsoft Academic Search

    Le Thien-Nga; Klara Hernadi; Edina Ljubovic; Slaven Garaj

    2002-01-01

    Ferromagnetic particles used for the catalytic growth of single-walled carbon nanotubes (SWNTs), which are embedded in a graphitic shell, represent a major obstacle in studying the bulk material. We have explored a purification method that is based on a mixing of the SWNT suspension with inorganic nanoparticles in an ultrasonic bath, which causes ferromagnetic particles to be mechanically removed from

  2. Effect of Chemical Oxidation on the Structure of Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Jin Zhang; Hongling Zou; Quan Qing; Yanlian Yang; Qingwen Li; Zhongfan Liu; Xinyong Guo; Zuliang Du

    2003-01-01

    In the present study, we report the systematic investigation of the effect of chemical oxidation on the structure of single-walled carbon nanotubes (SWNTs) by using different oxidants. The oxidation procedure was characterized by using infrared spectroscopy and transmission electron microscopy (TEM). The SWNTs were produced by chemical vapor deposition (CVD) and oxidized with three kinds of oxidants: (1) nitric acid

  3. Dynamic light scattering from acoustic modes in single-walled carbon nanotubes

    Microsoft Academic Search

    C. E. Bottani; A. Li Bassi; M. G. Beghi; A. Podestà; P. Milani; A. Zakhidov; R. Baughman; D. A. Walters; R. E. Smalley

    2003-01-01

    We report here the computation and measurement of inelastic light scattering from acoustic vibrational modes in single-walled carbon nanotubes (SWNT's). The measurement was made possible by the preparation of a sample of oriented SWNT's, partially aligned by means of a magnetic field. Long-wavelength confined longitudinal acoustic modes are described by a shell model. Their interaction with light is described by

  4. Dynamic light scattering from acoustic modes in single-walled carbon nanotubes

    Microsoft Academic Search

    C. E. Bottani; A. Li Bassi; M. G. Beghi; A. Zakhidov; R. Baughman; D. A. Walters; R. E. Smalley

    2003-01-01

    We report here the computation and measurement of inelastic light scattering from acoustic vibrational modes in single-walled carbon nanotubes ~SWNT's!. The measurement was made possible by the preparation of a sample of oriented SWNT's, partially aligned by means of a magnetic field. Long-wavelength confined longitudinal acoustic modes are described by a shell model. Their interaction with light is described by

  5. Theory of phonon thermal transport in single-walled carbon nanotubes and graphene

    Microsoft Academic Search

    Lucas Lindsay

    2010-01-01

    A theory is presented for describing the lattice thermal conductivities of graphene and single-walled carbon nanotubes. A phonon Boltzmann transport equation approach is employed to describe anharmonic phonon-phonon, crystal boundary, and isotopic impurity scattering. Full quantum mechanical phonon scattering is employed and an exact solution for the linearized Boltzmann transport equation is determined for each system without use of common

  6. Nitrogen-Incorporated Single-Walled Carbon Nanotubes for Devices Shigeo Maruyama1*

    E-print Network

    Maruyama, Shigeo

    Nitrogen-Incorporated Single-Walled Carbon Nanotubes for Devices Shigeo Maruyama1* ,TheerapolN)-mixed ethanol (EtOH) feedstock. Due to the presence of nitrogen (N) during synthesis, the SWNT mean diameter]. Surprisingly, the main nitrogen configuration was found to be encapsulated diatomic N2 molecules interior

  7. Alcohol Vapor Sensors Based on Single-Walled Carbon Nanotube Field

    E-print Network

    Kim, Philip

    Alcohol Vapor Sensors Based on Single-Walled Carbon Nanotube Field Effect Transistors Takao Someya-effect transistor (FET) geometry and investigated the device response to alcoholic vapors. We observe significant changes in FET drain current when the device is exposed to various kinds of alcoholic vapors

  8. Diffusive-Ballistic Heat Conduction along a Single-Walled Carbon Nanotube Shigeo Maruyama

    E-print Network

    Maruyama, Shigeo

    Diffusive-Ballistic Heat Conduction along a Single-Walled Carbon Nanotube Shigeo Maruyama *E-mail address: maruyama@photon.t.u-tokyo.ac.jp The diffusive-ballistic heat conduction of finite at room temperature. A gradual transition from nearly pure ballistic to diffusive-ballistic heat

  9. Molecular Dynamics of Diffusive-Ballistic Heat Conduction in Single-Walled Carbon Nanotubes

    E-print Network

    Maruyama, Shigeo

    Molecular Dynamics of Diffusive-Ballistic Heat Conduction in Single-Walled Carbon Nanotubes-3-1 Hongo, Bunkyo-ku Tokyo 113-8656, Japan Diffusive-ballistic heat conduction of finite-length single. A gradual transition from nearly pure ballistic to diffusive-ballistic heat conduction was identified from

  10. Ballistic switching and rectification in single wall carbon nanotube Y junctions

    E-print Network

    Srivastava, Deepak

    Ballistic switching and rectification in single wall carbon nanotube Y junctions Antonis N that such junctions, when symmetric, can support both ballistic rectification and/or the ballistic switching operating if the SWCN Y junction can operate in the ballistic rectification BR and/or the ballistic switching BS mode

  11. Polyglycerol-derived amphiphiles for single walled carbon nanotube suspension

    NASA Astrophysics Data System (ADS)

    Setaro, A.; Popeney, C. S.; Trappmann, B.; Datsyuk, V.; Haag, R.; Reich, S.

    2010-06-01

    Inspired by the commercially available SDS surfactant, a new polyglycerol-derived amphiphile has been synthesized for functionalizing carbon nanotubes. SDS' sulphate group was replaced by a polyglycerol dendron. The steric hindrance offered by the dendrons makes the compound much more efficient than SDS in isolating and stabilizing nanotubes in solution. Further amphiphiles have been synthesized by adding small aromatic moieties between head and tail groups. We show that this addition leads to selective interaction between surfactants and carbon nanotubes. Excitation photoluminescence and optical absorption spectroscopy analysis confirm the change in the distribution of nanotubes' chiralities in suspension, depending on the amphiphile.

  12. Go/No-Go Decision: Pure, Undoped Single Walled Carbon

    E-print Network

    , that may warrant additional R&D investment. Criteria used to make decision DOE reviewed the current status and results of carbon nanotube research activities and evaluated data against technical criteria, basing its Motors, Ford Motor Company, DaimlerChrysler, ConocoPhillips, Shell, Chevron, Argonne National Laboratory

  13. Gas Adsorption on Heterogeneous Single-Walled Carbon Nanotube Bundles

    Microsoft Academic Search

    Wei Shi; J. Karl Johnson

    2003-01-01

    Optimization of carbon nanotube bundles containing a distribution of nanotube diameters always gives structures with packing defects that form relatively large interstitial channels. Experimental data for CH4, Ar, and Xe adsorption are compared with simulations. Low coverage experimental isosteric heats are in excellent agreement with simulations of gases adsorbing into interstitial channels of defective nanotube bundles, whereas adsorption onto perfect

  14. Alternating patterns on single-walled carbon nanotubes

    Microsoft Academic Search

    Bing Li; Lingyu Li; Bingbing Wang; Christopher Y. Li

    2009-01-01

    Scientific and technological interest in one-dimensional nanomaterials, in particular carbon nanotubes, is a result of their fascinating properties and their ability to serve as templates for directed assembly. For applications in nanoelectronics it is necessary to create ordered arrays of nanotubes for large-scale integrated circuits, an area in which there has been significant progress, and to produce controllable patterns on

  15. Diffusion of H2 on Single Walled Carbon Nanotubes

    Microsoft Academic Search

    David Narehood; Jon Pearce; Peter Eklund; Paul Sokol; Ruep Lechner; Jörg Pieper; John Copely; Jeremy Cook

    2003-01-01

    From their discovery, carbon nanotubes have drawn interest for a variety of reasons. The attention has been focused on practical applications, such as hydrogen storage and isotope and spin selectivity, to novel effects resulting from the manifestation of reduced dimensionality due to the geometry of the tubes in the bundles. Of particular interest is the adsorption and storage of molecular

  16. Controlling the Crystalline Quality and the Purity of Single-walled Carbon Nanotubes Grown by Catalytic Chemical Vapor Deposition

    E-print Network

    Paris-Sud XI, Université de

    Controlling the Crystalline Quality and the Purity of Single-walled Carbon Nanotubes Grown observed that as-grown single-walled carbon nanotubes (SWCNTs) contain defects. Controlling the defect of the intensity ratio of the defect-induced D band to the graphenic G band [3,4]. The Raman D band is activated

  17. Polymer Brushes on Single-Walled Carbon Nanotubes by Atom Transfer Radical Polymerization of n-Butyl Methacrylate

    E-print Network

    Resasco, Daniel

    Polymer Brushes on Single-Walled Carbon Nanotubes by Atom Transfer Radical Polymerization of n-mail: wtford@okstate.edu Abstract: Polymer brushes with single-walled carbon nanotubes (SWNT) as backbones were the brush preparation to control growth of the brushes and to monitor the polymerization kinetics. Size

  18. Electronic transitions in single-walled carbon nanotubes: A resonance Raman study P. M. Rafailov,* H. Jantoljak, and C. Thomsen

    E-print Network

    Nabben, Reinhard

    nano- tubes. The sensitivity of the Raman cross section to the nano- tube band structure is enhancedElectronic transitions in single-walled carbon nanotubes: A resonance Raman study P. M. Rafailov Resonance excitation profiles of the high-frequency peaks in the Raman spectra of single-walled carbon

  19. Title: Decomposition of ethanol and dimethyl-ether during CVD synthesis of single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    of ethanol and dimethyl-ether during CVD synthesis of single-walled carbon nanotubes Author list: Bo Hou (single-walled carbon nanotubes) was investigated. Gas-phase thermal decomposition of ethanol and DME ethanol and DME decomposition, confirming expected reaction trends and primary byproducts. Peak

  20. Optical Spectroscopy of Single-Walled Carbon Nanotubes Under Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Searles, Thomas A., Jr.

    Single-walled carbon nanotubes (SWNTs) are one of the leading candidate materials to realize novel nanoscale photonic devices. In order to assess their performance characteristics as optoelectronic materials, it is crucial to examine their optical properties in highly non-equilibrium situations such as high magnetic fields, low temperatures, and under high photoexcitation. Therefore, we present our latest result on the magnetic susceptibility anisotropy of metallic carbon nanotubes due to the Aharonov-Bohm effect. Here, we performed magnetic linear dichroism on a metallic-enriched HiPco SWNT sample utilizing a 35 T Hybrid Magnet to measure absorption with light polarization both perpendicular and parallel to the magnetic field. By relating these values with the nematic order parameter for alignment, we found that the metallic carbon nanotubes do not follow a strict diameter dependence across the 7 chiralities present in our sample. In addition to the studying the absorption properties exhibited at high magnetic field, we performed temperature-dependent (300 K to 11 K) photoluminescence (PL) on HiPco SWNTs embedded in an iota-carrageenan matrix utilizing intense fs pulses from a wavelength-tunable optical parametric amplifier. We found that for each temperature the PL intensity saturates as a function of pump fluence and the saturation intensity increases from 300 K to a moderate temperature around 100-150 K. Within the framework of diffusion-limited exciton-exciton annihilation (EEA), we successfully estimated the density of 1D excitons in SWNTs as a function of temperature and chirality. These results coupled with our results of magnetic brightening, or an increase in PL intensity as a function of magnetic flux through each SWNT due to the Aharonov-Bohm effect, yield great promise that in the presence of a high magnetic field the density of excitons can be further increased.

  1. Nanocatalyst structure as a template to define chirality of nascent single-walled carbon nanotubes.

    PubMed

    Gómez-Gualdrón, Diego A; Zhao, Jin; Balbuena, Perla B

    2011-01-01

    Chirality is a crucial factor in a single-walled carbon nanotube (SWCNT) because it determines its optical and electronic properties. A chiral angle spanning from 0° to 30° results from twisting of the graphene sheet conforming the nanotube wall and is equivalently expressed by chiral indexes (n,m). However, lack of chirality control during SWCNT synthesis is an obstacle for a widespread use of these materials. Here we use first-principles density functional theory (DFT) and classical molecular dynamics (MD) simulations to propose and illustrate basic concepts supporting that the nanocatalyst structure may act as a template to control the chirality during nanotube synthesis. DFT optimizations of metal cluster (Co and Cu)?cap systems for caps of various chiralities are used to show that an inverse template effect from the nascent carbon nanostructure over the catalyst may exist in floating catalysts; such effect determines a negligible chirality control. Classical MD simulations are used to investigate the influence of a strongly interacting substrate on the structure of a metal nanocatalyst and illustrate how such interaction may help preserve catalyst crystallinity. Finally, DFT optimizations of carbon structures on stepped (211) and (321) cobalt surfaces are used to demonstrate the template effect imparted by the nanocatalyst surface on the growing carbon structure at early stages of nucleation. It is found that depending on the step structure and type of building block (short chains, single atoms, or hexagonal rings), thermodynamics favor armchair or zigzag termination, which provides guidelines for a chirality controlled process based on tuning the catalyst structure and the type of precursor gas. PMID:21219018

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    This Letter 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-layered 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 ? electrons from the carbon nanotubes. The single-walled carbon nanotube-folic acid conjugate presented herein is believed to lead the way to new potential applications as carbon nanotube-based drug delivery systems.

  3. Commercial single-walled carbon nanotubes effects in fibrinolysis of human umbilical vein endothelial cells.

    PubMed

    Rodríguez-Yáñez, Yury; Bahena-Uribe, Daniel; Chávez-Munguía, Bibiana; López-Marure, Rebeca; González-Monroy, Stuart; Cisneros, Bulmaro; Albores, Arnulfo

    2015-08-01

    Recent studies have demonstrated that carbon nanotubes (CNTs) induce platelet aggregation, endothelial dysfunction and vascular thrombosis. However, there is little information on the effects of CNTs on fibrinolysis. We investigated the role of pristine-commercial single-walled carbon nanotubes (SWCNTs) with <3% Co content in fibrinolysis and their contribution to the induction of pro-thrombotic processes in human vein endothelial cells (HUVEC). SWCNTs alone produced concentration-dependent oxidation, as measured by a dithiothreitol oxidation assay. Internalized SWCNTs were located in HUVEC treated with 25?g/ml using transmission electron microscopy, whereas treatment with 50?g/ml compromised cell viability, and oxidative stress increased significantly at 5?g/ml. The study showed that in HUVEC treated with 25?g SWCNT/ml, fibrinolysis-related gene expression and protein levels had increased by 3-12h after treatment (serpine-1: 13-fold; PLAT: 11-fold and PLAU: 2-fold), but only the PAI-1 protein was increased (1.5-fold), whereas tissue and urokinase plasminogen activator proteins (tPA and uPA, respectively) tended to decrease. In summary, pristine SWCNTs treatment resulted in evident HUVEC damage caused by cell fiber contact, internalization, and oxidative stress due to contaminant metals. The generation of endothelial dysfunction, as shown by the altered expression of genes and proteins involved in fibrinolysis, suggest that SWCNTs display pro-thrombotic effects. PMID:25790727

  4. Optical Transmittance and Sheet Resistance of B-doped Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoming; Romero, Hugo; Gutierrez, Humberto; Adu, Kofi; Eklund, Peter

    2007-03-01

    Thin films of carbon nanotubes have been reported to be a replacement for transparent conducting films of Indium-Tin-Oxide (ITO). Nanotube films can be deposited on flexible plastic and are predicted as a new technology for touch screens, solar cells, etc. Here we report results on thin films of boron-doped single-walled carbon nanotubes (B-SWNTs) obtained from CarboLex, Inc. Boron-doping is expected to raise the conductance of semiconducting nanotubes while not lowering significantly that of the metallic tubes. At room temperature, we have measured the four-probe sheet resistance and the optical transmission in the NIR-UV range to evaluate the performance of these chemically enhanced SWNT films. The structure in the optical spectrum is essentially the same as in pristine tubes, although the positions of optical absorption bands are slightly upshifted (˜ 50 meV) relative to pristine SWNTs. The B-loading, microstructure, bonding and defects of the B-doped SWNTs were characterized, respectively, by inelastic neutron scattering, transmission electron microscopy, electron energy loss spectroscopy and Raman spectroscopy. Our preliminary results on B-SWNTs show that the visible optical transmittance is higher and the sheet resistance is much lower than that of similar thickness SWNT films.

  5. Pulsed Laser CVD Investigations of Single-Wall Carbon Nanotube Growth Dynamics

    SciTech Connect

    Geohegan, David B [ORNL] [ORNL; Liu, Zuqin [ORNL] [ORNL; Styers-Barnett, David J [ORNL] [ORNL; Puretzky, Alexander A [ORNL] [ORNL; Rouleau, Christopher M [ORNL] [ORNL; Yuan, Dongning [Duke University] [Duke University; Ivanov, Ilia N [ORNL] [ORNL; Xiao, Kai [ORNL] [ORNL; Liu, Jie [Duke University] [Duke University

    2008-01-01

    The nucleation and rapid growth of single-wall carbon nanotubes (SWNTs) were explored by pulsed-laser assisted chemical vapor deposition (PLA-CVD). A special high-power, Nd:YAG laser system with tunable pulse width (> 0.5 ms) was implemented to rapidly heat (>30,000 C/s) metal catalyst-covered substrates to different growth temperatures for very brief (sub-second) and controlled time periods as measured by in situ optical pyrometry. Utilizing growth directly on transmission electron microscopy grids, exclusively SWNTs were found to grow under rapid heating conditions, with a minimum nucleation time of >0.10 s. By measuring the length of nanotubes grown by single laser pulses, extremely fast growth rates (up to 100 microns/s) were found to result from the rapid heating and cooling induced by the laser treatment. Subsequent laser pulses were found not to incrementally continue the growth of these nanotubes, but instead activate previously inactive catalyst nanoparticles to grow new nanotubes. Localized growth of nanotubes with variable density was demonstrated through this process, and was applied for the reliable direct-write synthesis of SWNTs onto pre-patterned, catalyst-covered metal electrodes for the synthesis of SWNT field-effect transistors.

  6. All-Organic Actuator Fabricated with Single Wall Carbon Nanotube Electrodes

    NASA Technical Reports Server (NTRS)

    Lowther, Sharon E.; Harrison, Joycelyn S.; Kang, Jinho; Park, Cheol; Park, Chan Eon

    2008-01-01

    Compliant electrodes to replace conventional metal electrodes have been required for many actuators to relieve the constraint on the electroactive layer. Many conducting polymers have been proposed for the alternative electrodes, but they still have a problem of poor thermal stability. This article reports a novel all-organic actuator with single wall carbon nanotube (SWCNT) films as the alternative electrode. The SWCNT film was obtained by filtering a SWCNT solution through an anodized alumina membrane. The conductivity of the SWCNT film was about 280 S/cm. The performance of the SWCNT film electrode was characterized by measuring the dielectric properties of NASA Langley Research Center - Electroactive Polymer (LaRC-EAP) sandwiched by the SWCNT electrodes over a broad range of temperature (from 25 C to 280 C) and frequency (from 1 KHz to 1 MHz). The all-organic actuator with the SWCNT electrodes showed a larger electric field-induced strain than that with metal electrodes, under identical measurement conditions.

  7. Hydrogen Adsorption in Purified Single Walled Carbon Nanotubes (SWNTs)

    NASA Astrophysics Data System (ADS)

    Pradhan, B. K.; Harutyunyan, A. R.; Sumanasekera, G. U.; Eklund, P. C.; Tokune, T.; Fujiwara, Y.

    2001-03-01

    We report results of H2 adsorption in SWNTs (produced by the arc-discharge method and purified), at 77K and moderate pressure (<20 atm.) We characterized the materials by HRTEM, Raman Spectroscopy and N2 adsorption isotherms, in order to determine the morphology and texture of sample for gas storage. HRTEM and temperature programed oxidation (TPO) results showed that the purified samples were clean from amorphous carbon, multishell carbons (MSC) and catalyst particles. In certain cases, HRTEM shows the tubes are in tact, while in other cases, it is observed that openings in the wall are created, and/or the tubes are cut into short tubelets. N2 adsorption studies allow us to obtain the specific surface area (SSA) and approximate pore size distribution. After purification, the SSA increases from ~280 m^2/g to 470 m^2/g. Measurements of H2 adsorption were performed in order to evaluate the adsorption capacity of the nanotubes at 77K and below 20 bar. We found up to 6 wt% H2 adsorbed in our purified material. (Work supported by Honda Motors R&D Co.)

  8. Highly efficient exfoliation of individual single-walled carbon nanotubes by biocompatible phenoxylated dextran

    NASA Astrophysics Data System (ADS)

    Kwon, Taeyun; Lee, Gyudo; Choi, Hyerim; Strano, Michael S.; Kim, Woo-Jae

    2013-07-01

    Highly efficient exfoliation of individual single-walled carbon nanotubes (SWNTs) was successfully demonstrated by utilizing biocompatible phenoxylated dextran, a kind of polysaccharide, as a SWNT dispersion agent. Phenoxylated dextran shows greater ability in producing individual SWNTs from raw materials than any other dispersing agent, including anionic surfactants and another polysaccharide. Furthermore, with this novel polymer, SWNT bundles or impurities present in raw materials are removed under much milder processing conditions compared to those of ultra-centrifugation procedures. There exists an optimal composition of phenoxy groups (~13.6 wt%) that leads to the production of high-quality SWNT suspensions, as confirmed by UV-vis-nIR absorption and nIR fluorescence spectroscopy. Furthermore, phenoxylated dextran strongly adsorbs onto SWNTs, enabling SWNT fluorescence even in solid-state films in which metallic SWNTs co-exist. By bypassing ultra-centrifugation, this low-energy dispersion scheme can potentially be scaled up to industrial production levels.Highly efficient exfoliation of individual single-walled carbon nanotubes (SWNTs) was successfully demonstrated by utilizing biocompatible phenoxylated dextran, a kind of polysaccharide, as a SWNT dispersion agent. Phenoxylated dextran shows greater ability in producing individual SWNTs from raw materials than any other dispersing agent, including anionic surfactants and another polysaccharide. Furthermore, with this novel polymer, SWNT bundles or impurities present in raw materials are removed under much milder processing conditions compared to those of ultra-centrifugation procedures. There exists an optimal composition of phenoxy groups (~13.6 wt%) that leads to the production of high-quality SWNT suspensions, as confirmed by UV-vis-nIR absorption and nIR fluorescence spectroscopy. Furthermore, phenoxylated dextran strongly adsorbs onto SWNTs, enabling SWNT fluorescence even in solid-state films in which metallic SWNTs co-exist. By bypassing ultra-centrifugation, this low-energy dispersion scheme can potentially be scaled up to industrial production levels. Electronic supplementary information (ESI) available: Additional spectra (UV-vis-nIR absorption) demonstrating the effect of centrifugation speed, dextran chain length (molecular weight), and dextran concentration on the quality of SWNT suspensions in SDS or P-dextran, the SWNT re-suspension procedure, additional spectra (fluorescence) of fluorescent freeze-dried P-dextran-SWNT suspensions. See DOI: 10.1039/c3nr01352a

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

    Microsoft Academic Search

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

    2008-01-01

    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%.

  10. Surface growth of single-walled carbon nanotubes from ruthenium nanoparticles

    Microsoft Academic Search

    Yong Qian; Chunyan Wang; Guangyuan Ren; Bin Huang

    2010-01-01

    In this paper, we report that ruthenium is an active and efficient catalyst for growth of single-walled carbon nanotubes (SWNTs) by a chemical vapor deposition (CVD) process for the first time. High density random and horizontally superlong well-oriented SWNTs on substrate can be fabricated via CH4 or EtOH as carbon source under suitable conditions. Scanning and transition electron microscopy investigations,

  11. Covalent functionalization of single walled carbon nanotubes with peptide nucleic acid: Nanocomponents for molecular level electronics

    Microsoft Academic Search

    Krishna V. Singh; Rajeev R. Pandey; Xu Wang; Roger Lake; Cengiz S. Ozkan; Kang Wang; Mihrimah Ozkan

    2006-01-01

    Imparting molecular recognition to carbon nanotubes (CNTs) by conjugating them with bio-molecules has been an area of great interest as the resulting highly functionalized CNT-bioconjugates find their applications in various fields like molecular level electronics, pharmaceuticals, drug delivery, novel materials and many others. In this work we demonstrate the synthesis of functionally engineered single walled carbon nanotubes (SWNTs)-peptide nucleic acid

  12. Toward Understanding of Hydrogen Storage in Single-Walled Carbon Nanotubes by Investigations of Chemisorption Mechanism

    Microsoft Academic Search

    T. C. Dinadayalane; Jerzy Leszczynski

    2010-01-01

    \\u000a We provide an overview of experimental and theoretical studies on hydrogen storage in single-walled carbon nanotubes (SWNTs)\\u000a via chemisorption mechanism. The atomic hydrogens that are generated by dissociation of H2 molecules bind with carbon atoms of nanotubes, leading to strong C–H bonds in the chemisorption process. Recent experimental\\u000a study indicates that 5.1?±?1.2 wt% hydrogen storage could be achieved by hydrogenation

  13. Large-scale production of single-walled carbon nanotubes by the electric-arc technique

    Microsoft Academic Search

    C. Journet; W. K. Maser; P. Bernier; A. Loiseau; M. Lamy de La Chapelle; S. Lefrant; P. Deniard; R. Lee; J. E. Fischer

    1997-01-01

    Single-walled carbon nanotubes (SWNTs) offer the prospect of both new fundamental science and useful (nano)technological applications. High yields (70-90%) of SWNTs close-packed in bundles can be produced by laser ablation of carbon targets. The electric-arc technique used to generate fullerenes and multi-walled nanotubes is cheaper and easier to implement, but previously has led to only low yields of SWNTs,. Here

  14. Oxidative stress and inflammatory response in dermal toxicity of single-walled carbon nanotubes

    Microsoft Academic Search

    A. R. Murray; E. Kisin; S. S. Leonard; S. H. Young; C. Kommineni; V. E. Kagan; V. Castranova; A. A. Shvedova

    2009-01-01

    Single-walled carbon nanotubes (SWCNT) represent a novel material with unique electronic and mechanical properties. The extremely small size (?1nm diameter) renders their chemical and physical properties unique. A variety of different techniques are available for the production of SWCNT; however, the most common is via the disproportionation of gaseous carbon molecules supported on catalytic iron particles (high-pressure CO conversion, HiPCO).

  15. Influence of single-walled carbon nanotubes on microbial availability of phenanthrene in sediment

    Microsoft Academic Search

    X. Y. Cui; F. Jia; Y. X. Chen; J. Gan

    Increasing production and use of single-walled carbon nanotubes (SWCNT) will inevitably lead to release of these nanoparticles\\u000a to aquatic ecosystems. Similar to black carbon (BC) particles, SWCNT have a high affinity for hydrophobic organic contaminants\\u000a (HOCs) and therefore the presence of SWCNT in sediment may lead to altered bioavailability of HOCs. We compared SWCNT with\\u000a biochar and charcoal on their

  16. Structure and Properties of poly (para phynelyne benzobisoxazole) (PBO) \\/single wall carbon nano tube composite fibers

    Microsoft Academic Search

    Satish Kumar; Xiefei Zhang; Arup R. Bhattacharyya; Byung G. Min; T. D. Dang; F. E. Arnold; Richard A. Vaia; S. Ramesh; P. A. Willis; R. H. Hauge; R. E. Smalley

    2002-01-01

    The liquid crystalline compositions are prepared by the in-situ polycondensation of diamines and diacid monomers in the presence of single wall carbon nano tubes (SWNT). Processing of the new compositions into fibers provide hybrid materials with improved mechanical properties. The in-situ polymerizations were carried out in polyphosphoric acid (PPA). Carbon nano tubes as high as 10 wt.polymer weight have been

  17. Polypropylene \\/Single Wall Carbon Nano Tube Composites Crystallization Behavior and Fiber Processing Studies

    Microsoft Academic Search

    T. V. Sreekumar; Arup R. Bhattacharyya; Atul Kumar; Huina Guo; Satish Kumar; Lars Ericson; Richard E. Smalley

    2002-01-01

    Single Wall Carbon Nanotubes (SWNTs) produced using high-pressure carbon monoxide (HiPCO) process have been purified using the previously developed method to remove the catalytic impurities. Polypropylene (PP) with 1 wtmelt blended in a Haake mixer at 240oC. The resulting PP\\/SWNT blend was optically inhomogeneous. The polymer melt was filtered through a 300, 250, 120 and 80 mesh stainless steel filter

  18. Fabrication of single-walled carbon nanotubes (SWNTs) field-effect transistor (FET) biosensor

    Microsoft Academic Search

    Danna Yang; Lin Wang; Qiang Zhao; Sai Li

    2010-01-01

    Due to their unique electrical, geometrical, mechanical and biocompatible properties, single-walled carbon nanotubes (SWNTs) are attractive materials for the construction of nanoscale field-effect transistor (FET) biosensors. At present, biosensors based on CNTFET are required in various applications, including clinical diagnostics, environmental testing, food analysis, and bioterrorism detection technologies. In this paper, we report the fabrication of carbon nanotube field-effect transistors

  19. Molecular beam-controlled nucleation and growth of vertically aligned single-wall carbon nanotube arrays.

    PubMed

    Eres, Gyula; Kinkhabwala, Anika A; Cui, Hongtao; Geohegan, David B; Puretzky, Alexandar A; Lowndes, Douglas H

    2005-09-01

    The main obstacle to widespread application of single-wall carbon nanotubes is the lack of reproducible synthesis methods of pure material. We describe a new growth method for single-wall carbon nanotubes that uses molecular beams of precursor gases that impinge on a heated substrate coated with a catalyst thin film. In this growth environment the gas and the substrate temperature are decoupled and carbon nanotube growth occurs by surface reactions without contribution from homogeneous gas-phase reactions. This controlled reaction environment revealed that SWCNT growth is a complex multicomponent reaction in which not just C, but also H, and O play a critical role. These experiments identified acetylene as a prolific direct building block for carbon network formation that is an order of magnitude more efficient than other small-molecule precursors. The molecular jet experiments show that with optimal catalyst particle size the incidence rate of acetylene molecules plays a critical role in the formation of single-wall carbon nanotubes and dense vertically aligned arrays in which they are the dominant component. The threshold for vertically aligned growth, the growth rate, the diameter, and the number of walls of the carbon nanotubes are systematically correlated with the acetylene incidence rate and the substrate temperature. PMID:16853123

  20. Seed crystals and catalyzed epitaxy of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Yuhuang

    This thesis demonstrates the continued growth of single-walled carbon nanotubes (SWNTs) from seeded SWNTs in a way analogous to epitaxy or cloning; that is, the SWNTs grow as a seamless extension to the existing seeded SWNTs and have the same diameter and chirality as those of the SWNT seeds. The experiments were carried out in three key steps, including: (1) preparing a macroscopic array of open-ended SWNTs; (2) reductively docking transition metals as a catalyst to the nanometer-sized open ends; and then (3) heating the whole up to 700--850°C in the presence of a carbon feedstock such as ethanol or ethylene. The resulting SWNT ropes inherit the diameters and chirality from the seeded SWNTs, as indicated by the closely matched frequencies of Raman radial breathing modes before and after the growth. As a control, only sparse nanotubes grew from closed-ended SWNTs, ruling out spontaneous nucleation as a dominating mechanism in our experiments. This experiment proved for the first time the growth of SWNTs can be separated from the nucleation step. The ability to separate the typically inefficient nucleation step from the growth of SWNTs and to restart the growth opens the possibility of amplifying SWNTs with only the desired (n, m). The success in the continued growth was enabled with the creation of macroscopic arrays of open-ended SWNTs from a neat SWNT fiber. A variety of techniques including cryo-microtoming and surface etching chemistry have been developed to produce a macroscopic (˜1200mum2), aligned, and clean---largely free of amorphous carbon, oxides, and metal residuals---SWNT substrate with open-ended SWNTs aligned along the fiber axis. Alternatively, the fiber was milled perpendicular to the fiber axis with a gallium focused ion beam to produce a planar, free-standing, ultra-thin, "bed-of-nails" SWNT membrane---a single layer of parallel SWNTs densely packed and aligned along the normal of the membrane.

  1. Cumulative and Continuous Laser Vaporization Synthesis of Single Wall Carbon Nanotubes and Nanohorns

    SciTech Connect

    Puretzky, Alexander A [ORNL; Styers-Barnett, David J [ORNL; Rouleau, Christopher M [ORNL; Hu, Hui [ORNL; Zhao, Bin [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL

    2008-01-01

    The conditions for the scaled synthesis of single wall carbon nanotubes (SWNTs) and single wall carbon nanohorns (SWNHs) by laser vaporization at high temperatures are investigated and compared using in situ diagnostics. An industrial Nd:YAG laser (600 W, 1-500 Hz repetition rate) with tunable pulse widths (0.5-50 ms) is utilized to explore conditions for high yield production. High-speed videography (50,000 frames/s) of the laser plume and pyrometry of the target surface are correlated with ex situ high resolution TEM analysis of the products for pure carbon targets and carbon/catalyst targets to understand the effects of the processing conditions on the resulting nanostructures. Carbon is shown to self-assemble into single-wall nanohorn structures at rates of ~ 1 nm/ms which is comparable to the catalystassisted SWNT growth rates. Two regimes of laser ablation, cumulative ablation by multiple pulses, and continuous ablation by individual pulses, were explored. Cumulative ablation with spatially overlapping 0.5 ms pulses is favorable for the high yield and production rate of SWNTs at ~ 6 g/h while continuous ablation by individual long laser pulses (~ 20 ms) at high temperatures results in the highest yield of SWNHs without graphitic impurities at ~ 10 g/h. Adjustment of the laser pulse width is shown to control SWNH morphology.

  2. Anchoring Pd nanoclusters onto pristine and functionalized single-wall carbon nanotubes: A combined DFT and experimental study

    NASA Astrophysics Data System (ADS)

    Prasomsri, Teerawit; Shi, Dachuan; Resasco, Daniel E.

    2010-09-01

    The dispersion of Pd nanoclusters on single-wall carbon nanotubes (SWCNT) can be enhanced by creating defects on the nanotube walls, which lead to a stronger metal-support interaction. The ONIOM (DFT:MM) calculations show that the binding energy of Pd is significantly enhanced when the SWCNT surface is oxygen-functionalized, compared to the case of the pristine SWCNT surface. The electronic interaction of Pd atoms with oxygen at the defect sites results in a stronger bonding. These calculations are consistent with experimental measurements. Microscopy images clearly show that the functionalized SWCNT surface is much more effective than the pristine surface in anchoring Pd nanoclusters.

  3. Review of Laser Ablation Process for Single Wall Carbon Nanotube Production

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram

    2003-01-01

    Different types of lasers are now routinely used to prepare single wall carbon nanotubes (SWCNTs). The original method developed by researchers at Rice University utilized a "double pulse laser oven" process. A graphite target containing about 1 atomic percent of metal catalysts is ablated inside a 1473K oven using laser pulses (10 ns pulse width) in slow flowing argon. Two YAG lasers with a green pulse (532 nm) followed by an IR pulse (1064 nm) with a 50 ns delay are used for ablation. This set up produced single wall carbon nanotube material with about 70% purity having a diameter distribution peaked around 1.4 nm. The impurities consist of fullerenes, metal catalyst clusters (10 to 100 nm diameter) and amorphous carbon. The rate of production with the initial set up was about 60 mg per hour with 10Hz laser systems. Several researchers have used variations of the lasers to improve the rate, consistency and study effects of different process parameters on the quality and quantity of SWCNTs. These variations include one to three YAG laser systems (Green, Green and IR), different pulse widths (nano to microseconds as well as continuous) and different laser wavelengths (Alexandrite, CO, CO2, free electron lasers in the near to far infrared). It is noted that yield from the single laser (Green or IR) systems is only a fraction of the two laser systems. The yield seemed to scale up with the repetition rate of the laser systems (10 to 60 Hz) and depended on the beam uniformity and quality of the laser pulses. The shift to longer wavelength lasers (free electron, CO and CO2) did not improve the quality, but increased the rate of production because these lasers are either continuous (CW) or high repetition rate pulses (kHz to MHz). The average power and the peak power of the lasers seem to influence the yields. Very high peak powers (MegaWatts per square centimeter) are noted to increase ablation of bigger particles with reduced yields of SWCNTs. Increased average powers seem to help the conversion of the carbon from target into vapor phase to improve formation of nanotubes. The use of CW far infrared lasers reduced the need for the oven, at the expense of controlled ablation. Some of these variations are tried with different combinations and concentrations of metal catalysts (Nickel with Cobalt, Iron, Palladium and Platinum) different buffer gases (e.g. Helium); with different oven temperatures (Room temperature to 1473K); under different flow conditions (1 to 1000 kPa) and even different porosities of the graphite targets. It is to be noted that the original Cobalt and Nickel combination worked best, possibly because of improved carbonization with stable crystalline phases. The mean diameter and yield seemed to increase with increasing oven temperatures. Thermal conductivity of the buffer gas and flow conditions dictate the quality as well as quantity of the SWCNTs. Faster flows, lower pressures and heavier gases seem to increase the yields. This review will attempt to cover all these variations and their relative merits. Possible growth mechanisms under these different conditions will also be discussed.

  4. Selective Synthesis of Subnanometer Diameter Semiconducting Single-Walled Carbon Nanotubes

    SciTech Connect

    Loebick, C.; Podila, R; Reppert, J; Chudow, J; Ren, F; Haller, G; Rao, A; Pfefferle, L

    2010-01-01

    Subnanometer single-walled carbon nanotubes (sub-nm SWNTs) were synthesized at different temperatures (600, 700, and 800 C) using CoMn bimetallic catalysts supported on MCM-41 silica templates. The state of the catalyst was investigated using X-ray absorption, and the (n,m) indices of the sub-nm SWNTs were determined from Raman spectroscopy and photoluminescence measurements. We find that the size of the metallic particles that seed the growth of sub-nm SWNTs (diameter {approx}0.5-1.0 nm) is highly sensitive to the reaction temperature. Low reaction temperature (600 C) favors the growth of semiconducting tubes whose diameters range from 0.5 to 0.7 nm. These results were also confirmed by electrical transport measurements. Interestingly, dominant intermediate frequency modes on the same intensity scale as the Raman breathing modes were observed. An unusual 'S-like' dispersion of the G-band was present in the Raman spectra of sub-nm SWNTs with diameters <0.7 nm.

  5. Optical Properties of Empty and Water-Filled Single-Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Simpson, J. R.; Fagan, J. A.; Huh, J. Y.; Hight Walker, A. R.; Blackburn, J. L.; Larsen, B. A.; Holt, J.

    2011-03-01

    The necessity for separation of single-wall carbon nanotube (SWCNT) populations to achieve desired properties presents a major technical barrier for the development of SWCNT-based applications, and has been the focus of significant academic and industrial research. Recent advances include the separation of SWCNT populations by diameter through buoyancy differences. Here we report on the optical spectroscopic properties of large diameter SWCNTs synthesized by laser ablation and electric arc methods and then separated by centrifugation to produced isolated bands of empty and water-filled nanotubes. This separation is consistent across multiple nanotube populations dispersed from different source material. Optical absorption, near-infrared fluorescence, and Raman spectroscopic measurements of the resulting empty and filled fractions reveal that water filling leads to systematic changes in the optical properties. Specifically, the peak locations in absorbance and fluorescence display red-shifts with the presence of water in the nanotube cavity and a hardening of the Raman radial breathing modes. The presence of water in the SWCNT interior is found to facilitate the subsequent separation into sub-populations of metallic and semiconducting SWCNTs.

  6. Raman spectroscopy of charge transfer interactions between single wall carbon nanotubes and [FeFe] hydrogenase.

    PubMed

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

    2008-10-28

    We report a Raman spectroscopy study of charge transfer interactions in complexes formed by single-walled carbon nanotubes (SWNTs) and [FeFe] hydrogenase I (CaHydI) from Clostridium acetobutylicum. The choice of Raman excitation wavelength and sample preparation conditions allows differences to be observed for complexes involving metallic (m) and semiconducting (s) species. Adsorbed CaHydI can reversibly inject electronic charge into the LUMOs of s-SWNTs, while charge can be injected and removed from m-SWNTs at lower potentials just above the Fermi energy. Time-dependent enzymatic assays demonstrated that the reduced and oxidized forms of CaHydI are deactivated by oxygen, but at rates that varied by an order of magnitude. The time evolution of the oxidative decay of the CaHydI activity reveals different time constants when complexed with m-SWNTs and s-SWNTs. The correlation of enzymatic assays with time-dependent Raman spectroscopy provides a novel method by which the charge transfer interactions may be investigated in the various SWNT-CaHydI complexes. Surprisingly, an oxidized form of CaHydI is apparently more resistant to oxygen deactivation when complexed to m-SWNTs rather than s-SWNTs. PMID:19082027

  7. Block copolymer assisted dispersion of single walled carbon nanotubes and integration into a trifunctional epoxy.

    PubMed

    González-Domínguez, J M; Castell, P; Ansón, A; Maser, W K; Benito, A M; Martinez, M T

    2009-10-01

    Arc discharge single walled carbon nanotubes were processed by acid treatment, dispersion in a Pluronic F68 block copolymer aqueous solution and centrifugation. The as-prepared material was characterized by transmission electron microscopy, X-ray diffraction and Raman spectroscopy, showing an important degree of debundling as well as the removal of most of the graphitic and metallic impurities from pristine nanotubes. The nanotube-Pluronic material was integrated into an advanced trifunctional epoxy resin, triglycidyl p-aminophenol, using 4,4'-diaminodiphenylsulfone as the curing agent. The material was incorporated into the epoxy system (0.1, 0.25, 0.50, 1.0, 2.0 wt%) throughout hot magnetic stirring and ultrasonication. Curing kinetics was studied using differential scanning calorimetry, applying the Vyazovkin's isoconversional method. In the early stages of curing, the kinetic study revealed a decrease in the activation energy for samples containing Pluronic, suggesting that Pluronic induced an improvement in the mobility of reactants. The cured composites were characterized by Raman spectroscopy, thermogravimetric analysis and scanning electron microscopy. Micrographs revealed successful integration and homogeneous distribution of the nanotube-Pluronic material in the epoxy matrix, while direct integration of bare nanotubes originated aggregates and inhomogeneity. PMID:19908501

  8. Structure-Dependent Thermal Defunctionalization of Single-Walled Carbon Nanotubes.

    PubMed

    Ghosh, Saunab; Wei, Fang; Bachilo, Sergei M; Hauge, Robert H; Billups, W E; Weisman, R Bruce

    2015-06-23

    Covalent sidewall functionalization of single-walled carbon nanotubes (SWCNTs) is an important tool for tailoring their properties for research purposes and applications. In this study, SWCNT samples were first functionalized by reductive alkylation using metallic lithium and 1-iodododecane in liquid ammonia. Samples of the alkyl-functionalized SWCNTs were then pyrolyzed under an inert atmosphere at selected temperatures between 100 and 500 °C to remove the addends. The extent of defunctionalization was assessed using a combination of thermogravimetric analysis, Raman measurements of the D, G, and radial breathing bands, absorption spectroscopy of the first- and second-order van Hove peaks, and near-IR fluorescence spectroscopy of (n,m)-specific emission bands. These measurements all indicate a substantial dependence of defunctionalization rate on nanotube diameter, with larger diameter nanotubes showing more facile loss of addends. The effective activation energy for defunctionalization is estimated to be a factor of ?1.44 greater for 0.76 nm diameter nanotubes as compared to those with 1.24 nm diameter. The experimental findings also reveal the quantitative variation with functionalization density of the Raman D/G intensity ratio and the relative near-IR fluorescence intensity. Pyrolyzed samples show spectroscopic properties that are equivalent to those of SWCNTs prior to functionalization. The strong structure dependence of the defunctionalization rate suggests an approach for scalable diameter sorting of mixed SWCNT samples. PMID:26027688

  9. Evidence for Luttinger-Liquid Behavior in Crossed Metallic Single-Wall Nanotubes

    Microsoft Academic Search

    B. Gao; A. Komnik; R. Egger; D. C. Glattli; A. Bachtold

    2004-01-01

    Transport measurements through crossed metallic single-wall nanotubes are presented. We observe a zero-bias anomaly in one tube which is suppressed by a current flowing through the other nanotube. These results are compared with a Luttinger-liquid model which takes into account electrostatic tube-tube coupling together with crossing-induced backscattering processes. Explicit solution of a simplified model is able to describe qualitatively the

  10. Side-Wall Functionalization of Single-Walled Carbon Nanotubes with 4-Hydroxymethylaniline Followed by Polymerization of -Caprolactone

    E-print Network

    Resasco, Daniel

    Side-Wall Functionalization of Single-Walled Carbon Nanotubes with 4-Hydroxymethylaniline Followed spectroscopy confirm the side-wall functionalization and show that it can be reversed by thermolysis. The OH attempted. 1. Introduction Because of their exceptional electronic and mechan- ical properties, single-walled

  11. Frequency-and electric-field-dependent conductivity of single-walled carbon nanotube networks of varying density

    E-print Network

    Gruner, George

    Frequency- and electric-field-dependent conductivity of single-walled carbon nanotube networks October 2007; published 20 February 2008 We present measurements of the frequency- and electric-field-dependent conductivity of single-walled car- bon nanotube SWCNT networks of various densities. The ac conductivity

  12. Electron transport properties of a single-walled carbon nanotube in the presence of hydrogen cyanide: first-principles analysis.

    PubMed

    Srivastava, Anurag; Sharma, Vikash; Kaur, Kamalpreet; Khan, Md Shahzad; Ahuja, Rajeev; Rao, V K

    2015-07-01

    First-principles analysis based on density functional theory was performed to compute the electronic and transport properties of a single-walled carbon nanotube in the presence of hydrogen cyanide. A chiral (4,1) carbon nanotube was found to become less metallic as the number of hydrogen cyanide molecules nearby increased. When there were a sufficient number of hydrogen cyanide molecules close to the nanotube, it became semiconducting. This metallic to semiconducting transformation of the nanotube was verified by analyzing its conductance and current as a function of the number of molecules of hydrogen cyanide present. The conductivity of the carbon nanotube was very high when no hydrogen cyanide molecules were present, but decreased considerably when even just a single hydrogen cyanide molecule approached the surface of the nanotube. Graphical Abstract SWCNT based HCN sensor and its Current vs Bias voltage characteristics. PMID:26072123

  13. Diameter selective electron transfer from encapsulated ferrocenes to single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Iizumi, Yoko; Suzuki, Hironori; Tange, Masayoshi; Okazaki, Toshiya

    2014-10-01

    The diameter selective photoluminescence quenching of single-walled carbon nanotubes (SWCNTs) is observed upon ferrocene encapsulation, which can be attributed to electron transfer from the encapsulated ferrocenes to the SWCNTs. Interestingly, the dependence of the electron transfer process on the nanotube diameter is governed by the molecular orientation of the ferrocenes in the SWCNT rather than the reduction potentials of the SWCNT.The diameter selective photoluminescence quenching of single-walled carbon nanotubes (SWCNTs) is observed upon ferrocene encapsulation, which can be attributed to electron transfer from the encapsulated ferrocenes to the SWCNTs. Interestingly, the dependence of the electron transfer process on the nanotube diameter is governed by the molecular orientation of the ferrocenes in the SWCNT rather than the reduction potentials of the SWCNT. Electronic supplementary information (ESI) available: Calculated binding energies of FeCp2@SWCNTs and additional spectroscopic characterization are described in ESI. See DOI: 10.1039/c4nr04398g

  14. Paper transistor made with regenerated cellulose and covalently bonded single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yun, Sungryul; Ko, Hyun-U.; Kim, Joo-Hyung; Lim, Byung-Wook; Kim, Jaehwan

    2011-04-01

    We report a flexible paper transistor made with regenerated cellulose and covalently bonded single-walled carbon nanotubes. Functionalized single-walled carbon nanotubes (SWNTs) are reacted with N, N-Carbonyldiimidazoles to obtain SWNTs-imidazolides. SWNTs can be covalently bonded to cellulose by acylation of cellulose with SWNTsimidazolides. Using the product, SWNTs covalently bonded cellulose (S/C) composite paper is fabricated and it is mechanically stretched to align SWNTs with cellulose chains. Finally, inter-digital comb shaped source and drain electrode and bottom gate electrode is formed on the paper via lift-off process. Aligned SWNTs can contribute to establishing stable electron channel paths in the cellulose layer. The alignment of SWNTs can be key a role in improving characteristics of the paper transistor. The characteristics of the paper transistor are evaluated by measuring mobility, onoff ratio depending on the alignment of SWNTs in S/C composite paper transistors.

  15. Molecular dynamics simulation studies of structural and mechanical properties of single-walled carbon nanotubes.

    PubMed

    Mashapa, Matete G; Ray, Suprakas Sinha

    2010-12-01

    Structural and mechanical properties of armchair, zig-zag and chiral single-walled carbon nanotubes are computed by employing Molecular Dynamics simulation technique using Discover code with Compass force field via Materials Studio program developed by the Accelrys. Consistent with the literature, we find that the armchair SWCNT is energetically favored over zig-zag and chiral nanotubes. Predicted structural parameters agree well with experimental observations. Observed radial distribution functions show that the single-walled carbon nanotubes remain crystalline after exposing them to 300 K. The predicted Young's and the Shear moduli were in reasonable agreement with other reports. Our predictions show that the Young's modulus of the tubes increases as the diameter of the tube decreases. PMID:21121299

  16. Effect of residual catalyst on the vibrational modes of single-walled carbon nanotubes

    SciTech Connect

    McNeil, L.E.; Park, H.; Lu, J.P.; Peters, M.J. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255 (United States); Department of Physics and Astronomy, Appalachian State University, Boone, North Carolina 28608 (United States)

    2004-11-01

    Raman scattering measurements of single-walled carbon nanotubes prepared by laser ablation with Ni/Co catalyst show that samples that have not been purified have a graphitic mode frequency that is 8 cm{sup -1} lower than that of samples from which most of the catalyst has been removed. The shift is attributed to charge transfer from the catalyst particles to the nanotubes. The charge transfer from the residual catalyst also affects the temperature dependence of the radial breathing mode.

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

    Microsoft Academic Search

    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\\u000a carbon nanotubes (SWCNTs) is obtained. The effects of tube chirality and tube diameter on the RBM frequency are investigated\\u000a and good agreement between the present results and existing data is found. The present analytical formula indicates that the\\u000a chirality and

  18. Temperature dependence of radial breathing mode Raman frequency of single-walled carbon nanotubes

    Microsoft Academic Search

    Nachiket R. Raravikar; Pawel Keblinski; Apparao M. Rao; Mildred S. Dresselhaus; Linda S. Schadler; Pulickel M. Ajayan

    2002-01-01

    Recent high-temperature studies of Raman-active modes in single-walled carbon nanotube (SWNT) bundles report a softening of the radial and tangential band frequencies with increasing sample temperature. A few speculations have been proposed in the past to explain the origin of these frequency downshifts. In the present study, based on experimental data and the results of molecular dynamics simulations, we estimate

  19. Functionalization of single-walled carbon nanotubes using isotropic plasma treatment: Resonant Raman spectroscopy study

    SciTech Connect

    Utegulov, Zhandos N.; Mast, David B.; He Peng; Shi Donglu; Gilland, Robert F. [Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (United States); Department of Chemical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio 45221 (United States); Department of Electrical and Computer Engineering and Computer Science, University of Cincinnati, Cincinnati, Ohio 45221 (United States)

    2005-05-15

    Functionalization of single-walled carbon nanotubes (SWNTs) by isotropic plasma treatment was studied using resonant Raman spectroscopy. It was shown that plasma-induced functionalization results in the uniaxial isotropic constriction of the nanotubes but preserves their overall structural integrity. It was demonstrated that NH{sub 3}{center_dot}H{sub 2}O and hexamethyldisiloxan plasmas yield various types of conductivity for semiconducting SWNTs.

  20. Molecular Ordering of Organic Molten Salts Triggered by Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Takanori Fukushima; Atsuko Kosaka; Yoji Ishimura; Takashi Yamamoto; Toshikazu Takigawa; Noriyuki Ishii; Takuzo Aida

    2003-01-01

    When mixed with imidazolium ion-based room-temperature ionic liquid, pristine single-walled carbon nanotubes formed gels after being ground. The heavily entangled nanotube bundles were found to untangle within the gel to form much finer bundles. Phase transition and rheological properties suggest that the gels are formed by physical cross-linking of the nanotube bundles, mediated by local molecular ordering of the ionic

  1. The Effects of Single-Wall Carbon Nanotubes on the Shear Piezoelectricity of Biopolymers

    NASA Technical Reports Server (NTRS)

    Lovell, Conrad; Fitz-Gerald, James M.; Harrison, Joycelyn S.; Park, Cheol

    2008-01-01

    Shear piezoelectricity was investigated in a series of composites consisting of increased loadings of single-wall carbon nanotubes (SWCNTs) in poly (gamma-benzyl-L-glutamate), or PBLG. The effects of the SWCNTs on this material property in PBLG will be discussed. Their influence on the morphology of the polymer (degree of orientation and crystallinity), and electrical and dielectric properties of the composite will be reported

  2. Effect of nanotube functionalization on the properties of single-walled carbon nanotube\\/polyurethane composites

    Microsoft Academic Search

    Fabian Buffa; Gustavo A. Abraham; Brian P. Grady; Daniel Resasco

    2007-01-01

    A commercially available aliphatic thermoplastic polyurethane formulated with a methylene bis(cyclohexyl) diisocyanate hard segment and a poly(tetramethylene oxide) soft segment and chain-extended with 1,4-butanediol was dissolved in dimethyl- formamide and mixed with dispersed single-walled carbon nanotubes. The properties of composites made with unfunctionalized nanotubes were compared with the proper- ties of composites made with nanotubes functionalized to contain hydroxyl groups.

  3. Chemical vapor deposition of methane for single-walled carbon nanotubes

    Microsoft Academic Search

    Jing Kong; Alan M. Cassell; Hongjie Dai

    1998-01-01

    We report the synthesis of high-quality single-walled carbon nanotubes (SWNT) by chemical vapor deposition (CVD) of methane at 1000°C on supported Fe2O3 catalysts. The type of catalyst support is found to control the formation of individual or bundled SWNTs. Catalysts supported on crystalline alumina nanoparticles produce abundant individual SWNTs and small bundles. Catalysts supported by amorphous silica particles produce only

  4. Electrochemical impedance spectroscopy at single-walled carbon nanotube network ultramicroelectrodes

    Microsoft Academic Search

    Ioana Dumitrescu; Patrick R. Unwin; Julie V. Macpherson

    2009-01-01

    Electrochemical impedance spectroscopy (EIS), coupled with chemical vapour deposition (CVD) grown single-walled carbon nanotube (SWNT) network disk-shaped ultramicroelectrodes (UMEs), gives stable, very well-defined and highly reproducible EIS responses for electrolysis of a simple outer sphere redox couple (FcTMA+\\/2+). The resulting EIS data can be fitted accurately using a simple electrical circuit model, enabling information on double-layer capacitance, diffusion coefficient of

  5. Electrospun single-walled carbon nanotube\\/polyvinyl alcohol composite nanofibers: structure property relationships

    Microsoft Academic Search

    Minoo Naebe; Tong Lin; Mark P. Staiger; Liming Dai; Xungai Wang

    2008-01-01

    Polyvinyl alcohol (PVA) nanofibers and single-walled carbon nanotube (SWNT)\\/PVA composite nanofibers have been produced by electrospinning. An apparent increase in the PVA crystallinity with a concomitant change in its main crystalline phase and a reduction in the crystalline domain size were observed in the SWNT\\/PVA composite nanofibers, indicating the occurrence of a SWNT-induced nucleation crystallization of the PVA phase. Both

  6. Nanoparticle-assisted microwave absorption by single-wall carbon nanotubes

    Microsoft Academic Search

    A. Wadhawan; D. Garrett; J. M. Perez

    2003-01-01

    We report the effects of microwave irradiation on both unpurified and purified iron-catalyzed high-pressure disproportionation (HiPco)-grown single-walled carbon nanotubes (SWNTs) in ultrahigh vacuum. Under microwave irradiation, we observe that unpurified HiPco SWNTs quickly reach temperatures of approximately 1850 °C. As a result, H2, H2O, CO, CO2, and CH4 gases are observed, and the Fe catalyst nanoparticles melt and coalesce into

  7. Electronic properties of optically transparent single-walled carbon nanotube films

    Microsoft Academic Search

    David Samuel Hecht

    2007-01-01

    Single-walled carbon nanotube (SWNT) films of various densities were fabricated and the optoelectronic properties studied. Several deposition techniques were developed, including filtration, stamping, self-assembly, spraying, and slot coating. Film conductivity was studied as a function of several parameters. At sub-monolayer densities, close to the percolation threshold, the film conductance follows the expected 2D percolation behavior. For films just thicker than

  8. A theoretical study of functionalized single-wall carbon nanotubes: ONIOM calculations

    Microsoft Academic Search

    Tapas Kar; Brahim Akdim; Xiaofeng Duan; Ruth Pachter

    2004-01-01

    In this study, we employed ONIOM calculations to study functionalized single-wall carbon nanotubes (SWCNTs), for assessing an appropriate level of theory for accurate binding energies calculations, particularly by considering ozone adsorption and arylation. Although ONIOM models reproduced the binding energies and geometries in relatively good agreement with the density functional theory B3LYP\\/6-31G* values in some cases, the `same level different

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

    Microsoft Academic Search

    Vadym M. Adamyan; Oleksii A. Smyrnov; Sergey V. Tishchenko

    2008-01-01

    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

  10. Gas adsorption in the inside and outside of single-walled carbon nanotubes

    Microsoft Academic Search

    Akihiko Fujiwara; Kenji Ishii; Hiroyoshi Suematsu; Hiromichi Kataura; Yutaka Maniwa; Shinzou Suzuki; Yohji Achiba

    2001-01-01

    Adsorption properties of nitrogen and oxygen gases in single-walled carbon nanotube (SWNT) bundles were investigated by the isotherm and X-ray diffraction (XRD) studies. In the as-grown (AG) nanotubes with close-ended caps, both the gases are adsorbed only in the interstitial channels between triangular packed nanotubes. In the heat-treated (HT) nanotubes with open ends, the gases are adsorbed first in the

  11. Single-walled carbon nanotubes-polymer modified graphite electrodes for DNA hybridization

    Microsoft Academic Search

    Mihrican Muti; Filiz Kuralay; Arzum Erdem

    Single-walled carbon nanotubes (SWCNT)-poly(vinylferrocenium) (PVF+) modified pencil graphite electrodes (PGEs) were developed in our study for the electrochemical monitoring of a sequence-selective DNA hybridization event. Firstly, SWCNT-PVF+ modified PGE, PVF+ modified PGE and unmodified PGE were characterized using scanning electron microscopy (SEM). The electrochemical behavior of these electrodes was then investigated using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry

  12. Phosphatidylserine Targets Single-Walled Carbon Nanotubes to Professional Phagocytes In Vitro and In Vivo

    Microsoft Academic Search

    Nagarjun V. Konduru; Yulia Y. Tyurina; Weihong Feng; Liana V. Basova; Natalia A. Belikova; Hülya Bayir; Katherine Clark; Marc Rubin; Donna Stolz; Helen Vallhov; Annika Scheynius; Erika Witasp; Bengt Fadeel; Padmakar D. Kichambare; Alexander Star; Elena R. Kisin; Ashley R. Murray; Anna A. Shvedova; Valerian E. Kagan; Arto Urtti

    2009-01-01

    Broad applications of single-walled carbon nanotubes (SWCNT) dictate the necessity to better understand their health effects. Poor recognition of non-functionalized SWCNT by phagocytes is prohibitive towards controlling their biological action. We report that SWCNT coating with a phospholipid “eat-me” signal, phosphatidylserine (PS), makes them recognizable in vitro by different phagocytic cells - murine RAW264.7 macrophages, primary monocyte-derived human macrophages, dendritic

  13. Adsorption of the insensitive explosive TATB on single-walled carbon nanotubes

    Microsoft Academic Search

    Luoxin Wang; Changhai Yi; Hantao Zou; Houlei Gan; Jie Xu; Weilin Xu

    2011-01-01

    The non-covalent adsorption of the insensitive explosive TATB (1,3,5-triamino-2,4,6-trinitrobenzene) on the sidewalls of single-walled carbon nanotubes (CNTs) has been calculated using an ONIOM approach. It was found that TATB deformed remarkably when attached non-covalently on the surface of CNTs, especially on the inner wall of the nanotubes. The diameter of the nanotube determined the degree of distortion of the inner-adsorbed

  14. Measurement of contact resistance in CdSe-single-walled carbon nanotube hybrids.

    PubMed

    Shin, Minkyung; Ahn, Juwon; Park, Taehee; Yi, Whikun

    2014-08-01

    The CdSe-single-walled carbon nanotube (SWNT) hybrids are synthesized for measuring contact resistance between CdSe quantum dots and SWNTs in two hybrid samples, i.e., spray-deposited CdSe on SWNTs, and pyrene-self assembled CdSe on SWNTs. Currents are measured through indium-tin oxide (ITO), CdSe-SWNT hybrids and the tip of conductive AFM (c-AFM) with and without light at 532 and 655 nm. PMID:25936076

  15. Enhanced photocurrent in single-walled carbon nanotubes by exciton interactions

    NASA Astrophysics Data System (ADS)

    Konabe, Satoru; Okada, Susumu

    2013-03-01

    We theoretically investigate the photocurrent generation efficiency of single-walled carbon nanotubes by considering the interplay between exciton many-body effects. We calculate the photocurrent by solving rate equations that incorporate the influences of the two competing processes, multiple exciton generation (MEG) and the Auger recombination (AR) processes. We find that MEG substantially enhances photocurrent generation in spite of the competing AR process. Our calculation shows that the generation efficiency is up to 150% higher than that without MEG.

  16. Diameter selective electron transfer from encapsulated ferrocenes to single-walled carbon nanotubes.

    PubMed

    Iizumi, Yoko; Suzuki, Hironori; Tange, Masayoshi; Okazaki, Toshiya

    2014-11-21

    The diameter selective photoluminescence quenching of single-walled carbon nanotubes (SWCNTs) is observed upon ferrocene encapsulation, which can be attributed to electron transfer from the encapsulated ferrocenes to the SWCNTs. Interestingly, the dependence of the electron transfer process on the nanotube diameter is governed by the molecular orientation of the ferrocenes in the SWCNT rather than the reduction potentials of the SWCNT. PMID:25310793

  17. The effects of different defects on the elastic constants of single-walled carbon nanotubes

    Microsoft Academic Search

    Lijie Chen; Qi Zhao; Zunqun Gong; Hongtao Zhang

    2010-01-01

    In this paper, based on the continuum mechanics method, we adopt the three-dimensional finite element (FE) models to study the effects of different atom vacancy defects on the elastic constants of armchair and zigzag single-walled carbon nanotubes (SWCNTs). Also, the variations of the elastic constants with the nanotube diameter and length are investigated. The diameters of SWCNTs vary from 0.5

  18. Single-walled carbon nanotubes produced by plasma-enhanced chemical vapor deposition

    Microsoft Academic Search

    Toshiaki Kato; Goo-Hwan Jeong; Takamichi Hirata; Rikizo Hatakeyama; Kazuyuki Tohji; Kenichi Motomiya

    2003-01-01

    Single-walled carbon nanotubes (SWNTs) are produced for the first time using plasma-enhanced chemical vapor deposition method. In this method, not only SWNTs in the form of thin bundles but also individually grown SWNTs are produced at a quite low-synthesis temperature (550 °C). According to analyses by field emission gun transmission electron microscopy and Raman scattering spectroscopy, it is conjectured that

  19. Elucidating Nucleation and Growth Behavior of Single-Walled Carbon Nanotubes obtained via Catalyzed Synthesis 

    E-print Network

    Burgos Beltran, Juan Carlos

    2014-11-07

    and support. vi NOMENCLATURE SWCNT Single-walled carbon nanotube MD Molecular dynamics RMD Reactive molecular dynamics AIMD Ab initio molecular dynamics BOMD Born-Oppenheimer molecular dynamics DFT Density functional theory CVD Chemical vapor deposition.... Among the different techniques employed to produce SWCNTs, we can distinguish arc discharge9, laser ablation10, and chemical vapor deposition (CVD)11 as the three most common methods. In this study, we will focus on the analyses of the catalytic CVD...

  20. Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma

    PubMed Central

    Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

    2012-01-01

    Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising application for molecular sensors, field effect transistor and super thin and flexible electronic devices1-4. Anodic arc discharge supported by the erosion of the anode material is one of the most practical and efficient methods, which can provide specific non-equilibrium processes and a high influx of carbon material to the developing structures at relatively higher temperature, and consequently the as-synthesized products have few structural defects and better crystallinity. To further improve the controllability and flexibility of the synthesis of carbon nanostructures in arc discharge, magnetic fields can be applied during the synthesis process according to the strong magnetic responses of arc plasmas. It was demonstrated that the magnetically-enhanced arc discharge can increase the average length of SWCNT 5, narrow the diameter distribution of metallic catalyst particles and carbon nanotubes 6, and change the ratio of metallic and semiconducting carbon nanotubes 7, as well as lead to graphene synthesis 8. Furthermore, it is worthwhile to remark that when we introduce a non-uniform magnetic field with the component normal to the current in arc, the Lorentz force along the J×B direction can generate the plasmas jet and make effective delivery of carbon ion particles and heat flux to samples. As a result, large-scale graphene flakes and high-purity single-walled carbon nanotubes were simultaneously generated by such new magnetically-enhanced anodic arc method. Arc imaging, scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy were employed to analyze the characterization of carbon nanostructures. These findings indicate a wide spectrum of opportunities to manipulate with the properties of nanostructures produced in plasmas by means of controlling the arc conditions. PMID:22330847

  1. Simultaneous synthesis of single-walled carbon nanotubes and graphene in a magnetically-enhanced arc plasma.

    PubMed

    Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

    2012-01-01

    Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising application for molecular sensors, field effect transistor and super thin and flexible electronic devices(1-4). Anodic arc discharge supported by the erosion of the anode material is one of the most practical and efficient methods, which can provide specific non-equilibrium processes and a high influx of carbon material to the developing structures at relatively higher temperature, and consequently the as-synthesized products have few structural defects and better crystallinity. To further improve the controllability and flexibility of the synthesis of carbon nanostructures in arc discharge, magnetic fields can be applied during the synthesis process according to the strong magnetic responses of arc plasmas. It was demonstrated that the magnetically-enhanced arc discharge can increase the average length of SWCNT (5), narrow the diameter distribution of metallic catalyst particles and carbon nanotubes (6), and change the ratio of metallic and semiconducting carbon nanotubes (7), as well as lead to graphene synthesis (8). Furthermore, it is worthwhile to remark that when we introduce a non-uniform magnetic field with the component normal to the current in arc, the Lorentz force along the J×B direction can generate the plasmas jet and make effective delivery of carbon ion particles and heat flux to samples. As a result, large-scale graphene flakes and high-purity single-walled carbon nanotubes were simultaneously generated by such new magnetically-enhanced anodic arc method. Arc imaging, scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy were employed to analyze the characterization of carbon nanostructures. These findings indicate a wide spectrum of opportunities to manipulate with the properties of nanostructures produced in plasmas by means of controlling the arc conditions. PMID:22330847

  2. Method for separating single-wall carbon nanotubes and compositions thereof

    NASA Technical Reports Server (NTRS)

    Smalley, Richard E. (Inventor); Hauge, Robert H. (Inventor); Kittrell, W. Carter (Inventor); Sivarajan, Ramesh (Inventor); Strano, Michael S. (Inventor); Bachilo, Sergei M. (Inventor); Weisman, R. Bruce (Inventor)

    2006-01-01

    The invention relates to a process for sorting and separating a mixture of (n, m) type single-wall carbon nanotubes according to (n, m) type. A mixture of (n, m) type single-wall carbon nanotubes is suspended such that the single-wall carbon nanotubes are individually dispersed. The nanotube suspension can be done in a surfactant-water solution and the surfactant surrounding the nanotubes keeps the nanotube isolated and from aggregating with other nanotubes. The nanotube suspension is acidified to protonate a fraction of the nanotubes. An electric field is applied and the protonated nanotubes migrate in the electric fields at different rates dependent on their (n, m) type. Fractions of nanotubes are collected at different fractionation times. The process of protonation, applying an electric field, and fractionation is repeated at increasingly higher pH to separated the (n, m) nanotube mixture into individual (n, m) nanotube fractions. The separation enables new electronic devices requiring selected (n, m) nanotube types.

  3. Nano-Plasticity of Single-Wall Carbon Nanotubes Under Uniaxial Compression

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Menon, Madu; Cho, Kyeongjae

    1999-01-01

    Nano-plasticity of thin single-wall carbon nanotubes under uniaxial compression is investigated through generalized tight-binding molecular dynamics (GTBMD) and ab-initio electronic structure methods. A novel mechanism of nano-plasticity of carbon nanotubes under uniaxial compression is observed in which bonding geometry collapses from a graphitic (sp(sup 2)) to a localized diamond like (sp(sup 3)) reconstruction. The computed critical stress (approximately equals 153 G Pa) and the shape of the resulting plastic deformation is in good agreement with recent experimental observation of collapse and fracture of compressed carbon nanotubes in polymer composites.

  4. Sonication mediated covalent cross-linking of DNA to single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Dolash, Bridget D.; Lahiji, Roya R.; Zemlyanov, Dmitry Y.; Drachev, Vladimir P.; Reifenberger, Ronald; Bergstrom, Donald E.

    2013-02-01

    Sonication with nucleic acids has become a standard method for obtaining aqueous dispersions of carbon nanotubes. On the basis of theoretical studies and scanning probe microscopy (SPM) imaging a widely accepted model for DNA association with SWCNT is one in which the DNA binds through non-covalent ?-stacking and hydrophobic interactions. Following the standard procedures established by others to prepare DNA associated single-wall carbon nanotubes (SWCNT), we have determined that sonication generates radical intermediates then form covalent anchors between the DNA and SWCNT. In light of this finding, results from studies on DNA associated carbon nanotubes, need to be more carefully interpreted.

  5. Surface chemical functionalized single-walled carbon nanotube with anchored phenol structures: Physical and chemical characterization

    NASA Astrophysics Data System (ADS)

    Bae, Jong Hyun; Shanmugharaj, A. M.; Noh, Woo Hyun; Choi, Won Seok; Ryu, Sung Hun

    2007-02-01

    Surface functionalization of single-walled carbon nanotube was carried out by introducing ylides groups containing anchored phenol structures. The functionalized nanotube is characterized using elemental analysis, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, Raman spectroscopy and zeta potential measurements. Elemental and FT-IR analysis reveal the successful functionalization of azomethine ylides. Raman spectroscopic studies corroborates that the surface functionalization does not affect the basic crystal domain size of the nanotubes. Functionalized carbon nanotubes exhibit higher zeta potential values showing its higher dispersant ability in water and acetone solvent in comparison to pure carbon nanotube.

  6. Computational study on structural modification of single-walled carbon nanotubes by electron irradiation

    SciTech Connect

    Yasuda, Masaaki; Mimura, Ryosuke; Kawata, Hiroaki; Hirai, Yoshihiko [Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan)

    2011-03-01

    Molecular dynamics simulation is carried out to investigate structural modifications of single-walled carbon nanotubes by electron irradiation. Electron irradiation effects are introduced by the Monte Carlo method using an elastic collision cross section. We demonstrate the applicability of the method to the analysis of structural modifications with electron beam such as cutting, shrinking, and bending. The behavior of the carbon atoms in the nanotube during the structural modification is revealed. The simulation results also show the variation of the mechanical properties of carbon nanotubes by electron irradiation.

  7. Practical considerations for the demonstration of a single walled carbon nanotube actuator

    NASA Astrophysics Data System (ADS)

    Minett, A. I.; Fraysse, J.; Gu, G.; Roth, S.

    2001-11-01

    The conversion of electrical energy into mechanical energy using macro scale sheets of carbon nanotubes (bucky paper) has been shown to exhibit comparable or superior performance to that of human skeletal muscle. This level of performance was not as high as predicted by theoretical calculations. Therefore, working from a bottom-up principle, it is of paramount interest to not only demonstrate a single carbon nanotube actuator, but to gain a better understanding of the process of nanotube actuation. In this paper, practical considerations and approaches to the preparation of suspended single walled carbon nanotube (SWNT) structures and the measurement of actuation force are discussed.

  8. Reduced Carbon Solubility in Fe Nanoclusters and Implications for the Growth of Single-Walled Carbon Nanotubes

    E-print Network

    Curtarolo, Stefano

    Reduced Carbon Solubility in Fe Nanoclusters and Implications for the Growth of Single of the minimum temperature necessary for the growth. We address this phenomenon in terms of solubility of C in Fe of single-walled carbon nanotubes, corresponding to unaffected, reduced, and no solubility of C

  9. AC field-induced polymer electroluminescence with single wall carbon nanotubes.

    PubMed

    Sung, Jinwoo; Choi, Yeon Sik; Kang, Seok Ju; Cho, Sung Hwan; Lee, Tae-Woo; Park, Cheolmin

    2011-03-01

    We developed a high-performance field-induced polymer electroluminescence (FPEL) device consisting of four stacked layers: a top metal electrode/thin solution-processed nanocomposite film of single wall carbon nanotubes (SWNTs) and a fluorescent polymer/insulator/transparent bottom electrode working under an alternating current (AC) electric field. A small amount of SWNTs that were highly dispersed in the fluorescent polymer matrix by a conjugate block copolymer dispersant significantly enhanced EL, and we were able to realize an SWNT-FPEL device with a light emission of approximately 350 cd/m(2) at an applied voltage of ±25 V and an AC frequency of 300 kHz. The brightness of the SWNT-FPEL device is much greater than those of other AC-based organic or even inorganic ELs that generally require at least a few hundred volts. Light is emitted from our SWNT-FPEL device because of the sequential injection of field-induced holes and then electron carriers through ambipolar carbon nanotubes under an AC field, followed by exciton formation in the conjugated organic layer. Field-induced bipolar charge injection provides great material design freedom for our devices; the energy level does not have to be aligned between the electrode and the emission layer, and the balance of the carrier injected and transported can be altered in contrast to that in conventional organic light-emitting diodes, leading to an extremely cost-effective and unified device architecture that is applicable to all red-green-blue fluorescent polymers. PMID:21280640

  10. Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes.

    PubMed

    Blancon, Jean-Christophe; Paillet, Matthieu; Tran, Huy Nam; Than, Xuan Tinh; Guebrou, Samuel Aberra; Ayari, Anthony; San Miguel, Alfonso; Phan, Ngoc-Minh; Zahab, Ahmed-Azmi; Sauvajol, Jean-Louis; Del Fatti, Natalia; Vallée, Fabrice

    2013-01-01

    The optical properties of single-wall carbon nanotubes are very promising for developing novel opto-electronic components and sensors with applications in many fields. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial. Here we determine using spatial modulation spectroscopy, over a broad optical spectral range, the spectrum and amplitude of the absorption cross-section of individual semiconducting single-wall carbon nanotubes. These quantitative measurements permit determination of the oscillator strength of the different excitonic resonances and their dependencies on the excitonic transition and type of semiconducting nanotube. A non-resonant background is also identified and its cross-section comparable to the ideal graphene optical absorbance. Furthermore, investigation of the same single-wall nanotube either free standing or lying on a substrate shows large broadening of the excitonic resonances with increase of oscillator strength, as well as stark weakening of polarization-dependent antenna effects, due to nanotube-substrate interaction. PMID:24071824

  11. Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Blancon, Jean-Christophe; Paillet, Matthieu; Tran, Huy Nam; Than, Xuan Tinh; Guebrou, Samuel Aberra; Ayari, Anthony; Miguel, Alfonso San; Phan, Ngoc-Minh; Zahab, Ahmed-Azmi; Sauvajol, Jean-Louis; Fatti, Natalia Del; Vallée, Fabrice

    2013-09-01

    The optical properties of single-wall carbon nanotubes are very promising for developing novel opto-electronic components and sensors with applications in many fields. Despite numerous studies performed using photoluminescence or Raman and Rayleigh scattering, knowledge of their optical response is still partial. Here we determine using spatial modulation spectroscopy, over a broad optical spectral range, the spectrum and amplitude of the absorption cross-section of individual semiconducting single-wall carbon nanotubes. These quantitative measurements permit determination of the oscillator strength of the different excitonic resonances and their dependencies on the excitonic transition and type of semiconducting nanotube. A non-resonant background is also identified and its cross-section comparable to the ideal graphene optical absorbance. Furthermore, investigation of the same single-wall nanotube either free standing or lying on a substrate shows large broadening of the excitonic resonances with increase of oscillator strength, as well as stark weakening of polarization-dependent antenna effects, due to nanotube-substrate interaction.

  12. 1D lead iodide crystals encapsulated within single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kuganathan, Navaratnarajah; Green, Jennifer C.

    The structure and binding energies of lead iodide crystals encapsulated within single-walled carbon noanotubes are studied using density functional theory. Calculations were performed on the simulated PbI2 structure encapsulated within a (12,12) single-walled nanotube, to investigate the perturbations on the PbI2 crystal and tube structure and electronic structure, and to estimate the binding energy. The calculation confirms the structure as a single chain of PbI6 octahedra bound by two chains of PbI5 square pyramids. The calculated binding energy shows that the encapsulation is noncovalent. Minimal charge transfer is observed between nanotube and the PbI2 crystals. The band gap is shown to increase from the bulk to the encapsulated structure.

  13. Preparation and characterisation of vertically aligned single-walled carbon nanotube arrays on porous silicon

    NASA Astrophysics Data System (ADS)

    Shearer, Cameron J.; Constantopoulos, Kristina T.; Voelcker, Nicolas H.; Shapter, Joseph G.; Ellis, Amanda V.

    2008-12-01

    Vertically aligning carbon nanotubes (VACNTs) onto 2D porous materials is advantageous for many conceivable electronic applications but also for investigating the unique water transport properties of CNTs and the molecular separation of molecules during fluid transport through their inner shell. Here we report a wet chemical technique to produce vertically-aligned single walled CNT arrays on porous silicon (pSi). The nanotubes were first acid treated to produce carboxylic acid functionalities on the single-walled CNT. The carboxy-functional nanotubes were then covalently immobilised on a pSi surface that had been either ozone treated or silanated with aminopropyl triethoxysilane (APTES). The VACNT surfaces were analysed with atomic force microscopy (AFM), confocal Raman spectral imaging and Fourier transform infrared (FTIR) spectroscopy. Dense arrays of VACNTs were observed with the obtained CNT orientation and surface coverage depending upon attachment method and attachment reaction time.

  14. One-step grown suspended n-type semiconducting single wall carbon nanotube field effect transistors with carbon nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Lee, Yun-Hi; Lee, Jong-Hee; Noh, Ji-Young

    2008-01-01

    The authors report on the in situ formation of n-type ferromagnetic single wall carbon nanotube field effect transistors for the first time using a rapid heating process with a continuous flow of H2 gas under a vacuum of millitorr and their electromagnetic transport properties. The suspended n-type single wall carbon nanotube (SWNT) bridge including nanosized Fe catalyst impurities also shows gate controlled magnetic field dependent field effect behavior. The interesting features of these devices can be understood qualitatively based on the influence of the nonoxidant interface and nano Fe residing at the growth site of the SWNT bridge.

  15. Carbon nanotunnels form from single-walled carbon nanotubes interacting with a diamond (100)-(2 X 1) surface.

    SciTech Connect

    Horner, D. A.; Sternberg, M.; Zapol, P.; Curtiss, L. A. (Center for Nanoscale Materials); ( MSD); (North Central Coll.)

    2011-08-01

    A quantum chemical study of the interaction of (5,5), (7,7), (9,9) and (8,0) single-walled carbon nanotubes with a clean (100)-(2 x 1) diamond surface is reported. Stable structures with covalent bonds at the interface were found for carbon nanotubes oriented parallel or perpendicular to the dimer rows on the reconstructed (100) surface. The binding energy of the most stable (5,5) nanotube-diamond structure is 1.7 eV/{angstrom}, and is attributed to strong covalent bonds formed between the carbon nanotube and the diamond surface. The structure of the nanotube is distorted by adsorption on the surface such that it adopts a tunnel-like geometry. Two other nanotunnel geometries were found for the (5,5) nanotube, with binding energies of 1.39 and 1.09 eV/{angstrom}. In the most stable (5,5) nanotube-diamond structure the interaction between the nanotube and the diamond surface produces a 0.6 eV band gap near the Fermi level, but the metallic character of the nanotube is maintained in the two other, less strongly bound nanotunnel structures. No charge transfer occurs between the diamond surface and the nanotunnels in any of the three orientations. Binding energies decrease with increases in tube diameter, to the extent that one of the three nanotunnel structures is not formed by (9,9) carbon nanotubes.

  16. The interaction of N 2 with active sites of a single-wall carbon nanotube

    NASA Astrophysics Data System (ADS)

    Xu, Yi-Jun; Li, Jun-Qian

    2005-09-01

    The adsorption of N 2 at the edge of a single-wall carbon nanotube (SWNT) has been investigated employing an ONIOM approach. It was found that N 2 can be chemisorbed at the edge site of zigzag SWNT surface and the N-N bond is activated. However, the adsorption at the edge site of armchair SWNT surface is rather weak. This can be attributed to the crucial effect of local edge carbon atoms arrangement of the defect SWNT surface with open tips. Furthermore, our results strongly reinforce the viewpoint from recent experimental observations and theoretical studies that SWNTs with open tips exhibit larger adsorption capacity than closed-ended SWNTs.

  17. Stable p-type properties of single walled carbon nanotubes by electrochemical doping.

    PubMed

    Park, Chang-Soo; Lee, Cheol Jin; Kim, Eun Kyu

    2015-07-01

    We report a highly stable p-type doping for single walled carbon nanotubes using an electrochemical method. The Raman spectroscopy showed the upshift of the G-band when the applied potential increased. Furthermore, the carbon core level shifted as much as 0.14 eV in binding energy of XPS measurement, which is an evidence of p-type doping with a Fermi level change. The highly doped SWCNTs at an applied potential of 1.5 V during the electrochemical doping process showed long time stability, as long as 28 days. PMID:26054834

  18. Suppressed Conductance of Individual Single Walled Carbon Nanotube/Polypyrole Composite Nanowires and Their Sensing Applications

    NASA Astrophysics Data System (ADS)

    Liu, Xiaolei

    2005-03-01

    We present synthesis of individual single walled carbon nanotube/polypyrrole composite nanowire by chemical vapor deposition followed by electrochemical deposition for the first time. The transport properties of the composite nanowire were studied and suppression in conduction through carbon nanotube channels was discovered and discussed. Moreover, we also demonstrated the composite nanowire devices can serve as chemical sensors, which responses to oxidizing and reducing gases. The studies on the transport of the composite and their sensing applications shed light on the interaction between the nanotubes and the electrochemically coated polymers and also opens the way toward high performance chemical/bio sensors with high selectivity.

  19. Carbohydrate conjugation through microwave-assisted functionalization of single-walled carbon nanotubes using perfluorophenyl azides.

    PubMed

    Kong, Na; Shimpi, Manishkumar R; Ramström, Olof; Yan, Mingdi

    2015-03-20

    Carbohydrate-functionalized single-walled carbon nanotubes (SWNTs) were synthesized using microwave-assisted reaction of perfluorophenyl azide with the nanotubes. The results showed that microwave radiation provides a rapid and effective means to covalently attach carbohydrates to SWNTs, producing carbohydrate-SWNT conjugates for biorecognition. The carbohydrate-functionalized SWNTs were furthermore shown to interact specifically with cognate carbohydrate-specific proteins (lectins), resulting in predicted recognition patterns. The carbohydrate-presenting SWNTs constitute a new platform for sensitive protein- or cell recognition, which pave the way for glycoconjugated carbon nanomaterials in biorecognition applications. PMID:25746392

  20. Chiral angle dependence of resonance window widths in (2n+m) families of single-walled carbon nanotubes

    E-print Network

    Hsieh, Ya-Ping

    Raman spectra of isolated single-walled carbon nanotubes (SWNTs) were obtained for a wide range of laser excitation energies to study the resonance excitation window of the radial breathing mode feature for members of ...

  1. Electronic detection of molecules on the exterior and molecular transport through the interior of single walled carbon nanotubes

    E-print Network

    Lee, Chang Young

    2010-01-01

    Single walled carbon nanotubes (SWNT) are unique materials with high surface to volume ratio and all atoms residing on the surface. Due to their tubular shape both exterior and interior of the SWNT are available for ...

  2. Alcohol CVD Growth of Horizontally Aligned Single-Walled Carbon Nanotubes on R-cut Crystal Quartz Substrates

    E-print Network

    Maruyama, Shigeo

    Alcohol CVD Growth of Horizontally Aligned Single-Walled Carbon Nanotubes on R-cut Crystal Quartz are desired. In this study, we performed alcohol chemical vapor deposition (CVD) growth [2] of SWCNTs on R

  3. Advanced Characterization and Optical Properties of Single-Walled Carbon Nanotubes and Graphene Oxide

    NASA Astrophysics Data System (ADS)

    Naumov, Anton Viatcheslavovich

    Photophysical, electronic, and compositional properties of single-walled carbon nanotubes (SWCNTs) and bulk nanotube samples were investigated together with graphene oxide photoluminescence. First, we studied the effect of external electric fields on SWCNT photoluminescence. Fields of up to 107 V/m caused dramatic, reversible decreases in emission intensity. Quenching efficiency was proportional to the projection of the field on the SWCNT axis, and showed inverse correlation with optical band gap. The magnitude of the effect was experimentally related to exciton binding energy, as consistent with a proposed field-induced exciton dissociation model. Further, the electronic composition of various SWCNT samples was studied. A new method was developed to measure the fraction of semiconducting nanotubes in as- grown or processed samples. SWCNT number densities were compared in images from near-IR photoluminescence (semiconducting species) and AFM (all species) to compute the semiconducting fraction. The results provide important information about SWCNT sample compositions that can guide controlled growth methods and help calibrate bulk characterization techniques. The nature of absorption backgrounds in SWCNT samples was also studied. A number of extrinsic perturbations such as extensive ultrasonication, sidewall functionalization, amorphous carbon impurities, and SWCNT aggregation were applied and their background contributions quantified. Spectral congestion backgrounds from overlapping absorption bands were assessed with spectral modeling. Unlike semiconducting nanotubes, metallic SWCNTs gave broad intrinsic absorption backgrounds. The shape of the metallic background component and its absorptivity coefficient were determined. These results can be used to minimize and evaluate SWCNT absorption backgrounds. Length dependence of SWCNT optical properties was investigated. Samples were dispersed by ultrasonication or shear processing, and then length-fractionated by gel electrophoresis or controlled ultrasonication shortening. Fractions from both methods showed no significant absorbance variations with SWCNT length. The photoluminescence intensity increased linearly with length, and the relative quantum yield gradually increased, approaching a limiting value. Finally, a strong pH dependence of graphene oxide photoluminescence was observed. Sharp and structured excitation/emission features resembling the spectra of molecular fluorophores were obtained in basic conditions. Based on the observed pH-dependence and quantum calculations, these spectral features were assigned to quasi-molecular fluorophores formed by the electronic coupling of oxygen-containing addends with nearby graphene carbon atoms.

  4. Optical Anisotropy in Single-Walled Carbon Nanotube Thin Films: Implications for Transparent and Conducting Electrodes in Organic Photovoltaics

    Microsoft Academic Search

    Giovanni Fanchini; Steve Miller; Bhavin B. Parekh; Manish Chhowalla

    2008-01-01

    Optical anisotropy in single-walled carbon nanotube thin film networks is reported. We obtain the real and imaginary parts of the in- (| )a nd out-of-plane (?) complex dielectric functions of the single-walled carbon nanotube (SWNT) thin films by combining transmission measurements at several incidence angles with spectroscopic ellipsometry data on different substrates. In sparse networks, the two components of the

  5. Advanced sorting of single-walled carbon nanotubes by nonlinear density-gradient ultracentrifugation

    NASA Astrophysics Data System (ADS)

    Ghosh, Saunab; Bachilo, Sergei M.; Weisman, R. Bruce

    2010-06-01

    Existing methods for growing single-walled carbon nanotubes produce samples with a range of structures and electronic properties, but many potential applications require pure nanotube samples. Density-gradient ultracentrifugation has recently emerged as a technique for sorting as-grown mixtures of single-walled nanotubes into their distinct (n,m) structural forms, but to date this approach has been limited to samples containing only a small number of nanotube structures, and has often required repeated density-gradient ultracentrifugation processing. Here, we report that the use of tailored nonlinear density gradients can significantly improve density-gradient ultracentrifugation separations. We show that highly polydisperse samples of single-walled nanotubes grown by the HiPco method are readily sorted in a single step to give fractions enriched in any of ten different (n,m) species. Furthermore, minor variants of the method allow separation of the mirror-image isomers (enantiomers) of seven (n,m) species. Optimization of this approach was aided by the development of instrumentation that spectroscopically maps nanotube contents inside undisturbed centrifuge tubes.

  6. Advanced sorting of single-walled carbon nanotubes by nonlinear density-gradient ultracentrifugation.

    PubMed

    Ghosh, Saunab; Bachilo, Sergei M; Weisman, R Bruce

    2010-06-01

    Existing methods for growing single-walled carbon nanotubes produce samples with a range of structures and electronic properties, but many potential applications require pure nanotube samples. Density-gradient ultracentrifugation has recently emerged as a technique for sorting as-grown mixtures of single-walled nanotubes into their distinct (n,m) structural forms, but to date this approach has been limited to samples containing only a small number of nanotube structures, and has often required repeated density-gradient ultracentrifugation processing. Here, we report that the use of tailored nonlinear density gradients can significantly improve density-gradient ultracentrifugation separations. We show that highly polydisperse samples of single-walled nanotubes grown by the HiPco method are readily sorted in a single step to give fractions enriched in any of ten different (n,m) species. Furthermore, minor variants of the method allow separation of the mirror-image isomers (enantiomers) of seven (n,m) species. Optimization of this approach was aided by the development of instrumentation that spectroscopically maps nanotube contents inside undisturbed centrifuge tubes. PMID:20453856

  7. Single-walled carbon nanotubes do not pierce aqueous phospholipid bilayers at low salt concentration.

    PubMed

    Shi, Liu; Shi, Dachuan; Nollert, Matthias U; Resasco, Daniel E; Striolo, Alberto

    2013-06-01

    Because of their unique physical, chemical, and electrical properties, carbon nanotubes are an attractive material for many potential applications. Their interactions with biological entities are, however, not yet completely understood. To fill this knowledge gap, we present experimental results for aqueous systems containing single-walled carbon nanotubes and phospholipid membranes, prepared in the form of liposomes. Our results suggest that dispersed single-walled carbon nanotubes, instead of piercing the liposome membranes, adsorb on them at low ionic strength. Transmission electron microscopy and dye-leakage experiments show that the liposomes remain for the most part intact in the presence of the nanotubes. Further, the liposomes are found to stabilize carbon nanotube dispersions when the surfactant sodium dodecylbenezenesulfonate is present at low concentrations. Quantifying the interactions between carbon nanotubes and phospholipid membranes could not only shed light on potential nanotubes cytotoxicity but also open up new research venues for their use in controlled drug delivery and/or gene and cancer therapy. PMID:23659213

  8. Capacitive tunnels in single-walled carbon nanotube networks on flexible substrate

    NASA Astrophysics Data System (ADS)

    Iqbal, M. Z.; Iqbal, M. W.; Eom, Jonghwa; Ahmad, Muneer; Ferrer-Anglada, Núria

    2012-03-01

    We report the analysis of single-walled carbon nanotube networks, which are expected to be suitable as miniaturized flexible radio frequency RC filters and also have important implications for high frequency devices. The surface morphology obtained by atomic force microscopy shows that most of the growth on polypropylene carbonate substrate is homogeneous. The large value of peak intensity ratio of G and D band in Raman spectra indicates the high purity network. Nyquist plots of carbon nanotube networks on a flexible substrate are close to real circles, indicating that the material is conducting, and suggest a simple equivalent circuit having a resistor in parallel with a capacitor. The Bode plots give the dependence of real and imaginary impedances on frequency. While at high frequency, the impedance decreases, due to generation of capacitance between a single-walled carbon nanotube; at low frequency, it shows the normal behavior, having constant value. The tunnels among different carbon nanotubes are capable of storing electric charge. The accumulative capacitances of tunnels for three varied concentrations are calculated by electrochemical impedance spectroscopy simulations to fit the observed Nyquist plots.

  9. Thin Single-Walled Carbon Nanotubes with Narrow Diameter Distribution Grown by Cold-Wall Chemical Vapor Deposition Combined with Co Nanoparticle Deposition

    Microsoft Academic Search

    Satoshi Ishii; Yutaka Ohno; Shigeru Kishimoto; Takashi Mizutani

    2011-01-01

    We have grown thin single-walled carbon nanotubes (SWNTs) with a narrow diameter distribution using the arc-discharge plasma (ADP) technique for Co catalyst metal deposition and a cold-wall chemical vapor deposition (CVD) system for SWNT growth. The diameters of the SWNTs ranged from 0.79 to 1.07 nm. In addition to depositing small and uniform-sized metal catalyst nanoparticles by the ADP technique,

  10. G-band resonant Raman study of 62 isolated single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Jorio, A.; Souza Filho, A. G.; Dresselhaus, G.; Dresselhaus, M. S.; Swan, A. K.; Ünlü, M. S.; Goldberg, B. B.; Pimenta, M. A.; Hafner, J. H.; Lieber, C. M.; Saito, R.

    2002-04-01

    We report G-band resonance Raman spectra of single-wall carbon nanotubes (SWNTs) at the single-nanotube level. By measuring 62 different isolated SWNTs resonant with the incident laser, and having diameters dt ranging between 0.95 nm and 2.62 nm, we have conclusively determined the dependence of the two most intense G-band features on the nanotube structure. The higher-frequency peak is not diameter dependent (?+G=1591 cm-1), while the lower-frequency peak is given by ?-G=?+G-C/d2t, with C being different for metallic and semiconducting SWNTs (CM>CS). The peak frequencies do not depend on nanotube chiral angle. The intensity ratio between the two most intense features is in the range 0.1

  11. Effect of different carbon sources on the growth of single-walled carbon nanotube from MCM-41 containing nickel

    Microsoft Academic Search

    Yuan Chen; Bo Wang; Lain-Jong Li; Yanhui Yang; Dragos Ciuparu; Sangyun Lim; Gary L. Haller; Lisa D. Pfefferle

    2007-01-01

    Chemical vapor deposition growth of single-walled carbon nanotubes (SWCNTs) was studied using three representative carbon source sources: CO, ethanol, and methane, and a catalyst of Ni ions incorporated in MCM-41. The resulting SWCNTs were compared for similar reaction conditions. Carbon deposits were analyzed by multi-excitation wavelength Raman, TGA, TEM and AFM. Catalytic particles in the Ni-MCM-41 catalysts were characterized by

  12. Electric double layer capacitance of highly pure single-walled carbon nanotubes ( HiPco™ Buckytubes™ ) in propylene carbonate electrolytes

    Microsoft Academic Search

    Soshi Shiraishi; Hideyuki Kurihara; Keiji Okabe; Denisa Hulicova; Asao Oya

    2002-01-01

    The double layer capacitance of highly pure single-walled carbon nanotubes (SWCNTs) prepared by the HiPco™ process was measured in 1.0moldm?3LiClO4\\/propylene carbonate solution. The unpurified SWCNT electrode was mainly composed of a bundle structure of SWCNTs with around 1.0 nm tube diameter, small amount of amorphous carbons, and Fe catalyst particles. The Fe catalysts in the surface of the SWCNT were

  13. Organic/hybrid nanoparticles and single-walled carbon nanotubes: preparation methods and chiral applications.

    PubMed

    Alhassen, Haysem; Antony, Vijy; Ghanem, Ashraf; Yajadda, Mir Massoud Aghili; Han, Zhao Jun; Ostrikov, Kostya Ken

    2014-11-01

    Nanoparticles are molecular-sized solids with at least one dimension measuring between 1-100 nm or 10-1000 nm depending on the individual discipline's perspective. They are aggregates of anywhere from a few hundreds to tens of thousands of atoms which render them larger than molecules but smaller than bulk solids. Consequently, they frequently exhibit physical and chemical properties somewhere between. On the other hand, nanocrystals are a special class of nanoparticles which have started gaining attention recently owing to their unique crystalline structures which provide a larger surface area and promising applications including chiral separations. Hybrid nanoparticles are supported by the growing interest of chemists, physicists, and biologists, who are researching to fully exploit them. These materials can be defined as molecular or nano-composites with mixed (organic or bio) and inorganic components, where at least one of the component domain has a dimension ranging from a few Å to several nanometers. Similarly, and due to their extraordinary physical, chemical, and electrical properties, single-walled carbon nanotubes have been the subject of intense research. In this short review, the focus is mainly on the current well-established simple preparation techniques of chiral organic and hybrid nanoparticles as well as single-walled carbon nanotubes and their applications in separation science. Of particular interest, cinchonidine, chitosan, and ?-CD-modified gold nanoparticles (GNPs) are discussed as model examples for organic and hybrid nanoparticles. Likewise, the chemical vapor deposition method, used in the preparation of single-walled carbon nanotubes, is discussed. The enantioseparation applications of these model nanomaterials is also presented. PMID:24811353

  14. Deformation And Polarization In Single Walled Carbon Nanotube Due To Doping Of Group-IV Elements: A First Principle Investigations

    NASA Astrophysics Data System (ADS)

    Chakraborty, Brahmananda; Modak, P.; Banerjee, S.

    2010-12-01

    We have performed first principles calculations using Density Functional Theory to study atomic and electronic structure of Single Walled Carbon Nanotube (SWNT) doped with group-IV elements (Si, Ge, Sn). Substitution doping of group-IV elements (Si, Ge, Sn) results in deformation and local polarization of perfect SWNT. Because of the large size of the dopant atom it stays 1-2 Å above the tube and introduces angular deformation where ?CSnC angle becomes 79.8 degree for Sn instead of 120 degree for perfect SWNT. For semi-conducting SWNT the band gap at the Fermi level reduces with doping of element having higher Z value and the system make a march towards metallic behavior. Silicon substitute SWNT is more stable compared to Sn and Ge substitution. This study will be helpful in finding stability and electronic structures of various new and hypothetical carbon nanomaterials formed with substitution doping of group-IV elements.

  15. Accelerated reliability testing of highly aligned single-walled carbon nanotube networks subjected to DC electrical stressing.

    PubMed

    Strus, Mark C; Chiaramonti, Ann N; Kim, Young Lae; Jung, Yung Joon; Keller, Robert R

    2011-07-01

    We investigate the electrical reliability of nanoscale lines of highly aligned, networked, metallic/semiconducting single-walled carbon nanotubes (SWCNTs) fabricated through a template-based fluidic assembly process. We find that these SWCNT networks can withstand DC current densities larger than 10 MA cm(-2) for several hours and, in some cases, several days. We develop test methods that show that the degradation rate, failure predictability and total device lifetime can be linked to the initial resistance. Scanning electron and transmission electron microscopy suggest that fabrication variability plays a critical role in the rate of degradation, and we offer an empirical method of quickly determining the long-term performance of a network. We find that well-fabricated lines subject to constant electrical stress show a linear accumulation of damage reminiscent of electromigration in metallic interconnects, and we explore the underlying physical mechanisms that could cause such behavior. PMID:21586818

  16. Helicity-selective photoreaction of single-walled carbon nanotubes with organosulfur compounds in the presence of oxygen.

    PubMed

    Maeda, Yutaka; Higo, Junki; Amagai, Yuri; Matsui, Jun; Ohkubo, Kei; Yoshigoe, Yusuke; Hashimoto, Masahiro; Eguchi, Kazuhiro; Yamada, Michio; Hasegawa, Tadashi; Sato, Yoshinori; Zhou, Jing; Lu, Jing; Miyashita, Tokuji; Fukuzumi, Shunichi; Murakami, Tatsuya; Tohji, Kazuyuki; Nagase, Shigeru; Akasaka, Takeshi

    2013-04-24

    This report describes a helicity-selective photoreaction of single-walled carbon nanotubes (SWNTs) with disulfide in the presence of oxygen. The SWNTs were characterized using absorption, photoluminescence (PL), Raman, and X-ray photoelectron spectroscopy, scanning electron microscopy, and current-voltage (I-V) measurements. Results showed remarkable helicity-selective (metallic SWNTs/semiconducting SWNTs and diameter) functionalization of SWNTs. The reaction rate decreases in the order of metallic SWNTs > semiconducting SWNTs and small-diameter SWNTs > large-diameter SWNTs. Control experiments conducted under various experimental conditions and ESR and femtosecond laser flash photolysis measurements revealed that the helicity-selective reaction proceeds via a photoinduced electron transfer reaction. The PL and I-V measurements showed that the photoreaction is effective not only to control SWNT conductivity but also for the band gap modulation of semiconducting SWNTs. PMID:23550804

  17. Ultrathin "bed-of-nails" membranes of single-wall carbon nanotubes.

    PubMed

    Wang, Yuhuang; Da, Sean; Kim, Myung Jong; Kelly, Kevin F; Guo, Wenhua; Kittrell, Carter; Hauge, Robert H; Smalley, Richard E

    2004-08-11

    Single-wall carbon nanotubes (SWNTs) were arranged in a membrane similar to a "bed-of-nails", in which a single layer of parallel SWNTs was densely packed and aligned along the normal to the membrane. The planar, free-standing, ultrathin SWNT membranes were prepared by milling a neat SWNT fiber with a gallium focused ion beam. The approach is readily applicable to cutting nanotubes to a desirable and precise length and enables further fabrication of devices using the "bed-of-nails" membranes to test the transport properties of SWNTs. PMID:15291529

  18. Fine Structure of the Low-Frequency Raman Phonon Bands of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Iliev, M. N.; Litvinchuk, A. P.; Arepalli, S.; Nikolaev, P.; Scott, C. D.

    1999-01-01

    The Raman spectra of singled-wall carbon nanotubes (SWNT) produced by laser and are process were studied between 5 and 500 kappa. The line width vs. temperature dependence of the low-frequency Raman bands between 150 and 200/ cm deviates from that expected for phonon decay through phonon-phonon scattering mechanism. The experimental results and their analysis provided convincing evidence that each of the low-frequency Raman lines is a superposition of several narrower Raman lines corresponding to tubes of nearly the same diameter. The application of Raman spectroscopy to probe the distribution of SWNT by both diameter and chirality is discussed.

  19. Raman Modes of Index-Identified Freestanding Single-Walled Carbon Nanotubes

    SciTech Connect

    Meyer, Jannik C.; Roth, Siegmar [Max Planck Institute for Solid State Research, Stuttgart (Germany); Paillet, Matthieu; Michel, Thierry; Sauvajol, Jean-Louis [Laboratoire des Verres, Colloiedes et Nanomateriaux, UMR CNRS 5587, Universite de Montpellier II (France); Moreac, Alain [Groupe Matiere Condensee et Materiaux, UMR CNRS 6626, Universite de Rennes I (France); Neumann, Anita; Duesberg, Georg S. [Infineon Technologies Corporate Research, Munich (Germany)

    2005-11-18

    Using electron diffraction on freestanding single-walled carbon nanotubes, we have determined the structural indices (n,m) of tubes in the diameter range from 1.4 to 3 nm. On the same freestanding tubes, we have recorded Raman spectra of the tangential modes and the radial breathing mode. For the smaller diameters (1.4-1.7 nm), these measurements confirm previously established radial breathing mode frequency versus diameter relations and would be consistent with the theoretically predicted proportionality to the inverse diameter. However, for extending the relation to larger diameters, either a yet unexplained environmental constant has to be assumed, or the linear relation has to be abandoned.

  20. Determination of electronic states of individually dissolved ( n, m) single-walled carbon nanotubes in solution

    NASA Astrophysics Data System (ADS)

    Tanaka, Yasuhiko; Hirayama, Kohei; Niidome, Yasuro; Nakashima, Naotoshi

    2009-11-01

    Solution redox chemistry is useful to understand the chirality-dependent electronic properties of single-walled carbon nanotubes (SWNTs). We have found that the electron transfer reactions of sodium dithionite with SWNTs cause photoluminescence (PL) quenching processes of 14 individually dissolved SWNTs in an aqueous micellar solution. Based on the analysis using the Nernst equation for the PL change, we have determined the conduction band ( c1) levels of the 14 isolated SWNTs. We have also estimated the valence band ( ?1) levels as well as the Fermi levels of the SWNTs using the reported bandgap values of the corresponding isolated SWNTs.

  1. Stable Dispersion of Single Wall Carbon Nanotubes in Polyimide: the Role of Noncovalent Interactions

    SciTech Connect

    Wise, Kristopher; Park, Cheol; Siochi, Emilie J.; Harrison, Joycelyn S.

    2004-06-21

    Single wall carbon nanotubes (SWNTs) have been dispersed in a nitrile functionalized polyimide matrix and the resulting composite shows excellent stability with respect to reaggregation of the nanotubes. This contrasts with the behavior of structurally similar polyimides in which the dispersion is only stable for short periods of time. Shifts in certain characteristic FTIR and Raman peaks which indicate a charge transfer interaction between the nanotubes and polymer matrix are observed. A simple model for charge transfer stabilization is presented and shown to be consistent with the experimental observations.

  2. A passively Q-switched thulium-doped fiber laser with single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ma, H. F.; Wang, Y. G.; Zhou, W.; Long, J. Y.; Shen, D. Y.; Wang, Y. S.

    2013-03-01

    We demonstrate a passively Q-switched thulium-doped fiber laser by using single-walled carbon nanotube (SWCNT) polyvinyl alcohol (PVA) composite film as the saturable absorber (SA). A relatively large mode area on the SA was employed to avoid damage of the SWCNT/PVA film and benefit pulsed laser operation. Stable pulses of 85–164 kHz repetition rate were generated at 1967 nm with a maximum average output power of 103 mW. The single pulse energy was up to ˜0.63 ?J with ˜0.87 ?s pulse duration.

  3. Thermal conductivity measurements of semitransparent single-walled carbon nanotube films by a bolometric technique.

    PubMed

    Itkis, Mikhail E; Borondics, Ferenc; Yu, Aiping; Haddon, Robert C

    2007-04-01

    We introduce a new technique for measurement of the thermal conductivity of ultrathin films of single-walled carbon nanotubes (SWNTs) utilizing IR radiation as heat source and the SWNT film as thermometer. The technique is applied to study the temperature dependence of the thermal conductivity of an as-prepared SWNT film obtained in the electric arc discharge process and a film of purified SWNTs prepared by vacuum filtration. The interplay between thermal and electrical transport in SWNT networks is analyzed in relation to the type of intertube junctions and the possibility of optimizing the thermal and electrical properties of SWNT networks for specific applications is discussed. PMID:17385930

  4. Aligned, ultralong single-walled carbon nanotubes: from synthesis, sorting, to electronic devices.

    PubMed

    Liu, Zhongfan; Jiao, Liying; Yao, Yagang; Xian, Xiaojun; Zhang, Jin

    2010-06-01

    Aligned, ultralong single-walled carbon nanotubes (SWNTs) represent attractive building blocks for nanoelectronics. The structural uniformity along their tube axis and well-ordered two-dimensional architectures on wafer surfaces may provide a straightforward platform for fabricating high-performance SWNT-based integrated circuits. On the way towards future nanoelectronic devices, many challenges for such a specific system also exist. This Review summarizes the recent advances in the synthesis, identification and sorting, transfer printing and manipulation, device fabrication and integration of aligned, ultralong SWNTs in detail together with discussion on their major challenges and opportunities for their practical application. PMID:20358529

  5. Influence of cysteine doping on photoluminescence intensity from semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kurnosov, N. V.; Leontiev, V. S.; Linnik, A. S.; Karachevtsev, V. A.

    2015-03-01

    Photoluminescence (PL) from semiconducting single-walled carbon nanotubes can be applied for detection of cysteine. It is shown that cysteine doping (from 10-8 to 10-3 M) into aqueous suspension of nanotubes with adsorbed DNA leads to increase of PL intensity. The PL intensity was enhanced by 27% at 10-3 M cysteine concentration in suspension. Most likely, the PL intensity increases due to the passivation of p-defects on the nanotube by the cysteine containing reactive thiol group. The effect of doping with other amino acids without this group (methionine, serine, aspartic acid, lysine, proline) on the PL intensity is essentially weaker.

  6. A Facile High-speed Vibration Milling Method to Water-disperse Single- walled Carbon Nanohorns

    SciTech Connect

    Shu, Chunying [Virginia Polytechnic Institute and State University (Virginia Tech); Zhang, Jianfei [Virginia Polytechnic Institute and State University (Virginia Tech); Sim, Jae Hyun [Virginia Polytechnic Institute and State University (Virginia Tech); Burke, Brian [University of Virginia, Charlottesville; Williams, Keith A [University of Virginia, Charlottesville; Rylander, Nichole M [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; Geohegan, David B [ORNL; More, Karren Leslie [ORNL; Esker, Alan R [Virginia Polytechnic Institute and State University (Virginia Tech); Gibson, Harry W [Virginia Polytechnic Institute and State University (Virginia Tech); Dorn, Harry C [Virginia Polytechnic Institute and State University (Virginia Tech)

    2010-01-01

    A high-speed vibration milling (HSVM) method was applied to synthesize water dispersible single- walled carbon nanohorns (SWNHs). Highly reactive free radicals (HOOCCH2CH2 ) produced from an acyl peroxide under HSVM conditions react with hydrophobic SWNHs to produce a highly water dispersible derivative (f-SWNHs), which has been characterized in detail by spectroscopic and microscopic techniques together with thermogravimetric analysis (TGA) and dynamic light scatter- ing (DLS). The carboxylic acid functionalized, water-dispersible SWNHs material are versatile precursors that have potential applications in the biomedical area.

  7. Fabrication and mechanical properties of single-wall carbon nanotubes and hyperbranched diazonium salt multilayers

    Microsoft Academic Search

    Xinyang Li; Pengwei Fan; Xinlin Tuo; Xiaogong Wang

    2008-01-01

    Acidized single-wall carbon nanotubes (SWNTs) were fabricated into multilayers with a hyperbranched azobenzene-containing\\u000a polymeric diazonium salt (PDAS) using the layer-by-layer adsorption technique. The fabrication process, multilayer thickness\\u000a variation, multilayer surface morphology and the interaction between SWNTs and PDAS were monitored by UV-Vis absorption spectroscopy,\\u000a optical ellipsometry, Atomic Force Microscopy, Scanning Electron Microscopy and Raman spectroscopy. Moreover, the nanomechanical\\u000a properties of

  8. Purification and alignment of arc-synthesis single-walled carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Huang, Houjin; Kajiura, Hisashi; Yamada, Atsuo; Ata, Masafumi

    2002-04-01

    We report here a scalable method for purification and alignment of single-walled carbon nanotubes (SWNT) in an aqueous solution. Arc-synthesis soot containing SWNTs is first treated with a concentrated nitric acid. After removal of most of the impurities and water, macroscopic and well-aligned SWNT bundles up to several centimeters long are formed in a rotary evaporator. Alignment of the SWNT bundles is ascribed to the liquid flow induced by rotary evaporation and van der Waals interactions among the bundles. The aligned SWNT bundles are further purified by ultrasonic Soxhlet extraction and annealing.

  9. Anomaly of X-ray Diffraction Profile in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Maniwa, Yutaka; Kumazawa, Yoshinori; Saito, Yumi; Tou, Hideki; Kataura, Hiromichi; Ishii, Hiroyoshi; Suzuki, Shinzou; Achiba, Yohji; Fujiwara, Akihiko; Suematsu, Hiroyoshi

    1999-06-01

    X-ray diffraction (XRD) studies on single-walled carbon nanotube (SWNT) samples prepared by the arc-discharge method were reported. The XRD profile was basically explained to be a result of triangular packing of SWNTs with a lattice constant of 17.1 Å and an average nanotube radius of 7.1 Å. We found an anomalous change in XRD profiles before and after heat-treatment of the SWNT samples in air at ˜350°C. Combined with gravimetric measurements and resistivity measurements, a detailed simulation of the XRD profiles showed that air (oxygen, and/or nitrogen and/or water) can be condensed inside the SWNTs.

  10. All printed edge-triggered register using single walled carbon nanotube-based thin film transistor.

    PubMed

    Noh, Jinsoo; Jung, Minhun; Jung, Kyunghwan; Lee, Gwangyong; Lim, Soyeon; Kim, Daae; Subramanian, Vivek; Cho, Gyoujin

    2012-05-01

    We have studied the fabrication of Single Walled Carbon Nanotube (SWNT)-based Thin Film Transistors (TFTs) using Roll-to-Roll (R2R) gravure printer and inkjet printer on PET foils to show the possibility of printed electronics in point of mass production and low cost. In this paper, for realization of all printed multi-bits digital circuit, all printed positive-edge triggered master-slave D flip-flop (DFF) was fabricated on PET foil using printed SWNT TFTs. The printed DFF, consists of 8 NAND gates and 4 inverters, exhibit propagation delay of 75 ms at the input clock signal of 5 Hz. PMID:22852386

  11. Transplanted tumor growth inhibition by functionalized short single-walled carbon nanotubules.

    PubMed

    Kit, O I; Zlatnik, E Yu; Peredreyeva, L V; Chervonobrodov, S P

    2014-01-01

    The effects of short single-walled carbon nanotubules functionalized by COOH- and NH2- containing groups (NT-COOH and NT-NH2), on the dynamics of transplanted Pliss lymphosarcoma growth were studied after tumor cell preincubation with nanotubules and after injection of nanotubules into the developing tumor. Tumor growth was inhibited and the lifespan of rats with tumors was prolonged by 1.7 times after transplantation of tumor preincubated with NT-NH2, while NT-COOH caused no effect of this kind. Intratumor injection of NT-NH2 inhibited tumor growth over 3 weeks and prolonged animal lifespan. PMID:24771378

  12. En route toward high performance electronics based on single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cao, Qing

    2014-06-01

    Single-walled carbon nanotubes (SWNT) could replace silicon in high-performance electronics with their exceptional electrical properties and intrinsic ultra-thin body. During the past five years, the major focus of this field is gradually shifting from proof-of-concept prototyping in academia to technology development in industry with emphasis on manufacturability and integration issues. Here we will review some most significant recent advances, with focus on assembling high purity semiconducting SWNTs into well aligned arrays. Future challenges and research opportunities in this field will also be discussed.

  13. Photoluminescence microscopy and spectroscopy of individualized and aggregated single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Schöppler, Friedrich; Rühl, Nicolas; Hertel, Tobias

    2013-02-01

    We have studied photophysical properties of individual single-wall carbon nanotubes (SWNTs) and SWNT aggregates in colloidal suspensions using fluorescence microscopy, -spectroscopy and time-correlated single photon counting. The results suggest that SWNT aggregates, formed by addition of a divalent salt to a monomer SWNT suspension, have an open structure with a density of ?12 SWNTs ?m-3. We also find a sizable spectral red-shift of 16 nm, line-broadening of 23 nm and reduced PL lifetimes in coagulated structures, independent of aggregate size for the range of structures studied here. Such changes may be used as fingerprint of SWNT aggregate formation in similar environments.

  14. Nonlinear photoluminescence properties of trions in hole-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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. Moreover, the effective radiative lifetime of a trion was evaluated to be approximately 20 ns.

  15. Chemical doping-induced changes in optical properties of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Okano, Makoto; Nishihara, Taishi; Yamada, Yasuhiro; Kanemitsu, Yoshihiko

    2014-01-01

    We studied the changes in the optical properties of single-walled carbon nanotubes (SWCNTs) induced by chemical doping. An enhancement in the photoluminescence (PL) of the SWCNTs was observed after doping with reducing agents, whereas a reduction in the PL intensity and the appearance of fast exciton decay resulted from doping with oxidizing agents. Comparisons of the measured PL and transient absorption obtained with the two different types of dopants demonstrated that the PL properties of SWCNTs are strongly linked to the non-radiative exciton recombination processes. Chemical doping strongly modulates the exciton dynamics in SWCNTs.

  16. Optical Behaviors of Single-Wall Carbon Nanotubes in Complex Environments

    NASA Astrophysics Data System (ADS)

    Duque, Juan G.; Crochet, Jared; Lounis, Brahim; Cognet, Laurent; Doorn, Stephen

    2013-03-01

    The optical properties of single-walled carbon nanotubes (SWNTs) offer great promises. However, the realization of their potential is limited by degree of interactions with their immediate surroundings. Here, we present an innovative approach to control and manipulate the intrinsic optical properties of SWNTs to develop optical sensors as a direct or indirect means to measure physical changes and convert such a response to a signal. We probe the mechanism of photoluminescence brightening via surfactant restructuring using time-resolved PL measurements and show an original way to visualize complex fluid behaviors controlling the intrinsic optical properties of SWNTs.

  17. Controlled growth of single-walled carbon nanotubes on patterned substrates.

    PubMed

    Zhou, Xiaozhu; Boey, Freddy; Zhang, Hua

    2011-11-01

    Single-walled carbon nanotubes (SWCNTs) have attracted great interest in the last two decades because of their unique electrical, optical, thermal, mechanical properties, etc. One major research field of SWCNTs is the controlled growth of them from the patterned catalysts on substrates, since the integration of SWCNTs into nanoelectronics and other devices requires well-organized SWCNT arrays. This tutorial review describes the commonly used lithographic techniques to pattern catalysts used for controlled growth of SWCNTs, specifically confined to the horizontal direction. Advantages and disadvantages of each method will be briefly discussed. Applications of the SWCNT arrays grown from the catalyst patterns will also be introduced. PMID:21713267

  18. Femtosecond four-wave-mixing spectroscopy of suspended individual semiconducting single-walled carbon nanotubes.

    PubMed

    Myllyperkiö, Pasi; Herranen, Olli; Rintala, Jyri; Jiang, Hua; Mudimela, Prasantha R; Zhu, Zhen; Nasibulin, Albert G; Johansson, Andreas; Kauppinen, Esko I; Ahlskog, Markus; Pettersson, Mika

    2010-11-23

    Femtosecond four-wave-mixing (FWM) experiments of individual suspended semiconducting single-walled carbon nanotubes (SWCNTs) are presented. The chiral indices of the tubes were determined by electron diffraction as (28,14) and (24,14) having diameters of 2.90 and 2.61 nm, respectively. The diameter and semiconducting character of the tubes were additionally confirmed by resonance Raman measurements. The FWM signal showed electronic response from the SWCNTs. The results demonstrate that ultrafast dynamics of individual SWCNTs can be studied by FWM spectroscopies. PMID:20939509

  19. Indirect magnetic coupling in light-element-doped single-walled carbon nanotubes.

    PubMed

    Krsti?, Vojislav; Ewels, Christopher P; Wågberg, Thomas; Ferreira, Mauro S; Janssens, Anne M; Stéphan, Odile; Glerup, Marianne

    2010-09-28

    Single-walled carbon nanotubes substitutionally doped with the light-element phosphorus are synthesized and are investigated by electrical and nuclear magnetic resonance measurements. Decreased spin-lattice relaxation times compared to undoped tubes point toward enhanced spin-sensitive scattering. Temperature dependence of the zero-bias conductance shows step-like features, a signature of scattering from a very low density (few sites per nanotube) of localized spin moments at oxidized phosphorus sites, consistent with density functional calculations. This supports recent predictions that localized magnetic moments must be indirectly magnetically coupled through the nanotube conduction electrons. PMID:20684527

  20. Molecular adsorption study of nicotine and caffeine on single-walled carbon nanotubes from first principles

    NASA Astrophysics Data System (ADS)

    Lee, Hyung-June; Kim, Gunn; Kwon, Young-Kyun

    2013-08-01

    Using first-principles calculations, we investigate the electronic structures and binding properties of nicotine and caffeine adsorbed on single-walled carbon nanotubes to determine whether CNTs are appropriate for filtering or sensing nicotine and caffeine molecules. We find that caffeine adsorbs more strongly than nicotine. The different binding characteristics are discussed by analyzing the modification of the electronic structure of the molecule-adsorbed CNTs. We also calculate the quantum conductance of the CNTs in the presence of nicotine or caffeine adsorbates and demonstrate that the influence of caffeine is stronger than nicotine on the conductance of the host CNT.

  1. Application of Electron Energy Loss Spectroscopy for Single Wall Carbon Nanotubes (Review)

    NASA Astrophysics Data System (ADS)

    Mittal, N.; Jain, S.; Mittal, J.

    2015-03-01

    Electron energy loss spectroscopy (EELS) is among the few techniques that are available for the characterization of modified single wall carbon nanotubes (SWCNTs) having nanometer dimensions (~1-3 nm). CNTs can be modified either by surface functionalization or coating, between bundles of nanotubes by doping, intercalation and fully or partially filling the central core. EELS is an exclusive technique for the identification, composition analysis, and crystallization studies of the chemicals and materials used for the modification of SWCNTs. The present paper serves as a compendium of research work on the application of EELS for the characterization of modified SWCNTs.

  2. Electrocatalytic oxidation of 3,4-dihydroxyphenylacetic acid at a glassy carbon electrode modified with single-wall carbon nanotubes

    Microsoft Academic Search

    Jianxiu Wang; Meixian Li; Zujin Shi; Nanqiang Li; Zhennan Gu

    2001-01-01

    The voltammetric behavior of 3,4-dihydroxyphenylacetic acid (DOPAC) was studied at a glassy carbon (GC) electrode modified with single-wall carbon nanotubes (SWNTs). In 0.1 M HAc–NaAc buffer solution (pH 4.4), the SWNT-modified electrode shows high electrocatalytic activity toward oxidation of DOPAC. One well-defined redox couple is obtained. The peak current increases linearly with the concentration of DOPAC in the range of

  3. Electric field dependence of photoluminescence from individual single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

    Using suspended single-walled carbon nanotubes, we investigate electric field effects on photoluminescence. Trenches are fabricated on Si O2 /Si substrates, and Pt is deposited for electrical contacts. Carbon nanotubes are grown by patterned chemical vapor deposition. These devices operate as back-gate field effect transistors, allowing application of electric fields on as-grown ultraclean nanotubes. Individual suspended carbon nanotubes are identified by taking photoluminescence images using a home-built laser-scanning confocal microscope. After determining the chirality by photoluminescence excitation spectra, we measure gate voltage dependence of photoluminescence. We observe quenching of photoluminescence intensity and shifts of emission wavelength as gate voltages are applied. This work is supported by KAKENHI, Mizuho Foundation for the Promotion of Sciences, Research Foundation for Opto-Science and Technology, TEPCO Research Foundation, SCAT, SCOPE, and Photon Frontier Network Program of MEXT, Japan.

  4. Tip-to-tip growth of aligned single-walled carbon nanotubes under an electric field

    NASA Astrophysics Data System (ADS)

    Chiu, Chien-Chao; Tai, Nyan-Hwa; Yeh, Meng-Kao; Chen, Bo-Yi; Tseng, Shih-Hao; Chang, Ying-Huang

    2006-04-01

    An electric field was applied during the chemical vapor deposition process for fabricating directional single-walled carbon nanotubes (SWNTs). The electric field significantly affected the direction of the carbon nanotubes (CNTs) synthesized on multi-layered substrate. Acetylene and hydrogen were used as carbon precursor and reducing gas, respectively. Thin Ni and Fe films were used as catalysts for CNT growth. The Ni film with a thickness ranging from 1 to 10 nm was coated on Cr layer, which was patterned on SiO 2/Si substrate. The Cr layer, acting as an electrode, was etched to form a tip-to-tip pattern. The sharp edge of Cr electrode yields an enhanced electric field, which promotes the growth of SWNTs between the two tips. A theoretical analysis was proposed to model the electric field in the process, and the simulated electric field is quite consistent with the SWNT growth region around the tips.

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

    PubMed Central

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

    2014-01-01

    In cancer imaging, nanoparticle biodistribution is typically visualised in living subjects using ‘bulk’ imaging modalities such as magnetic resonance imaging, computerized tomography and whole-body fluorescence. As such the 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 ie, 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. Next, we 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 p.i.). The remarkable selectivity of this tumour targeting mechanism demonstrates an advanced immune-based delivery strategy for enhancing specific tumour delivery with substantial penetration. PMID:24727688

  6. Comparative Dynamics and Sequence Dependence of DNA and RNA Binding to Single Walled Carbon Nanotubes

    PubMed Central

    Landry, Markita P.; Vukovi?, Lela; Kruss, Sebastian; Bisker, Gili; Landry, Alexandra M.; Islam, Shahrin; Jain, Rishabh; Schulten, Klaus; Strano, Michael S.

    2015-01-01

    Noncovalent polymer-single walled carbon nanotube (SWCNT) conjugates have gained recent interest due to their prevalent use as electrochemical and optical sensors, SWCNT-based therapeutics, and for SWCNT separation. However, little is known about the effects of polymer-SWCNT molecular interactions on functional properties of these conjugates. In this work, we show that SWCNT complexed with related polynucleotide polymers (DNA, RNA) have dramatically different fluorescence stability. Surprisingly, we find a difference of nearly 2500-fold in fluorescence emission between the most fluorescently stable DNA-SWCNT complex, C30 DNA-SWCNT, compared to the least fluorescently stable complex, (AT)7A-(GU)7G DNA-RNA hybrid-SWCNT. We further reveal the existence of three regimes in which SWCNT fluorescence varies nonmonotonically with SWCNT concentration. We utilize molecular dynamics simulations to elucidate the conformation and atomic details of SWCNT-corona phase interactions. Our results show that variations in polynucleotide sequence or sugar backbone can lead to large changes in the conformational stability of the polymer SWCNT corona and the SWCNT optical response. Finally, we demonstrate the effect of the coronae on the response of a recently developed dopamine nanosensor, based on (GT)15 DNA- and (GU)15 RNA-SWCNT complexes. Our results clarify several features of the sequence dependence of corona phases produced by polynucleotides adsorbed to single walled carbon nanotubes, and the implications for molecular recognition in such phases. PMID:26005509

  7. Development of novel single-wall carbon nanotube epoxy composite ply actuators

    NASA Astrophysics Data System (ADS)

    Yun, Yeo-Heung; Shanov, Vesselin; Schulz, Mark J.; Narasimhadevara, Suhasini; Subramaniam, Srinivas; Hurd, Douglas; Boerio, F. J.

    2005-12-01

    This paper describes a carbon nanotube epoxy ply material that has electrochemical actuation properties. The material was formed by dispersing single-wall carbon nanotubes in a solvent and then solution casting a thin paper using a mold and vacuum oven. In order to take advantage of the high elastic modulus of carbon nanotubes for actuation, epoxy as a chemically inert polymer is considered. An epoxy layer was cast on the surface of the nanotube paper to make a two-layer ply. A wet electrochemical actuator was formed by placing the nanotube epoxy ply in a 2 M NaCl electrolyte solution. Electrochemical impedance spectroscopy and cyclic voltammetry were carried out to characterize the electrochemical properties of the actuator. The voltage-current relationship and power to drive the actuator material were also determined. Compared to previous single-wall carbon nanotube buckypaper tape actuators, which had poor adhesion between the nanotubes and tape, and other nanotube-thermal plastic polymer actuators, which could not provide high strength, the epoxy based actuator has a higher elastic modulus and strength, which will be useful for future structural applications. This demonstrates that a polymer layer can reinforce nanotube paper, which is an important step in building a new structural material that actuates. Further work is under way to develop a solid electrolyte to allow dry actuation. Finally, these actuator plies will be laminated to build a carbon nanocomposite material. This smart structural material will have potential applications that range from use in robotic surgical tools to use as structures that change shape.

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

    NASA Astrophysics Data System (ADS)

    Sokolov, A. V.; Aseychev, A. V.; Kostevich, V. A.; Gusev, A. A.; Gusev, S. A.; Vlasova, I. I.

    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.

  9. Self-aligned lateral dual-gate suspended-body single-walled carbon nanotube field-effect transistors

    NASA Astrophysics Data System (ADS)

    Cao, Ji; Ionescu, Adrian M.

    2012-02-01

    Self-aligned lateral dual-gate suspended-body single-walled carbon nanotube (CNT) field-effect transistors (CNFETs) have been demonstrated. A nano-precision assembly method using resist-assisted ac-dielectrophoresis is applied. Superior I-V characteristics controlled by two independent lateral gates spaced sub-100 nm away from the CNT body are experimentally observed and studied. The dual-gate operation mode effectively boosts the device performance: 34% smaller subthreshold slope, three times larger on-current, and four times higher transconductance. The proposed dual-gate suspended-body CNFETs hold promise for bottom-up fabrication of advanced complementary metal-oxide-semiconductor circuits and nano-electro-mechanical systems devices, such as tunable/switchable resonators for sensing and radio-frequency applications.

  10. Single-walled carbon nanotube/metalloporphyrin composites for the chemiresistive detection of amines and meat spoilage.

    PubMed

    Liu, Sophie F; Petty, Alexander R; Sazama, Graham T; Swager, Timothy M

    2015-05-26

    Chemiresistive detectors for amine vapors were made from single-walled carbon nanotubes by noncovalent modification with cobalt meso-arylporphyrin complexes. We show that through changes in the oxidation state of the metal, the electron-withdrawing character of the porphyrinato ligand, and the counteranion, the magnitude of the chemiresistive response to ammonia could be improved. The devices exhibited sub-ppm sensitivity and high selectivity toward amines as well as good stability to air, moisture, and time. The application of these chemiresistors in the detection of various biogenic amines (i.e. putrescine, cadaverine) and in the monitoring of spoilage in raw meat and fish samples (chicken, pork, salmon, cod) over several days was also demonstrated. PMID:25867821

  11. Extraction of semiconducting single-walled carbon nanotubes encapsulating fullerenes by poly(9,9-dioctylfluorene-alt-benzothiadiazole)

    NASA Astrophysics Data System (ADS)

    Tange, Masayoshi; Kwon, Jin Kyoung; Okazaki, Toshiya; Iijima, Sumio

    2014-04-01

    Single-walled carbon nanotubes (SWCNTs) encapsulating fullerenes, the so-called “nanopeapods (NPDs)”, are expected as building blocks in future nanoelectronics because the mechanical and electronic properties of SWCNTs frequently undergo considerable modification with the encapsulation of molecules at a nanometer scale. The separation of semiconducting species from metallic counterparts is the next step in the application of NPDs in electronics and photonics. Here, semiconducting NPDs are successfully extracted in toluene using a fluorene-based polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT). Although F8BT shows a high extraction selectivity for (15, 4) SWCNTs, such a high selectivity disappears in the obtained photoluminescence excitation (PLE) map of NPDs. The change in electronic energy level by the encapsulation of C60 may induce the loss of the selectivity.

  12. Zipping, entanglement, and the elastic modulus of aligned single-walled carbon nanotube films

    PubMed Central

    Won, Yoonjin; Gao, Yuan; Panzer, Matthew A.; Xiang, Rong; Maruyama, Shigeo; Kenny, Thomas W.; Cai, Wei; Goodson, Kenneth E.

    2013-01-01

    Reliably routing heat to and from conversion materials is a daunting challenge for a variety of innovative energy technologies––from thermal solar to automotive waste heat recovery systems––whose efficiencies degrade due to massive thermomechanical stresses at interfaces. This problem may soon be addressed by adhesives based on vertically aligned carbon nanotubes, which promise the revolutionary combination of high through-plane thermal conductivity and vanishing in-plane mechanical stiffness. Here, we report the data for the in-plane modulus of aligned single-walled carbon nanotube films using a microfabricated resonator method. Molecular simulations and electron microscopy identify the nanoscale mechanisms responsible for this property. The zipping and unzipping of adjacent nanotubes and the degree of alignment and entanglement are shown to govern the spatially varying local modulus, thereby providing the route to engineered materials with outstanding combinations of mechanical and thermal properties. PMID:24309375

  13. Low voltage electron diffractive imaging of atomic structure in single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kamimura, Osamu; Maehara, Yosuke; Dobashi, Takashi; Kobayashi, Keita; Kitaura, Ryo; Shinohara, Hisanori; Shioya, Hiroyuki; Gohara, Kazutoshi

    2011-04-01

    The demand for atomic-scale analysis without serious damage to the specimen has been increasing due to the spread of applications with light-element three-dimensional (3D) materials. Low voltage electron diffractive imaging has the potential possibility to clarify the atomic-scale structure of 3D materials without causing serious damage to specimens. We demonstrate low-voltage (30 kV) electron diffractive imaging of single-wall carbon nanotube at a resolution of 0.12 nm. In the reconstructed pattern, the intensity difference between single carbon atom and two overlapping atoms can be clearly distinguished. The present method can generally be applied to other materials including biologically important ones.

  14. Multi-Fractal Hierarchy of Single-Walled Carbon Nanotube Hydrophobic Coatings

    PubMed Central

    De Nicola, Francesco; Castrucci, Paola; Scarselli, Manuela; Nanni, Francesca; Cacciotti, Ilaria; De Crescenzi, Maurizio

    2015-01-01

    A hierarchical structure is an assembly with a multi-scale morphology and with a large and accessible surface area. Recent advances in nanomaterial science have made increasingly possible the design of hierarchical surfaces with specific and tunable properties. Here, we report the fractal analysis of hierarchical single-walled carbon nanotube (SWCNT) films realized by a simple, rapid, reproducible, and inexpensive filtration process from an aqueous dispersion, then deposited by drytransfer printing method on several substrates, at room temperature. Furthermore, by varying the thickness of carbon nanotube random networks, it is possible tailoring their wettability due to capillary phenomena in the porous films. Moreover, in order to describe the wetting properties of such surfaces, we introduce a two-dimensional extension of the Wenzel-Cassie-Baxter theory. The hierarchical surface roughness of SWCNT coatings coupled with their exceptional and tunable optical and electrical properties provide an ideal hydrophobic composite surface for a new class of optoelectronic and nanofluidic devices. PMID:25716718

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

    NASA Astrophysics Data System (ADS)

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Atyabi, Fatemeh; Omidvar, Ramin; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2015-06-01

    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.

  16. Short-wavelength electroluminescence from single-walled carbon nanotubes with high bias voltage.

    PubMed

    Hibino, Norihito; Suzuki, Satoru; Wakahara, Hiroyuki; Kobayashi, Yoshihiro; Sato, Tetsuya; Maki, Hideyuki

    2011-02-22

    Short-wavelength electroluminescence (EL) emission is observed from unipolar and ambipolar carbon nanotube field-effect transistors (CNFETs) under high bias voltage. EL measurements were carried out with an unsuspended single-walled carbon nanotube (SWNT) in high vacuum to prevent the oxidation damage induced by current heating. Short-wavelength emission under high bias voltage is obtained because of the Schottky barrier reduction and the electric field increase in a SWNT. The simultaneous measurements of transport and EL spectra revealed the excitation mechanism of impact excitation or electron and hole injection dependent on the conduction type of unipolar or ambipolar characteristics. In addition to the EL emission, blackbody radiation was also observed in a p-type CNFET. Taking into account the device temperature estimated from blackbody radiation, the contribution of impact excitation and thermal effect to the exciton production rate was evaluated. PMID:21204568

  17. Adsorption behavior of ternary mixtures of noble gases inside single-walled carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Foroutan, Masumeh; Nasrabadi, Amir Taghavi

    2010-09-01

    In order to study the gas-storage and gas-filtering capability of carbon nanotube (CNT) bundles simultaneously, we considered the adsorption behavior of a ternary mixture of noble gases, including Argon (Ar), Krypton (Kr), and Xenon (Xe), i.e., Ar-Kr-Xe mixture, on (10, 10) single-walled carbon nanotube (SWCNT) bundles. Molecular dynamics (MD) simulations at different temperatures of (75, 100, 150, 200, 250, and 300) K were performed, and adsorption energies, self-diffusion coefficients, activation energies, and radial distribution functions (RDFs) were computed to analyze the thermodynamics, transport and structural properties of the adsorption systems. It is observed that the SWCNT bundles have larger contents of heavier noble gases compared to the lighter ones. This interesting behavior of SWCNT bundles makes them proper candidates for gas-storage and gas molecular-sieving processes.

  18. Surface growth of single-walled carbon nanotubes from ruthenium nanoparticles

    NASA Astrophysics Data System (ADS)

    Qian, Yong; Wang, Chunyan; Ren, Guangyuan; Huang, Bin

    2010-04-01

    In this paper, we report that ruthenium is an active and efficient catalyst for growth of single-walled carbon nanotubes (SWNTs) by a chemical vapor deposition (CVD) process for the first time. High density random and horizontally superlong well-oriented SWNTs on substrate can be fabricated via CH 4 or EtOH as carbon source under suitable conditions. Scanning and transition electron microscopy investigations, Raman spectroscopy and atomic force microscopy measurements show the tubular structure, the high crystallinity, and the properties of the grown nanotubes. The results show that the SWNTs from ruthenium have better structural uniformity with less defects and provides an alternative catalyst for SWNTs growth. The successful growth of SWNTs by Ru catalyst provides new experimental information for understanding the growth mechanism of SWNTs, which may be helpful for their controllable synthesis.

  19. Thermal expansion of single-walled carbon nanotube (SWNT) bundles: X-ray diffraction studies

    NASA Astrophysics Data System (ADS)

    Maniwa, Yutaka; Fujiwara, Ryuji; Kira, Hiroshi; Tou, Hideki; Kataura, Hiromichi; Suzuki, Shinzo; Achiba, Yohji; Nishibori, Eiji; Takata, Masaki; Sakata, Makoto; Fujiwara, Akihiko; Suematsu, Hiroyoshi

    2001-12-01

    Thermal expansion coefficient in single-walled carbon nanotube bundles was determined as (-0.15+/-0.20)×10-5 (1/K) for the tube diameter and (0.75+/-0.25)×10-5 (1/K) for the triangular lattice constant by means of x-ray scattering between 300 K to 950 K. The value for the intertube gap was (4.2+/-1.4)×10-5 (1/K), which is larger than 2.6×10-5 (1/K) for the c-axis thermal expansion in graphite. The results reveal the presence of a remarkably larger lattice anharmonicity in nanotube bundles than that of graphite. The small value for the tube diameter is consistent with the seamless tube structure formed by a strong covalent bond between carbon atoms comparable to that in graphite.

  20. Wave propagation analysis in nonlinear curved single-walled carbon nanotubes based on nonlocal elasticity theory

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Deng, Zichen; Ouyang, Huajiang; Zhou, Jiaxi

    2015-02-01

    Theoretical predictions are presented for wave propagation in nonlinear curved single-walled carbon nanotubes (SWCNTs). Based on the nonlocal theory of elasticity, the computational model is established, combined with the effects of geometrical nonlinearity and imperfection. In order to use the wave analysis method on this topic, a linearization method is employed. Thus, the analytical expresses of the shear frequency and flexural frequency are obtained. The effects of the geometrical nonlinearity, the initial geometrical imperfection, temperature change and magnetic field on the flexural and shear wave frequencies are investigated. Numerical results indicate that the contribution of the higher-order small scale effect on the shear deformation and the rotary inertia can lead to a reduction in the frequencies compared with results reported in the published literature. The theoretical model derived in this study should be useful for characterizing the mechanical properties of carbon nanotubes and applications of nano-devices.

  1. Zipping, entanglement, and the elastic modulus of aligned single-walled carbon nanotube films.

    PubMed

    Won, Yoonjin; Gao, Yuan; Panzer, Matthew A; Xiang, Rong; Maruyama, Shigeo; Kenny, Thomas W; Cai, Wei; Goodson, Kenneth E

    2013-12-17

    Reliably routing heat to and from conversion materials is a daunting challenge for a variety of innovative energy technologies--from thermal solar to automotive waste heat recovery systems--whose efficiencies degrade due to massive thermomechanical stresses at interfaces. This problem may soon be addressed by adhesives based on vertically aligned carbon nanotubes, which promise the revolutionary combination of high through-plane thermal conductivity and vanishing in-plane mechanical stiffness. Here, we report the data for the in-plane modulus of aligned single-walled carbon nanotube films using a microfabricated resonator method. Molecular simulations and electron microscopy identify the nanoscale mechanisms responsible for this property. The zipping and unzipping of adjacent nanotubes and the degree of alignment and entanglement are shown to govern the spatially varying local modulus, thereby providing the route to engineered materials with outstanding combinations of mechanical and thermal properties. PMID:24309375

  2. Second-Harmonic Generation of Aligned Single-Walled 0.4nm Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Wong, Kam Sing; Su, Huimin; Ye, Jianting; Tang, Zikang

    2007-03-01

    The second-harmonic generation (SHG) is measured for the first time from monosized and well-aligned single-walled carbon nanotubes (SWCNT) in the channel of aluminophosphate AlPO4-5 (AFI) zeolite. The SHG yield scales as quadratic function of the pump laser intensity. Due to the different polarization preference, we are able to discriminate the SHG contribution from the chiral (4,2) CNTs and those from the AFI template. The polarization direction and the anisotropic dependence of the SHG intensity on the excitation polarizations are investigated in the transmission geometry. In the case of normal incidence, the intensity of SHG is maximized when the excitation polarization is 45 degree against the tube axis and the SH radiation is linear-polarized on the plane perpendicular to the tube axis. The experiment results are in excellent agreement with the theoretical prediction of the second-order nonlinear optical process in chiral carbon nanotubes.

  3. Fabrication and performance of contamination free individual single-walled carbon nanotube optical devices.

    PubMed

    Zhou, Yuxiu; Cheng, Rong; Liu, Jianqiang; Li, Tie

    2014-06-01

    Contamination free individual single-walled carbon nanotube (SWCNT) optical devices are fabricated using a hybrid method in the purpose of increase sensitivity as well as further understanding the sensing mechanism. The devices were tested in vacuum to avoid contamination. Three typical devices are discussed comparatively. Under infrared lamp illumination, photovoltaic and photoconductive properties are revealed in device A and B respectively, while device C shows no detectable signal. The photoresponse of device B reaches 108% at 78 K, much larger than that of horizontally aligned or network carbon nanotube devices, indicating priority of the individual nanotube device structure. Interestingly, the temperature characteristics of device A and B are just the opposite. The individual SWCNT devices hold promise in high performance and low cost optical sensors as well as nano-scale solar cells. PMID:24738376

  4. Temperature-dependent thermal properties of single-walled carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Duzynska, A.; Taube, A.; Korona, K. P.; Judek, J.; Zdrojek, M.

    2015-05-01

    We herein report the determination of the intrinsic thermal conductivity (?) and interfacial thermal conductance (g) of single-walled carbon nanotube thin films (50 nm) on top of a SiO2 substrate. The study was performed as a function of temperature (300-450 K) using the opto-thermal technique. The value of ? decreases nonlinearly by approximately 60% from a value of 26 Wm-1 K-1 at 300 K to a value of 9 Wm-1 K-1 at 450 K. This effect stems from the increase of multi-phonon scattering at higher temperatures. The g increases with temperature, reaching a saturation plateau at 410 K. These findings may contribute to a better understanding of the thermal properties of the supported carbon nanotube thin films, which are crucial for any heat dissipation applications.

  5. Activated sludge microbial community responses to single-walled carbon nanotubes: community structure does matter.

    PubMed

    Ma, Qiao; Qu, Yuanyuan; Shen, Wenli; Wang, Jingwei; Zhang, Zhaojing; Zhang, Xuwang; Zhou, Hao; Zhou, Jiti

    2015-01-01

    The ecological effects of carbon nanotubes (CNTs) have been a worldwide research focus due to their extensive release and accumulation in environment. Activated sludge acting as an important gathering place will inevitably encounter and interact with CNTs, while the microbial responses have been rarely investigated. Herein, the activated sludges from six wastewater treatment plants were acclimated and treated with single-walled carbon nanotubes (SWCNTs) under identical conditions. Illumina high-throughput sequencing was applied to in-depth analyze microbial changes and results showed SWCNTs differently perturbed the alpha diversity of the six groups (one increase, two decrease, three no change). Furthermore, the microbial community structures were shifted, and specific bacterial performance in each group was different. Since the environmental and operational factors were identical in each group, it could be concluded that microbial responses to SWCNTs were highly depended on the original community structures. PMID:25909735

  6. Multi-Fractal Hierarchy of Single-Walled Carbon Nanotube Hydrophobic Coatings

    NASA Astrophysics Data System (ADS)

    de Nicola, Francesco; Castrucci, Paola; Scarselli, Manuela; Nanni, Francesca; Cacciotti, Ilaria; de Crescenzi, Maurizio

    2015-02-01

    A hierarchical structure is an assembly with a multi-scale morphology and with a large and accessible surface area. Recent advances in nanomaterial science have made increasingly possible the design of hierarchical surfaces with specific and tunable properties. Here, we report the fractal analysis of hierarchical single-walled carbon nanotube (SWCNT) films realized by a simple, rapid, reproducible, and inexpensive filtration process from an aqueous dispersion, then deposited by drytransfer printing method on several substrates, at room temperature. Furthermore, by varying the thickness of carbon nanotube random networks, it is possible tailoring their wettability due to capillary phenomena in the porous films. Moreover, in order to describe the wetting properties of such surfaces, we introduce a two-dimensional extension of the Wenzel-Cassie-Baxter theory. The hierarchical surface roughness of SWCNT coatings coupled with their exceptional and tunable optical and electrical properties provide an ideal hydrophobic composite surface for a new class of optoelectronic and nanofluidic devices.

  7. Synthesis and Raman Characterization of Boron Doped Single Walled Carbon Nanotubes (SWNTs)

    NASA Astrophysics Data System (ADS)

    McGuire, K.; Gothard, N.; Gai, P. L.; Chao, S. G.; Dresselhaus, M. S.; Rao, A. M.

    2003-11-01

    Boron-doped SWNTs were prepared by pulsed laser vaporization of carbon targets containing boron with concentrations ranging between 0.5 - 10 at%. As-prepared samples were characterized using Raman spectroscopy and HRTEM measurements. Above a threshold boron concentration of 3 at%, the growth of SWNT bundles ceases due to the low solubility of boron in carbon at ˜1200 ^oC. Interestingly, a few ˜0.5 nm diameter single walled tubes are found, along with nanographitic material in the soot generated from a target with a boron concentration of ˜7 at%. As expected, the intensity of the ˜1350 cm-1 D-band increases with increasing boron concentration due to boron substitution into the honeycomb lattice. Both the radial breathing mode and tangential G- bands were observed in the Raman spectra in samples with <3 at % boron at ˜186 cm-1 and ˜1591 cm-1, respectively. Implications of boron doping in the nanotube shell will be discussed.

  8. Synthesis and Raman Characterization of Boron Doped Single Walled Carbon Nanotubes (SWNTs)

    NASA Astrophysics Data System (ADS)

    McGuire, K.; Gothard, N.; Gai, P. L.; Chou, S. G.; Dresselhaus, M. S.; Rao, A. M.

    2003-03-01

    Boron-doped SWNTs were prepared by pulsed laser vaporization of carbon targets containing boron with concentrations ranging between 0.5 - 10 at%. As-prepared samples were characterized using Raman spectroscopy and HRTEM measurements. Above a threshold boron concentration of 3 at%, the growth of SWNT bundles ceases due to the low solubility of boron in carbon at ˜1200 ^oC. Interestingly, a few ˜0.5 nm diameter single walled tubes are found, along with nanographitic material in the soot generated from a target with a boron concentration of ˜7 at%. As expected, the intensity of the ˜1350 cm-1 D-band increases with increasing boron concentration due to boron substitution into the honeycomb lattice. Both the radial breathing mode and tangential G- bands were observed in the Raman spectra in samples with <3 at % boron at ˜186 cm-1 and ˜1591 cm-1, respectively. Implications of boron doping in the nanotube shell will be discussed.

  9. Production and characterization of polymer nanocomposites with highly aligned single-walled carbon nanotubes.

    PubMed

    Haggenmuller, R; Zhou, W; Fischer, J E; Winey, K I

    2003-01-01

    We report the production and characterization of polymer nanocomposites with single-walled carbon nanotubes having improved mechanical properties and exceptional nanotube alignment. High-pressure carbon monoxide nanotubes (HiPco) were efficiently distributed in polystyrene (PS) and polyethylene (PE) with a twin-screw compounder. Nanotube concentrations were 1, 5, 10, and 20 wt% in PE composites and 0.7 wt% in PS composites. PE composites were melt-spun into fibers to achieve highly aligned nanotubes. Polarized Raman spectroscopy shows that the degree of alignment increases with decreasing fiber diameter and decreases with increasing nanotube loading. The orientation distribution function of a 1 wt% HiPco/PE composite had a full width at half-maximum of approximately 5 degrees. The elastic modulus increases up to 450% relative to PE fibers for 20 wt% nanotube loading at an intermediate fiber diameter of 100 microns. PMID:12908237

  10. Magnetic Property Measurements on Single Wall Carbon Nanotube-Polyimide Composites

    NASA Technical Reports Server (NTRS)

    Sun, Keun J.; Wincheski, Russell A.; Park, Cheol

    2008-01-01

    Temperature and magnetic field dependent magnetization measurements were performed on polyimide nanocomposite samples, synthesized with various weight percentages of single wall carbon nanotubes. It was found that the magnetization of the composite, normalized to the mass of nanotube material in the sample, decreased with increasing weight percentage of nanotubes. It is possible that the interfacial coupling between the carbon nanotube (CNT) fillers and the polyimide matrix promotes the diamagnetic response from CNTs and reduces the total magnetization of the composite. The coercivity of the samples, believed to originate from the residual magnetic catalyst particles, was enhanced and had a stronger temperature dependence as a result of the composite synthesis. These changes in magnetic properties can form the basis of a new approach to investigate the interfacial properties in the CNT nanocomposites through magnetic property measurements.

  11. Dispersion and characterization of arc discharge single-walled carbon nanotubes--towards conducting transparent films.

    PubMed

    Rösner, B; Guldi, D M; Chen, J; Minett, A I; Fink, R H

    2014-04-01

    This study addresses a combination of a well-developed and mild dispersion method and high-quality arc discharge single-walled carbon nanotubes (SWCNTs) as starting materials. Thus, we advance in fabrication of transparent, conducting films with extraordinary low material loss during SWCNT processing. The starting material was characterized by means of thermogravimetric analysis, high-resolution transmission electron microscopy and Raman spectroscopy. The quality of the starting material and produced dispersions was evaluated by ultraviolet and visible light absorption spectroscopy and Raman spectroscopy. A transparent conductive film was fabricated by drop-casting, whereas films were obtained with electrical to optical conductivity ratios (?DC/?Op) as high as 2.2, combined with a loss of nanotube material during processing well below 20 wt%. High pressure carbon monoxide conversion (HiPCO) SWCNTs, which are very well described in the literature, were used for comparison. PMID:24567084

  12. Adsorption equilibrium of organic vapors on single-walled carbon nanotubes

    USGS Publications Warehouse

    Agnihotri, S.; Rood, M.J.; Rostam-Abadi, M.

    2005-01-01

    Gravimetric techniques were employed to determine the adsorption capacities of commercially available purified electric arc and HiPco single-walled carbon nanotubes (SWNTs) for organic compounds (toluene, methyl ethyl ketone (MEK), hexane and cyclohexane) at relative pressures, p/p0, ranging from 1 ?? 10-4 to 0.95 and at isothermal conditions of 25, 37 and 50 ??C. The isotherms displayed both type I and type II characteristics. Adsorption isotherm modeling showed that SWNTs are heterogeneous adsorbents, and the Freundlich equation best describes the interaction between organic molecules and SWNTs. The heats of adsorption were 1-4 times the heats of vaporization, which is typical for physical adsorption of organic vapors on porous carbons. ?? 2005 Elsevier Ltd. All rights reserved.

  13. Electronic properties of optically transparent single-walled carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Hecht, David Samuel

    Single-walled carbon nanotube (SWNT) films of various densities were fabricated and the optoelectronic properties studied. Several deposition techniques were developed, including filtration, stamping, self-assembly, spraying, and slot coating. Film conductivity was studied as a function of several parameters. At sub-monolayer densities, close to the percolation threshold, the film conductance follows the expected 2D percolation behavior. For films just thicker than a monolayer, the conductivity weakly increases up to a critical thickness, due to interlayer tube coupling. The frequency dependence of the conductivity follows the ac universality power law predicted for disordered systems. Due to the large intertube barriers (relative to the intratube resistance), the film conductivity increases as a power law in the constituent tube length. DC conductivities up to 2400 S/cm were measured, and increased to 6000 S/cm upon exposure to various dopants; however the binding is not stable at room temperature. The overall electrical stability of SWNT films is considered under various conditions. Nanotube films thinner than 100 nm are transparent in the visible and infrared spectrum, with the transmission limited by absorption, rather than by reflection. The visible spectrum is relatively featureless, apart from a weak interband transition at 700 nm; therefore, the films have a neutral, "gray" color. The large ratio of DC to optical conductivity make SWNT films useful for several applications including displays, solar cells, and touch screens. A prototype organic solar cell using a SWNT anode as shown to have efficiencies comparable to cells using an indium tin oxide anode; integration with a metallic grid was demonstrated. Films were coated onto fabric and shown to impart electrical conductivity to the fabric. Films of various densities were fabricated as both the gate and the conducting channel of a field effect transistor (FET), making the first transparent and flexible transistor incorporating SWNTs. SWNT FETs non-covalently functionalized with a porphyrin derivative, were used to monitor the light induced electron transfer between nanotubes and porphyrin. The wavelength and intensity dependence of this process was measured, indicating that the optical changes in the porphyrin electronic structure are coupled to the charge transport through the network.

  14. High-temperature transformation of Fe-decorated single-wall carbon nanohorns to nanooysters: a combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Chandrakumar, K. R. S.; Readle, Jason D.; Rouleau, Chris; Puretzky, Alex; Geohegan, David B.; More, Karren; Krishnan, Veena; Tian, Mengkun; Duscher, Gerd; Sumpter, Bobby; Irle, Stephan; Morokuma, Keiji

    2013-02-01

    The processes by which single-wall carbon nanohorns are transformed by iron nanoparticles at high temperatures to form ``nanooysters'', hollow graphene capsules containing metal particles that resemble pearls in an oyster shell, are examined both experimentally and theoretically. Quantum chemical molecular dynamics (QM/MD) simulations based on the density-functional tight-binding (DFTB) method were performed to investigate their growth mechanism. The simulations suggest that the nanoparticles self-encapsulate to form single-wall nanooysters (SWNOs) by assisting the assembly of dangling carbon bonds, accompanied by migration of the metal particle inside the carbon structure. These calculations indicate that the structure of the oyster consists primarily of hexagons along with a few pentagons that are predominantly formed near the former nanohorn edges as a result of their fusion. Experimental observations of large diameter nanoparticles inside multiwall carbon shells indicate that migration and coalescence of many iron particles must occur, perhaps by the convergence of smaller SWNOs or carbon-coated Fe-nanoparticles, whereby the void space is generated by the corresponding increase in the carbon shell surface area to metal nanoparticle volume.The processes by which single-wall carbon nanohorns are transformed by iron nanoparticles at high temperatures to form ``nanooysters'', hollow graphene capsules containing metal particles that resemble pearls in an oyster shell, are examined both experimentally and theoretically. Quantum chemical molecular dynamics (QM/MD) simulations based on the density-functional tight-binding (DFTB) method were performed to investigate their growth mechanism. The simulations suggest that the nanoparticles self-encapsulate to form single-wall nanooysters (SWNOs) by assisting the assembly of dangling carbon bonds, accompanied by migration of the metal particle inside the carbon structure. These calculations indicate that the structure of the oyster consists primarily of hexagons along with a few pentagons that are predominantly formed near the former nanohorn edges as a result of their fusion. Experimental observations of large diameter nanoparticles inside multiwall carbon shells indicate that migration and coalescence of many iron particles must occur, perhaps by the convergence of smaller SWNOs or carbon-coated Fe-nanoparticles, whereby the void space is generated by the corresponding increase in the carbon shell surface area to metal nanoparticle volume. Electronic supplementary information (ESI) available: Final structures of trajectories A-J at 1500 K and 2500 K. See DOI: 10.1039/c2nr31788e

  15. Semiconducting single-walled carbon nanotubes sorting with a removable solubilizer based on dynamic supramolecular coordination chemistry

    NASA Astrophysics Data System (ADS)

    Toshimitsu, Fumiyuki; Nakashima, Naotoshi

    2014-10-01

    Highly pure semiconducting single-walled carbon nanotubes (SWNTs) are essential for the next generation of electronic devices, such as field-effect transistors and photovoltaic applications; however, contamination by metallic SWNTs reduces the efficiency of their associated devices. Here we report a simple and efficient method for the separation of semiconducting- and metallic SWNTs based on supramolecular complex chemistry. We here describe the synthesis of metal-coordination polymers (CP-Ms) composed of a fluorene-bridged bis-phenanthroline ligand and metal ions. On the basis of a difference in the ‘solubility product’ of CP-M-solubilized semiconducting SWNTs and metallic SWNTs, we readily separated semiconducting SWNTs. Furthermore, the CP-M polymers on the SWNTs were simply removed by adding a protic acid and inducing depolymerization to the monomer components. We also describe molecular mechanics calculations to reveal the difference of binding and wrapping mode between CP-M/semiconducting SWNTs and CP-M/metallic SWNTs. This study opens a new stage for the use of such highly pure semiconducting SWNTs in many possible applications.

  16. Semiconducting single-walled carbon nanotubes sorting with a removable solubilizer based on dynamic supramolecular coordination chemistry.

    PubMed

    Toshimitsu, Fumiyuki; Nakashima, Naotoshi

    2014-01-01

    Highly pure semiconducting single-walled carbon nanotubes (SWNTs) are essential for the next generation of electronic devices, such as field-effect transistors and photovoltaic applications; however, contamination by metallic SWNTs reduces the efficiency of their associated devices. Here we report a simple and efficient method for the separation of semiconducting- and metallic SWNTs based on supramolecular complex chemistry. We here describe the synthesis of metal-coordination polymers (CP-Ms) composed of a fluorene-bridged bis-phenanthroline ligand and metal ions. On the basis of a difference in the 'solubility product' of CP-M-solubilized semiconducting SWNTs and metallic SWNTs, we readily separated semiconducting SWNTs. Furthermore, the CP-M polymers on the SWNTs were simply removed by adding a protic acid and inducing depolymerization to the monomer components. We also describe molecular mechanics calculations to reveal the difference of binding and wrapping mode between CP-M/semiconducting SWNTs and CP-M/metallic SWNTs. This study opens a new stage for the use of such highly pure semiconducting SWNTs in many possible applications. PMID:25277810

  17. Single-walled metal oxide nanotubes and nanotube membranes for molecular separations

    NASA Astrophysics Data System (ADS)

    Kang, Dun-Yen

    Single-walled nanotubes have been considered essential “building-blocks” in nanotechnology and emerging materials for molecular recognition-based applications, such as molecular sensing, catalysis, and separations. Two critical obstacles in the development of functional nanotube-based devices are: (a) the difficulty of creating diverse functionality at the interior surfaces of single-walled nanotubes, and (b) the lack of effective approaches for fabricating scalable technological platforms with nanotube materials. This thesis describes my work addressing key fundamental issues in nanotube science and technology; particularly regarding the synthesis, characterization, and functionalization of single-walled metal oxide nanotubes (SWNTs) (Chapters 2, 3, 4),and approaches for applying SWNTs in scalable separation platforms for potentially achieving high performance (Chapters 5, 6, 7). The above, rather ambitious, objectives were addressed in a step-wise manner in this work. First, I acquired a detailed fundamental understanding of the inner surface properties of aluminosilicate SWNTs (Chapter 2). The investigations included elucidating molecular level details of dehydration and dehydroxylation phenomena in aluminosilicate single-walled nanotubes with a combination of several temperature-dependent solid-state characterization techniques. Critical information from this study enables a number of subsequent processes such as interior modification, molecular transport, and controlled delivery of molecules. In Chapter 3, a successful post-synthesis interior functionalization methodology is discussed, with the appropriately dehydrated or dehydroxylated nanotubes as the starting materials. Through surface reactions involving organosilane precursors and the inner wall of the nanotube, diverse organic entities can be immobilized at the inner surface of aluminosilicate nanotubes and thereby the hydrophilicity and interior surface properties can be tailored. This study was the first unambiguous demonstration of covalent modification of the interior of single-walled nanotube materials. The investigations in Chapter 4 reveal a direct (in situ) route for synthesizing organic-functionalized alumino-silicate nanotubes via the use of organosilanes with functional groups in the synthesis itself (as opposed to post-synthesis modification). This work creates a one-step route for the incorporation of functional groups at the interior of nanotubes, thus bypassing the limitations of the low functional group loading as well as additional processing steps in the post-synthesis functionalization methodology of Chapter 3. The two functionalization methods developed (post-synthesis and direct functionalization) together may enable a range of applications of nanotube materials, including separations, catalysis, and molecular capture/encapsulation/storage. The direction of the work then turned to the fabrication of nanotube-containing membranes. In view of the absence of a good predictive model for the performance of nanotube-containing membranes, Chapter 5 describes the development of analytical models for quantitatively predicting the separation properties of composite membranes containing (nano)tubular fillers. These models provide useful guidance for evaluating/optimizing existing nanotube-based membranes as well as preparing nanotube-based membranes with novel device architectures and enhanced separation performance. In Chapter 6, the fabrication and characterization of free-standing nanotube/ polymer composite membranes with good organic-inorganic interface adhesion and good nanotube dispersion is discussed. A detailed investigation of the structure and propreties of these membranes (at nano-, micro-, and macro- length scales) is presented. It is shown that hese nanocomposite membranes could be effectively used to construct scalable membrane separation devices. This work is the first demonstration of a defect-free membrane containing well-dispersed nanotube materials. Molecular level insights on the morphological changes of polymer chains due to

  18. Current and arc pushing force effects on the synthesis of single-walled carbon nanotubes by arc discharge.

    PubMed

    Zhao, Tingkai; Liu, Yongning; Li, Tiehu; Zhao, Xiang

    2010-06-01

    The current and arc pushing force of arcing process effects on the synthesis of single-walled carbon nanotubes were investigated by a temperature-controlled arc discharging furnace with Co-Ni alloy powder as catalyst at 600 degrees C. By experimental investigations, the optimal parameters of the process were obtained. The appropriate conditions included the current and arc pushing force of arcing process was 100 A and 80 A respectively, the buffer gas was helium and the gas pressure was kept at 500 torr. The experimental results indicated that the cooperative function of current and arc pushing force of arcing process played an important role in the production rate and purity of single-walled carbon nanotubes. The uniform diameter of single-walled carbon nanotubes was about 1.27 nm and the production rate was about 7 g/h and the purity was around 70%. PMID:20355418

  19. Electro-oxidized Epitaxial Graphene Channel Field-Effect Transistors with Single-Walled Carbon Nanotube Thin Film

    E-print Network

    with previous work on the fullerenes 21,22 and carbon nanotubes.23-27 The rich covalent chemistry availableElectro-oxidized Epitaxial Graphene Channel Field-Effect Transistors with Single-Walled Carbon Nanotube Thin Film Gate Electrode Palanisamy Ramesh, Mikhail E. Itkis, Elena Bekyarova

  20. Large-Scale Production of Single-Walled Carbon Nanotubes Using Ultrafast Pulses from a Free Electron Laser

    Microsoft Academic Search

    P. C. Eklund; B. K. Pradhan; U. J. Kim; Q. Xiong; J. E. Fischer; A. D. Friedman; B. C. Holloway; M. W. Smith

    2002-01-01

    We report the first use of ultrafast (subpicosecond) laser pulses for large-scale production of single wall carbon nanotubes (SWNT's) by the pulsed laser vaporization (PLV) technique. Very high production rates were achieved; using only 20% of the nominal average power of the 1 kW Jefferson Lab free electron laser (Jlab FEL), carbon soots rich in high quality bundles of SWNT's

  1. Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect of Alignment and Selective Breakdown

    E-print Network

    with a limited number of nano- tubes aligned across the electrodes as a consequence of mechanical flowFull Paper Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect DOI: 10.1002/elan.200900314 1. Introduction Carbon nanotubes have many potential applications

  2. Transfer-matrix simulations of electronic transport in single-wall and multi-wall carbon nanotubes

    E-print Network

    Mayer, Alexandre

    transport properties of carbon nano- tubes are another interesting aspect of these structures (see [7 law [1­4] with an emitter work function around 5eV depending on the type of nano- tube. They are alsoTransfer-matrix simulations of electronic transport in single-wall and multi-wall carbon nanotubes

  3. Effect of Mild Nitric Acid Oxidation on Dispersability, Size, and Structure of Single-Walled Carbon Nanotubes

    E-print Network

    Resasco, Daniel

    Effect of Mild Nitric Acid Oxidation on Dispersability, Size, and Structure of Single-Walled Carbon) with nitric acid increases their dispersability in water, methanol, and N,N-dimethylformamide. Two oxidation conditions carefully. Nitric acid has been the most frequently utilized agent for oxidation of carbon

  4. Theoretical Elastic Properties of Single Walled Carbon Nanotubes J. T. Alford, B. A. Landis, J. W. Mintmire

    E-print Network

    Mintmire, John W.

    materials. SWNTs are extremely promising as a fiber in composites to strengthen materials due to their low. Mintmire Department of Physics Oklahoma State University Stillwater, OK 74078-3072 Abstract Carbon fiber graphite. #12;- 2 - Introduction Single-walled carbon nanotubes (SWNTs) have attracted considerable

  5. Gas sensing with long, diffusively contacted single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kaul, Anupama B.

    2009-04-01

    A carbon nanotube thermal-conductivity-based pressure or gas sensor is described, which utilizes 5-10 µm long, diffusively contacted single-walled nanotubes (SWNTs). Low temperature electrical transport measurements for these tubes were suggestive of a thermally activated hopping mechanism for electron localization, where a hopping energy of ~39 meV was computed. A negative differential conductance regime was also detected in suspended tubes, released using critical point drying, at high bias voltages. The pressure or gas sensitivity increased more dramatically as the bias power was increased up to 14 µW, which was interpreted in the context of the high optical phonon density in the suspended SWNTs. Such devices are promising for use as pressure sensors, as well as for the chemical identification of species having differing gas thermal conductivities.

  6. Gold deposition effects on photoluminescence and Raman scattering spectra of suspended single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ozao, Akihiko; Chiashi, Shohei; Watanabe, Satoshi; Yamaguchi, Genta; Kato, Hiroki; Homma, Yoshikazu

    2015-05-01

    Gold (Au) deposition effects on suspended single-walled carbon nanotubes (SWCNTs) were investigated by photoluminescence (PL) and Raman scattering spectroscopies. Deposited Au atoms formed particles on the SWCNT surface. The PL intensity decreased with increasing Au coverage, while the enhancement of the G-band in Raman scattering spectra was observed owing to the surface-enhancement Raman scattering (SERS) effect. The changes in the optical transition energy obtained from the PL spectra and Raman shift of the G-band revealed that tensile strain, which reached 5 × 10?3, occurred along the tube axis and was proportional to the Au coverage. The Au coverage dependence of the uniaxial strain can be understood in terms of the difference in the thermal expansion between SWCNT and Au.

  7. Investigation of Aromatic/Aliphatic Polyimides as Dispersants for Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delozier, Donavon M.; Watson, Kent A.; Smith, Joseph G., Jr.; Clancy, Thomas C.; Connell, John W.

    2006-01-01

    Novel aromatic/aliphatic polyimides were prepared from 2,7-diamino-9,9'- dioctylfluorene (AFDA) and aromatic dianhydrides. Upon investigating the effectiveness of these polyimides for dispersing single wall carbon nanotubes (SWNTs) in solution, three were discovered to disperse SWNTs in N,N-dimethylacetamide (DMAc). Two of these polyimides, one from 3,3',4,4'-oxydiphthalic anhydride (ODPA) and one from symmetric 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), were used to prepare nanocomposites. Homogeneous polyimide/SWNT suspensions from both polymers were used in the preparation of films and fibers containing up to 1 wt% SWNTs. The samples were thermally treated to remove residual solvent and the films were characterized for SWNT dispersion by optical and high resolution scanning electron microscopy (HRSEM). Electrical and mechanical properties of the films were also determined. Electrospun fibers were examined by HRSEM to characterize SWNT alignment and orientation.

  8. Molecular scale buckling mechanics in individual aligned single-wall carbon nanotubes on elastomeric substrates.

    PubMed

    Khang, Dahl-Young; Xiao, Jianliang; Kocabas, Coskun; MacLaren, Scott; Banks, Tony; Jiang, Hanqing; Huang, Yonggang Y; Rogers, John A

    2008-01-01

    We have studied the scaling of controlled nonlinear buckling processes in materials with dimensions in the molecular range (i.e., approximately 1 nm) through experimental and theoretical studies of buckling in individual single-wall carbon nanotubes on substrates of poly(dimethylsiloxane). The results show not only the ability to create and manipulate patterns of buckling at these molecular scales, but also, that analytical continuum mechanics theory can explain, quantitatively, all measurable aspects of this system. Inverse calculation applied to measurements of diameter-dependent buckling wavelengths yields accurate values of the Young's moduli of individual SWNTs. As an example of the value of this system beyond its use in this type of molecular scale metrology, we implement parallel arrays of buckled SWNTs as a class of mechanically stretchable conductor. PMID:18072798

  9. Dependence of single-walled carbon nanotube adsorption kinetics on temperature and binding energy.

    PubMed

    Rawat, D S; Krungleviciute, V; Heroux, L; Bulut, M; Calbi, M M; Migone, A D

    2008-12-01

    We present results for the isothermal adsorption kinetics of methane, hydrogen, and tetrafluoromethane on closed-ended single-walled carbon nanotubes. In these experiments, we monitor the pressure decrease as a function of time as equilibrium is approached, after a dose of gas is added to the cell containing the nanotubes. The measurements were performed at different fractional coverages limited to the first layer. The results indicate that, for a given coverage and temperature, the equilibration time is an increasing function of E/(k(B)T), where E is the binding energy of the adsorbate and k(B)T is the thermal energy. These findings are consistent with recent theoretical predictions and computer simulations results that we use to interpret the experimental measurements. PMID:18954094

  10. Photoinduced charge transfer and acetone sensitivity of single-walled carbon nanotube-titanium dioxide hybrids.

    PubMed

    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

  11. Preparing a magnetically responsive single-wall carbon nanohorn colloid by anchoring magnetite nanoparticles.

    PubMed

    Utsumi, Shigenori; Urita, Koki; Kanoh, Hirofumi; Yudasaka, Masako; Suenaga, Kazutomo; Iijima, Sumio; Kaneko, Katsumi

    2006-04-13

    A single-wall carbon nanohorn (SWNH) colloid was made to be magnetically responsive by anchoring magnetite nanoparticles prepared by the homogeneous mixing of FeCl(2)-FeCl(3) and NaOH solutions. Transmission electron microscopy observation showed the high dispersion of magnetite particles of 2-9 nm on the surface of the SWNH colloid, coinciding with the broad X-ray diffraction peaks of the magnetites. The magnetization measurements showed that the magnetite nanoparticles-anchored SWNH (mag-SWNH) colloid has the hybrid property of ferrimagnetism and superparamagnetism. It was demonstrated that mag-SWNH colloid dispersed in water by sonication responded to an external magnetic field, gathering toward a magnet. N(2) adsorption experiments showed the high nanoporosity of mag-SWNHs and that magnetite nanoparticles were preferably anchored at "nanowindow" sites and the entrance sites of interstitial pores. This magnetically responsive SWNH colloid should contribute to the field of drug delivery. PMID:16599481

  12. Photophysical properties of zinc phthalocyanine-uridine single walled carbon nanotube - conjugates

    NASA Astrophysics Data System (ADS)

    Ogbodu, Racheal O.; Amuhaya, Edith K.; Mashazi, Philani; Nyokong, Tebello

    2015-10-01

    The photophysical properties of the conjugate of uridine and zinc mono carboxy phenoxy phthalocyanine (ZnMCPPc-uridine, 4) are reported in this work. The conjugate was also adsorbed onto single walled carbon nanotubes (ZnMCPPc-uridine-SWCNT, 5). The X-ray photoelectron spectroscopy of 4 showed three N 1s peaks while that of 5 showed four N 1s peak, a new peak at 399.4 eV of 5 was assigned to pyrrolidonic nitrogen, due to the interaction of the pyrrolic nitrogen of 4 with the oxygen moiety of SWCNT-COOH in 5. The triplet lifetime, triplet and singlet oxygen quantum yields of the zinc mono carboxy phenoxy phthalocyanine increased by over 40% in the presence of uridine. SWCNTs resulted in only a small quenching of the triplet state parameters of 4.

  13. Phonon thermal conductivities of single-walled carbon nanotubes and the graphene limit

    NASA Astrophysics Data System (ADS)

    Lindsay, L.; Broido, D. A.; Mingo, N.

    2010-03-01

    We employ a recently developed Boltzmann transport approach to calculate the intrinsic lattice thermal conductivity of a wide range of chiral and large-diameter single-walled carbon nanotubes. This approach uses a Tersoff empirical interatomic potential [1] and exploits symmetry based selection rules for anharmonic phonon-phonon scattering [2]. We also use this Boltzmann transport approach to calculate the thermal conductivity of graphene where we find an additional selection rule that strongly limits the anharmonic phonon-phonon scattering of out-of-plane modes. The phonon dispersion curves and thermal conductivities of successively larger diameter nanotubes approach that of two-dimensional graphene. [1] J. Tersoff, Phys. Rev. Lett. 61, 2879 1988 [2] L. Lindsay, D. A. Broido, and N. Mingo, Phys. Rev. B 80, 125407 (2009).

  14. Long-term stem cell labeling by collagen-functionalized single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Mao, Hongli; Cai, Rong; Kawazoe, Naoki; Chen, Guoping

    2014-01-01

    The monitoring of grafted stem cells is crucial to assess the efficiency, effectiveness and safety of such stem cell-based therapies. In this regard, a reliable and cytocompatible labeling method for stem cells is critically needed. In this study, the collagen-functionalized single-walled carbon nanotubes (Col-SWCNTs) were used as imaging probes for labeling of human mesenchymal stem cells (hMSCs) and the inherent Raman scattering of SWCNTs was used to image the SWCNT-labeled cells. The results showed that the Col-SWCNTs exhibit efficient cellular internalization by hMSCs without affecting their proliferation and differentiation. The prolonged dwell time of Col-SWCNTs in cells ensured the long-term labeling for up to 2 weeks. This work reveals the potential of Col-SWCNTs as probes for long-term stem cell labeling.

  15. Interaction of single-walled carbon nanotubes with poly(propyl ether imine) dendrimers

    SciTech Connect

    Jayamurugan, G.; Rajesh, Y. B. R. D.; Jayaraman, N. [Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012 (India); Vasu, K. S.; Kumar, S.; Sood, A. K. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Vasumathi, V.; Maiti, P. K. [Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2011-03-14

    We study the complexation of nontoxic, native poly(propyl ether imine) dendrimers with single-walled carbon nanotubes (SWNTs). The interaction was monitored by measuring the quenching of inherent fluorescence of the dendrimer. The dendrimer-nanotube binding also resulted in the increased electrical resistance of the hole doped SWNT, due to charge-transfer interaction between dendrimer and nanotube. This charge-transfer interaction was further corroborated by observing a shift in frequency of the tangential Raman modes of SWNT. We also report the effect of acidic and neutral pH conditions on the binding affinities. Experimental studies were supplemented by all atom molecular dynamics simulations to provide a microscopic picture of the dendrimer-nanotube complex. The complexation was achieved through charge transfer and hydrophobic interactions, aided by multitude of oxygen, nitrogen, and n-propyl moieties of the dendrimer.

  16. Deformation of single-walled carbon nanotubes by interaction with graphene: a first-principles study.

    PubMed

    Wang, Xiao; Yang, Juan; Li, Ruoming; Jiang, Hong; Li, Yan

    2015-04-15

    The interaction between single-walled carbon nanotubes (SWNTs) and graphene were studied with first-principles calculations. Both SWNTs and single-layer graphene (SLG) or double-layer graphene (DLG) display more remarkable deformations with the increase of SWNT diameter, which implies a stronger interaction between SWNTs and graphene. Besides, in DLG, deformation of the upper-layer graphene is less than in SLG. Zigzag SWNTs show stronger interactions with SLG than armchair SWNTs, whereas the order is reversed for DLG, which can be interpreted by the mechanical properties of SWNTs and graphene. Density of states and band structures were also studied, and it was found that the interaction between a SWNT and graphene is not strong enough to bring about obvious influence on the electronic structures of SWNTs. PMID:25689637

  17. Haldane State Formed by Oxygen Molecules Encapsulated in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Hagiwara, Masayuki; Ikeda, Masami; Kida, Takanori; Matsuda, Kazuyuki; Tadera, Shin; Kyakuno, Haruka; Yanagi, Kazuhiro; Maniwa, Yutaka; Okunishi, Kouichi

    2014-11-01

    We report on the results of X-ray diffraction (XRD), magnetic susceptibility, and high-field magnetization measurements of oxygen molecules, which are unique magnetic homonuclear diatomic molecules with spin-1, encapsulated in single-walled carbon nanotubes (SWCNTs) with diameters of about 0.8 nm. Antiferromagnetic interactions between neighboring oxygen molecules are expected in SWCNTs, resulting in the formation of a spin-1 one-dimensional Heisenberg antiferromagnet, known as a Haldane magnet. The XRD pattern can be predicted accurately by considering the expected oxygen molecule alignment. The temperature evolution of the magnetic susceptibility and the high-field magnetization curve are typical of those for a Haldane magnet with spin-1. The results indicate that the Haldane state has been realized in a nanospaced material for the first time. This provides an alternative to the conventional condensed matter approach to forming quantum spin systems.

  18. Predicting excitonic gaps of semiconducting single walled carbon nanotubes from a field theoretic analysis

    DOE PAGESBeta

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-01

    We demonstrate that a non-perturbative 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. Wemore »test this theory explicitly on the data reported in NanoLetters 5, 2314 (2005) and Phys. Rev. B 82, 195424 (2010) and so demonstrate the method works over a wide range of reported excitonic spectra.« less

  19. Charge trapping in aligned single-walled carbon nanotube arrays induced by ionizing radiation exposure

    SciTech Connect

    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.

  20. Hybrid solar cells based on single-walled carbon nanotubes/Si heterojunctions.

    PubMed

    Ong, Pang-Leen; Euler, William B; Levitsky, Igor A

    2010-03-12

    Photovoltaic devices based on single-walled carbon nanotubes (SWNTs) and n-silicon heterojunctions have been fabricated by a spray deposition process. We provide direct evidence that nanotubes serve as an active photosensing material involved directly in the photon absorption process as well as contributing to charge separation, transport and collection. The characteristic band of the SWNT band in the photoconductivity spectrum matches the S(11) absorption band of semiconducting SWNTs of 7,6 chirality. Centrifugation of the SWNTs provides two fractions. The sediment fraction exhibits a conversion efficiency ( approximately 1.7%) higher by a factor of eight compared to the supernatant fraction. SEM images and conductivity measurements show that the SWNT network morphology of the sediment fraction has longer and thicker nanotube bundles forming highly porous films, accounting for the enhanced conductivity and higher transparency. PMID:20157233

  1. The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Bagatskii, M. I.; Barabashko, M. S.; Dolbin, A. V.; Sumarokov, V. V.; Sundqvist, B.

    2012-06-01

    The specific heat at constant pressure C(T) of bundles of single-walled carbon nanotubes (SWNTs) closed at their ends has been investigated in the temperature interval of 2-120 K. It is found that the curve C(T) has features near 5, 36, 80, and 100 K. The experimental results on the C(T) and the radial thermal expansion coefficient ?R(T) of bundles of SWNTs oriented perpendicular to the sample axis have been compared. It is found that the curves C(T) and ?R(T) exhibit a similar temperature behavior at T > 10 K. The temperature dependence of the Grüneisen coefficient ?(T) has been calculated. The curve ?(T) also has a feature near 36 K. Above 36 K the Grüneisen coefficient is practically independent of temperature (? ~ 4). Below 36 K, ?(T) decreases monotonically with lowering temperature and becomes negative at T < 6 K.

  2. The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Bagatskii, M. I.; Barabashko, M. S.; Dolbin, A. V.; Sumarokov, V. V.; Sundqvist, B.

    2012-06-01

    The specific heat at constant pressure C(T) of bundles of single-walled carbon nanotubes (SWNTs) closed at their ends has been investigated in the temperature interval of 2-120 K. It is found that the curve C(T) has features near 5, 36, 80, and 100 K. The experimental results on the C(T) and the radial thermal expansion coefficient ?R(T) of bundles of SWNTs oriented perpendicular to the sample axis have been compared. It is found that the curves C(T) and ?R(T) exhibit a similar temperature behavior at T > 10 K. The temperature dependence of the Grüneisen coefficient ?(T) has been calculated. The curve ?(T) also has a feature near 36 K. Above 36 K the Grüneisen coefficient is practically independent of temperature (? ? 4). Below 36 K, ?(T) decreases monotonically with lowering temperature and becomes negative at T < 6 K.

  3. Suspended single-walled carbon-nanotube field-effect transistor for gas sensing application

    NASA Astrophysics Data System (ADS)

    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.

  4. Photoluminescence saturation independent of excitation pathway in air-suspended single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Xiao, Yee-fang; Anderson, Mitchell D.; Fraser, James M.

    2014-06-01

    Photoluminescence (PL) spectroscopy is a useful probe of excitonic interactions in optically excited nanostructures. Under intense optical excitation, the diffusion-annihilation of excitons in single-walled carbon nanotubes (SWCNTs) results in strong nonlinear PL. This behavior has been observed in a number of samples and has, until recently, been believed to be independent of excitation pathway. Contrary to this assumption, recent studies show that nonlinear PL in encapsulated SWCNTs, excited resonant to E22, is not dominated by diffusion-annihilation but instead by laser induced quenching sites. In this paper, we show that, unlike encapsulated SWCNTs, air-suspended SWCNT PL saturation is independent of excitation pathway, validating the use of a diffusion model for excitons generated via E22 excitation. In addition, we show that the diffusion of excitons in air-suspended SWCNTs is independent of atmospheric adsorbates, strengthening the assertion that in this system exciton diffusion is intrinsic and not disorder limited.

  5. Alignment and Alignment Modulation of Single Wall Carbon Nanotubes Using Lyotropic Chromonic Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Islam, M. F.; Smalyukh, I. I.; Lavrentovich, O. D.; Yodh, A. G.

    2006-03-01

    We report alignment and local alignment modulation of single wall carbon nanotubes (SWNTs) dispersed in a nematic solvent of lyotropic chromonic liquid crystals (LCLCs). Polarized optical absorption suggests that when SWNTs are coated with surfactant molecules, e.g., sodium dodecyl benzene sulfonate (NaDDBS), the SWNTs align along the nematic director of the LCLCs, possibly due to elastic interaction between the anisotropic SWNTs and the nematic field of the LCLCs. In contrast, if the SWNTs are not coated with surfactant, then SWNTs align normal to the LCLC nematic director, possibly due to ?-? interactions between the aromatic groups of the LCLCs and the graphitic surface of SWNTs. We describe these observations and show that SWNTs can easily be realigned via realignment of nematic LCLCs using a magnetic field of only a few KGauss. This work is supported by grants from NSF (MRSEC DMR 05-20020 and DMR-0505048) and NASA NAG8-2172.

  6. Effects of electron exchange-correlation potential on electrostatic oscillations in single-walled carbon nanotubes

    SciTech Connect

    Khan, S. A., E-mail: sakhan@ncp.edu.pk; Hassan, Sunia [National Centre for Physics, Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan)

    2014-05-28

    Using macroscopic quantum hydrodynamic formulation, we study the dispersion properties of electrostatic electron plasma oscillations in single-walled carbon nanotubes. The electrons and ions are considered uniformly distributed over the cylindrical surface of a nanotube thus forming a two-component (electron-ion) quantum plasma system. Electron degeneracy via Fermi-Dirac statistics as well as electron exchange and correlation effects is taken into account. It is found that the quantum (Bohm) potential arising due to fermionic nature of electrons and exchange-correlations effects has significant impact on the wave. The frequency of wave is influenced by variation in azimuthal index and radius of the nanotube. The results are analyzed numerically for typical systems for relatively longer wavelength waves and possible consequences are discussed. The results can be important in general understanding of the role of exchange-correlation potential in quantum hydrodynamic treatment of charge-carriers in nanotubes.

  7. Photodynamic effect of functionalized single-walled carbon nanotubes: a potential sensitizer for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Shi, Jinjin; Liu, Ruiyuan; Liu, Yan; Zhang, Jing; Yu, Xiaoyuan; Gao, Jun; Zhang, Chaofeng; Zhang, Zhenzhong

    2014-04-01

    Single-walled carbon nanotubes (SWNTs) possess unique physical and chemical properties, which make them very attractive for a wide range of applications. In particular, SWNTs and their composites have shown a great potential for photodynamic therapy (PDT). SWNTs have usually been used for photothermal therapy; herein, the photodynamic effect of two functionalized SWNTs are detected under visible light illumination in vitro and in vivo. The results indicated that the photodynamic effect is not entirely dependent on illumination time, but also on the modification method of the SWNTs. The ability of SWNTs complexes to combine with photodynamic therapy significantly improved the therapeutic efficacy of cancer treatment, and the combined treatment demonstrated a synergistic effect. These findings suggest that the SWNTs composite has great potential as sensitizer for PDT.

  8. Single-walled carbon nanotube film-silicon heterojunction radioisotope betavoltaic microbatteries

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Chang, Yiyang; Zhang, Jinwen

    2014-05-01

    Ever since the appearance of nanomaterials and nanotechnologies, they have been used in almost every type of microbattery except for nuclear ones. Here we present a radioisotope betavoltaic (BV) microbattery based on a single-walled carbon nanotube (SWCNT) film that acts as a carrier separator. SWCNT film also provides a shortcut for carrier transportation. The energy conversion efficiency of a BV microbattery can reach up to 0.15% after the subtraction of the energy loss of beta particles in air and SWCNT film, proving that the SWCNT film-silicon heterojunction presents a promising configuration suitable for use in radioisotope BV microbatteries. Tracing the particle route, we achieved a charge collection rate of 59.9%, indicating that our device could potentially achieve higher performance. Primary strategies to improve the performance of the BV microbattery are discussed.

  9. The Effects of Single-Walled Carbon Nanotubes On Plant Growth

    NASA Astrophysics Data System (ADS)

    Ray, Matthew

    Nanotechnology is not only being used to enhance commercial goods but the research into the use of nanomaterials as soil and groundwater remediation options has been underway for some time. The research to date suggests that once CNTs have been taken up by humans, or other species they may cause inflammation, oxidative stress, cell damage, or adverse effects on cell performance. However, when considering the interactions between CNTs and plants cells or developing plants the outcomes are less certain and may be counterintuitive. Interactions between developing plants seem to show neutral or positive short-term effects. Research conducted thus far shows unfunctionalized single-walled carbon nanotubes, when suspended in an aquatic environment, seem to enhance the growth of plant life in the short term.

  10. Photoluminescence Imaging of Oxygen Doped Individual Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Yalcin, Sibel Ebru; Yamaguchi, Hisato; Galande, Charudatta; Crochet, Jared J.; Mohite, Aditya D.; Gupta, Gautam; Ma, Xuedan; Htoon, Han; Doorn, Stephen K.; Los Alamos National Laboratory Collaboration; Rice University Collaboration

    2014-03-01

    Semiconducting single-walled carbon nanotubes (SWNTs) are attractive candidates for near-IR optoelectronic applications. But they show low fluorescence quantum yield. Recent oxygen doping studies have shown that the quantum yield of the excitons can be enhanced by an order of magnitude due to the formation of local 0D sites on the SWNT surface. However, these studies have been limited to ensemble measurements. Understanding the dopant site, exciton migration and trapping dynamics on individual SWNTs is critical for controllably tuning the photo-physical behavior. We have studied ozonated individual (6,5) nanotubes as a function of progressive ozonation. We spatially resolved the pristine and doped state using visible and NIR sensitive cameras. We demonstrate PL imaging as a probe of the emission dynamics as a function of dopant concentration. The spectral studies show the red-shifted emission in the PL of the NTs due to the ozonated site.

  11. Spectroscopic investigation of electrochemically charged individual (6,5) single-walled carbon nanotubes.

    PubMed

    Schäfer, Sebastian; Cogan, Nicole M B; Krauss, Todd D

    2014-06-11

    Individual single-walled carbon nanotubes (SWNTs) of (6,5) chirality were investigated by means of optical spectroscopy while their charge state was controlled electrochemically. The photoluminescence of the SWNTs was found to be quenched at positive and negative potentials, where the onset and offset varied for each individual SWNT. We propose that differences in the local environment of the individual SWNT lead to a shift of the Fermi energy, resulting in a distribution of the oxidation and reduction potentials. The exciton emission energy was found to correlate with the oxidation and reduction potential. Further proof of a correlation was found by deliberately doping individual SWNTs and monitoring their photoluminescence spectral shift. PMID:24797608

  12. Triplet-triplet exciton interactions and delayed fluorescence in single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hertel, Tobias; Spath, Florian; Stich, Dominik; Kraus, Hannes; Sperlich, Andreas; Dyakonov, Vladimir

    2013-03-01

    We present pump-probe-, time-correlated single photon counting and spin-sensitive photoluminescence studies of semiconducting single-wall carbon nanotubes (SWNTs) which unambiguously identify triplet-triplet annihilation as the mechanism underlying a long-lived delayed fluorescence (DF) signal. DF decays with a t - 0 . 9 power-law, characteristic of diffusion-limited annihilation reactions in 1-dimensional systems. The experiments allow to determine triplet diffusion constants in SWNTs to be on the order of 1cm2s-1 and the triplet lifetime which is found to be 60 +/- 30 ?s . The experiments indicate that the rate of diffusion-limited photo-reactions, here exemplified by triplet-triplet annihilation, can be reduced by one-dimensional confinement. A comparison of optical transients in aqueous and organic solvent environments also indicates how polaron pair dynamics can be influenced by the environment.

  13. Immunoassay with single-walled carbon nanotubes as near-infrared fluorescent labels.

    PubMed

    Iizumi, Yoko; Okazaki, Toshiya; Ikehara, Yuzuru; Ogura, Mutsuo; Fukata, Shinsuke; Yudasaka, Masako

    2013-08-28

    The intrinsic photoluminescence of single-walled carbon nanotubes (CNTs) in the near-infrared (NIR) above 1000 nm makes them promising candidates for biological probes owing to low interference by bioorganic molecules and deep tissue penetration. We here demonstrate an immunoassay by using a NIR CNT labels conjugated to immunoglobulin G (IgG) antibodies. Most of the CNT-conjugated IgG was successfully immunoprecipitated with protein G-attached magnetic beads and eluted from them, which was confirmed by the NIR emission of the conjugated CNTs at 1000-1200 nm. The photoluminescence intensity of the CNT labels was strong enough to detect antigens at 600 pM by our simple procedures. PMID:23927721

  14. Mechanism of electrolyte-induced brightening in single-wall carbon nanotubes.

    PubMed

    Duque, Juan G; Oudjedi, Laura; Crochet, Jared J; Tretiak, Sergei; Lounis, Brahim; Doorn, Stephen K; Cognet, Laurent

    2013-03-01

    While addition of electrolyte to sodium dodecyl sulfate suspensions of single-wall carbon nanotubes has been demonstrated to result in significant brightening of the nanotube photoluminescence (PL), the brightening mechanism has remained unresolved. Here, we probe this mechanism using time-resolved PL decay measurements. We find that PL decay times increase by a factor of 2 on addition of CsCl as the electrolyte. Such an increase directly parallels an observed near-doubling of PL intensity, indicating the brightening results primarily from changes in nonradiative decay rates associated with exciton diffusion to quenching sites. Our findings indicate that a reduced number of these sites results from electrolyte-induced reorientation of the surfactant surface structure that partially removes pockets of water from the tube surface where excitons can dissociate, and thus underscores the contribution of interfacial water in exciton recombination processes. PMID:23421604

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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 environments. The solvatochromic shift depends on the structural properties of the nanotubes and reaches almost 100 milli-electron volts in the case of (7, 5) tubes. These experimental results allow deriving a relationship between the PL shift and the structure of SWNTs. Moreover, the dynamics of 'bright' excitons in semiconducting SWNTs and the effect of the medium on the decay of the excitons are discussed by using time-resolved spectroscopy.

  16. Ultrafast formation and decay dynamics of trions in p-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Koyama, Takeshi; Shimizu, Satoru; Miyata, Yasumitsu; Shinohara, Hisanori; Nakamura, Arao

    2013-04-01

    We present the formation and decay dynamics of a trion (charged exciton) and exciton system in chemically p-doped single-walled carbon nanotubes (SWNTs) investigated by time-resolved photoluminescence measurements at 300 K. In (6,5) SWNTs with hole densities in the range of 0.27-1.05 nm-1, a trion is formed from the coalescence of an exciton and a free hole, with a rate of 1.7×1013 nm s-1. The linear dependence of the trion decay rate on the hole density allows us to find that the trion decay is governed by both a trion-hole Auger recombination process and an internal Auger recombination process. The observed high efficiencies of Auger processes dominate over the radiative recombination rate of trions, which demonstrates dynamic properties of excitonic complexes in the presence of enhanced Coulomb interactions in one-dimensional systems.

  17. Controlling exciton decay dynamics in semiconducting single-walled carbon nanotubes by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Regler, M. E.; Krenner, H. J.; Green, A. A.; Hersam, M. C.; Wixforth, A.; Hartschuh, A.

    2013-02-01

    We show that the photoluminescence intensity and decay dynamics of semiconducting single-walled carbon nanotube films can be remotely controlled by surface acoustic waves (SAW) launched on the piezoelectric substrate LiNbO3. Time-resolved measurements in the picosecond regime reveal that photoluminescence quenching results from a decrease of the radiative recombination rate by up to 25% for the accessible SAW amplitudes. The SAW-induced piezoelectric field acts as a quasi-static perturbation that polarizes the luminescent exciton state reducing the oscillator strength of the radiative transition following a quadratic field dependence. Surface acoustic waves could be used for the remote and contact-free electrical control of high-speed electronic and optoelectronic nanotube-based devices.

  18. Photoluminescence of Single-Walled Carbon Nanotubes: The Role of Stokes Shift and Impurity Levels

    NASA Astrophysics Data System (ADS)

    Mu, Jinglin; Ma, Yuchen; Yin, Huabing; Liu, Chengbu; Rohlfing, Michael

    2013-09-01

    Recent experiments have indicated that dopants and defects can trigger new redshifted photoluminescence (PL) peaks below the E11 peak in single-walled carbon nanotubes (SWCNTs). To understand the origin of the new PL peaks, we study theoretically the excited-state properties of SWCNTs with some typical dopants and defects by ab initio many-body perturbation theory. Our calculations demonstrate that the Stokes shift in doped centers can be as large as 170 meV, which is much larger than that of intact SWCNTs and must be taken into account. We find dipole-allowed transitions from localized midgap and shallow impurity levels, which can give rise to pronounced PL peaks. Dark excitons, on the other hand, seem to have oscillator strengths that are too small to account for the new PL peaks.

  19. Optical properties of graphene nanoribbons encapsulated in single-walled carbon nanotubes.

    PubMed

    Chernov, Alexander I; Fedotov, Pavel V; Talyzin, Alexandr V; Suarez Lopez, Inma; Anoshkin, Ilya V; Nasibulin, Albert G; Kauppinen, Esko I; Obraztsova, Elena D

    2013-07-23

    We report the photoluminescence (PL) from graphene nanoribbons (GNRs) encapsulated in single-walled carbon nanotubes (SWCNTs). New PL spectral features originating from GNRs have been detected in the visible spectral range. PL peaks from GNRs have resonant character, and their positions depend on the ribbon geometrical structure in accordance with the theoretical predictions. GNRs were synthesized using confined polymerization and fusion of coronene molecules. GNR@SWCNTs material demonstrates a bright photoluminescence both in infrared (IR) and visible regions. The photoluminescence excitation mapping in the near-IR spectral range has revealed the geometry-dependent shifts of the SWCNT peaks (up to 11 meV in excitation and emission) after the process of polymerization of coronene molecules inside the nanotubes. This behavior has been attributed to the strain of SWCNTs induced by insertion of the coronene molecules. PMID:23795665

  20. Photoluminescence of single-walled carbon nanotubes: the role of Stokes shift and impurity levels.

    PubMed

    Mu, Jinglin; Ma, Yuchen; Yin, Huabing; Liu, Chengbu; Rohlfing, Michael

    2013-09-27

    Recent experiments have indicated that dopants and defects can trigger new redshifted photoluminescence (PL) peaks below the E11 peak in single-walled carbon nanotubes (SWCNTs). To understand the origin of the new PL peaks, we study theoretically the excited-state properties of SWCNTs with some typical dopants and defects by ab initio many-body perturbation theory. Our calculations demonstrate that the Stokes shift in doped centers can be as large as 170 meV, which is much larger than that of intact SWCNTs and must be taken into account. We find dipole-allowed transitions from localized midgap and shallow impurity levels, which can give rise to pronounced PL peaks. Dark excitons, on the other hand, seem to have oscillator strengths that are too small to account for the new PL peaks. PMID:24116815