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Sample records for metallic single-wall carbon

  1. Metal-doped single-walled carbon nanotubes and production thereof

    DOEpatents

    Dillon, Anne C.; Heben, Michael J.; Gennett, Thomas; Parilla, Philip A.

    2007-01-09

    Metal-doped single-walled carbon nanotubes and production thereof. The metal-doped single-walled carbon nanotubes may be produced according to one embodiment of the invention by combining single-walled carbon nanotube precursor material and metal in a solution, and mixing the solution to incorporate at least a portion of the metal with the single-walled carbon nanotube precursor material. Other embodiments may comprise sputter deposition, evaporation, and other mixing techniques.

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

    NASA Technical Reports Server (NTRS)

    Sun, Ya-Ping (Inventor)

    2008-01-01

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

  3. Molecular dynamics simulation of metal coating on single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Inoue, Shuhei; Matsumura, Yukihiko

    2008-10-01

    Behaviors of various metals coating on single-walled carbon nanotubes are simulated by molecular dynamics. Some of the potential parameter sets are derived by DFT calculations. The results indicate that each metal species can be smoothly coated on an isolated carbon nanotube, depending on the coating condition; however, continuous coating may not always be possible. The equilibrium position on the carbon nanotube is fixed; therefore, the coating is discontinuous for a large sized atom to reduce the distortion. The diffusion rate of the metal atoms is expressed in terms of the ratios of the binding energies of metal-metal and metal-carbon bonds.

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

    SciTech Connect

    Chung, Hyun-Jong; Woo Uhm, Tae; Won Kim, Sung; Gyu You, Young; Wook Lee, Sang; Ho Jhang, Sung; Campbell, Eleanor E. B.; Woo Park, Yung

    2014-05-12

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

  5. First-principles study of transition-metal-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Mao, Yu-Liang; Yan, Xiao-Hong; Xiao, Yang

    2005-12-01

    We study the effect of doping transition metals (TMs) into single-wall carbon nanotubes by using first-principles calculations. For metallic isolated (3,3) single-wall carbon nanotubes, doping of Mn, Fe and Co makes them semi-metallic, while Ni doping leads to semiconductors. For (3,3) nanotube bundles, a Co atom in the unit cell makes it exhibit semiconductor character. With two or three Co and Ni atoms doped into the bundle, the impurity atoms change the nanotube to semi-metal. In particular, the Mn2C12 and Mn3C12 bundle have comparable large magnetic moments, suggesting that such TM-doped nanotubes could be useful as nanomagnets.

  6. Growth of metal-catalyst-free nitrogen-doped metallic single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Jin-Cheng; Hou, Peng-Xiang; Zhang, Lili; Liu, Chang; Cheng, Hui-Ming

    2014-09-01

    Nitrogen-doped (N-doped) single-wall carbon nanotubes (SWCNTs) were synthesized by chemical vapor deposition using SiOx nanoparticles as a catalyst and ethylenediamine as the source of both carbon and nitrogen. The N-doped SWCNTs have a mean diameter of 1.1 nm and a narrow diameter range, with 92% of them having diameters from 0.7 to 1.4 nm. Multi-wavelength laser Raman spectra and temperature-dependent electrical resistance indicate that the SWCNT sample is enriched with metallic nanotubes. These N-doped SWCNTs showed excellent electrocatalytic activity for the oxygen reduction reaction and highly selective and sensitive sensing ability for dopamine detection.Nitrogen-doped (N-doped) single-wall carbon nanotubes (SWCNTs) were synthesized by chemical vapor deposition using SiOx nanoparticles as a catalyst and ethylenediamine as the source of both carbon and nitrogen. The N-doped SWCNTs have a mean diameter of 1.1 nm and a narrow diameter range, with 92% of them having diameters from 0.7 to 1.4 nm. Multi-wavelength laser Raman spectra and temperature-dependent electrical resistance indicate that the SWCNT sample is enriched with metallic nanotubes. These N-doped SWCNTs showed excellent electrocatalytic activity for the oxygen reduction reaction and highly selective and sensitive sensing ability for dopamine detection. Electronic supplementary information (ESI) available: Additional information including Raman spectra, ORR polarization curves, CV curves, etc. See DOI: 10.1039/c4nr03172e

  7. 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.

  8. 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 .

  9. Novel in-situ decoration of single-walled carbon nanotube transistors with metal nanoparticles.

    PubMed

    Zhou, Jianyun; Barbara, Paola; Paranjape, Makarand

    2010-06-01

    The carbon nanotube-metal nanoparticle complex has attracted a lot of research interest because of their potential applications in catalysis and gas sensing. Here we introduce a novel electrochemical method to realize in-situ decoration of single-walled carbon nanotube field effect transistors (CNT-FET) with metal nanoparticles using a sacrificial electrode. In this process, metal atoms are first ionized into an electrolyte solution by applying a potential difference between the sacrificial electrode and the grounded source/drain electrodes connecting the nanotube of the CNT-FET. The positive metal ions migrate under the influence of the electric field, and deposit on the grounded nanotube as metal nanoparticles. This method provides for better control over the quantity and size of the deposited nanoparticles compared to other decoration methods. We demonstrate successful deposition of Au and Ag nanoparticles on carbon nanotube field effect devices, with the quantity and size of the nanoparticles varying as a function of the applied potential. We show that the metal nanoparticle size can vary from 10 nm to over 300 nm, and the spatial distribution can change from very scarce decoration to a near continuous coating. Such metal nanoparticles have potential applications in chemical sensors, as they interact with gas molecules and generate an electrical signal in the nanotube, which can be detected. They can also be explored as biological anchoring sites for bio-functionalization of the nanotube, which is critical to developing highly sensitive and selective bio-sensors. PMID:20355385

  10. Effects of hydrogen adsorption on single-wall carbon nanotubes: Metallic hydrogen decoration O. Gulseren,1,2

    E-print Network

    Yildirim, Taner

    Effects of hydrogen adsorption on single-wall carbon nanotubes: Metallic hydrogen decoration O. Gu of carbon nanotubes undergo dramatic changes with hydrogen chemisorption from first principle calculations other isomers can be insulating. For both zigzag and armchair nanotubes, hydrogenation of each carbon

  11. Selective Removal of Metallic Single-Walled Carbon Nanotubes with Small Diameters by Using Nitric and Sulfuric Acids

    E-print Network

    Kim, Bongsoo

    in a mixed solution of nitric and sulfuric acids (HNO3 and H2SO4), they did not report on the metallicitySelective Removal of Metallic Single-Walled Carbon Nanotubes with Small Diameters by Using Nitric and Sulfuric Acids Cheol-Min Yang, Jin Sung Park, Kay Hyeok An, Seong Chu Lim, Kwanyong Seo, Bongsoo Kim, Kyung

  12. Transport of metal oxide nanoparticles and single-walled carbon nanotubes in human mucus

    PubMed Central

    Jachak, Ashish; Lai, Samuel K; Hida, Kaoru; Suk, Jung Soo; Markovic, Nina; Biswal, Shyam; Breysse, Patrick N.; Hanes, Justin

    2015-01-01

    Whether mucus layers lining entrance points into the body, including the lung airways, provide protection against the penetration of engineered nanoparticles remains poorly understood. We measured the diffusion coefficients of hundreds of individual nanoparticles of three different metal oxides (nMeOs) and two types of single-walled carbon nanotubes (SWCNTs) in undiluted human mucus. We found that the vast majority of these nanoparticles are efficiently trapped in human mucus and, further, that the mechanism of trapping is adhesive interactions as opposed to steric obstruction. However, a small fraction of zinc oxide (ZnO) nanoparticles moved at rates fast enough to penetrate airway mucus layers. We conclude that human mucus layers probably provide considerable protection for mucosal tissues from the penetration of most nMeOs and SWCNTs, and suggest that further investigation of the potential health risks of exposure to ZnO nanoparticles is warranted. PMID:21800953

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

    NASA Astrophysics Data System (ADS)

    Cao, Zeyuan; Wei, Bingqing

    2015-05-01

    Nanocomposites consisting of transition-metal oxides and carbon nanomaterials with a desired size and structure are highly demanded for high performance energy storage devices. Here, a facile two-step and cost-efficient approach relying on directly thermal treatment of chemical-vapor-deposition products is developed as a general synthetic method to prepare a family of metal oxides (MxOy (M=Fe, Co, Ni))/single-walled carbon nanotube (SWNT) macrofilm nanocomposites. The MxOy nanoparticles obtained are of 3-17 nm in diameter and homogeneously anchor on the free-standing SWNT macrofilms. NiO/SWNT also exhibits a high specific capacitance of 400 F g-1 and fast charge-transfer Faradaic redox reactions to achieve asymmetric supercapacitors with a high power and energy density. All MxOy/SWNT nanocomposites could deliver a high capacity beyond 1000 mAh g-1 and show excellent cycling stability for lithium-ion batteries. The impressive results demonstrate the promise for energy storage devices and the general approach may pave the way to synthesize other functional nanocomposites.

  15. 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.

  16. Thermal analysis for laser selective removal of metallic single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Song, Jizhou; Li, Yuhang; Du, Frank; Xie, Xu; Huang, Yonggang; Rogers, John A.

    2015-04-01

    Single-walled carbon nanotubes (SWNTs) have been envisioned as one of the best candidates for future semiconductors due to their excellent electrical properties and ample applications. However, SWNTs grow as mixture of both metallic and semiconducting tubes and this heterogeneity hampers their practical applications. Laser radiation shows promises to remove metallic SWNTs (m-SWNTs) in air under an appropriate condition. We established a scaling law, validated by finite element simulations, for the temperature rise of m-SWNTs under a pulsed laser with a Gaussian spot. It is shown that the maximum normalized m-SWNT temperature rise only depends on two non-dimensional parameters: the normalized pulse duration time and the normalized interfacial thermal resistance. In addition, the maximum temperature rise is inversely proportional to the square of spot size and proportional to the incident laser power. These results are very helpful to understand the underlying physics associated with the removal process and provides easily interpretable guidelines for further optimizations.

  17. Thermal analysis for laser selective removal of metallic single-walled carbon nanotubes

    SciTech Connect

    Song, Jizhou; Li, Yuhang; Du, Frank; Xie, Xu; Rogers, John A.; Huang, Yonggang

    2015-04-28

    Single-walled carbon nanotubes (SWNTs) have been envisioned as one of the best candidates for future semiconductors due to their excellent electrical properties and ample applications. However, SWNTs grow as mixture of both metallic and semiconducting tubes and this heterogeneity hampers their practical applications. Laser radiation shows promises to remove metallic SWNTs (m-SWNTs) in air under an appropriate condition. We established a scaling law, validated by finite element simulations, for the temperature rise of m-SWNTs under a pulsed laser with a Gaussian spot. It is shown that the maximum normalized m-SWNT temperature rise only depends on two non-dimensional parameters: the normalized pulse duration time and the normalized interfacial thermal resistance. In addition, the maximum temperature rise is inversely proportional to the square of spot size and proportional to the incident laser power. These results are very helpful to understand the underlying physics associated with the removal process and provides easily interpretable guidelines for further optimizations.

  18. 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.

  19. Corrugation-induced metal-semiconductor transition in single-wall carbon nanotubes with a small radius

    NASA Astrophysics Data System (ADS)

    Lu, Hongxia; Wu, Jianbao; Zhang, Weiyi

    2013-07-01

    Armchair single-wall carbon nanotubes (SWCNTs) are theoretically predicted to be metallic in the simple zone-folding scheme and protected from the curvature effects. They are, however, found to be small-gap semiconductors, experimentally. Lacking the genuine band-gap opening mechanism for armchair SWCNTs, the Mott insulator concept was proposed previously for the nominally metallic carbon nanotubes. Using the ab initio local density approximation method, we show, in this paper, that the carbon nanotubes without corrugation are, in fact, not metastable. The corrugated structures are always lower in energy than those without corrugation. The size of corrugation increases rapidly with the nanotubes’ curvature and vanishes for flat graphene. The corrugation breaks the local symmetry between two types of carbon sites, and a true band gap starts to develop once graphene sheets are rolled up into nanotubes.

  20. Effect of first row transition metals on the conductivity of semiconducting single-walled carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Wang, Feihu; Itkis, Mikhail E.; Bekyarova, Elena B.; Tian, Xiaojuan; Sarkar, Santanu; Pekker, Aron; Kalinina, Irina; Moser, Matthew L.; Haddon, Robert C.

    2012-05-01

    We demonstrate the ability of first row transition metals to form electrically conducting interconnects between semiconducting single-walled carbon nanotubes (SWNTs) by constructive rehybridization between sidewall benzene rings as a result of the formation of bis-hexahapto-metal-bonds [(?6-SWNT)M(?6-SWNT)], which bridge adjacent SWNTs. Metal deposition on SWNT films enhances the conductivity by three distinct mechanisms: physisorption of gold leads to the formation of a non-interacting gold film and a monotonic conductivity increase; ionic chemisorption of lithium strongly increases the conductivity due to charge transfer to the SWNTs; covalent chemisorption of first row transition metals leads to an abrupt change in conductivity due to formation of (?6-SWNT)M(?6-SWNT) interconnects.

  1. 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.

  2. Rare-earth metal halogenide encapsulation-induced modifications in Raman spectra of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kharlamova, M. V.

    2015-01-01

    In the present work, a detailed Raman spectroscopy investigation on the single-walled carbon nanotubes (SWCNTs) filled with praseodymium chloride, terbium chloride and thulium chloride was performed. The salts were incorporated inside the SWCNTs by a capillary filling method using melts, and the high-resolution transmission electron microscopy data proved the high filling degree of the nanotube channels. A thorough analysis of the radial breathing mode and G-band of the Raman spectra of the pristine and filled SWCNTs showed that the encapsulated salts cause acceptor doping of the host nanotubes, and the doping efficiency depends on the compound. The incorporated thulium chloride has the strongest doping effect on the SWCNTs, whereas praseodymium chloride has the weakest effect. It was found that the encapsulated salts modify more significantly the electronic structure of metallic nanotubes than semiconducting SWCNTs.

  3. 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.

  4. Effect of Lanthanide Metal Complexation on the Properties and Electronic Structure of Single-Walled Carbon Nanotube Films.

    PubMed

    Moser, Matthew L; Pekker, Aron; Tian, Xiaojuan; Bekyarova, Elena; Itkis, Mikhail E; Haddon, Robert C

    2015-12-30

    We spectroscopically analyze the effect of e-beam deposition of lanthanide metals on the electronic structure and conductivities of films of semiconducting (SC) single-walled carbon nanotubes (SWNTs) in high vacuum. We employ near-infrared and Raman spectroscopy to interpret the changes in the electronic structure of SWNTs on exposure to small amounts of the lanthanides (Ln = Sm, Eu, Gd, Dy, Ho, Yb), based on the behavior of the reference metals (M = Li, Cr) which are taken to exemplify ionic and covalent bonding, respectively. The analysis shows that while the lanthanides are more electropositive than the transition metals, in most cases they exhibit similar conductivity behavior which we interpret in terms of the formation of covalent bis-hexahapto bonds [(?(6)-SWNT)M(?(6)-SWNT), where M = La, Nd, Gd, Dy, Ho]. However, only M = Eu, Sm, Yb show the continually increasing conductivity characteristic of Li, and this supports our contention that these metals provide the first examples of mixed covalent-ionic bis-hexahapto bonds [(?(6)-SWNT)M(?(6)-SWNT), where M = Sm, Eu, Yb]. PMID:25902843

  5. Chirality assignment for metallic species via coherent phonon oscillations in arc-discharge single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Shin, Seong-Il; Lim, Yong-Sik; Kim, Myung Jong

    2015-09-01

    We performed transient absorption measurements with sub-10-fs pulses to observe coherent phonon (CP) oscillations of species in a micelle-suspended arc-discharge single-walled carbon nanotube (SWNT) ensemble. We applied a spectral-resolved measurement scheme to investigate the photon-wavelength dependence of CP oscillations of the radial breathing mode (RBM) specific to each species, covering a broad photon wavelength range from 700 to 1000 nm (1.771 - 1.240 eV). With a linear prediction singular value decomposition (LPSVD) method as a robust alternative for resolving closely-overlapped vibration modes, we divided multiple RBM peaks into two components, the M 11-excited metallic species and the S 22-excited semiconducting species, respectively. We resolved the RBM peaks into 22 metallic and 29 semiconducting species. Resolved metallic tubes showed a wide distribution in diameters from 1.3 to 2.3 nm, forming a chirality distribution from (2 n + m) = 33 family to 51 family.

  6. Influence of uniaxial strain on the linear optical spectra in the metallic single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yu, Guili; Li, Guichen; Jia, Yonglei; Tang, Gang

    2015-12-01

    The linear absorption spectra of metallic zigzag single-walled carbon nanotubes (SWNTs) have been theoretically studied under the uniaxial strain by using the standard formulas of Orr and Ward. Due to the trigonal warping effect, the linear absorption spectra of M11 and M22 transitions are dominated by two major peaks, which come from the split Mii- and Mii+ excitons with different band index q. As the uniaxial strain is applied, it is interesting to find that the split peaks will overlap at one point of the uniaxial strain, and the splitting is zero at this point. Hence, we can also describe this variation tendency as the size of splitting, which first decreases to zero and then increases with increasing the uniaxial strain, based on which a supplemented tool is offered to detect the deformation degree of a metallic SWNT under uniaxial strain. In addition, the linear absorption spectra of the bands that nearest to the Fermi level have also been calculated, displaying an increase with the increase of the uniaxial strain, which can offer some useful information for the THz applications. The results obtained here are expected to be confirmed by the future experiment.

  7. Raman spectroscopy of single wall carbon nanotubes

    E-print Network

    Son, HyungBin, 1981-

    2008-01-01

    A single wall carbon nanotube (SWNT) is a new form of carbon, whose atomic arrangement is equivalent to a graphene sheet rolled into a cylinder in a seamless way. The typical diameter of a SWNT ranges from 0.6 nm to several ...

  8. Metal nanoparticles and DNA co-functionalized single-walled carbon nanotube gas sensors.

    PubMed

    Su, Heng C; Zhang, Miluo; Bosze, Wayne; Lim, Jae-Hong; Myung, Nosang V

    2013-12-20

    Metal/DNA/SWNT hybrid nanostructure-based gas sensor arrays were fabricated by means of ink jet printing of metal ion chelated DNA/SWNTs on microfabricated electrodes, followed by electroless deposition to reduce metal ions to metal. DNA served as a dispersing agent to effectively solubilize pristine SWNTs in water and as metal ion chelating centers for the formation of nanoparticles. Noble metals including palladium, platinum, and gold were used because the high binding affinity toward specific analytes enhances the selectivity and sensitivity. The sensitivity and selectivity of the gas sensors toward various gases such as H2, H2S, NH3, and NO2 were determined at room temperature. Sensing results indicated the enhancement of the sensitivity and selectivity toward certain analytes by functionalizing with different metal nanoparticles (e.g., Pd/DNA/SWNTs for H2 and H2S). The combined responses give a unique pattern or signature for each analyte by which the system can identify and quantify an individual gas. PMID:24284477

  9. 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.

  10. 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

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

    NASA Astrophysics Data System (ADS)

    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

    2014-04-01

    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.

  12. Intra- and inter-tube exciton relaxation dynamics in high purity semiconducting and metallic single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ichida, Masao; Saito, Shingo; Miyata, Yasumitsu; Yanagi, Kazuhiro; Kataura, Hiromichi; Ando, Hiroaki

    2013-02-01

    We have measured the exciton and carrier dynamics in the high purity semiconducting (S-) and metallic (M-) single-walled carbon nanotubes (SWNTs) in the isolated and aggregated (bundled) forms. The exciton relaxation decay times are measured by using the pump-probe spectroscopy. For bundled samples, the relaxation time becomes shorter than that for isolated SWNTs sample, because of the existence of inter-tube relaxation. We estimate the relaxation rates from S-SWNT to S-SWNT and S-SWNT to M-SWNT using the decay times for isolated SWNTs, high purity S-SWNTs bundle, and doped S-SWNTs in high purity M-SWNTs bundle. For S-SWNTs, inter-tube relaxation plays an important role in the relaxation dynamics. However, for M-SWNTs, the inter-tube relaxation is not so important, and the transition energy and intensity of exciton in M-SWNTs is strongly affected by the photoexcited carriers which plays like as photo doping.

  13. Surfactant free fractions of metallic and semiconducting single-walled carbon nanotubes via optimised gel chromatography

    SciTech Connect

    Lukaszczuk, Pawel; Ruemmeli, Mark H.; Knupfer, Martin; Kalenczuk, Ryszard J.; Borowiak-Palen, Ewa

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The application of gel permeation chromatography technique in a field of SWCNT separation. Black-Right-Pointing-Pointer Non-commercial agarose gel used as a column filling. Black-Right-Pointing-Pointer Purification route is presented, quality and quantity estimation is shown. Black-Right-Pointing-Pointer Process is ready for high-scale separation of SWCNTs. -- Abstract: We report the procedure of sorting/purification of carbon nanotubes by electronic type using chromatographic column with sodium dodecylsulfate (SDS) and sodium deoxycholate (DOC) solutions as the eluents. The non-commercial agarose gel in different concentrations has been tested in the process. It was found that in optimal gel concentration the fractionation resulted in {approx}96.2% yield of semiconducting species. Importantly, to get surfactant-free fractions the post-separation purification procedure has been carried out. The UV-vis-NIR and Raman spectroscopy have been utilised for the samples analysis. High resolution transmission microscopy and thermogravimetric analysis allowed to study the sample morphology and purity, respectively.

  14. 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.

  15. Electrochemical and in situ studies of the insertion of alkali metals in single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Claye, Agnes Sandrine

    2000-10-01

    In this thesis, we used electrochemistry and in-situ techniques to investigate the mechanism for alkali insertion in single wall carbon nanotubes (SWNT) and the properties of these doped compounds. SWNT were reversibly doped electrochemically with Li and K, up to stoichiometries of Li1.27C6 and KC24. No first order phase transition vs. composition was observed, distinguishing this new carbon guest-host system from graphite, C60 and polyacetylene. Ion insertion and removal proceed on a wide range of potentials, yielding steep voltage profiles characteristic of electrochemical capacitors. In-situ X-ray diffraction showed that alkali insertion in SWNT does not yield crystalline superlattices, but creates irreversible structural disorder in the rope lattice. We explain the absence of ordered phase in doped SWNT by the polydispersity in tube diameters and symmetries within a rope. The effect of alkali doping on the electronic properties of SWNT was investigated using in-situ conductivity, in-situ electron spin resonance and in-situ Raman scattering. All three methods showed a reversible charge transfer between the dopants and the host, similar to that in graphite intercalation compounds. The conductivity and spin susceptibility of SWNT increase monotonically and reversibly with alkali concentration, and the SWNT tangential phonon mode is downshifted in frequency upon doping. These phenomena are reversible upon de-doping, showing that SWNT constitute the newest generation of synthetic metals, analogous to GICs, fullerides and polyacetylene. Finally, electrochemical impedance spectroscopy was used to study the diffusion kinetics of alkalis in SWNT. An equivalent circuit was developed to model the complex impedance of SWNT electrodes. Three processes with different time constants were identified: charge transfer across the electrode/electrolyte interface, diffusion through mats of bulk SWNT, and diffusion inside SWNT ropes. The diffusion kinetics of alkalis in SWNT were found to be similar to those in polyacetylene films. Based on these results, we propose an inhomogeneous structural model for alkali-doped SWNT, in which alkalis decorate the external and internal surfaces of the ropes. We believe that alkali-doped SWNT consist of small fully doped domains embedded into undoped or very lightly doped regions. As doping proceeds the number and/or size of these saturated domains increases until saturation.

  16. Strain Sensitivity in Single Walled Carbon Nanotubes for Multifunctional Materials

    NASA Technical Reports Server (NTRS)

    Heath, D. M. (Technical Monitor); Smits, Jan M., VI

    2005-01-01

    Single walled carbon nanotubes represent the future of structural aerospace vehicle systems due to their unparalleled strength characteristics and demonstrated multifunctionality. This multifunctionality rises from the CNT's unique capabilities for both metallic and semiconducting electron transport, electron spin polarizability, and band gap modulation under strain. By incorporating the use of electric field alignment and various lithography techniques, a single wall carbon nanotube (SWNT) test bed for measurement of conductivity/strain relationships has been developed. Nanotubes are deposited at specified locations through dielectrophoresis. The circuit is designed such that the central, current carrying section of the nanotube is exposed to enable atomic force microscopy and manipulation in situ while the transport properties of the junction are monitored. By applying this methodology to sensor development a flexible single wall carbon nanotube (SWNT) based strain sensitive device has been developed. Studies of tensile testing of the flexible SWNT device vs conductivity are also presented, demonstrating the feasibility of using single walled HiPCO (high-pressure carbon monoxide) carbon nanotubes as strain sensing agents in a multi-functional materials system.

  17. 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.

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

    E-print Network

    Maruyama, Shigeo

    Bond-order potential for transition metal carbide cluster for the growth simulation of a single for transition metal carbide cluster is developed in the form of the bond-order type potential function-order potential; Carbon nanotube; transition metal carbide cluster *Corresponding Author. Fax: +81-3-5841-8653 E

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

    E-print Network

    Goddard III, William A.

    applications. In 1993, the simplest kind of carbon nanotubes, single-walled carbon nanotubes were discovered13 Chapter 2 Simulation of Single Walled Carbon Nano Tubes SWNT 2.1 Introduction Carbon nanotubes were discovered in 1991 by Iijima of NEC Corporation.1 Since then, e orts in synthesis

  20. Condensed phase growth of single-wall carbon nanotubes from laser annealed nanoparticulates

    E-print Network

    Geohegan, David B.

    Condensed phase growth of single-wall carbon nanotubes from laser annealed nanoparticulates D. B Ridge National Laboratory, Oak Ridge, Tennessee 37831 D. A. Blom and D. C. Joy Metals and Ceramics for publication 19 March 2001 Single-wall carbon nanotubes SWNT were grown to micron lengths by laser

  1. Second-order harmonic and combination modes in graphite, single wall carbon nanotube bundles, and isolated single wall carbon nanotubes

    E-print Network

    , carbon fibers, and other forms important to our industrial society [1]. The recently discovered carbonSecond-order harmonic and combination modes in graphite, single wall carbon nanotube bundles, and isolated single wall carbon nanotubes V. W. Brara , Ge. G. Samsonidzeb , M. S. Dresselhausa,b , G

  2. Individual Single-Walled Carbon Nanotubes as Nanoelectrodes for

    E-print Network

    Dekker, Cees

    Individual Single-Walled Carbon Nanotubes as Nanoelectrodes for Electrochemistry Iddo Heller, Jing single-walled carbon nanotubes (SWNTs) as nanoelectrodes for electrochemistry. SWNTs were contacted. These studies demonstrate the potential of using a SWNT as a model carbon nanoelectrode for electrochemistry

  3. Coating Single-Walled Carbon Nanotubes with Tin Oxide

    E-print Network

    Zettl, Alex

    Coating Single-Walled Carbon Nanotubes with Tin Oxide Wei-Qiang Han and A. Zettl* Department ABSTRACT Single-walled carbon nanotubes coated with crystalline tin oxide by a simple chemical@Rice are used in this work. These SWCNTs are produced by a laser ablation method using nickel as a catalyst

  4. Density Enhancement of Aligned Single-Walled Carbon Nanotube Thin

    E-print Network

    Liu, Jie

    Density Enhancement of Aligned Single-Walled Carbon Nanotube Thin Films on Quartz Substrates July 31, 2009 ABSTRACT The density of the aligned single-walled carbon nanotubes (SWNTs) grown. It was discovered that the addition of a sulfur-containing compound (thiophene) to the reaction mixture improved

  5. Metal-functionalized single-walled graphitic carbon nitride nanotubes: a first-principles study on magnetic property

    PubMed Central

    2011-01-01

    The magnetic properties of metal-functionalized graphitic carbon nitride nanotubes were investigated based on first-principles calculations. The graphitic carbon nitride nanotube can be either ferromagnetic or antiferromagnetic by functionalizing with different metal atoms. The W- and Ti-functionalized nanotubes are ferromagnetic, which are attributed to carrier-mediated interactions because of the coupling between the spin-polarized d and p electrons and the formation of the impurity bands close to the band edges. However, Cr-, Mn-, Co-, and Ni-functionalized nanotubes are antiferromagnetic because of the anti-alignment of the magnetic moments between neighboring metal atoms. The functionalized nanotubes may be used in spintronics and hydrogen storage. PMID:21711614

  6. 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.

  7. Comparison of sample digestion techniques for the determination of trace and residual catalyst metal content in single-wall carbon nanotubes by inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Grinberg, Patricia; Sturgeon, Ralph E.; Diehl, Liange de O.; Bizzi, Cezar A.; Flores, Erico M. M.

    2015-03-01

    A single-wall carbon nanotube material produced by laser ablation of renewable biochar in the presence of Ni and Co catalyst was characterized for residual catalyst (Co and Ni) as well as trace metal impurity content (Fe, Mo, Cr, Pb and Hg) by isotope dilution ICP-MS following sample digestion. Several matrix destruction procedures were evaluated, including a multi-step microwave-assisted acid digestion, dry ashing at 450 °C and microwave-induced combustion with oxygen. Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements. Although laborious to execute, the multi-step microwave-assisted acid digestion proved to be most reliable for recovery of the majority of the analytes, although content of Cr remained biased low for each approach, likely due to its presence as refractory carbide.

  8. Self-formation of highly aligned metallic, semiconducting and single chiral single-walled carbon nanotubes assemblies via a crystal template method

    SciTech Connect

    Kawai, Hideki; Hasegawa, Kai; Yanagi, Kazuhiro; Oyane, Ayako; Naitoh, Yasuhisa

    2014-09-01

    The fabrication of an aligned array of single-walled carbon nanotubes (SWCNTs) with a single chiral state has been a significant challenge for SWCNT applications as well as for basic science research. Here, we developed a simple, unique technique to produce assemblies in which metallic, semiconducting, and single chiral state SWCNTs were densely and highly aligned. We utilized a crystal of surfactant as a template on which mono-dispersed SWCNTs in solution self-assembled. Micro-Raman measurements and scanning electron microscopy measurements clearly showed that the SWCNTs were highly and densely aligned parallel to the crystal axis, indicating that approximately 70% of the SWCNTs were within 7° of being parallel. Moreover, the assemblies exhibited good field effect transistor characteristics with an on/off ratio of 1.3?×?10{sup 5}.

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

    NASA Technical Reports Server (NTRS)

    Kaul, Anupama B. (Inventor)

    2013-01-01

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

  10. Single Walled Carbon Nanotubes as Active Elements in Nanotransducers

    NASA Astrophysics Data System (ADS)

    Stampfer, Christoph; Jungen, Alain; Hierold, Christofer

    2005-09-01

    We present the fabrication and characterization of a nanometer-scale electromechanical transducer based on individual single walled carbon nanotubes (SWNTs). Each nano electro-mechanical device incorporates one electrically connected suspended SWNT, which is placed underneath a freestanding metal bridge. By introducing a mechanical load to the freestanding bridge (e.g. by pushing with an AFM tip) the suspended SWNT is mechanically deformed (i.e. local deformation at the edges and global strain in the branches) leading to a remarkable change in resistance of the SWNT. We present mechanical and electromechanical measurements and show that the resistance changes significantly under mechanical load.

  11. 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

  12. Molecular nanowires of 1 nm diameter from capillary filling of single-walled carbon nanotubes

    SciTech Connect

    Kiang, C.H.; Choi, J.S.; Tran, T.T.; Bacher, A.D.

    1999-09-02

    Molecular nanowires inside single-walled carbon nanotubes are produced by capillary filling. Bismuth was drawn into single-walled carbon nanotubes, where it formed single-crystal nanowires of nanometer dimensions. Metal was introduced in its gas, solution, and solid phases, with the solution phase process the most efficient and versatile method of filling. The majority of fillings are one-dimensional nanowires with high length to diameter ratios. The strong capillary effect in single-walled carbon nanotubes should allow these materials to host a wide variety of nanoscale materials.

  13. Evaluations of single walled carbon nanotubes using resonance Raman spectroscopy

    E-print Network

    Brar, Victor W. (Victor Watson), 1981-

    2004-01-01

    This work reports the results of two studies which use resonance Raman scattering to evaluate the vibrational properties of single walled carbon nanotubes (SWNTs). In the first study, we report an evaluation of second-order ...

  14. Modeling Catalyzed Growth of Single-Walled Carbon Nanotubes 

    E-print Network

    Beetge, Jenni Mignon

    2013-02-27

    ABSTRACT Modeling Catalyzed Growth of Single-Walled Carbon Nanotubes. (May 2013) Jenni M. Beetge Artie McFerrin Department of Chemical Engineering Texas A&M University Research Advisor: Dr. Perla B. Balbuena Artie McFerrin Department...

  15. 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 applications...

  16. Single chirality single-walled carbon nanotubes : isolation and application

    E-print Network

    Jain, Rishabh M

    2015-01-01

    Single Walled Carbon Nanotubes are of great interest as a semiconducting material with diameters around 1nm and length in the 100s of nm to mm range. The large aspect ratio, near-infrared wavelength bandgap and a high ...

  17. Metal-Organic Polymers Containing Discrete Single-Walled Nanotube as a Heterogeneous Catalyst for the Cycloaddition of Carbon Dioxide to Epoxides.

    PubMed

    Zhou, Zhen; He, Cheng; Xiu, Jinghai; Yang, Lu; Duan, Chunying

    2015-12-01

    The cycloaddition of carbon dioxide to epoxides to produce cyclic carbonates is quite promising and does not result in any side products. A discrete single-walled metal-organic nanotube was synthesized by incorporating a tetraphenyl-ethylene moiety as the four-point connected node. The assembled complex has a large cross-section, with an exterior wall diameter of 3.6 nm and an interior channel diameter of 2.1 nm. It features excellent activity toward the cycloaddition of carbon dioxide, with a turnover number of 17,500 per mole of catalyst and an initial turnover frequency as high as 1000 per mole of catalyst per hour. Only minimal decreases in the catalytic activity were observed after 70 h under identical reaction conditions, and a total turnover number as high as 35,000 was achieved. A simple comparison of relative porous MOFs suggested that the cross-section of the channels is an important factor influencing the transport of the substrates and products through the channel. PMID:26584402

  18. 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.

  19. Roping of Single-Walled Carbon Nanotube Bundles

    NASA Astrophysics Data System (ADS)

    Qin, Lu-Chang; Liu, Zejian

    2003-03-01

    Though single-walled carbon nanotubes often form raft-like bundles in which the individual carbon nanotubes of about the same diameter stack together in parallel in a hexagonal close-packed structure, it has also been observed that single-walled carbon nanotubes sometimes form a ropelike structure in which the constituent nanotubes are intertwisted when they are produced by the laser evaporation technique [1]. An experimental analysis of the helicities of the thus produced single-walled carbon nanotubes using electron nanodiffraction indicates that the helicity has a rather uniform distribution between the zigzag (helicity = 0) and the armchair (helicity = 30 degrees) structures. We will present the experimental characterization as well as numerical simulations of the morphology and energetics of the ropelike bundles of single-walled carbon nanotubes. The role of the helicity of the single-walled carbon nanotubes will also be discussed. [1] L.-C. Qin and S. Iijima, Mat. Res. Soc. Symp. Proc. Vol. 593 (2000) 33. lcqin@physics.unc.edu

  20. Single Wall Carbon Nanotube-Based Structural Health Sensing Materials

    NASA Technical Reports Server (NTRS)

    Watkins, A. Neal; Ingram, JoAnne L.; Jordan, Jeffrey D.; Wincheski, Russell A.; Smits, Jan M.; Williams, Phillip A.

    2004-01-01

    Single wall carbon nanotube (SWCNT)-based materials represent the future aerospace vehicle construction material of choice based primarily on predicted strength-to-weight advantages and inherent multifunctionality. The multifunctionality of SWCNTs arises from the ability of the nanotubes to be either metallic or semi-conducting based on their chirality. Furthermore, simply changing the environment around a SWCNT can change its conducting behavior. This phenomenon is being exploited to create sensors capable of measuring several parameters related to vehicle structural health (i.e. strain, pressure, temperature, etc.) The structural health monitor is constructed using conventional electron-beam lithographic and photolithographic techniques to place specific electrode patterns on a surface. SWCNTs are then deposited between the electrodes using a dielectrophoretic alignment technique. Prototypes have been constructed on both silicon and polyimide substrates, demonstrating that surface-mountable and multifunctional devices based on SWCNTs can be realized.

  1. 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.

  2. Individual single-walled carbon nanotubes as electrochemical probes

    NASA Astrophysics Data System (ADS)

    Lemay, S. G.; Heering, H. A.; Heller, I.; Kong, J.; Williams, K. A.; Dekker, C.

    2004-03-01

    We have performed cyclic voltammetry measurements using individual single-walled carbon nanotubes as working electrodes. The nanotubes were first grown on silicon oxide substrates and contacted using titanium. An insulating layer was then deposited and sub-micron-sized windows opened, leaving only the sidewalls of selected nanotubes exposed. These devices were exposed to an electrolyte containing redox-active ferrocene derivatives and cyclic voltammetry measurements were performed. Our results suggest that metallic nanotubes behave as ideal cylindrical electrodes and exhibit a diffusion-limited redox current. The behavior of semiconducting nanotubes is more complex due to the interplay between band bending, quantum capacitance and the potential drop at the liquid-nanotube interface.

  3. Electronic Structure of Tubular Aromatic Molecules Derived from the Metallic (5,5) Armchair Single Wall Carbon Nanotube

    E-print Network

    optimization, are performed on tubular molecules up to C210H20 that are finite sections of the (5,5) metallic. For the especially low band gap molecules C120H20, C150H20, and C180H20, alternation increases, and a second nearly toward a predicted bulk work function near 3.9 eV. A detailed study of C190H20 with up to eight extra

  4. Electronic Transport in Single Wall Carbon Kasper Grove-Rasmussen

    E-print Network

    Nygård, Jesper

    Electronic Transport in Single Wall Carbon Nanotubes Kasper Grove-Rasmussen Ph.D. Thesis Niels Bohr Wall Carbon Nanotubes Ph.D. thesis c Kasper Grove-Rasmussen 2006 E-mail: k grove@fys.ku.dk Niels Bohr years of Ph.D. studies at the Nano-Science Center, Niels Bohr Institute, University of Copen- hagen

  5. Purification Procedures for Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Gorelik, Olga P.; Nikolaev, Pavel; Arepalli, Sivaram

    2001-01-01

    This report summarizes the comparison of a variety of procedures used to purify carbon nanotubes. Carbon nanotube material is produced by the arc process and laser oven process. Most of the procedures are tested using laser-grown, single-wall nanotube (SWNT) material. The material is characterized at each step of the purification procedures by using different techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), Raman, X-ray diffractometry (XRD), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR), and high-performance liquid chromatography (HPLC). The identified impurities are amorphous and graphitic carbon, catalyst particle aggregates, fullerenes, and hydrocarbons. Solvent extraction and low-temperature annealing are used to reduce the amount of volatile hydrocarbons and dissolve fullerenes. Metal catalysts and amorphous as well as graphitic carbon are oxidized by reflux in acids including HCl, HNO3 and HF and other oxidizers such as H2O2. High-temperature annealing in vacuum and in inert atmosphere helps to improve the quality of SWNTs by increasing crystallinity and reducing intercalation.

  6. 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.

  7. 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.

  8. Light induced aggregation of specific single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Gopannagari, Madhusudana; Chaturvedi, Harsh

    2015-10-01

    We report optically induced aggregation and consequent separation of specific diameters of nanotubes from stable solutions of pristine single walled carbon nanotubes (SWNTs). Dispersed solutions of pristine SWNTs in different solvents show rapid and selective aggregation. The separated SWNTs show enrichment in specific diameters of SWNTs aggregating under UV, visible and NIR illumination.

  9. 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…

  10. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

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

  11. Synthesis of NiO/carbon shell/single-walled carbon nanotube composites as anode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Ma, Yufan; Sheng, Leimei; Zhao, Hongbin; An, Kang; Yu, Liming; Xu, Jiaqiang; Zhao, Xinluo

    2015-08-01

    In this study, NiO/carbon shell/single-walled carbon nanotube composites are prepared by heat treating the single-walled carbon nanotube samples synthesized by direct current arc discharge method. The morphology and nanostructure of the composites are affected by the heat treatment temperature according to the X-ray diffraction, Raman spectra and high-resolution transmission electron microscopy results. The electrochemical measurements are evaluated in coin-type cells versus metallic lithium. After heat treatment in H2 at 600 °C for 1 h and in air at 300 °C for 10 h, the NiO nanoparticles encapsulated by carbon shells are evenly distributed on the surface of web-like single-walled carbon nanotubes and a perfect NiO/carbon shell/single-walled carbon nanotube nanostructure is formed. This NiO/carbon shell/single-walled carbon nanotube composite shows a high reversible specific capacity of 758 mA h g-1 after 60 cycles at a current density of 100 mA g-1 and an excellent rate capacity of about 594 mA h g-1 even at a high current density of 1600 mA g-1. Therefore, the NiO/carbon shell/single-walled carbon nanotube composites have significant potential for applications in energy storage devices.

  12. Thermionic Emission of Single-Wall Carbon Nanotubes Measured

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Krainsky, Isay L.; Bailey, Sheila G.; Elich, Jeffrey M.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

    2004-01-01

    Researchers at the NASA Glenn Research Center, in collaboration with the Rochester Institute of Technology, have investigated the thermionic properties of high-purity, single-wall carbon nanotubes (SWNTs) for use as electron-emitting electrodes. Carbon nanotubes are a recently discovered material made from carbon atoms bonded into nanometer-scale hollow tubes. Such nanotubes have remarkable properties. An extremely high aspect ratio, as well as unique mechanical and electronic properties, make single-wall nanotubes ideal for use in a vast array of applications. Carbon nanotubes typically have diameters on the order of 1 to 2 nm. As a result, the ends have a small radius of curvature. It is these characteristics, therefore, that indicate they might be excellent potential candidates for both thermionic and field emission.

  13. Chirality Characterization of Dispersed Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Namkung, Min; Williams, Phillip A.; Mayweather, Candis D.; Wincheski, Buzz; Park, Cheol; Namkung, Juock S.

    2005-01-01

    Raman scattering and optical absorption spectroscopy are used for the chirality characterization of HiPco single wall carbon nanotubes (SWNTs) dispersed in aqueous solution with the surfactant sodium dodecylbenzene sulfonate. Radial breathing mode (RBM) Raman peaks for semiconducting and metallic SWNTs are identified by directly comparing the Raman spectra with the Kataura plot. The SWNT diameters are calculated from these resonant peak positions. Next, a list of (n, m) pairs, yielding the SWNT diameters within a few percent of that obtained from each resonant peak position, is established. The interband transition energies for the list of SWNT (n, m) pairs are calculated based on the tight binding energy expression for each list of the (n, m) pairs, and the pairs yielding the closest values to the corresponding experimental optical absorption peaks are selected. The results reveal that (1, 11), (4, 11), and (0, 11) as the most probable chiralities of the semiconducting nanotubes. The results also reveal that (4, 16), (6, 12) and (8, 8) are the most probable chiralities for the metallic nanotubes. Directly relating the Raman scattering data to the optical absorption spectra, the present method is considered the simplest technique currently available. Another advantage of this technique is the use of the E(sup 8)(sub 11) peaks in the optical absorption spectrum in the analysis to enhance the accuracy in the results.

  14. 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.

  15. Spectroscopy-Based Characterization of Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Namkung, Min; Namkung, Juock S.; Wincheski, Russell A.; Seo, J.; Park, Cheol

    2003-01-01

    We present the initial results of our combined investigation of Raman scattering and optical absorption spectroscopy in a batch of single wall carbon nanotubes (SWNTs). The SWNT diameters are first estimated from the four radial breathing mode (RBM) peaks using a simple relation of omega(sub RBM) = 248/cm nm/d(sub t)(nm). The calculated diameter values are related to the optical absorption peaks through the expressions of first interband transition energies, i.e., E(sup S)(sub 11) = 2a gamma/d(sub t) for semiconducting and E(sup S)(sub 11) = 6a gamma/d(sub t) for metallic SWNTs, respectively, where a is the carbon-carbon bond length (0.144 nm) and gamma is the energy of overlapping electrons from nearest neighbor atoms, which is 2.9 eV for a SWNT. This analysis indicates that three RBM peaks are from semiconducting tubes, and the remaining one is from metallic tubes. The detailed analysis in the present study is focused on these three peaks of the first absorption band by determining the values of the representative (n,m) pairs. The first step of analysis is to construct a list of possible (n,m) pairs from the diameters calculated from the positions of the RBM peaks. The second step is to compute the first interband transition energy, E(sub 11), by substituting the constructed list of (n,m) into the expression of Reich and Thomsen, and Saito et al. Finally, the pairs with the energies closest to the experimental values are selected.

  16. 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

  17. Synthesis, assembly, and applications of single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Ryu, Koungmin

    This dissertation presents the synthesis and assembly of aligned carbon nanotubes, and their applications in both nano-electronics such as transistor and integrated circuits and macro-electronics in energy conversion devices as transparent conducting electrodes. Also, the high performance chemical sensor using metal oxide nanowire has been demonstrated. Chapter 1 presents a brief introduction of carbon nanotube, followed by discussion of a new synthesis technique using nanosphere lithography to grow highly aligned single-walled carbon nanotubes atop quartz and sapphire substrates. This method offers great potential to produce carbon nanotube arrays with simultaneous control over the nanotube orientation, position, density, diameter and even chirality. Chapter 3 introduces the wafer-scale integration and assembly of aligned carbon nanotubes, including full-wafer scale synthesis and transfer of massively aligned carbon nanotube arrays, and nanotube device fabrication on 4 inch Si/SiO2 wafer to yield submicron channel transistors with high on-current density ˜ 20 muA/mum and good on/off ratio and CMOS integrated circuits. In addition, various chemical doping methods for n-type nanotube transistors are studied to fabricate CMOS integrated nanotube circuits such as inverter, NAND and NOR logic devices. Furthermore, defect-tolerant circuit design for NAND and NOR is proposed and demonstrated to guarantee the correct operation of logic circuit, regardless of the presence of mis-aligned or mis-positioned nanotubes. Carbon nanotube flexible electronics and smart textiles for ubiquitous computing and sensing are demonstrated in chapter 4. A facile transfer printing technique has been introduced to transfer massively aligned single-walled carbon nanotubes from the original sapphire/quartz substrates to virtually any other substrates, including glass, silicon, polymer sheets, and even fabrics. The characterization of transferred nanotubes reveals that the transferred nanotubes are highly conductive, transparent, and flexible as well. Based on transferred nanotube arrays on fabric, we have successfully demonstrated nanotube transistors with on/off ratios ˜ 105, and chemical sensors for low-concentration NO2 and 2,4,6-trinitrotoluene (TNT). In Chapter 5, I present the study of transparent conductive thin films made with two kinds of commercial carbon nanotubes: HiPCO and arc-discharge nanotubes. These films have been further exploited as hole-injection electrodes for organic light emitting diodes (OLEDs) on both rigid glass and flexible substrates. Our experiments reveal that films based on arc discharge nanotubes are overwhelmingly better than HiPCO-nanotube-based films in all the critical aspects, including the surface roughness, sheet resistance, and transparency. The optimized films show a typical sheet resistance of ˜160O/? at 87% transparency and have been successfully used to make OLEDs with high stability and long lifetime. Lastly, I present the fast and scalable integration of nanowire chemical sensors with micromachined hotplates built on SiN membranes. These hotplates allowed nanowire chemical sensors to operate at elevated temperatures in order to enhance the sensitivity of chemical sensors to target gases. By applying different current through the platinum heating filament, we can easily vary the device temperature from room temperature to 350°C. These nanosensors with integrated hot plates have been exploited for the detection of ethanol, CO and hydrogen down to concentrations of 1 ppm, 10 ppm and 50 ppm, respectively.

  18. Electrochemistry at Single-Walled Carbon Nanotubes: The Role of Band Structure and Quantum Capacitance

    E-print Network

    Dekker, Cees

    Electrochemistry at Single-Walled Carbon Nanotubes: The Role of Band Structure and Quantum the electrode kinetics. We model electrochemistry at metallic and semiconducting SWNTs as well as at graphene) as electrodes for electrochemistry.2-4 This interest mostly originates from the prospect of using individual

  19. 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, ...

  20. Fermi energy dependence of the G-band resonance Raman spectra of single-wall carbon nanotubes

    E-print Network

    Park, J. S.

    The Fermi energy dependence of the G-band resonance Raman spectra of single-wall carbon nanotubes (SWNTs) is calculated, including the Kohn anomaly effect for metallic tubes. The gate voltage dependence of the G-band Raman ...

  1. Reinforcement of Epoxies Using Single Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Krishnamoorti, Ramanan; Sharma, Jitendra; Chatterjee, Tirtha

    2008-03-01

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

  2. Titanium dioxide, single-walled carbon nanotube composites

    DOEpatents

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

    2015-07-14

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

  3. Suspended architecture formation process of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Homma, Yoshikazu; Takagi, Daisuke; Kobayashi, Yoshihiro

    2006-01-01

    The formation processes of suspended structures and bundles of single-walled carbon nanotubes (SWNTs) are directly observed by in situ scanning electron microscopy during chemical vapor deposition of SWNTs on a patterned specimen. SWNTs exhibit lively movements during extension from micropillar patterns, resulting in bridging, bundling, merging, and debundling. Fluctuation of the extension direction of a SWNT cantilever is observed. Swing of the SWNT cantilever is the reason for the enhanced-nearest-neighbor interconnection.

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

    SciTech Connect

    Sahoo, Sangeeta; Lastella, Sarah; Maranganti, Ravi; Sharma, Pradeep; Mallick, Govind; Karna, Shashi; Ajayan, Pulickel M.

    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.

  5. Modified Single-Wall Carbon Nanotubes for Reinforce Thermoplastic Polyimide

    NASA Technical Reports Server (NTRS)

    Lebron-COlon, Marisabel; Meador, Michael A.

    2006-01-01

    A significant improvement in the mechanical properties of the thermoplastic polyimide film was obtained by the addition of noncovalently functionalized single-wall carbon nanotubes (SWNTs). Polyimide films were reinforced using pristine SWNTs and functionalized SWNTs (F-SWNTs). The tensile strengths of the polyimide films containing F-SWNTs were found to be approximately 1.4 times higher than those prepared from pristine SWNTs.

  6. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  7. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  8. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  9. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Single-walled carbon nanotubes... Specific Chemical Substances § 721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance... single-walled carbon nanotubes (PMN P-08-328) is subject to reporting under this section for...

  10. Mixing at 50 GHz using a single-walled carbon nanotube transistor Sami Rosenblatt,a

    E-print Network

    McEuen, Paul L.

    Mixing at 50 GHz using a single-walled carbon nanotube transistor Sami Rosenblatt,a Hao Lin, Vera have probed the electrical properties of top-gated single-walled carbon nanotube transistors­6 As a result, they offer promise as very high-frequency transistors. A short single-walled carbon nanotube

  11. 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

  12. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Single-walled carbon nanotubes (generic). 721.10156 Section...721.10156 Single-walled carbon nanotubes (generic). (a) Chemical substance...generically as single-walled carbon nanotubes (PMN P-08-328) is...

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

    PubMed

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

    2015-12-21

    Elucidating the roles played by carbon solubility in catalyst nanoparticles is required to better understand the growth mechanisms of single-walled carbon nanotubes (SWNTs). Here, we highlight that controlling the level of dissolved carbon is of key importance to enable nucleation and growth. We first performed tight binding based atomistic computer simulations to study carbon incorporation in metal nanoparticles with low solubilities. For such metals, carbon incorporation strongly depends on their structures (face centered cubic or icosahedral), leading to different amounts of carbon close to the nanoparticle surface. Following this idea, we then show experimentally that Au nanoparticles effectively catalyze SWNT growth when in a face centered cubic structure, and fail to do so when icosahedral. Both approaches emphasize that the presence of subsurface carbon in the nanoparticles is necessary to enable the cap lift-off, making the nucleation of SWNTs possible. PMID:26580292

  14. Tunable intertube spacing in single-walled carbon nanotube bundles

    SciTech Connect

    Cambedouzou, J.; Rols, S.; Bendiab, N.; Almairac, R.; Sauvajol, J.-L.; Petit, P.; Mathis, C.; Mirebeau, I.; Johnson, M.

    2005-07-15

    The structure of ternary compounds involving alkali, tetrahydrofuran (THF) and single-walled carbon nanotubes have been investigated using neutron diffraction (ND). Hydrogen-deuterium substitution in THF, as well as the study of different alkali-based compounds, allow a layered structure around the nanotubes to be determined. ND results indicate that the alkali cations form a monolayer surrounding each tube of the bundle, while THF molecules intercalate between the decorated tubes and at the surface of the bundles. In spite of this insertion, the triangular bundle structure is preserved, albeit with a much larger lattice parameter, which depends on the size of the inserted cation.

  15. 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 Combined. Introduction Carbon materials are of interest for fundamental science and technological applications.1 After

  16. Characterization of single-walled carbon nanotubes for environmental implications

    USGS Publications Warehouse

    Agnihotri, S.; Rostam-Abadi, M.; Rood, M.J.

    2004-01-01

    Adsorption capacities of N2 and various organic vapors (methyl-ethyl ketone (MEK), toluene, and cyclohexane) on select electric-arc and HiPco produced single walled carbon nanotubes (SWNT) were measured at 77 and 298 K, respectively. The amount of N2 adsorbed on a SWNT sample depended on the sample purity, methodology, and on the sample age. Adsorption capacities of organic vapors (100-1000 ppm vol) on SWNT in humid conditions were much higher than those for microporous activated carbons. These results established a foundation for additional studies related to potential environmental applications of SWNT. The MEK adsorption capacities of samples EA95 and CVD80 and mesoporous tire-derived activated carbon in humid conditions were lower than in dry conditions. This is an abstract of a paper presented at the AIChE Annual Meeting (Austin, TX 11/7-12/2004).

  17. Storage of Hydrogen in Single-Walled Carbon Nanotubes

    SciTech Connect

    Dillon, A. C.; Jones, K. M.; Bekkedahl, T. A.; Kiang, C. H.; Bethune, D. S.; Heben, M. J.

    1997-03-27

    Pores of molecular dimensions can adsorb large quantities of gases owing to the enhanced density of the adsorbed material inside the pores, a consequence of the attractive potential of the pore walls. Pederson and Broughton have suggested that carbon nanotubes, which have diameters of typically a few nanometres, should be able to draw up liquids by capillarity, and this effect has been seen for low-surface-tension liquids in large-diameter, multi-walled nanotubes. Here we show that a gas can condense to high density inside narrow, single-walled nanotubes (SWNTs). Temperature-programmed desorption spectroscopy shows that hydrogen will condense inside SWNTs under conditions that do not induce adsorption within a standard mesoporous activated carbon. The very high hydrogen uptake in these materials suggests that they might be effective as a hydrogen-storage material for fuel-cell electric vehicles.

  18. Single-walled carbon nanotubes based chemicapacitive sensors.

    PubMed

    Lim, Jae-Hong; Mulchandani, Ashok; Myung, Nosang V

    2012-02-01

    Carboxylated single-walled carbon nanotubes (SWNTs) based chemicapacitive gas sensors were fabricated by AC dielectrophoretically aligning SWNTs across microfabricated gold electrodes with controlled density/device resistance. Two different sensing configurations (i.e., horizontal/in-plane and vertical/out-of-plane) were utilized to compare their sensing performance. Upon exposure to water vapor at room temperature, the response (R = [(C--C0)/C0] x 100%) increased with an increase in water vapor concentration similar to that of resistance response. In horizontal configuration, the response was increased with an increase in device resistance which might be attributed to preferentially alignment of semiconducting SWNTs during initial phase of alignment. However, the response was independent of device resistance in vertical/out-of-plane configuration which indicated that the sensing mechanism is based on the change of dielectric constant of gate and atmosphere. PMID:22629991

  19. Hyperelastic axial buckling of single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Saavedra Flores, E. I.; Adhikari, S.; Friswell, M. I.; Scarpa, F.

    2011-11-01

    This paper proposes a hyperelastic finite element-based lattice approach for the description of buckling behaviour in single wall carbon nanotubes (SWCNTs). A one-term incompressible Ogden-type hyperelastic model is adopted to describe the equivalent mechanical response of C-C bonds in SWCNTs under axial compression. The material constants of the model are chosen by matching the linearised response with the elastic constants adopted in the AMBER force field and by establishing equivalence between the Ogden strain energy and the variation of the interatomic strain energy obtained from molecular mechanics simulations. Numerical experiments are carried out and the results are compared to atomistic simulations, demonstrating the predictive capabilities of the present model in capturing initial buckling strain, deformation mechanisms and post-buckling behaviour under very large compressive deformations.

  20. Magnetic fullerenes inside single-wall carbon nanotubes.

    PubMed

    Simon, F; Kuzmany, H; Náfrádi, B; Fehér, T; Forró, L; Fülöp, F; Jánossy, A; Korecz, L; Rockenbauer, A; Hauke, F; Hirsch, A

    2006-09-29

    C(59)N magnetic fullerenes were formed inside single-wall carbon nanotubes by vacuum annealing functionalized C(59)N molecules encapsulated inside the tubes. A hindered, anisotropic rotation of C(59)N was deduced from the temperature dependence of the electron spin resonance spectra near room temperature. Shortening of the spin-lattice relaxation time T(1) of C(59)N indicates a reversible charge transfer toward the host nanotubes above approximately 350 K. Bound C(59)N-C(60) heterodimers are formed at lower temperatures when C(60) is coencapsulated with the functionalized C(59)N. In the 10-300 K range, T(1) of the heterodimer shows a relaxation dominated by the conduction electrons on the nanotubes. PMID:17026062

  1. Radiation Protection Using Single-Wall Carbon Nanotube Derivatives

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  2. 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.

  3. 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.

  4. Controlled Patterning and Growth of Single Wall and Multi-wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D. (Inventor)

    2005-01-01

    Method and system for producing a selected pattern or array of at least one of a single wall nanotube and/or a multi-wall nanotube containing primarily carbon. A substrate is coated with a first layer (optional) of a first selected metal (e.g., Al and/or Ir) and with a second layer of a catalyst (e.g., Fe, Co, Ni and/or Mo), having selected first and second layer thicknesses provided by ion sputtering, arc discharge, laser ablation, evaporation or CVD. The first layer and/or the second layer may be formed in a desired non-uniform pattern, using a mask with suitable aperture(s), to promote growth of carbon nanotubes in a corresponding pattern. A selected heated feed gas (primarily CH4 or C2Hn with n=2 and/or 4) is passed over the coated substrate and forms primarily single wall nanotubes or multiple wall nanotubes, depending upon the selected feed gas and its temperature. Nanofibers, as well as single wall and multi-wall nanotubes, are produced using plasma-aided growth from the second (catalyst) layer. An overcoating of a selected metal or alloy can be deposited, over the second layer, to provide a coating for the carbon nanotubes grown in this manner.

  5. Sensory Arrays of Covalently Functionalized Single-Walled Carbon Nanotubes for Explosive Detection

    E-print Network

    van der Zwaag, Daan

    Chemiresistive sensor arrays for cyclohexanone and nitromethane are fabricated using single-walled carbon nanotubes (SWCNTs) that are covalently functionalized with urea, thiourea, and squaramide containing selector units. ...

  6. 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.

  7. Cancer photothermal therapy in the near-infrared region by using single-walled carbon nanotubes

    E-print Network

    Resasco, Daniel

    Cancer photothermal therapy in the near-infrared region by using single-walled carbon nanotubes-walled carbon nanotubes SWNTs have a high op- tical absorbance in the near-infrared NIR region. In this special.1117/1.3078803 Keywords: Near-infarred region; CoMoCAT nanotubes; photothermal therapy; floate single-walled carbon

  8. CONTROLLED CVD SYNTHESIS OF SINGLE-WALLED CARBON NANOTUBES FROM ALCOHOL

    E-print Network

    Maruyama, Shigeo

    CONTROLLED CVD SYNTHESIS OF SINGLE-WALLED CARBON NANOTUBES FROM ALCOHOL S Maruyama, Y Miyauchi, Y-ku, Tokyo 113-8656, Japan By using alcohol as carbon source, high-purity single-walled carbon nanotubes [1]. Based on these findings, we have proposed alcohol catalytic CVD (ACCVD) technique. In addition

  9. 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

  10. Sensitive Detection of H2S Using Gold Nanoparticle Decorated Single-Walled Carbon

    E-print Network

    Sensitive Detection of H2S Using Gold Nanoparticle Decorated Single-Walled Carbon Nanotubes Syed nanoparticles on single-walled carbon nanotube (SWNT) networks. Adjusting the electrodeposition conditions from the modulation of electron exchange between the gold and carbon nanotube defect sites when exposed

  11. Nonlocal Elasticity Theory for Free Vibration of Single-walled Carbon Nanotubes

    E-print Network

    Li, Teng

    Since carbon nanotubes (CNTs) had been discovered by Iijima [1] in 1991, extensive researches had beenNonlocal Elasticity Theory for Free Vibration of Single-walled Carbon Nanotubes Chawis Thongyothee1.chu@kmutt.ac.th, c LiT@umd.edu Keywords: Single-walled carbon nanotubes, Nonlocal elasticity, Finite element model

  12. 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.

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

    NASA Astrophysics Data System (ADS)

    Morris, Darius T., Jr.

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

  14. Localized and delocalized charge transport in single-wall carbon-nanotube mats

    NASA Astrophysics Data System (ADS)

    Hilt, O.; Brom, H. B.; Ahlskog, M.

    2000-02-01

    We measured the complex dielectric constant in mats of single-wall carbon nanotubes between 2.7 K and 300 K up to 0.5 THz. The data are well understood in a Drude approach with a negligible temperature dependence of the plasma frequency ?p and scattering time ? with an additional contribution of localized charges. The dielectric properties resemble those of the best ``metallic'' polypyrroles and polyanilines. The absence of metallic islands makes the mats a relevant piece in the puzzle of the interpretation of ? and ?p in these polymers.

  15. Donor doping of single-walled carbon nanotubes by filling of channels with silver

    SciTech Connect

    Kharlamova, M. V.; Niu, J. J.

    2012-09-15

    The channels of single-walled carbon nanotubes (SWNTs) are filled with metallic silver. The synthesized nanocomposites are studied by Raman spectroscopy and optical absorption spectroscopy, and these data indicate a substantial modification of the electronic structure of the nanotubes upon their filling. Moreover, X-ray photoelectron spectroscopy shows that the incorporation of the metal leads to a change in the work function of SWNTs due to the Fermi level upshift and to the transfer of an electron density from inserted nanoparticles to the nanotube walls. Thus, the filling of the channels with silver results in donor doping of the nanotubes.

  16. Laser-induced forward transfer of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Palla-Papavlu, A.; Dinescu, M.; Wokaun, A.; Lippert, T.

    2014-10-01

    The objective of this work is the application of laser-induced forward transfer (LIFT) for the fabrication of chemiresistor sensors. The receiver substrate is an array with metal electrodes and the active materials placed by LIFT are single-walled carbon nanotubes (SWCNT). The functionality of such sensors depends on the geometry of the active material onto the metallic electrodes. First the best geometry for the sensing materials and electrodes was determined, including the optimization of the process parameters for printing uniform pixels of SWCNT onto the sensor electrodes. The sensors were characterized in terms of their sensing characteristics, i.e., upon exposure to ammonia, proving the feasibility of LIFT.

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

    SciTech Connect

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

    2011-12-11

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

  18. HEAT CONDUCTION OF SINGLE-WALLED CARBON NANOTUBE IN VARIOUS ENVIRONMENTS

    E-print Network

    Maruyama, Shigeo

    HEAT CONDUCTION OF SINGLE-WALLED CARBON NANOTUBE IN VARIOUS ENVIRONMENTS Junichiro Shiomi-ku, Tokyo 113-8656, Japan ABSTRACT Some of our recent studies on the heat conduction of single-walled carbon, the heat conduction is investigated in more practical situations under the influence of inter

  19. Hydrogenation of Single-Wall Carbon Nanotubes Using Polyamine Reagents: Combined Experimental and

    E-print Network

    Tománek, David

    oxidation of SWNTs using some combination of sulfuric acid, nitric acid, and occasionally hydrogen peroxide9Hydrogenation of Single-Wall Carbon Nanotubes Using Polyamine Reagents: Combined Experimental hydrogenation of single-wall carbon nanotubes using high boiling polyamines as hydrogenation reagents. Our

  20. A MOLECULAR DYNAMICS SIMULATION OF HEAT CONDUCTION OF A FINITE LENGTH SINGLE-WALLED CARBON NANOTUBE

    E-print Network

    Maruyama, Shigeo

    A MOLECULAR DYNAMICS SIMULATION OF HEAT CONDUCTION OF A FINITE LENGTH SINGLE-WALLED CARBON NANOTUBE Heat conduction of finite length single walled carbon nanotubes (SWNTs) was simulated by the molecular by the phantom technique, and the thermal conductivity was calculated with Fourier's law from the measured

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

    DOEpatents

    Biris, Alexandru S.; Li, Zhongrui

    2012-11-06

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

  2. 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

  3. 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…

  4. 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 80­550 K is investigated. We observe that the frequency decreases with increasing temperature for all Raman

  5. 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

  6. Microwave Absorption of Single-Walled Carbon Nanotubes/Soluble Cross-Linked Polyurethane Composites

    E-print Network

    Gao, Hongjun

    (EMI) shielding and radar cross section (RCS) reduction applications with both commercial and defenseMicrowave Absorption of Single-Walled Carbon Nanotubes/Soluble Cross-Linked Polyurethane Composites composites of single-walled carbon nanotubes (SWNTs) with soluble cross-linked polyurethane (SCPU) were

  7. Heat conduction of single-walled carbon nanotube isotope-superlattice structures: A molecular dynamics study

    E-print Network

    Maruyama, Shigeo

    1 Heat conduction of single-walled carbon nanotube isotope-superlattice structures: A molecular-mail address: maruyama@photon.t.u-tokyo.ac.jp Heat conduction of single-walled carbon nanotubes (SWNTs) isotope and junctions, which alter the heat conduction. In general, these nanoscale impurities, having scales comparable

  8. 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

  9. Single-walled carbon nanotubes as near-infrared optical biosensors for life sciences and biomedicine.

    PubMed

    Jain, Astha; Homayoun, Aida; Bannister, Christopher W; Yum, Kyungsuk

    2015-03-01

    Single-walled carbon nanotubes that emit photostable near-infrared fluorescence have emerged as near-infrared optical biosensors for life sciences and biomedicine. Since the discovery of their near-infrared fluorescence, researchers have engineered single-walled carbon nanotubes to function as an optical biosensor that selectively modulates its fluorescence upon binding of target molecules. Here we review the recent advances in the single-walled carbon nanotube-based optical sensing technology for life sciences and biomedicine. We discuss the structure and optical properties of single-walled carbon nanotubes, the mechanisms for molecular recognition and signal transduction in single-walled carbon nanotube complexes, and the recent development of various single-walled carbon nanotube-based optical biosensors. We also discuss the opportunities and challenges to translate this emerging technology into biomedical research and clinical use, including the biological safety of single-walled carbon nanotubes. The advances in single-walled carbon nanotube-based near-infrared optical sensing technology open up a new avenue for in vitro and in vivo biosensing with high sensitivity and high spatial resolution, beneficial for many areas of life sciences and biomedicine. PMID:25676253

  10. 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

  11. 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-walled carbon nanotubes to investigate this process. The isotope shifts of phonons and vibrons are observed

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

    E-print Network

    Maruyama, Shigeo

    Isotope-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 (SWNTs) was investigated by resonance Raman scattering measurements of more than 600 sus- pended, isotope

  13. 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

  14. Characterizing thermal conductivity of vertically-aligned single-walled carbon nanotube films

    E-print Network

    Maruyama, Shigeo

    Characterizing thermal conductivity of vertically-aligned single-walled carbon nanotube films Kei-0196 Single-walled carbon nanotubes (SWNTs) are expected to possess high thermal conductivity. Thermal reported works on the thermal conductivity of vertically-aligned SWNTs (VA-SWNTs); experimental

  15. Enhanced thermal conductivity of ethylene glycol with single-walled carbon nanotube inclusions

    E-print Network

    Maruyama, Shigeo

    Enhanced thermal conductivity of ethylene glycol with single-walled carbon nanotube inclusions S report measurements of the effective thermal conductivity of dispersions of single-walled carbon nanotube. Thermal conductivity measurements were performed by the transient hot-wire technique. Good agreement

  16. 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

  17. On the Stability and Abundance of Single Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Hedman, Daniel; Reza Barzegar, Hamid; Rosén, Arne; Wågberg, Thomas; Andreas Larsson, J.

    2015-11-01

    Many nanotechnological applications, using single-walled carbon nanotubes (SWNTs), are only possible with a uniform product. Thus, direct control over the product during chemical vapor deposition (CVD) growth of SWNT is desirable, and much effort has been made towards the ultimate goal of chirality-controlled growth of SWNTs. We have used density functional theory (DFT) to compute the stability of SWNT fragments of all chiralities in the series representing the targeted products for such applications, which we compare to the chiralities of the actual CVD products from all properly analyzed experiments. From this comparison we find that in 84% of the cases the experimental product represents chiralities among the most stable SWNT fragments (within 0.2?eV) from the computations. Our analysis shows that the diameter of the SWNT product is governed by the well-known relation to size of the catalytic nanoparticles, and the specific chirality is normally determined by the product’s relative stability, suggesting thermodynamic control at the early stage of product formation. Based on our findings, we discuss the effect of other experimental parameters on the chirality of the product. Furthermore, we highlight the possibility to produce any tube chirality in the context of recent published work on seeded-controlled growth.

  18. On the Stability and Abundance of Single Walled Carbon Nanotubes

    PubMed Central

    Hedman, Daniel; Reza Barzegar, Hamid; Rosén, Arne; Wågberg, Thomas; Andreas Larsson, J.

    2015-01-01

    Many nanotechnological applications, using single-walled carbon nanotubes (SWNTs), are only possible with a uniform product. Thus, direct control over the product during chemical vapor deposition (CVD) growth of SWNT is desirable, and much effort has been made towards the ultimate goal of chirality-controlled growth of SWNTs. We have used density functional theory (DFT) to compute the stability of SWNT fragments of all chiralities in the series representing the targeted products for such applications, which we compare to the chiralities of the actual CVD products from all properly analyzed experiments. From this comparison we find that in 84% of the cases the experimental product represents chiralities among the most stable SWNT fragments (within 0.2?eV) from the computations. Our analysis shows that the diameter of the SWNT product is governed by the well-known relation to size of the catalytic nanoparticles, and the specific chirality is normally determined by the product’s relative stability, suggesting thermodynamic control at the early stage of product formation. Based on our findings, we discuss the effect of other experimental parameters on the chirality of the product. Furthermore, we highlight the possibility to produce any tube chirality in the context of recent published work on seeded-controlled growth. PMID:26581125

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

    SciTech Connect

    Desai, S. C.; Willitsford, A. H.; Sumanasekera, G. U.; Yu, M.; Jayanthi, C. S.; Wu, S. Y.; Tian, W. Q.

    2010-06-15

    Accurate and reliable detection of hypergolic fuels such as hydrazine (N{sub 2}H{sub 4}) and its derivatives is vital to missile defense, aviation, homeland security, and the chemical industry. More importantly these sensors need to be capable of operation at low temperatures (below room temperature) as most of the widely used chemical sensors operate at high temperatures (above 300 deg. C). In this research a simple and highly sensitive single walled carbon nanotube (SWNT) network sensor was developed for real time monitoring of hydrazine leaks to concentrations at parts per million levels. Upon exposure to hydrazine vapor, the resistance of the air exposed nanotubes (p-type) is observed to increase rapidly while that of the vacuum-degassed nanotubes (n-type) is observed to decrease. It was found that the resistance of the sample can be recovered through vacuum pumping and exposure to ultraviolet light. The experimental results support the electrochemical charge transfer mechanism between the oxygen redox couple of the ambient and the Fermi level of the SWNT. Theoretical results of the hydrazine-SWNT interaction are compared with the experimental observations. It was found that a monolayer of water molecules on the SWNT is necessary to induce strong interactions between hydrazine and the SWNT by way of introducing new occupied states near the bottom of the conduction band of the SWNT.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  1. Bundling dynamics of single walled carbon nanotubes in aqueous suspensions

    NASA Astrophysics Data System (ADS)

    Eda, Goki; Fanchini, Giovanni; Kanwal, Alokik; Chhowalla, Manish

    2008-05-01

    A simple optical method based on absorption of monochromatic light to investigate the dynamics of single walled carbon nanotube (SWCNT) suspensions is described. The well dispersed suspensions display a complex behavior, exhibiting peaks due to resonant scattering from SWCNT bundles with increasing diameters as a function of time. The results indicate that the bundling of SWCNTs initiates almost immediately after termination of sonication (after ˜0.1 h) and continues to increase up to a critical time (˜10 h), above which precipitation according to the Stokes relationship occurs. The absorbance behavior can be explained by the depletion of the effective medium as well as the Mie scattering from growth of bundles. A semiquantitative analysis of the experimental data based on the Mie theory of light scattering from cylindrical particles allows the extraction of diameters at the nucleation and growth of SWCNT bundles. The bundling dynamics have been correlated with the electrical properties such as the sheet resistance and transistor characteristics of the SWCNT thin films. Our work is a useful step toward reproducible solution processed electronics because it provides a simple method to monitor the quality of SWCNT suspensions in real time and correlate it to device characteristics.

  2. Dispersion of single walled carbon nanotubes in amidine solvents

    NASA Astrophysics Data System (ADS)

    Barman, S. N.; Pan, D.; Vosgueritchian, M.; Zoombelt, A. P.; Galli, G.; Bao, Z.

    2012-08-01

    The excellent electronic and material properties of single walled carbon nanotubes (SWNTs) makes this nanomaterial very attractive for incorporation into flexible and stretchable electronics. However, the widespread application of SWNTs in electronic devices is still limited. To purify, process and place SWNTs, appropriate solvents for dispersion are needed. However, a fundamental understanding of the reasons why certain solvents are capable of dispersing SWNTs is still missing. Here we report on two new potential solvents containing amidine moieties, 1,8-diazabicycloundec-7-ene (DBU) and 1,5-diazabicyclo(4.3.0)non-5-ene (DBN). Even though these solvents’ molecular structures differ by only two -CH2- groups, we found that DBU is capable of dispersing SWNTs, while DBN is not. We carried out density functional theory (DFT) calculations to investigate the interaction between DBU and DBN, and we elucidated the reasons for the different performances of the two solvents. DBU has a preferential edge-on interaction with the SWNT, thus allowing for a higher solvent coverage than DBN. In addition, the CH2-SWNT interaction present for DBU substantially increases the adsorption energy compared to DBN. Our results point to the important interplay between the interaction of pi electrons, nitrogen lone pairs and the -CH2- groups present in aprotic solvent molecules and the delocalized pi electrons in SWNTs.

  3. Dispersion of single walled carbon nanotubes in amidine solvents.

    PubMed

    Barman, S N; Pan, D; Vosgueritchian, M; Zoombelt, A P; Galli, G; Bao, Z

    2012-08-31

    The excellent electronic and material properties of single walled carbon nanotubes (SWNTs) makes this nanomaterial very attractive for incorporation into flexible and stretchable electronics. However, the widespread application of SWNTs in electronic devices is still limited. To purify, process and place SWNTs, appropriate solvents for dispersion are needed. However, a fundamental understanding of the reasons why certain solvents are capable of dispersing SWNTs is still missing. Here we report on two new potential solvents containing amidine moieties, 1,8-diazabicycloundec-7-ene (DBU) and 1,5-diazabicyclo(4.3.0)non-5-ene (DBN). Even though these solvents' molecular structures differ by only two -CH(2)- groups, we found that DBU is capable of dispersing SWNTs, while DBN is not. We carried out density functional theory (DFT) calculations to investigate the interaction between DBU and DBN, and we elucidated the reasons for the different performances of the two solvents. DBU has a preferential edge-on interaction with the SWNT, thus allowing for a higher solvent coverage than DBN. In addition, the CH(2)-SWNT interaction present for DBU substantially increases the adsorption energy compared to DBN. Our results point to the important interplay between the interaction of pi electrons, nitrogen lone pairs and the -CH(2)- groups present in aprotic solvent molecules and the delocalized pi electrons in SWNTs. PMID:22885377

  4. Coarse-grained potentials of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhao, Junhua; Jiang, Jin-Wu; Wang, Lifeng; Guo, Wanlin; Rabczuk, Timon

    2014-11-01

    We develop the coarse-grained (CG) potentials of single-walled carbon nanotubes (SWCNTs) in CNT bundles and buckypaper for the study of the static and dynamic behaviors. The explicit expressions of the CG stretching, bending and torsion potentials for the nanotubes are obtained by the stick-spiral and the beam models, respectively. The non-bonded CG potentials between two different CG beads are derived from analytical results based on the cohesive energy between two parallel and crossing SWCNTs from the van der Waals interactions. We show that the CG model is applicable to large deformations of complex CNT systems by combining the bonded potentials with non-bonded potentials. Checking against full atom molecular dynamics calculations and our analytical results shows that the present CG potentials have high accuracy. The established CG potentials are used to study the mechanical properties of the CNT bundles and buckypaper efficiently at minor computational cost, which shows great potential for the design of micro- and nanomechanical devices and systems.

  5. 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.

  6. 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

  7. Suspended single-walled carbon nanotube fluidic sensors.

    PubMed

    Son, B H; Park, Ji-Yong; Lee, Soonil; Ahn, Y H

    2015-10-01

    In this paper, we demonstrate the fabrication of liquid flow sensors employing partially suspended single-walled carbon nanotubes (SWNTs). We have found that the sign of the conductance change in SWNT flow sensors is not influenced by the direction of water flow for both supported and suspended devices. Therefore, the streaming potential is not the principal mechanism of the SWNT sensor response. Instead, the conductance change is more likely due to a reduction in the cation density in the electrical double layer, whose equilibrium conditions are determined by the liquid flow rate. More importantly, we have found that the sensitivity of suspended SWNT devices is more than 10 times greater than that of supported SWNT devices. A reduced screening effect and an increase in effective sensing volume are responsible for the enhanced sensitivity, which is consistent with the ion depletion model. We also have measured conductance as a function of gate bias at different flow rates and have determined the flow-rate dependent effective charge density, which influences the electrostatic configuration around SWNT devices. PMID:26335376

  8. Single-walled carbon nanotube-induced mitotic disruption?

    PubMed Central

    Sargent, L.M.; Hubbs, A.F.; Young, S.-H.; Kashon, M.L.; Dinu, C.Z.; Salisbury, J.L.; Benkovic, S.A.; Lowry, D.T.; Murray, A.R.; Kisin, E.R.; Siegrist, K.J.; Battelli, L.; Mastovich, J.; Sturgeon, J.L.; Bunker, K.L.; Shvedova, A.A.; Reynolds, S.H.

    2015-01-01

    Carbon nanotubes were among the earliest products of nanotechnology and have many potential applications in medicine, electronics, and manufacturing. The low density, small size, and biological persistence of carbon nanotubes create challenges for exposure control and monitoring and make respiratory exposures to workers likely. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to 24, 48 and 96 ?g/cm2 single-walled carbon nanotubes (SWCNT). To investigate mitotic spindle aberrations at concentrations anticipated in exposed workers, primary and immortalized human airway epithelial cells were exposed to SWCNT for 24–72 h at doses equivalent to 20 weeks of exposure at the Permissible Exposure Limit for particulates not otherwise regulated. We have now demonstrated fragmented centrosomes, disrupted mitotic spindles and aneuploid chromosome number at those doses. The data further demonstrated multipolar mitotic spindles comprised 95% of the disrupted mitoses. The increased multipolar mitotic spindles were associated with an increased number of cells in the G2 phase of mitosis, indicating a mitotic checkpoint response. Nanotubes were observed in association with mitotic spindle microtubules, the centrosomes and condensed chromatin in cells exposed to 0.024, 0.24, 2.4 and 24 ?g/cm2 SWCNT. Three-dimensional reconstructions showed carbon nanotubes within the centrosome structure. The lower doses did not cause cytotoxicity or reduction in colony formation after 24 h; however, after three days, significant cytotoxicity was observed in the SWCNT-exposed cells. Colony formation assays showed an increased proliferation seven days after exposure. Our results show significant disruption of the mitotic spindle by SWCNT at occupationally relevant doses. The increased proliferation that was observed in carbon nanotube-exposed cells indicates a greater potential to pass the genetic damage to daughter cells. Disruption of the centrosome is common in many solid tumors including lung cancer. The resulting aneuploidy is an early event in the progression of many cancers, suggesting that it may play a role in both tumorigenesis and tumor progression. These results suggest caution should be used in the handling and processing of carbon nanotubes. PMID:22178868

  9. New Method Developed To Purify Single Wall Carbon Nanotubes for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Lebron, Marisabel; Meador, Michael A.

    2003-01-01

    Single wall carbon nanotubes have attracted considerable attention because of their remarkable mechanical properties and electrical and thermal conductivities. Use of these materials as primary or secondary reinforcements in polymers or ceramics could lead to new materials with significantly enhanced mechanical strength and electrical and thermal conductivity. Use of carbon-nanotube-reinforced materials in aerospace components will enable substantial reductions in component weight and improvements in durability and safety. Potential applications for single wall carbon nanotubes include lightweight components for vehicle structures and propulsion systems, fuel cell components (bipolar plates and electrodes) and battery electrodes, and ultra-lightweight materials for use in solar sails. A major barrier to the successful use of carbon nanotubes in these components is the need for methods to economically produce pure carbon nanotubes in large enough quantities to not only evaluate their suitability for certain applications but also produce actual components. Most carbon nanotube synthesis methods, including the HiPCO (high pressure carbon monoxide) method developed by Smalley and others, employ metal catalysts that remain trapped in the final product. These catalyst impurities can affect nanotube properties and accelerate their decomposition. The development of techniques to remove most, if not all, of these impurities is essential to their successful use in practical applications. A new method has been developed at the NASA Glenn Research Center to purify gram-scale quantities of single wall carbon nanotubes. This method, a modification of a gas phase purification technique previously reported by Smalley and others, uses a combination of high-temperature oxidations and repeated extractions with nitric and hydrochloric acid. This improved procedure significantly reduces the amount of impurities (catalyst and nonnanotube forms of carbon) within the nanotubes, increasing their stability significantly. The onset of decomposition of the purified nanotubes (determined by thermal gravimetric analysis in air) is more than 300 C higher than that of the crude nanotubes. Transmission electron microscopy analysis of nanotubes purified by this method reveals near complete removal of iron catalyst particles. Analysis of the nanotubes using inductively coupled plasma spectroscopy revealed that the iron content of the nanotubes was reduced from 22.7 wt% in the crude nanotubes to less than 0.02 wt%. X-ray photoelectron spectroscopy revealed a decrease in iron content after purification as well as an increase in oxygen content due to the formation of carboxylic acid groups on the surface of the nanotubes. Nanotubes purified by this improved method can be readily dispersed in common organic solvents, in particular N,N-dimethylformamide, using prolonged ultrasonic treatment. These dispersions can then be used to incorporate single wall carbon nanotubes into polymer films.

  10. 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

  11. Synthesis of Single-Walled Carbon Nanotubes in a Glow Discharge Fine Particle Plasma

    SciTech Connect

    Imazato, N.; Imano, M.; Hayashi, Y.

    2008-09-07

    Carbon fine particles were synthesized being negatively charged and confined in a glow discharge plasma. The deposited fine particles were analyzed by Raman spectroscopy and transmission electron microscopy (TEM) and were confirmed to include single-walled carbon nanotubes.

  12. Improved temperature characteristics of single-wall carbon nanotube single electron transistors using carboxymethylcellulose dispersant

    NASA Astrophysics Data System (ADS)

    Mori, Takahiro; Omura, Kazuo; Sato, Shunsuke; Suzuki, Masaki; Uchida, Katsumi; Yajima, Hirofumi; Ishibashi, Koji

    2007-12-01

    Single-wall carbon nanotube (SWNT) based single electron transistors were fabricated by the dispersion method using carboxymethylcellulose (CMC) as a dispersant to make SWNT suspension. The temperature characteristics were improved compared to the one fabricated with a Triton X-100/water SWNT suspension, so that the regular Coulomb oscillations were observed up to 80K. This could be due to the increased barrier height, which may be originated from extra dipoles induced by the adsorbed CMC molecules at the SWNT/metal interface.

  13. Stabilities and mechanical and electronic properties on BN doped zigzag single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Vongachariya, Arthit; Parasuk, Vudhichai

    2015-12-01

    Electronic structures of undoped and BN doped zigzag (8,0) single-walled carbon nanotube (SWCNT) were investigated using density functional theoretical calculations. Their stabilities due to BN doping and spin states were considered and those with the shortest B-N distance and singlet spin is the most stable. The BN substitution also causes the reduction of the band gap energy. While the BN doping reduces the band gap energy from 0.606 to 0.183 eV, it has no effect on the Young's modulus value. The band gap energy of SWCNTs can be varied upon applying stress. At high stress ratio, SWCNT could become metallic.

  14. Fast Characterization of Magnetic Impurities in Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Chen, Feng; Xue, Y. Y.; Hadijiev, Viktor G.; Chu, C. W.; Nikolaev, Pasha; Arepalli, Sivaram

    2003-01-01

    We have demonstrated that the magnetic susceptibility measurement is a non-destructive, fast and accurate method to determine the residual metal catalysts in a few microgram single-wall carbon nanotube (SWCNT) sample. We have studied magnetic impurities in raw and purified SWCNT by magnetic susceptibility measurements, transmission electron microscopy, and thermogravimetry. The data suggest that the saturation magnetic moment and the effective field, which is caused by the interparticle interactions, decreases and increases respectively with the decrease of the particle size. Methods are suggested to overcome the uncertainty associated.

  15. A simple combinatorial method to discover Co-Mo binary catalysts that grow vertically aligned single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    A simple combinatorial method to discover Co-Mo binary catalysts that grow vertically aligned single-walled carbon nanotubes Suguru Noda a,* , Hisashi Sugime a , Toshio Osawa a , Yoshiko Tsuji-ku, Tokyo 113-8656, Japan Abstract A simple yet versatile combinatorial method to discover binary metal

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

    NASA Astrophysics Data System (ADS)

    Bassiouk, María; Basiuk, Vladimir A.; Basiuk, Elena V.; Álvarez-Zauco, Edgar; Martínez-Herrera, Melchor; Rojas-Aguilar, Aaron; Puente-Lee, Iván

    2013-06-01

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

  17. Toroidal Single Wall Carbon Nanotubes in Fullerene Crop Circles

    NASA Technical Reports Server (NTRS)

    Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We investigate energetics and structure of circular and polygonal single wall carbon nanotubes (SWNTs) using large scale molecular simulations on NAS SP2, motivated by their unusual electronic and magnetic properties. The circular tori are formed by bending tube (no net whereas the polygonal tori are constructed by turning the joint of two tubes of (n, n), (n+1, n-1) and (n+2, n-2) with topological pentagon-heptagon defect, in which n =5, 8 and 10. The strain energy of circular tori relative to straight tube decreases by I/D(sup 2) where D is torus diameter. As D increases, these tori change from buckling to an energetically stable state. The stable tori are perfect circular in both toroidal and tubular geometry with strain less than 0. 03 eV/atom when D greater than 10, 20 and 40 nm for torus (5,5), (8,8) and (10, 10). Polygonal tori, whose strain is proportional to the number of defects and I/D are energetically stable even for D less than 10 nm. However, their strain is higher than that of perfect circular tori. In addition, the local maximum strain of polygonal tori is much higher than that of perfect circular tori. It is approx. 0.03 eV/atom or less for perfect circular torus (5,5), but 0.13 and 0.21 eV/atom for polygonal tori (6,4)/(5,5) and (7,3)/(5,5). Therefore, we conclude that the circular tori with no topological defects are more energetically stable and kinetically accessible than the polygonal tori containing the pentagon-heptagon defects for the laser-grown SWNTs and Fullerene crop circles.

  18. 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.

  19. 78 IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 1, NO. 1, MARCH 2002 Single-Walled Carbon Nanotube Electronics

    E-print Network

    Walsworth, Ronald L.

    78 IEEE TRANSACTIONS ON NANOTECHNOLOGY, VOL. 1, NO. 1, MARCH 2002 Single-Walled Carbon Nanotube--Field-effect transistors (FETs), interconnections, nanotechnology, nanotube. I. INTRODUCTION SINGLE-WALLED carbon nanotubes

  20. 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.

  1. Single-Wall Carbon Nanotube Production by the Arc Process: A Parametric Study

    NASA Technical Reports Server (NTRS)

    Scott, Carl D.; Gorelik, Olga; Proft, William J.

    2000-01-01

    Single wall carbon nanotubes are produced using the arc discharge process. Graphite anodes are filled with a mixture of nickel and yttrium metallic powders, then vaporized by creating a high current arc. By varying the current, gap distance, and ambient pressure it is shown that the best yield of single wall carbon nanotubes is obtained within a narrow range of conditions. The relative yield and purity of the product are indicated semi-quantitatively from scanning electric microscopy (SEM) and thermogravimetric analysis (TGA). Two types of anodes have been investigated. The first is hollow and filled with a powder mixture of graphite, nickel and yttrium. The second is filled with a paste made of a mixture of metal nitrates, graphite powder and carbon adhesive, then reduced in an argon atmosphere at high temperature. Product purity and yield will be compared for the two types of anodes. The graphite in the anodes may have hydrogen attached in the pores. To remove this impurity anodes have been baked up to 1400 - 1500 C. The effect of baking the anodes on impurities in the product will be given.

  2. Low Bias Electron Scattering in Structure-Identified Single Wall Carbon Nanotubes: Role of Substrate Polar Phonons

    E-print Network

    Heinz, Tony F.

    .80.Rj, 73.63.Fg Discovered nearly two decades ago, single wall carbon nanotubes (SWNTs) remain oneLow Bias Electron Scattering in Structure-Identified Single Wall Carbon Nanotubes: Role temperature-dependent electrical transport measurements on known structure single wall carbon nanotubes at low

  3. Ultrafast optical spectroscopy of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ostojic, Gordana

    Wavelength-dependent, near-infrared pump-probe study of micelle-suspended Single-Walled Carbon Nanotubes (SWCNTs) whose linear absorption spectra show chirality-assigned peaks is presented. Two distinct relaxation regimes were observed: fast (0.3--1.2 ps) and slow (5--20 ps). The slow component, which has previously been unobserved in pump-probe measurements of bundled tubes, was resonantly enhanced whenever the pump photon energy matched with an interband absorption peak, and it is attributed to interband carrier recombination. It represents the lower limit of the intrinsic radiative recombination time of photoexcited carriers in SWCNTs since the exact value of this parameter depends on the presence of possible nonradiative recombination channels. The slow decay component was highly dependent on the pH of the solution, suggesting that the surrounding H+ ions strongly affect electronic states in nanotubes through the Burnstein-Moss effect. The effect was bandgap energy dependent, affecting the smaller bandgap tubes more significantly. To elucidate carrier dynamics in more detail, nondegenerate pump-probe experiments with wide and continuum probing throughout the lowest and second lowest energy transition ranges of SWCNTs were used. Complex signals were revealed with photoinduced absorption and bleaching, both of which were strongly wavelength dependent. Due to the high optical quality of unbundled SWCNT samples, clear signs of band filling and broadening of the exciton absorption peaks were found to be the main nonlinear mechanisms. The identification of these nonlinear mechanisms presents a novel explanation of the observed nonlinear behavior of nanotubes in general and helps clarify the controversial issues presented in previously published work. This explanation is also consistent with the previously observed pump-probe signals in bundled nanotube samples. Another novel and important conclusion drawn from the nondegenerate pump-probe experiments is that the position of the exciton absorption peaks is unchanged in the presence of high density electron-hole pairs, even when their density is comparable to the Mott density. The stability of the excitons observed for the first time in nanotubes is similar to what has been seen in the studies on the emission properties of GaAs-based semiconductor quantum wires. Although binding energies of these two 1D material systems are very different, the exciton stability seems to be a mark of their unique 1D nature.

  4. Antimicrobial Biomaterials based on Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Aslan, Seyma

    Biomaterials that inactivate bacteria are needed to eliminate medical device infections. We investigate the antimicrobial nature of single-walled carbon nanotubes (SWNT) incorporated within biomedical polymers. In the first part, we focus on SWNT dispersed in the common biomedical polymer poly(lactic-co-glycolic acid) (PLGA) as a potential antimicrobial biomaterial. We find Escherichia coli and Staphylococcus epidermidis viability and metabolic activity to be significantly diminished in the presence of SWNT-PLGA, and to correlate with SWNT length and concentration. Up to 98 % of bacteria die within one hour of SWNT-PLGA versus 15-20% on pure PLGA. Shorter SWNT are found to be more toxic, possibly due to an increased density of open tube ends. In the second part, we investigate the antimicrobial activity of SWNT layer-by-layer (LbL) assembled with the polyelectrolytes poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA). The dispersibility of SWNT in aqueous solution is significantly improved via the biocompatible nonionic surfactant polyoxyethylene(20)sorbitan monolaurate (Tween 20) and the amphiphilic polymer phospholipid-poly(ethylene glycol) (PL-PEG). Absorbance spectroscopy and transmission electron microscopy (TEM) show SWNT with either Tween 20 or PL-PEG in aqueous solution to be well dispersed. Quartz crystal microgravimetry with dissipation (QCMD) measurements show both SWNT-Tween and SWNT-PL-PEG to LbL assemble with PLL and PGA into multilayer films, with the PL-PEG system yielding the greater final SWNT content. Bacterial inactivation rates are significantly higher (up to 90%) upon 24 hour incubation with SWNT containing films, compared to control films (ca. 20%). In the third part, we study the influence of bundling on the LbL assembly of SWNT with charged polymers, and on the antimicrobial properties of the assembled film. QCMD measurements show the bundled SWNT system to adsorb in an unusually strong fashion—to an extent three times greater than that of isolated SWNT. Scanning electron micrographs reveal Escherichia coli on bundled SWNT films to be essentially engulfed by the nanotubes, whereas the bacteria rest upon the isolated SWNT films. While both systems inactivate 90% of bacteria following 24 h, the bundled SWNT system is "fast-acting", reaching this inactivation rate in 1 hr. This thesis demonstrates the potential usefulness of SWNT/polymer thin films as antimicrobial biomaterials.

  5. Single Walled Carbon Nanohorns as Photothermal Cancer Agents

    SciTech Connect

    Whitney, John; Sarkar, Saugata; Zhang, Jianfei; Do, Thao; Manson, Mary kyle; Campbell, Tom; Puretzky, Alexander A; Rouleau, Christopher M; More, Karren Leslie; Geohegan, David B; Rylander, Christopher; Dorn, Harry C; Rylander, Nichole M

    2011-01-01

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

  6. Diffusion of single-walled carbon nanotube under physiological conditions.

    PubMed

    Judkins, John; Lee, Hyun Ho; Tung, Steve; Kim, Jin-Woo

    2013-06-01

    Single-walled carbon nanotube (SWNT) can be functionalized to target cells for drug delivery or cancer cells for their detection and therapy. Understanding their transport phenomena in vivo is a necessary step to unlock their medical potential. This work estimates the diffusion characteristics of SWNTs and their DNA-conjugated bio-hybrids under simulated or postulated physiological conditions using EPI-fluorescence microscopy (EFM). SWNT was shortened and dispersed in aqueous solution with the average length and diameter of 253 nm (+/-30.6 nm) and 1.6 nm (+/-0.34 nm), respectively, and tagged with a fluorophore, 1-pyrenebutanoic succinimidyl ester (PSE), through non-covalent pi stacking. DNA was attached to the PSE-SWNTs through carboxiimide based coupling procedure. Using the EFM, real-time videos were recorded under four different viscosities corresponding to four kinds of human body fluids: lymph (1.4 cP), bile (2.4 cP), blood (3-6 cP), and cytoplasm (10-30 cP), and processed to calculate diffusion coefficients based on random walk and speed. At 37 degreeC, diffusion coefficients of the SWNTs were estimated to be: 1.45 (+/-0.652) x 10(4) nm2/s (lymph), 0.91 (+/-0.205) x 10(4) nm2/s (bile), 0.59 (+/-0.179)x 10(4) nm2/s (blood), and 0.26 (+/-0.114)x 10(4) nm2/s (cytoplasm). Estimated diffusion coefficients of SWNT-DNA bio-hybrids were: 1.45 (+/-0.402) x 10(4) nm2/s (plasma), 0.62 (+/-0.212) x 10(4) nm2/s (bile), 0.41 (+/-0.142) x 10(4) nm2/s (blood), 0.38 (+/-0.257) x 10(4) nm2/s (cytoplasm). These outcomes should serve as key data for developing mathematical models of SWNT-based drug delivery, cell targeting, and its biodistribution. PMID:23858971

  7. Optical and vibrational properties of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kennedy, W. Joshua

    This work is a study of the optical properties of single-wall carbon nanotubes (SWNTs) using continuous wave (CW) modulation spectroscopy and resonant Raman scattering. SWNTs comprise a nanoscale, quasi-1D system in which the electrons are strongly interacting, resulting in the photo-generation of excitons. Our optical studies have revealed the behavior of these excitons under a number of different perturbations to the system. We have used absorption, reflectance, electro-absorption (EA), photo-induced absorption (PA), charge-induced absorption (CIA), and resonant Raman scattering (RRS) on films of SWNTs. Our EA results provide strong evidence for the dominance of excitons in the optical absorption spectra of SWNT films. The absence of Franz-Keldysh oscillations and the presence of a derivative-like structure of the EA spectra indicate that the oscillator strength goes to the generation of excitons and not to interband electronic transitions. Furthermore, some of the photo-generated excitons are long-lived due to charge trapping in individual tubes within bundles, and this leads to a PA spectrum that is extraordinarily similar to the EA signal. When SWNTs are electrochemically doped we see that the exciton absorption is bleached due to k-space filling and screening of the excitons by the modified local dielectric, while there is very little shift in the exciton transition energies due to band-gap renormalization. Simultaneously the infrared absorption, which is due to Drude free-carriers absorption, is enhanced. A similar behavior is observed in the case of direct charge injection. The RRS of doped SWNT samples shows a frequency shift of many of the Raman-active modes that is commensurate with the macroscopic actuation observed in nanotube-based electrochemical devices. This indicates that doping-induced changes in the lattice are connected with softening and stiffening of the vibrational modes. Our results impact many proposed technologies that exploit the unique properties of SWNTs. Displays, batteries, and even photovoltaics that incorporate nanotubes are already in development. The performance and robustness of these devices could be improved when our results are taken into account.

  8. 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.

  9. A remote sensor for detecting methane based on palladium-decorated single walled carbon nanotubes.

    PubMed

    Liu, Jian; Li, Guomin

    2013-01-01

    The remote detection of the concentration of methane at room temperature is performed by a sensor that is configured by the combination of radio frequency identification (RFID), and functionalized carbon nanotubes (CNTs). The proposed sensor is schemed as a thin film RFID tag in a polyethylene substrate, on which a metal trace dipole, a metal trace T impedance matching networks, a 0.5 µm-CMOS RF/DC rectifier chipset and a sensor head of palladium-decorated single walled carbon nanotubes (Pd-SWCNTs) are surface mounted in cascade. The performances of the sensor are examined and described by the defined parameters of the received signal strength index (RSSI) and the comparative analog identifier (?AID). Results validate the sensor's ability to detect molecules of methane at room temperature, showing that the RSSI can increase 4 dB and the ?AID can increase 3% in response to methane concentrations ranging from zero to 100 ppm. PMID:23845931

  10. Identification of nitrogen dopants in single-walled carbon nanotubes by scanning tunneling microscopy.

    PubMed

    Tison, Yann; Lin, Hong; Lagoute, Jérôme; Repain, Vincent; Chacon, Cyril; Girard, Yann; Rousset, Sylvie; Henrard, Luc; Zheng, Bing; Susi, Toma; Kauppinen, Esko I; Ducastelle, François; Loiseau, Annick

    2013-08-27

    Using scanning tunnelling microscopy and spectroscopy, we investigated the atomic and electronic structure of nitrogen-doped single walled carbon nanotubes synthesized by chemical vapor deposition. The insertion of nitrogen in the carbon lattice induces several types of point defects involving different atomic configurations. Spectroscopic measurements on semiconducting nanotubes reveal that these local structures can induce either extended shallow levels or more localized deep levels. In a metallic tube, a single doping site associated with a donor state was observed in the gap at an energy close to that of the first van Hove singularity. Density functional theory calculations reveal that this feature corresponds to a substitutional nitrogen atom in the carbon network. PMID:23829349

  11. Robust Cyclohexanone Selective Chemiresistors Based on Single-Walled Carbon Nanotubes

    E-print Network

    Frazier, Kelvin Mitchell

    Functionalized single-walled carbon nanotube (SWCNT)-based chemiresistors are reported for a highly robust and sensitive gas sensor to selectively detect cyclohexanone, a target analyte for explosive detection. The ...

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

    E-print Network

    Warren, Graham

    2010-07-14

    This work is mainly focused upon the preparation, processing and evaluation of mechanical and material properties of epoxy/single walled carbon nanotube (SWCNT) nanocomposite thin films. B-staged epoxy/SWCNT nanocomposite ...

  13. Exciton energy Kataura plot and excitonic effect of single wall carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    Exciton energy Kataura plot and excitonic effect of single wall carbon nanotubes Kentaro Sato1 in the different environment. From our calculation we show the exciton energy Kataura plot for different samples

  14. 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 ...

  15. Elucidating Nucleation and Growth Behavior of Single-Walled Carbon Nanotubes obtained via Catalyzed Synthesis 

    E-print Network

    Burgos Beltran, Juan Carlos

    2014-11-07

    The catalytic growth of single-walled carbon nanotubes (SWCNTs) is studied using reactive molecular dynamics (RMD) simulations and density functional theory (DFT) calculations. Computational calculations are performed in order to achieve a better...

  16. 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

  17. Effect of single walled carbon nanotubes (SWNTs) on the electromechanical properties of polyimide nanocomposites 

    E-print Network

    Deshmukh, Sujay

    2007-04-25

    , toughness, and electromechanical coupling. The broad goal of this thesis was to investigate potential electromechanical behavior in single walled carbon nanotube (SWNT)-polyimide (PI) composites. The specific objective was to measure and characterize...

  18. Exciton diffusion in semiconducting single-walled carbon nanotubes studied by transient absorption microscopy

    E-print Network

    Ruzicka, Brian Andrew; Wang, Rui; Lohrman, Jessica; Ren, Shenqiang; Zhao, Hui

    2012-11-09

    Spatiotemporal dynamics of excitons in isolated semiconducting single-walled carbon nanotubes are studied using transient absorption microscopy. Differential reflection and transmission of an 810-nm probe pulse after excitation by a 750-nm pump...

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

    E-print Network

    Heller, Daniel A.

    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. ...

  20. In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes

    E-print Network

    Iverson, Nicole M.

    Single-walled carbon nanotubes are particularly attractive for biomedical applications, because they exhibit a fluorescent signal in a spectral region where there is minimal interference from biological media. Although ...

  1. Anomalous thermal conduction characteristics of phase change composites with single walled carbon nanotube inclusions

    E-print Network

    Maruyama, Shigeo

    Anomalous thermal conduction characteristics of phase change composites with single walled carbon 113-8656, Japan. We report large contrasts in the thermal conductivity enhancement of phase change change alkane using sodium deoxycholate (DOC) surfactant. Thermal conductivity measurements in solid

  2. 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.

  3. Formation of single-walled bimetallic coinage alloy nanotubes in confined carbon nanotubes: molecular dynamics simulations.

    PubMed

    Han, Yang; Zhou, Jian; Dong, Jinming; Yoshiyuki, Kawazoe

    2013-10-28

    The growth of single-walled bimetallic Au-Ag, Au-Cu and Ag-Cu alloy nanotubes (NTs) and nanowires (NWs) in confined carbon nanotubes (CNTs) has been investigated by using the classical molecular dynamics (MD) method. It is found that three kinds of single-walled gold-silver, gold-copper and silver-copper alloy NTs could indeed be formed in confined CNTs at any alloy concentration, whose geometric structures are less sensitive to the alloy concentration. And an extra nearly pure Au (Cu) chain will exist at the center of Au-Ag (Au-Cu and Ag-Cu) NTs when the diameters of the outside CNTs are big enough, thus producing a new type of tube-like alloy NWs. The bonding energy differences between the mono- and hetero-elements of the coinage metal atoms and the quasi-one-dimensional confinement from the CNT play important roles in suppressing effectively the "self-purification" effects, leading to formation of these coinage alloy NTs. In addition, the fluid-solid phase transition temperatures of the bimetallic alloy NTs are found to locate between those of the corresponding pure metal tubes. Finally, the dependences of the radial breathing mode (RBM) frequencies and the tube diameters of the alloy NTs on the alloying concentration were obtained, which will be very helpful for identifying both the alloying concentration and the alloy tube diameters in future experiments. PMID:24013729

  4. Separation of surfactant functionalized single-walled carbon nanotubes via free solution electrophoresis method

    NASA Astrophysics Data System (ADS)

    Scheibe, Blazej; Rümmeli, Mark; Borowiak-Palen, Ewa; Kalenczuk, Ryszard

    2011-04-01

    This work presents the application of the free solution electrophoresis method (FSE) in the metallic / semiconductive (M/S) separation process of the surfactant functionalized single-walled carbon nanotubes (SWCNTs). The SWCNTs synthesized via laser ablation were purified through high vacuum annealing and subsequent refluxing processes in aqua regia solution. The purified and annealed material was divided into six batches. First three batches were dispersed in anionic surfactants: sodium dodecyl sulfate (SDS), sodium cholate (SC) and sodium deoxycholate (DOC). The next three batches were dispersed in cationic surfactants: cetrimonium bromide (CTAB), benzalkonium chloride (BKC) and cetylpyridinium chloride (CPC). All the prepared SWCNTs samples were subjected to FSE separation process. The fractionated samples were recovered from control and electrode areas and annealed in order to remove the adsorbed surfactants on carbon nanotubes (CNTs) surface. The changes of the van Hove singularities (vHS) present in SWCNTs spectra were investigated via UV-Vis-NIR optical absorption spectroscopy (OAS).

  5. Lithium intercalation into single-walled carbon nanotubes network electrode: Storage mechanisms and impurity effects

    NASA Astrophysics Data System (ADS)

    Montoro, Luciano Andrey; Matsubara, Elaine Yoshiko; Rosolen, José Maurício

    2014-07-01

    This is a detailed study of how impurities can affect the mechanisms of lithium storage in composite electrodes consisting of a three-dimensional single-walled carbon nanotube (SWCNT) bundles network. To remove impurities such as fullerenes, amorphous carbon, catalyst, and nanographite, we submitted the SWCNT bundles to an appropriate chemical treatment before using them to prepare the electrode. Then, we analyzed how this treatment influenced electrode potential, fading capacity, and specific capacity. Additionally, we evaluated the electrode prepared with high-purity SWNCT bundles by galvanostatic intermittent titration, to obtain lithium transport parameters under thermodynamic conditions. We achieved an intrinsic specific capacity of 400 mAh g-1 for the purified SWCNT bundles prepared by an arc-reactor method. The transport parameters revealed that the electrode underwent electronic transition of the semiconducting-metal type. The chemical diffusion coefficient ranged from 10-4 to 10-18 cm2 s-1 with decreasing electrode potential.

  6. Properties of single wall carbon nanotubes array antennas in the optical regime

    NASA Astrophysics Data System (ADS)

    Wu, Xiaofang; Jiang, Yuesong; Hua, Houqiang

    2014-11-01

    Single wall carbon nanotubes (SWCNTs) can be metallic, depending on their chirality. For their nanoscale geometric dimension, SWCNTs can be used as antennas to convert high-frequency electromagnetic radiation such as optical radiation into localized energy and vice versa. However, at optical frequencies, traditional antenna design theory fails for metals behave as strongly coupled plasmas. As a matter of fact, an optical antenna responds to a shorter effective wavelength which depends on the material properties and geometric parameters. In this letter, we derived the relationship of effective wavelength with the wavelength of incident radiation for SWCNTs optical antenna, assuming that the SWCNTs can be described by a free electron gas according to the Drude model. SWCNTs optical antenna holds great promise for increasing solar energy conversion efficiency.

  7. Large scale highly organized single-walled carbon nanotube networks for electrical devices

    NASA Astrophysics Data System (ADS)

    Jaber-Ansari, Laila; Hahm, Myung Gwan; Kim, Tae Hoon; Somu, Sivasubramanian; Busnaina, Ahmed; Jung, Yung Joon

    2009-08-01

    Large-scale room-temperature liquid-phase directed assembly of highly organized single-walled carbon nanotubes (SWNT) over large areas is demonstrated. The presented process utilizes lithographically patterned template to guide the fluidic self-assembly of SWNTs on a silicon-dioxide substrate. The width of these highly organized SWNT structures are in the micron range while their heights are in orders of nanometers. Room temperature electrical I- V characterization of these fabricated high coverage SWNT wires show linear ohmic behavior. The resistivity of these assembled SWNT network is in the order of 10-6 ? m demonstrating their metallic characteristics during conductance. Scaling of the assembly processes on a wafer level with high yield is demonstrated. Our developed assembly process is compatible with complimentary metal oxide semiconductor (CMOS) processes and provides a simple and flexible way of building SWNT nanotube-based electronics in a large scale.

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

    SciTech Connect

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

    2015-06-14

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

  9. Single 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.

  10. Continuous growth of single-wall carbon nanotubes using chemical vapor deposition

    DOEpatents

    Grigorian, Leonid (Raymond, OH); Hornyak, Louis (Evergreen, CO); Dillon, Anne C (Boulder, CO); Heben, Michael J (Denver, CO)

    2008-10-07

    The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

  11. Continuous growth of single-wall carbon nanotubes using chemical vapor deposition

    DOEpatents

    Grigorian, Leonid; Hornyak, Louis; Dillon, Anne C; Heben, Michael J

    2014-09-23

    The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

  12. Low temperature conductive tip scanning of single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Prior, Matthew

    The low temperature conductance measurements of Carbon Nanotubes (CNT), and other nanostructures, are commonly conducted on samples with fixed leads, which provide the global information about the nanostructure's electronic properties. To measure local electronic properties, we have built a conductive tip Atomic Force Microscope (AFM). This AFM allows us to place a mobile contact anywhere along the tube and carry out local transport investigation, including measurements taken while we radially deform the nanotube with the tip. Our low temperature conductive tip AFM is suitable for operation in a helium refrigerator with a bore 1.25" or more, at temperatures of 4K or less. It uses a thermally compensated, nonmagnetic design based on the "Besocke Beetle". All movements are achieved by piezotubes, so heat load at low temperatures is small. For tip-surface distance control, we use a homemade frequency detection system based on a commercially available quartz tuning fork. The scanning tip is mounted on the tuning fork. We use a platinum/iridium tip rather than the more commonly used tungsten, as it does not form a native oxide. The tip is independently wired which allows us to measure the current flow along the tube. Previous low temperature AFMs used the conductive tip only to gate the nanotube. Our samples are CVD grown carbon nanotubes upon a silicon dioxide substrate, contacted by a palladium/gold grid. With our AFM, we have carried out the first low temperature scanning of conductance along nanotubes on insulating substrates. While radially deforming a metallic carbon nanotube with our tip, we have observed a reversible gap opening, indicating a metallic to semi-conducting transition. This result qualitatively matches theoretical predictions. We have observed Coulomb blockade in transport between carbon nanotubes and the tip by AFM for the first time. By gently perturbing the nanotube with the tip, we have increased the strength of some single electron conductance peaks while diminishing others. This result is probably due the perturbation of the probability density functions inside the nanotube. This novel instrument will allow us to study the local properties of a broad class of conductive nanostructures positioned on insulating substrates.

  13. Enhanced sidewall functionalization of single-wall carbon nanotubes using nitric acid.

    PubMed

    Tobias, Gerard; Shao, Lidong; Ballesteros, Belin; Green, Malcolm L H

    2009-10-01

    When a sample of as-made single-walled carbon nanotubes (SWNTs) is treated with nitric acid, oxidation debris are formed due to the functionalization (mainly carboxylation) of the amorphous carbon present in the sample and a continuous coating along the carbon nanotube walls is created preventing the sidewall functionalization of the SWNTs. This oxidation debris can be easily removed by an aqueous base wash leaving behind a sample with a low degree of functionality. After removal of the amorphous carbon (by steam purification) from a sample of as-made SWNTs, the resulting purified SWNTs are readily carboxylated on the walls by nitric acid treatment. The use of steam for the purification of SWNTs samples allows the removal of the amorphous carbon and graphitic layers coating the metal particles present in the sample without altering the tubular structure of the SWNTs. The exposed metal particles can then be easily removed by an acid wash. Comparison between the steam treatment and molten sodium hydroxide treatment is made. PMID:19908496

  14. Analysis of Stress Responsive Genes Induced by Single-Walled Carbon Nanotubes in BJ Foreskin Cells

    PubMed Central

    Sarkar, Shubhashish; Sharma, Chidananda; Yog, Rajeshwari; Periakaruppan, Adaikkappan; Jejelowo, Olufisayo; Thomas, Renard; Barrera, Enrique V.; Rice-Ficht, Allison C.; Wilson, Bobby L.; Ramesh, Govindarajan T.

    2009-01-01

    Nanotechnology is finding its use as a potential technology in consumer products, defense, electronics, and medical applications by exploiting the properties of nanomaterials. Single-walled carbon nanotubes are novel forms of these nanomaterials with potential for large applications. However, the toxicity studies on this material are not explored in detail and therefore limiting its use. It has been earlier reported that single-walled carbon nanotubes induces oxidative stress and also dictates activation of specific signaling pathway in keratinocytes. The present study explores the effect of single-walled carbon nanotubes on stress genes in human BJ Foreskin cells. The results show induction of oxidative stress in BJ Foreskin cells by single-walled carbon nanotubes and increase in stress responsive genes. The genes included inducible genes like HMOX1, HMOX2, and Cyp1B1. In addition we validated increase for four genes by SWCNT, namely ATM, CCNC, DNAJB4, and GADD45A by RT-PCR. Moreover results of the altered stress related genes have been discussed and that partially explains some of the toxic responses induced by single-walled carbon nanotubes. PMID:17450800

  15. Light radiation through a transparent cathode plate with single-walled carbon nanotube field emitters

    NASA Astrophysics Data System (ADS)

    Jang, E. S.; Goak, J. C.; Lee, H. S.; Lee, S. H.; Han, J. H.; Lee, C. S.; Sok, J. H.; Seo, Y. H.; Park, K. S.; Lee, N. S.

    2010-09-01

    In the conventional carbon nanotube backlight units (CNT-BLUs), light passes through the phosphor-coated anode glass plate, which thus faces closely the thin film transistor (TFT) backplate of a liquid crystal display panel. This configuration makes heat dissipation structurally difficult because light emission and heat generation occur simultaneously at the anode. We propose a novel configuration of a CNT-BLU where the cathode rather than the anode faces the TFT backplate by turning it upside down. In this design, light passes through the transparent cathode glass plate while heating occurs at the anode. We demonstrated a novel design of CNT-BLU by fabricating transparent single-walled CNT field emitters on the cathode and by coating a reflecting metal layer on the anode. This study hopefully provides a clue to solve the anode-heating problem which would be inevitably confronted for high-luminance and large-area CNT-BLUs.

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

    PubMed

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

    2013-08-01

    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. PMID:23714851

  17. 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.

  18. Vertical single-wall carbon nanotube forests as plasmonic heat pipes.

    PubMed

    Nemilentsau, Andrei M; Rotkin, Slava V

    2012-05-22

    High thermal conductivity of carbon nanotubes (NTs) is attractive for the heat removal applications. However, the problem of efficient thermal coupling to the heater/cooler still needs to be resolved. We study near-field electromagnetic tunneling as a mechanism of heat transfer across the interface. We report interface thermal (Kapitza) conductance between a low-density vertical metallic single-wall NT forest and a quartz substrate on the order of 50 MW/Km(2) and explain it by strong electromagnetic interaction and near-field entanglement between the surface phonon-polaritons in the polar dielectric and the NT plasmons. We predict that the thickness of the NT film can be tweaked to the resonance wavelength of these entangled modes for performance optimization of nanocarbon thermal interconnects. PMID:22480248

  19. Spin-orbit coupling and the static polarizability of single-wall carbon nanotubes

    SciTech Connect

    Diniz, Ginetom S. Ulloa, Sergio E.

    2014-07-14

    We calculate the static longitudinal polarizability of single-wall carbon tubes in the long wavelength limit taking into account spin-orbit effects. We use a four-orbital orthogonal tight-binding formalism to describe the electronic states and the random phase approximation to calculate the dielectric function. We study the role of both the Rashba as well as the intrinsic spin-orbit interactions on the longitudinal dielectric response, i.e., when the probing electric field is parallel to the nanotube axis. The spin-orbit interaction modifies the nanotube electronic band dispersions, which may especially result in a small gap opening in otherwise metallic tubes. The bandgap size and state features, the result of competition between Rashba and intrinsic spin-orbit interactions, result in drastic changes in the longitudinal static polarizability of the system. We discuss results for different nanotube types and the dependence on nanotube radius and spin-orbit couplings.

  20. Mean free paths in single-walled carbon nanotubes measured by Kelvin probe force microscopy

    NASA Astrophysics Data System (ADS)

    Fuller, Elliot J.; Pan, Deng; Corso, Brad L.; Gul, O. Tolga; Collins, Philip G.

    2014-06-01

    The inelastic mean free path ?MFP is a critical parameter for electronic devices. Here, we demonstrate Kelvin probe force microscopy (KPFM) as a technique for studying ?MFP in biased, semi-metallic single-walled carbon nanotubes (SWNTs). Having one of the longest room-temperature ?MFP values of any known material, SWNTs provide a unique platform for probing mesoscopic transport. KPFM directly determined ?MFP as a function of bias, quantitatively determined the contributions of different scattering mechanisms, and enabled comparative study of individual SWNTs with and without disorder. The room-temperature mean free paths for optical phonon and surface plasmon-polariton scattering were measured to be 62 ± 20 nm and 260 ± 50 nm, respectively. The optical phonon scattering length is significantly longer than inferred from previous measurements, and it resolves a longstanding discrepancy between SWNT theory and experiment, suggesting that KPFM could become a preferred quantitative technique for studying transport in nanoscale systems.

  1. 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

  2. Effect of static and dynamic charges on the electronic transport properties of single wall carbon nanotube transistors and interconnects

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, Aravind

    In recent years, carbon nanotubes have emerged as a subject of considerable curiosity and attention, due to their unique properties. From an electronic materials perspective, carbon nanotubes have been repeatedly touted as the future of micro- and nano-electronics technology. Capable of being both metallic and semiconducting, single wall carbon nanotubes have generated visions of an all-nanotube architecture in the not too distant future. Single wall carbon nanotubes have also displayed exotic behavior at low temperatures, spurring a rush of new discoveries and advances down to the level of manipulating individual electrons in nanotubes, the ultimate miniaturization. As research makes significant advances towards these goals, a number of challenges have also appeared. Particularly, it has been realized that single wall carbon nanotubes are extremely sensitive to perturbations in their immediate environment, which might drastically alter their fundamental properties. While single wall nanotubes are physically robust, they appear to electronically very fragile. On the other hand, the effect of external perturbations has actually opened a new door to providing further insights into the fundamental electronic structure and properties of these nanotubes. The research leading to this thesis has focused on unraveling the origin and effect of some such perturbations on electronic and electrical transport properties of individual single wall carbon nanotubes. In order to reach this stage, a number of recent fundamental observations pertaining to nanotube field effect transistors, single electron transistors and ballistic conductors were first reproduced. Single wall carbon nanotubes were grown by thermal chemical vapor deposition techniques on silicon dioxide substrates under optimum conditions. The nanotubes were characterized by techniques like scanning probe microscopy and Raman spectroscopy. Test structures were fabricated by photolithography and electron beam lithography and metallization. Electrical measurements were conducted at temperatures ranging from room temperature to 25K. One of the most obvious environmental effects appeared in the form of hysteresis in the transfer characteristics of nanotube field effect transistors and single electron transistors. While this hysteresis has been reported previously, its origins have remained a subject of significant debate. A detailed study of the hysteresis phenomenon as a function of various parameters revealed convincing evidence to support the theory that the origin of this hysteresis is in fact different from similar hysteresis observed in silicon bases MOSFETs. Based on these findings, a model was developed allowing us to simulate the effect of various parameters on the hysteresis, and show excellent fitting of experimental data to the model.

  3. Shape transition of unstrained flattest single-walled carbon nanotubes under pressure

    SciTech Connect

    Mu, Weihua E-mail: muwh@itp.ac.cn; Cao, Jianshu; Ou-Yang, Zhong-can

    2014-01-28

    Single walled carbon nanotube's (SWCNT's) cross section can be flattened under hydrostatic pressure. One example is the cross section of a single walled carbon nanotube successively deforms from the original round shape to oval shape, then to peanut-like shape. At the transition point of reversible deformation between convex shape and concave shape, the side wall of nanotube is flattest. This flattest tube has many attractive properties. In the present work, an approximate approach is developed to determine the equilibrium shape of this unstrained flattest tube and the curvature distribution of this tube. Our results are in good agreement with recent numerical results, and can be applied to the study of pressure controlled electric properties of single walled carbon nanotubes. The present method can also be used to study other deformed inorganic and organic tube-like structures.

  4. Shape transition of unstrained flattest single-walled carbon nanotubes under pressure

    NASA Astrophysics Data System (ADS)

    Mu, Weihua; Cao, Jianshu; Ou-Yang, Zhong-can

    2014-01-01

    Single walled carbon nanotube's (SWCNT's) cross section can be flattened under hydrostatic pressure. One example is the cross section of a single walled carbon nanotube successively deforms from the original round shape to oval shape, then to peanut-like shape. At the transition point of reversible deformation between convex shape and concave shape, the side wall of nanotube is flattest. This flattest tube has many attractive properties. In the present work, an approximate approach is developed to determine the equilibrium shape of this unstrained flattest tube and the curvature distribution of this tube. Our results are in good agreement with recent numerical results, and can be applied to the study of pressure controlled electric properties of single walled carbon nanotubes. The present method can also be used to study other deformed inorganic and organic tube-like structures.

  5. Dissolution of single-walled carbon nanotubes in alkanol-cholic acid mixtures

    NASA Astrophysics Data System (ADS)

    Dyshin, A. A.; Eliseeva, O. V.; Bondarenko, G. V.; Kiselev, M. G.

    2015-09-01

    A procedure for dispersing the single-walled carbon nanotubes (SWCNTs) for preparing stable suspensions with high concentrations of individual nanotubes in various alcohols was described. The obtained suspensions were studied by Raman spectroscopy. The solubility of the single-walled carbon nanotubes in alcohols was found to depend on the concentration of cholic acid. The ethanol-surfactant mixture was shown to be the best solvent for all alkanol-cholic acid mixtures (0.018 mol/kg) under study used for preparing time-stable suspensions of single-walled carbon nanotubes. The dissolving ability of aliphatic alcohols was found to decrease in the series: ethanol-isopropanol- tert-butanol-butanol-propanol.

  6. Effects of temperature and torsion speed on torsional properties of single-walled carbon nanotubes

    E-print Network

    Chen, Zhongping

    by performing experimental tests, such as the direct tension test [13], bending experiment [14], and torsionEffects of temperature and torsion speed on torsional properties of single-walled carbon nanotubes Available online 4 December 2010 Keywords: Carbon nanotube Molecular dynamics Temperature effect Torsion

  7. Fracture resistance of single-walled carbon nanotubes through atomistic Qiang Lu & Baidurya Bhattacharya

    E-print Network

    Bhattacharya, Baidurya

    Fracture resistance of single-walled carbon nanotubes through atomistic simulation Qiang Lu 19716, USA Keywords: Atomistic simulation, carbon nanotube, fracture resistance, strain-energy, brittle-based materials and devices, fracture of CNTs due to mechanical loading becomes an important issue. Presumably

  8. Patterned Growth of High-quality Single-walled Carbon Nanotubes from Dip-coated Catalyst

    E-print Network

    Maruyama, Shigeo

    1 Patterned Growth of High-quality Single-walled Carbon Nanotubes from Dip-coated Catalyst Rong carbon nanotube structures can also be applied to a dip-coating method. High-quality vertically aligned the growth on chemically modified surfaces. KEYWORDS: SWNT, pattern, ACCVD, dip-coating, growth mechanism #12

  9. Adsorption Dynamics of Alkanes on Single-Wall Carbon Nanotubes: A Molecular Beam Scattering Study

    E-print Network

    Turro, Nicholas J.

    Adsorption Dynamics of Alkanes on Single-Wall Carbon Nanotubes: A Molecular Beam Scattering Study S, 2007 The adsorption dynamics of n-/isobutane on "closed"-end (as-prepared, c-CNTs) and open-end (vacuum- annealed) carbon nanotubes (o-CNTs) have been studied by molecular beam scattering adsorption probability

  10. 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

  11. 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

  12. 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

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

    E-print Network

    Heinz, Tony F.

    of Rayleigh scattering spectra at the single nanotube level reveals clear exciton­phonon sideExcitonic signatures in the optical response of single-wall carbon nanotubes Christophe Voisin*,1, accepted 14 December 2011 Published online 30 January 2012 Keywords carbon nanotubes, excitons

  14. 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.

  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. 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.

  17. Optical Spectroscopy of Individual Single-Walled Carbon Nanotubes of

    E-print Network

    Heinz, Tony F.

    atoms wrapped around its circumference. Rolling up a graphene sheet leads to zone-folding in momentum and observed predicted energy splittings of optical transitions in metallic nanotubes. T he electronic, with distinctive energy-level structures corre- sponding to both metallic and semiconducting species (1­4). Here

  18. Controlled Multistep Purification of Single-Walled Carbon Nanotubes

    E-print Network

    Wikswo, John

    . In this study, iron nanoparticles, coated by carbon, are exposed and oxidized by multiple step oxidation damaging the SWNT. To remove catalyst (typically iron, cobalt, and nickel) and obtain high- purity SWNTs

  19. Work functions of functionalized singled-walled carbon nanotubes

    E-print Network

    Ryu, Janet. (Janet Sun)

    2006-01-01

    Introduction: Carbon nanotube (CNT) structures were discovered by Sumio Iijima in 1991 at NEC laboratories in Japan. Since their discovery, scientists and engineers have been fascinated by their electrical and mechanical ...

  20. Chirality-controlled synthesis of single-wall carbon nanotubes using vapour phase epitaxy

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Wang, Chuan; Tu, Xiaomin; Liu, Bilu; Chen, Liang; Zheng, Ming; Zhou, Chongwu; NIST Collaboration

    2013-03-01

    Due to the superior electrical properties such as high intrinsic carrier mobility and current-carrying capacity, single wall carbon nanotubes (SWCNT) hold great promise for electronic application. Since the electronic property of a SWCNT strongly depends on its chirality, the lack of synthetic control in chirality has long been recognized as a fundamental impediment in the science and application of SWCNTs Here we demonstrate a general strategy for producing carbon nanotubes with predefined chiralities by using purified single-chirality nanotubes as seeds for subsequent metal-catalyst-free growth, resembling vapour phase epitaxy commonly used for semiconductor films. In particular, we have successfully synthesized (7, 6), (6, 5), and (7, 7) nanotubes, and used Raman spectroscopy to show unambiguously that the original chiralities of the nanotube seeds are preserved. Furthermore, we have performed electrical measurements on synthesized individual (7, 6) and (6, 5) nanotubes, confirming their semiconducting nature. The vapour phase epitaxy approach is found to be highly robust and should enable a wide range of fundamental studies and technological developments. Due to the superior electrical properties such as high intrinsic carrier mobility and current-carrying capacity, single wall carbon nanotubes (SWCNT) hold great promise for electronic application. Since the electronic property of a SWCNT strongly depends on its chirality, the lack of synthetic control in chirality has long been recognized as a fundamental impediment in the science and application of SWCNTs Here we demonstrate a general strategy for producing carbon nanotubes with predefined chiralities by using purified single-chirality nanotubes as seeds for subsequent metal-catalyst-free growth, resembling vapour phase epitaxy commonly used for semiconductor films. In particular, we have successfully synthesized (7, 6), (6, 5), and (7, 7) nanotubes, and used Raman spectroscopy to show unambiguously that the original chiralities of the nanotube seeds are preserved. Furthermore, we have performed electrical measurements on synthesized individual (7, 6) and (6, 5) nanotubes, confirming their semiconducting nature. The vapour phase epitaxy approach is found to be highly robust and should enable a wide range of fundamental studies and technological developments. We acknowledge financial support from the SRC FCRP FENA centre and the Office of Naval Research

  1. 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

  2. Dispersion of Single Wall Carbon Nanotubes by in situ Polymerization Under Sonication

    NASA Technical Reports Server (NTRS)

    Park, Cheol; Ounaies, Zoubeida; Watson, Kent A.; Crooks, Roy E.; Smith, Joseph, Jr.; Lowther, Sharon E.; Connell, John W.; Siochi, Emilie J.; Harrison, Joycelyn S.; St.Clair, Terry L.

    2002-01-01

    Single wall nanotube reinforced polyimide nanocomposites were synthesized by in situ polymerization of monomers of interest in the presence of sonication. This process enabled uniform dispersion of single wall carbon nanotube (SWNT) bundles in the polymer matrix. The resultant SWNT-polyimide nanocomposite films were electrically conductive (antistatic) and optically transparent with significant conductivity enhancement (10 orders of magnitude) at a very low loading (0.1 vol%). Mechanical properties as well as thermal stability were also improved with the incorporation of the SWNT.

  3. Nanoscale soldering of axially positioned single-walled carbon nanotubes: a molecular dynamics simulation study.

    PubMed

    Cui, Jianlei; Yang, Lijun; Zhou, Liang; Wang, Yang

    2014-02-12

    The miniaturization of electronics devices into the nanometer scale is indispensable for next-generation semi-conductor technology. Carbon nanotubes (CNTs) are considered to be the promising candidates for future interconnection wires. To study the carbon nanotubes interconnection during nanosoldering, the melting process of nanosolder and nanosoldering process between single-walled carbon nanotubes are simulated with molecular dynamics method. As the simulation results, the melting point of 2 nm silver solder is about 605 K because of high surface energy, which is below the melting temperature of Ag bulk material. In the nanosoldering process simulations, Ag atoms may be dragged into the nanotubes to form different connection configuration, which has no apparent relationship with chirality of SWNTs. The length of core filling nanowires structure has the relationship with the diameter, and it does not become longer with the increasing diameter of SWNT. Subsequently, the dominant mechanism of was analyzed. In addition, as the heating temperature and time, respectively, increases, more Ag atoms can enter the SWNTs with longer length of Ag nanowires. And because of the strong metal bonds, less Ag atoms can remain with the tight atomic structures in the gap between SWNT and SWNT. The preferred interconnection configurations can be achieved between SWNT and SWNT in this paper. PMID:24392855

  4. Gas Sensing Mechanism of Gold Nanoparticles Decorated Single-Walled Carbon Nanotubes

    E-print Network

    Gas Sensing Mechanism of Gold Nanoparticles Decorated Single- Walled Carbon Nanotubes Syed Mubeen towards different gas analytes, however the sensing mechanism was not clearly elucidated. The detailed sensing mechanism of hybrid gold-SWNT nanostructures toward hydrogen sulfide was investigated using field

  5. 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 K, resulting from the interplay between quantum zero-point motion and nonlinear interaction. The CTE, we investigate the CTE in SWCNT and graphene sheets by the nonequilibrium Green's function GF

  6. On-line detection of single-walled carbon nanotube formation during aerosol synthesis methods

    E-print Network

    to the measurement. Despite the different product morphology and concentration, the on-line measurement was ableOn-line detection of single-walled carbon nanotube formation during aerosol synthesis methods Anna,c,* a Department of Engineering Physics and Mathematics Center for New Materials, Helsinki University of Technology

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

    PubMed

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

    2015-11-24

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

  8. Isotropic-Nematic Phase Transition of Single-Walled Carbon Nanotubes in Strong Acids

    E-print Network

    Natelson, Douglas

    Isotropic-Nematic Phase Transition of Single-Walled Carbon Nanotubes in Strong Acids Pradeep K. Rai nanotubes (SWNTs) in Brønsted-Lowry acids. We employ a centrifugation technique in conjunction with UV of SWNTs in strong acids. Centrifugation of biphasic dispersions of SWNTs, that is, acid dispersions

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

    E-print Network

    Maruyama, Shigeo

    the realizations of the vertically-aligned single-walled carbon nanotube (VA-SWNT) forests1) by alcohol chemical conditions.3-6) Among these methods, the water-assisted method, the so-called "super growth" method,3 structure with a diameter and areal density that depended on the initial Fe thickness.8) After the heat

  10. Investigating the Growth Process of Vertically Aligned Single-Walled Carbon Nanotubes Synthesized from Alcohol

    E-print Network

    Maruyama, Shigeo

    from Alcohol Erik Einarsson, Rong Xiang, Kazuaki Ogura, Jun Okawa, Zhengyi Zhang, and Shigeo Maruyama on the synthesis of vertically aligned single-walled carbon nanotubes (VA-SWNTs) by the alcohol catalytic chemical to be approximately 1.5 eV. The root-growth mechanism of VA-SWNTs synthesized by the alcohol CVD method was also

  11. Diameter-controlled Growth of Single-walled Carbon Nanotubes by Using Nano-Diamonds

    E-print Network

    Maruyama, Shigeo

    Diameter-controlled Growth of Single-walled Carbon Nanotubes by Using Nano-Diamonds Shohei Chiashi diameter attract attention. Here, we perform CVD growth by using nano-diamond particles as the catalyst [1] and investigate the CVD condition dependence of SWNT tube diameter. The average diameter of the as-received nano-diamond

  12. Dip-Pen Nanolithography of Electrical Contacts to Single-Walled Carbon

    E-print Network

    Dokmeci, Mehmet

    Dip-Pen Nanolithography of Electrical Contacts to Single-Walled Carbon Nanotubes Wechung Maria Wang an alternative method for fabri- cating SWNT devices via dip-pen nano- lithography (DPN), a scanning probe at nanoscale resolution using dip-pen nanolithography, with proof-of-concept demonstrated by creating single

  13. Manipulation of horizontally aligned single-wall carbon Taiki Inoue, Keigo Otsuka, Shohei Chiashi, Shigeo Maruyama

    E-print Network

    Maruyama, Shigeo

    Manipulation of horizontally aligned single-wall carbon nanotubes Taiki Inoue, Keigo Otsuka, Shohei,2] and characterization of chirality distribution of aligned SWNTs, we will discuss two manipulation techniques) in the same way as in-air breakdown [3]. The second manipulation technique is the bundling of a part

  14. Guided Growth of Horizontal Single-Wall Carbon Nanotubes on MPlane Sapphire

    E-print Network

    Joselevich, Ernesto

    Guided Growth of Horizontal Single-Wall Carbon Nanotubes on MPlane Sapphire Nitzan Shadmi, Ella of single-crystal substrates, including sapphire and quartz, has stood out as very effective and robust and nanowires on R-plane (1102) and A-plane (1120) sapphire (- Al2O3), nanotubes, unlike nanowires, have been

  15. On the Likelihood of Single-Walled Carbon Nanotubes Causing Adverse Marine Ecological Effects

    EPA Science Inventory

    This brief article discusses the ecological effects of single-walled carbon nanotubes (SWNTs)in the marine environment. Based on new research and a review of the scientific literature, the paper concludes that SWNTs are unlikely to cause adverse ecological effects in the marine ...

  16. 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

  17. Electronic properties of mechanically induced kinks in single-walled carbon nanotubes

    E-print Network

    Walsworth, Ronald L.

    in electron backscattering, increasing the resistance of the tubes.7­11 In this letter, we present experimental data that demon- strate this predicted increase of electron backscattering due to mechanicallyElectronic properties of mechanically induced kinks in single-walled carbon nanotubes Dolores

  18. TEMPERATURE MEASUREMENTS OF SINGLE-WALLED CARBON NANOTUBES BY RAMAN SCATTERINGS

    E-print Network

    Maruyama, Shigeo

    TEMPERATURE MEASUREMENTS OF SINGLE-WALLED CARBON NANOTUBES BY RAMAN SCATTERINGS Shohei Chiashi studies of heat transfer involving SWNTs are not easy. In this study, temperature measurements of SWNTs were demonstrated using the temperature dependence of Raman scattering, as the first step of heat

  19. Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics simulations

    E-print Network

    Maruyama, Shigeo

    Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics of the simulations exhibit non-Fourier heat conduction where the distinct amount of heat is transported in a wavelike called non-Fourier heat conduction equations in order to investigate the applicability

  20. 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, and clusters at 1000 °C in flowing 500 Torr Ar. These laser-induced emission images under typical synthesis

  1. Microwave shielding of transparent and conducting single-walled carbon nanotube films

    E-print Network

    Gruner, George

    Microwave shielding of transparent and conducting single-walled carbon nanotube films Hua Xu films in the microwave frequency range from 10 MHz to 30 GHz by using the Corbino reflection technique from temperatures of 20­400 K. Based on the real and imaginary parts of the microwave conductivity

  2. 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 ...

  3. 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

  4. 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

  5. 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 unique stationary and non-stationary heat conduction characteristics [3,4]. Furthermore, several issues

  6. Optical Characterization of Single-Walled Carbon Nanotubes Synthesized by Catalytic Decomposition of Alcohol

    E-print Network

    Maruyama, Shigeo

    of Alcohol Shigeo Maruyama, Yuhei Miyauchi, Yoichi Murakami and Shohei Chiashi Department of Mechanical The single-walled carbon nanotubes (SWNTs) synthesized by a catalytic decomposition of alcohol (Alcohol CVD feasible solution to this concern, we have proposed the use of alcohol, especially ethanol and methanol

  7. MICROWAVE-INDUCED RAPID CHEMICAL FUNCTIONALIZATION OF SINGLE-WALLED CARBON NANOTUBES (R830901)

    EPA Science Inventory


    Abstract

    The microwave-induced chemical functionalization of single-walled carbon nanotubes (SWNTs) is reported. The major advantage of this high-energy procedure is that it reduced the reaction time to the order of minutes and the number of steps in the reac...

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

    DOEpatents

    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.

  9. 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

  10. Stretchable Supercapacitors Based on Buckled Single-Walled Carbon Nanotube Macrofilms

    E-print Network

    Jiang, Hanqing

    Stretchable Supercapacitors Based on Buckled Single-Walled Carbon Nanotube Macrofilms By Cunjiang to accommodate large strains while retaining intact function. Of various power-source devices, supercapacitors in supercapacitors is the development of new electrode materials. Recently, CNTs have been studied as good candidates

  11. Integration of Single-Walled Carbon Nanotubes on to CMOS Circuitry with Parylene-C Encapsulation

    E-print Network

    Dokmeci, Mehmet

    Integration of Single-Walled Carbon Nanotubes on to CMOS Circuitry with Parylene-C Encapsulation for the placement of the SWNTs on to these electrodes. Encapsulating the CMOS chip with a thin (1m) parylene-C layer. Keywords-CMOS circuitry; Dielectrophoretic assembly; Nano scale integration; Parylene-C encapsulation

  12. pubs.acs.org/langmuir Single-Walled Carbon Nanotube Pillars: A Superhydrophobic Surface

    E-print Network

    Resasco, Daniel

    pubs.acs.org/langmuir Single-Walled Carbon Nanotube Pillars: A Superhydrophobic Surface Liang Zhang angle. The novel SWNT pillars exhibit superhydrophobicity (i.e., contact angle 160°). To quantify surface has been found necessary to achieve stable superhydrophobicity.14-17 A re- cent report18 indicates

  13. Nanoscale Optical Imaging of Excitons in Single-Walled Carbon Nanotubes

    E-print Network

    Novotny, Lukas

    Nanoscale Optical Imaging of Excitons in Single-Walled Carbon Nanotubes Achim Hartschuh,*, Huihong 20 nm in length. The PL from micelle-encapsulated SWNTs on mica is extended along the tube up than for Raman scattering, an observation that is explained by the low intrinsic quantum yield of SWNTs

  14. Conductivity scaling with bundle length and diameter in single walled carbon nanotube networks

    E-print Network

    Gruner, George

    Conductivity scaling with bundle length and diameter in single walled carbon nanotube networks evaluated the dc conductivity dc as a function of the average bundle length Lav in the network. They find dc windows,5 sensors,6 and transparent transistors.7 However, further improvement in the conductivity

  15. Controlled Growth of Single-Walled Carbon Nanotubes for CNT-Si heterojunction solar cell

    E-print Network

    Maruyama, Shigeo

    -Si heterojunction solar cell shows a record- high fill factor of 72 % as well as a power conversion efficiency (PCEControlled Growth of Single-Walled Carbon Nanotubes for CNT-Si heterojunction solar cell Shigeo two different SWNT assemblies for SWNT-Si heterojuction solar cells. We proposed a water vapor

  16. CVD growth control and solar cell application of single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    demonstrated the air-stable SWNT/Si solar cells with power conversion efficiency (PCE) approaching 11 CVD growth control and solar cell application of single-walled carbon nanotubes ( CVD ) #12;#12; Doctoral Dissertation CVD Growth Control and Solar Cell Application of Single

  17. Horizontally-Alignment Growth of Single-Walled Carbon Nanotubes on Quartz Substrates

    E-print Network

    Maruyama, Shigeo

    Horizontally-Alignment Growth of Single-Walled Carbon Nanotubes on Quartz Substrates Shohei Chiashi was horizontally- alignment. It is well-known that SWNTs can grow on sapphire [1] and crystal quartz substrates [2] along specific directions. Crystal quartz substrates have various cut angles, as shown in Fig. 1. ST

  18. Vertically Aligned Single-Walled Carbon Nanotubes on Quartz Substrates Catalytically Grown from

    E-print Network

    Maruyama, Shigeo

    Vertically Aligned Single-Walled Carbon Nanotubes on Quartz Substrates Catalytically Grown from chemical vapor deposition (CVD) on quartz substrates. Low-temperature CVD from ethanol was performed by using densely mono-dispersed Co-Mo catalyst of around 1.0 - 2.0 nm prepared on quartz substrates

  19. INFLUENCE OF VAN DER WAALS INTERACTIONS ON THE RAMAN MODES IN SINGLE WALLED CARBON NANOTUBES

    E-print Network

    Tománek, David

    INFLUENCE OF VAN DER WAALS INTERACTIONS ON THE RAMAN MODES IN SINGLE WALLED CARBON NANOTUBES A. M bundle contains on the order of 100 well-aligned SWNTs that are held together by the van der Waals (vd. Rao 1 , J. Chen 2 , E. Richter 3 , U. Schlecht4 , P. C. Eklund5 , R. C. Haddon6 , U. D. Venkateswaran

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

    EPA Science Inventory

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

  1. Anisotropic Thermal Properties of Single-Wall Carbon Nanotube Reinforced Nanoceramics

    SciTech Connect

    Zhan, Guodong; Kuntz, Joshua D.; Wang, Hsin; Wang, Chong M.; Mukherjee, Amiya K.

    2004-07-01

    Dense single-wall carbon nanotube (SWCNT) reinforced alumina nanocomposites have been fabricated by novel spark-plasma-sintering (SPS) technique. Anisotropic thermal properties have been found in the carbon nanotube composites. The introduction of ropes of SWCNT gives rise to a decrease of the transverse thermal diffusivity with increasing carbon nanotube content while it does not change the in-plane thermal diffusivity. This is scientifically interesting and technologically important for the development of materials for novel thermal barrier coatings.

  2. Advantages of flattened electrode in bottom contact single-walled carbon nanotube field-effect transistor

    SciTech Connect

    Setiadi, Agung; Akai-Kasaya, Megumi Saito, Akira; Kuwahara, Yuji

    2014-09-01

    We fabricated single-walled carbon nanotube (SWNT) field-effect transistor (FET) devices on flattened electrodes, in which there are no height difference between metal electrodes and the substrate. SWNT-FET fabricated using bottom contact technique have some advantages, such that the SWNTs are free from electron irradiation, have direct contact with the desired metal electrodes, and can be functionalized before or after deposition. However, the SWNTs can be bent at the contact point with the metal electrodes leading to a different electrical characteristic of the devices. The number of SWNT direct junctions in short channel length devices is drastically increased by the use of flattened electrodes due to strong attractive interaction between SWNT and the substrate. The flattened electrodes show a better balance between their hole and electron mobility compared to that of the non-flattened electrodes, that is, ambipolar FET characteristic. It is considered that bending of the SWNTs in the non-flattened electrode devices results in a higher Schottky barrier for the electrons.

  3. Doping single-walled carbon nanotubes through molecular charge-transfer: a theoretical study.

    PubMed

    Manna, Arun K; Pati, Swapan K

    2010-07-01

    We study the effect of the molecular charge transfer on the electronic structure of metallic (5,5) and semiconducting (8,0) single-walled carbon nanotubes (SWNTs) induced by surface adsorption of various organic donor-acceptor molecules of different affinities using ab initio density functional theory. Our results, obtained from first-principles spin-polarized calculations show that the adsorption of molecules with different affinities reflects the difference in interaction strength that measure the overall energy of adsorption. Moderate values of the binding energy of these surface adsorbed molecular charge-transfer complexes suggest that the nature of interaction is in the physisorption regime, and mainly governs by Coulombic forces. We also find that the large band gap of semiconducting (8,0) SWNT can be tuned through the surface adsorption of selective organic molecules which gives rise to mid-gap localized molecular levels near the Fermi energy with tuning of band gap region. Interestingly, we find that the metallic (5,5) SWNT and semiconducting (8,0) SWNT turn into semiconducting and metallic nanotubes respectively in presence of selective surface adsorbed molecules, corroborating recent experimental findings. We also suggest that these charge transfer effect can be probed through optical conductivity measurement, as the low-frequency profiles are affected by charge transfer. PMID:20648348

  4. Doping single-walled carbon nanotubes through molecular charge-transfer: a theoretical study

    NASA Astrophysics Data System (ADS)

    Manna, Arun K.; Pati, Swapan K.

    2010-07-01

    We study the effect of the molecular charge transfer on the electronic structure of metallic (5,5) and semiconducting (8,0) single-walled carbon nanotubes (SWNTs) induced by surface adsorption of various organic donor-acceptor molecules of different affinities using ab initio density functional theory. Our results, obtained from first-principles spin-polarized calculations show that the adsorption of molecules with different affinities reflects the difference in interaction strength that measure the overall energy of adsorption. Moderate values of the binding energy of these surface adsorbed molecular charge-transfer complexes suggest that the nature of interaction is in the physisorption regime, and mainly governs by Coulombic forces. We also find that the large band gap of semiconducting (8,0) SWNT can be tuned through the surface adsorption of selective organic molecules which gives rise to mid-gap localized molecular levels near the Fermi energy with tuning of band gap region. Interestingly, we find that the metallic (5,5) SWNT and semiconducting (8,0) SWNT turn into semiconducting and metallic nanotubes respectively in presence of selective surface adsorbed molecules, corroborating recent experimental findings. We also suggest that these charge transfer effect can be probed through optical conductivity measurement, as the low-frequency profiles are affected by charge transfer.

  5. 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.

  6. Resonant micro-Raman spectroscopy of aligned single-walled carbon nanotubes on a-plane sapphire

    E-print Network

    Zhou, Chongwu

    Resonant micro-Raman spectroscopy of aligned single-walled carbon nanotubes on a-plane sapphire to characterize aligned single-walled carbon nanotubes grown on a-plane sapphire to address the alignment massively aligned nanotubes on insulating substrates such as sapphire and quartz.2­7 Epitaxial growth

  7. Single wall carbon nanotube fibers extruded from super-acid suspensions: Preferred orientation, electrical, and thermal transport

    E-print Network

    Natelson, Douglas

    Single wall carbon nanotube fibers extruded from super-acid suspensions: Preferred orientation September 2003 Fibers of single wall carbon nanotubes extruded from super-acid suspensions exhibit preferred orientation along their axes. We characterize the alignment by x-ray fiber diagrams and polarized Raman

  8. Nanoscale thermocapillarity enabled purification for horizontally aligned arrays of single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Jin, Sung Hun; Dunham, Simon; Xie, Xu; Rogers, John A.

    2015-09-01

    Among the remarkable variety of semiconducting nanomaterials that have been discovered over the past two decades, single-walled carbon nanotubes remain uniquely well suited for applications in high-performance electronics, sensors and other technologies. The most advanced opportunities demand the ability to form perfectly aligned, horizontal arrays of purely semiconducting, chemically pristine carbon nanotubes. Here, we present strategies that offer this capability. Nanoscale thermos-capillary flows in thin-film organic coatings followed by reactive ion etching serve as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous aligned arrays grown on quartz substrates. The low temperatures and unusual physics associated with this process enable robust, scalable operation, with clear potential for practical use. Especially for the purpose of selective joule heating over only metallic nanotubes, two representative platforms are proposed and confirmed. One is achieved by selective joule heating associated with thin film transistors with partial gate structure. The other is based on a simple, scalable, large-area scheme through microwave irradiation by using micro-strip dipole antennas of low work-function metals. In this study, based on purified semiconducting SWNTs, we demonstrated field effect transistors with mobility (> 1,000 cm2/Vsec) and on/off switching ratio (~10,000) with current outputs in the milliamp range. Furthermore, as one demonstration of the effectiveness over large area-scalability and simplicity, implementing the micro-wave based purification, on large arrays consisting of ~20,000 SWNTs completely removes all of the m-SWNTs (~7,000) to yield a purity of s-SWNTs that corresponds, quantitatively, to at least to 99.9925% and likely significantly higher.

  9. Control of the Diameter and Chiral Angle Distributions during Production of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Nikolaev, Pavel

    2009-01-01

    Many applications of single wall carbon nanotubes (SWCNT), especially in microelectronics, will benefit from use of certain (n,m) nanotube types (metallic, small gap semiconductor, etc.) Especially fascinating is the possibility of quantum conductors that require metallic armchair nanotubes. However, as produced SWCNT samples are polydisperse, with many (n,m) types present and typical approx.1:2 metal/semiconductor ratio. Nanotube nucleation models predict that armchair nuclei are energetically preferential due to formation of partial triple bonds along the armchair edge. However, nuclei can not reach any meaningful thermal equilibrium in a rapidly expanding and cooling plume of carbon clusters, leading to polydispersity. In the present work, SWCNTs were produced by a pulsed laser vaporization (PLV) technique. The carbon vapor plume cooling rate was either increased by change in the oven temperature (expansion into colder gas), or decreased via "warm-up" with a laser pulse at the moment of nucleation. The effect of oven temperature and "warm-up" on nanotube type population was studied via photoluminescence, UV-Vis-NIR absorption and Raman spectroscopy. It was found that reduced temperatures leads to smaller average diameters, progressively narrower diameter distributions, and some preference toward armchair structures. "Warm-up" shifts nanotube population towards arm-chair structures as well, but the effect is small. Possible improvement of the "warm-up" approach to produce armchair SWCNTs will be discussed. These results demonstrate that PLV production technique can provide at least partial control over the nanotube (n,m) population. In addition, these results have implications for the understanding the nanotube nucleation mechanism in the laser oven.

  10. 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.

  11. Transparent silica glasses containing single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    DiMaio, Jeffrey R.; Rhyne, Suzette L.; Ballato, John M.; Czerw, Richard; Xu, Jianfeng; Webster, Scott; Carroll, David L.; Fu, Kefu; Sun, Ya-Ping

    2001-11-01

    Organic - Inorganic matrix nano composites have been created using an acid catalyzed, tetraethyl orthosilicate-based sol- gel technique with SWNTs. By utilizing nanotubes functionalized with the dendron methyl 3,5- di(methyltrigycoloxy)benzylic alcohol, ultrasonication blending in the sol phase prior to gelation yields excellent dispersion characteristics of the nanotube phase. Further, glasses could easily be dried by heating to 600 degrees C yielding 80 percent of theoretical density wit little change in the nanotube content. These materials exhibited intrinsic Rayleigh scattering, suggesting near ideal dispersion. Nonlinear optical transmissivity was observed for 1064 and 532 nm light suggesting that the matrix has a strong broad band coupling to the optical field. Such composites allow for a host of applications based on the novel confinement properties of carbon nanotubes in a robust host.

  12. 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 3-12 h 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

  13. Effect of gelatin on the water dispersion and centrifugal purification of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hanium Maria, Kazi; Mieno, Tetsu

    2016-01-01

    We report a convenient and effective procedure for the water dispersion and purification of single-walled carbon nanotubes (SWNTs). The purification procedure involves a combination of dispersion and centrifugation, in which gelatin; an environmentally friendly material is used as a dispersing agent. It has been found that an aqueous solution of gelatin effectively disperses SWNTs for more than a month. Another advantage of using gelatin as a dispersing agent is that it can be easily removed by washing with water and filtration. The centrifugation procedure employs a centrifugal force of about 2500 times the gravitational force to separate the particles. Although carbonaceous and metallic impurities usually have higher density than SWNTs in arc-produced carbon soot, the centrifugation can easily remove impurities leaving undamaged SWNTs in solution when appropriate centrifugal force and a centrifugation time are used. Centrifugation is carried out for three times to sufficiently remove impurities. Finally, the SWNTs are separated from the gelatin by heating in water and filtering.

  14. Micro-photoluminescence spectroscopy of excitons in individual single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Srivastava, Ajit

    Single-walled carbon nanotubes (SWNTs) are fascinating materials to study one-dimensional photophysics. Their optical properties are strongly affected by strong Coulomb interactions and are determined by "excitons" which represent the quantum of polarization in non-metallic solids. In this thesis dissertation we have experimentally investigated both the structure and the dynamics of excitons in non-metallic SWNTs. In particular, we have performed micro-photoluminescence spectroscopy of individual semiconducting SWNTs at low temperature to study their intrinsic optical properties and investigate the excitonic fine structure. Using magnetic field parallel to the tube axis we were able to directly observe theoretically predicted dark states for the first time in SWNTs. In addition, we found that the inter-valley and exchange energy, which determines the energy separation between the dark and the bright state, to be very sensitive to the surrounding environment of the nanotube. We have also studied the temperature dependent lineshape of SWNT photoluminescence in order to gain insight into the dynamics of exciton-phonon interaction, finding evidence for acoustic phonon scattering. For the rest of this thesis dissertation, we have developed a model based on reaction-diffusion processes to theoretically explain the observation of photoluminescence saturation in SWNTs. Our model shows that efficient exciton-exciton annihilation under high pumping conditions can explain this observed behavior quantitatively.

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

    SciTech Connect

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

    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.

  16. 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.

  17. Microwave purification of large-area horizontally aligned arrays of single-walled carbon nanotubes.

    PubMed

    Xie, Xu; Jin, Sung Hun; Wahab, Muhammad A; Islam, Ahmad E; Zhang, Chenxi; Du, Frank; Seabron, Eric; Lu, Tianjian; Dunham, Simon N; Cheong, Hou In; Tu, Yen-Chu; Guo, Zhilin; Chung, Ha Uk; Li, Yuhang; Liu, Yuhao; Lee, Jong-Ho; Song, Jizhou; Huang, Yonggang; Alam, Muhammad A; Wilson, William L; Rogers, John A

    2014-01-01

    Recent progress in the field of single-walled carbon nanotubes (SWNTs) significantly enhances the potential for practical use of this remarkable class of material in advanced electronic and sensor devices. One of the most daunting challenges is in creating large-area, perfectly aligned arrays of purely semiconducting SWNTs (s-SWNTs). Here we introduce a simple, scalable, large-area scheme that achieves this goal through microwave irradiation of aligned SWNTs grown on quartz substrates. Microstrip dipole antennas of low work-function metals concentrate the microwaves and selectively couple them into only the metallic SWNTs (m-SWNTs). The result allows for complete removal of all m-SWNTs, as revealed through systematic experimental and computational studies of the process. As one demonstration of the effectiveness, implementing this method on large arrays consisting of ~20,000 SWNTs completely removes all of the m-SWNTs (~7,000) to yield a purity of s-SWNTs that corresponds, quantitatively, to at least to 99.9925% and likely significantly higher. PMID:25387684

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

    PubMed

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

    2016-12-01

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

  19. Single Wall Carbon Nanotube Alignment Mechanisms for Non-Destructive Evaluation

    NASA Technical Reports Server (NTRS)

    Hong, Seunghun

    2002-01-01

    As proposed in our original proposal, we developed a new innovative method to assemble millions of single wall carbon nanotube (SWCNT)-based circuit components as fast as conventional microfabrication processes. This method is based on surface template assembly strategy. The new method solves one of the major bottlenecks in carbon nanotube based electrical applications and, potentially, may allow us to mass produce a large number of SWCNT-based integrated devices of critical interests to NASA.

  20. Thermal transpiration through single walled carbon nanotubes and graphene channels

    SciTech Connect

    Thekkethala, Joe Francis; Sathian, Sarith P.

    2013-11-07

    Thermal transpiration through carbon nanotubes (CNTs) and graphene channels is studied using molecular dynamics (MD) simulations. The system consists of two reservoirs connected by a CNT. It is observed that a flow is developed inside the CNT from the low temperature reservoir to the high temperature reservoir when the two reservoirs are maintained at different temperatures. The influence of channel size and temperature gradient on the mean velocity is analysed by varying the CNT diameter and the temperature of one of the reservoirs. Larger flow rate is observed in the smaller diameter CNTs showing an increase in the mean velocity with increase in the temperature gradient. For the flow developed inside the CNTs, slip boundaries occur and the slip length is calculated using the velocity profile. We examine the effect of fluid-wall interaction strength (?{sub fw}), diffusivity (D), and viscosity of the fluid (?) on the temperature induced fluid transport through the CNTs. Similar investigations are also carried out by replacing the CNT with a graphene channel. Results show that the mean velocity of the fluid atoms in the graphene channel is lower than that through the CNTs. This can be attributed to the higher degree of confinement observed in the CNTs.

  1. Dielectric constants of single-wall carbon nanotubes at various frequencies.

    PubMed

    Li, Yan-Huei; Lue, Juh-Tzeng

    2007-09-01

    A cylindrical rod composed of a uniform mixture of single-wall carbon nanotubes and alumina powders dissolved in paraffin was inserted in the center of a radio frequency cavity. The complex dielectric constant of carbon tubes at various frequencies was measured by a resistance-inductance-capacitance (RLC) meter and a microwave network analyzer. The cylindrical rod benefits the protection of the sample from adsorbing moisture and preventing the rod from filling with air, thus making accuracy experiment values. The real part and the imaginary part of the dielectric constants of single-wall carbon nanotubes are, respectively, increase and decrease in magnitudes as frequency increases satisfactorily in complying with the portray from the free electron Drude model. PMID:18019147

  2. Peptide secondary structure modulates single-walled carbon nanotube fluorescence as a chaperone sensor for nitroaromatics

    PubMed Central

    Heller, Daniel A.; Pratt, George W.; Zhang, Jingqing; Nair, Nitish; Hansborough, Adam J.; Boghossian, Ardemis A.; Reuel, Nigel F.; Barone, Paul W.; Strano, Michael S.

    2011-01-01

    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. In response to the binding of specific nitroaromatic species, such peptide–nanotube complexes form a virtual “chaperone sensor,” which reports modulation of the peptide secondary structure via changes in single-walled carbon nanotubes, near-infrared photoluminescence. A split-channel microscope constructed to image quantized spectral wavelength shifts in real time, in response to nitroaromatic adsorption, results in the first single-nanotube imaging of solvatochromic events. The described indirect detection mechanism, as well as an additional exciton quenching-based optical nitroaromatic detection method, illustrate that functionalization of the carbon nanotube surface can result in completely unique sites for recognition, resolvable at the single-molecule level. PMID:21555544

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

    SciTech Connect

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

    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.

  4. Chirality-specific growth of single-walled carbon nanotubes on solid alloy catalysts.

    PubMed

    Yang, Feng; Wang, Xiao; Zhang, Daqi; Yang, Juan; Luo, Da; Xu, Ziwei; Wei, Jiake; Wang, Jian-Qiang; Xu, Zhi; Peng, Fei; Li, Xuemei; Li, Ruoming; Li, Yilun; Li, Meihui; Bai, Xuedong; Ding, Feng; Li, Yan

    2014-06-26

    Carbon nanotubes have many material properties that make them attractive for applications. In the context of nanoelectronics, interest has focused on single-walled carbon nanotubes (SWNTs) because slight changes in tube diameter and wrapping angle, defined by the chirality indices (n,?m), will shift their electrical conductivity from one characteristic of a metallic state to one characteristic of a semiconducting state, and will also change the bandgap. However, this structure-function relationship can be fully exploited only with structurally pure SWNTs. Solution-based separation methods yield tubes within a narrow structure range, but the ultimate goal of producing just one type of SWNT by controlling its structure during growth has proved to be a considerable challenge over the last two decades. Such efforts aim to optimize the composition or shape of the catalyst particles that are used in the chemical vapour deposition synthesis process to decompose the carbon feedstock and influence SWNT nucleation and growth. This approach resulted in the highest reported proportion, 55 per cent, of single-chirality SWNTs in an as-grown sample. Here we show that SWNTs of a single chirality, (12,?6), can be produced directly with an abundance higher than 92 per cent when using tungsten-based bimetallic alloy nanocrystals as catalysts. These, unlike other catalysts used so far, have such high melting points that they maintain their crystalline structure during the chemical vapour deposition process. This feature seems crucial because experiment and simulation both suggest that the highly selective growth of (12,?6) SWNTs is the result of a good structural match between the carbon atom arrangement around the nanotube circumference and the arrangement of the catalytically active atoms in one of the planes of the nanocrystal catalyst. We anticipate that using high-melting-point alloy nanocrystals with optimized structures as catalysts paves the way for total chirality control in SWNT growth and will thus promote the development of SWNT applications. PMID:24965654

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

    E-print Network

    Maruyama, Shigeo

    -------------------------------------------------------------------- Title: Decomposition, the effect of carbon feedstock decomposition conditions in CVD (chemical vapor deposition) synthesis of SWNTs (single-walled carbon nanotubes) was investigated. Gas-phase thermal decomposition of ethanol and DME

  6. Improved memory behaviour of single-walled carbon nanotubes charge storage nodes

    NASA Astrophysics Data System (ADS)

    Alba-Martin, Maria; Firmager, Timothy; Atherton, Joseph; Rosamond, Mark C.; Ashall, Daniel; Ghaferi, Amal Al; Ayesh, Ahmad; Gallant, Andrew J.; Mabrook, Mohammed F.; Petty, Michael C.; Zeze, Dagou A.

    2012-07-01

    To investigate their memory behaviours, single-walled carbon nanotubes (SWCNTs) were embedded in the floating gate of a hybrid metal-insulator-semiconductor structure using layer-by-layer deposition, and polymethylmethacrylate (PMMA) as the dielectric. Unlike longer SWCNT-based structures, shortened SWCNTs were shown to exhibit reliable and large memory windows by virtue of a better encapsulation which reduces charge leakage. The capacitance-voltage characteristics of the devices were consistent with electron injection into the SWCNT charge storage elements (in the floating) from the top electrode through the PMMA, using localized defects and crossing the PMMA energy barrier. In terms of material formulation, a combination of SWCNTs dispersed in sodium dodecyl sulfate and polyethyleneimine used as charge storage elements in the floating gate was shown to lead to repeatable and reliable memory characteristics. Fast switching and very large memory windows (˜7 V) exhibiting high charge density (2.6 × 1012 cm-2) and charge retention in excess of ˜76% were achieved under a ±10 V sweep voltage range. These results suggest that SWCNTs could lead to improved memory behaviour with the potential for application in plastic electronics.

  7. Nonlinear optical properties of boron doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Anand, Benoy; Podila, Ramakrishna; Ayala, Paola; Oliveira, Luciana; Philip, Reji; Sankara Sai, S. Siva; Zakhidov, Anvar A.; Rao, Apparao M.

    2013-07-01

    Single-walled carbon nanotubes (SWCNTs) exhibit excellent nonlinear optical (NLO) properties due to the delocalized ? electron states present along their tube axis. Using the open aperture Z-scan method in tandem with X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, we demonstrate the simultaneous tailoring of both electronic and NLO properties of SWCNTs, from ultrafast (femtosecond) to relatively slow (nanosecond) timescales, by doping with a single substituent, viz., boron. SWCNTs were doped via a wet chemical method using B2O3, and the boron content and bonding configurations were identified using XPS. While in the ns excitation regime, the nonlinear absorption was found to increase with increasing boron concentration in the SWCNTs (due to the increasing disorder and enhanced metallicity of the SWCNTs), the saturation intensity in the fs excitation regime decreased. We attribute this counter-intuitive behavior to excited state absorption on ns timescales, and saturable absorption combined with weak two-photon transitions on fs timescales between van Hove singularities.

  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. Flexible single-walled carbon nanotube/polycellulose papers for lithium-ion batteries.

    PubMed

    Wang, Jin; Li, Linlin; Wong, Chui Ling; Madhavi, Srinivasan

    2012-12-14

    Flexible and highly conductive single-walled carbon nanotube/polycellulose papers (SWCNT/PPs) were developed as current collectors for lithium-ion batteries by a simple and scalable process. The flexible electrodes based on SWCNT/PP conductors consisted of a unique three-dimensional interwoven structure of electrode materials and cellulose fibers with CNTs and exhibited flexibility, good electrochemical performance and excellent cyclic stability. Full cells using Li(4)Ti(5)O(12) and LiFePO(4) electrodes based on SWCNT/PPs showed a first discharge capacity of 153.5 mA h g(-1) with Coulombic efficiencies of 90.6% at 0.1 C and discharge capacity of 102.6 mA h g(-1) at high rate (10 C). Full cells based SWCNT/PP conductors showed higher capacities and lower electrochemical interfacial resistance compared to metallic current collectors. Half cells using anatase TiO(2) hierarchical spheres based on SWCNT/PP conductors also exhibited outstanding electrochemical performance, verifying the stability of SWCNT/PP conductors to various electrode materials. Our results demonstrated the potential versatility of composite electrodes and conductive SWCNT/PPs for flexible and portable micropower devices. PMID:23150071

  10. Temperature and voltage dependent current-voltage behavior of single-walled carbon nanotube transparent conducting films

    NASA Astrophysics Data System (ADS)

    Zhang, Ze-Chen; Geng, Hong-Zhang; Wang, Yan; Yang, Hai-Jie; Da, Shi-Xun; Ding, Er-Xiong; Liu, Juncheng; Yu, Ping; Fu, Yun-Qiao; Li, Xu; Pan, Hui

    2015-11-01

    High purified single-walled carbon nanotubes (SWCNTs) were dispersed in water and transparent conducting films (TCFs) were fabricated by a spray coating. The produced uniform SWCNT-TCFs treated by nitric acid have a relatively low sheet resistance and high transmittance. The current-voltage (I-V) behaviors of the TCFs were measured at room to higher temperature during the heating or cooling process. It was found that the I-V behavior of TCFs strongly dependent on the temperature and applied voltage. The sheet resistance showed semiconductor behavior at low temperature and low voltage, while it showed metallic behavior at high temperature and high voltage.

  11. Surface-enhanced and normal stokes and anti-stokes Raman spectroscopy of single-walled carbon nanotubes.

    PubMed

    Kneipp, K; Kneipp, H; Corio, P; Brown, S D; Shafer, K; Motz, J; Perelman, L T; Hanlon, E B; Marucci, A; Dresselhaus, G; Dresselhaus, M S

    2000-04-10

    Surface enhancement factors of at least 10(12) for the Raman scattering of single-walled carbon nanotubes in contact with fractal silver colloidal clusters result in measuring very narrow Raman bands corresponding to the homogeneous linewidth of the tangential C-C stretching mode in semiconducting nanotubes. Normal and surface-enhanced Stokes and anti-Stokes Raman spectra are discussed in the framework of selective resonant Raman contributions of semiconducting or metallic nanotubes to the Stokes or anti-Stokes spectra, respectively, of the population of vibrational levels due to the extremely strong surface-enhanced Raman process, and of phonon-phonon interactions. PMID:11019117

  12. 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.

  13. Synthesis of Single Wall Carbon Nanotubes by Plasma Arc: Role of Plasma Parameters

    NASA Technical Reports Server (NTRS)

    Farhart, Samir; Scott, Carl D.

    2000-01-01

    Single wall carbon nanotubes (SWNT) are porous objects on the molecular scale and have a low density, which gives them potential applications as adsorbent for molecular hydrogen. Their H2 absorption capacity published in the literature varies from 4 to 10% by mass according to the purity of the materials and storage conditions. Optimization of production methods of SWNTs should permit improving these new materials for storage of hydrogen. In this article, we show the potential of using SWNTs in hydrogen storage. In particular, we pose problems associated with synthesis, purification, and opening up of the nanotubes. We present an electric arc process currently used at laboratory scale to produce single wall carbon nanotubes. We discuss, in particular, operating conditions that permit growth of nanotubes and some plasma parameters that assure control of the material. Analysis of the process is carried out with the aid of local measurements of temperature and scanning and transmission electron microscopy of the materials.

  14. Structural modeling of dahlia-type single-walled carbon nanohorn aggregates by molecular dynamics.

    PubMed

    Hawelek, L; Brodka, A; Dore, John C; Hannon, Alex C; Iijima, S; Yudasaka, M; Ohba, T; Kaneko, K; Burian, A

    2013-09-19

    The structure of dahlia-type single-walled carbon nanohorn aggregates has been modeled by classical molecular dynamics simulations, and the validity of the model has been verified by neutron diffraction. Computer-generated models consisted of an outer part formed from single-walled carbon nanohorns with diameters of 20-50 Å and a length of 400 Å and an inner turbostratic graphite-like core with a diameter of 130 Å. The diffracted intensity and the pair correlation function computed for such a constructed model are in good agreement with the neutron diffraction experimental data. The proposed turbostratic inner core explains the occurrence of the additional (002) and (004) graphitic peaks in the diffraction pattern of the studied sample and provides information about the interior structure of the dahlia-type aggregates. PMID:23978218

  15. A black body absorber from vertically aligned single-walled carbon nanotubes

    PubMed Central

    Mizuno, Kohei; Ishii, Juntaro; Kishida, Hideo; Hayamizu, Yuhei; Yasuda, Satoshi; Futaba, Don N.; Yumura, Motoo; Hata, Kenji

    2009-01-01

    Among all known materials, we found that a forest of vertically aligned single-walled carbon nanotubes behaves most similarly to a black body, a theoretical material that absorbs all incident light. A requirement for an object to behave as a black body is to perfectly absorb light of all wavelengths. This important feature has not been observed for real materials because materials intrinsically have specific absorption bands because of their structure and composition. We found a material that can absorb light almost perfectly across a very wide spectral range (0.2–200 ?m). We attribute this black body behavior to stem from the sparseness and imperfect alignment of the vertical single-walled carbon nanotubes. PMID:19339498

  16. Length-dependent optical effects in single-wall carbon nanotubes.

    PubMed

    Fagan, Jeffrey A; Simpson, Jeffrey R; Bauer, Barry J; Lacerda, Silvia H De Paoli; Becker, Matthew L; Chun, Jaehun; Migler, Kalman B; Walker, Angela R Hight; Hobbie, Erik K

    2007-08-29

    Among the novel chemical and physical attributes of single-wall carbon nanotubes (SWCNTs), the optical properties are perhaps the most compelling. Although much is known about how such characteristics depend on nanotube chirality and diameter, relatively little is known about how the optical response depends on length, the next most obvious and fundamental nanotube trait. We show here that the intrinsic optical response of single-wall carbon nanotubes exhibits a strong dependence on nanotube length, and we offer a simple explanation that relates this behavior to the localization of a bound exciton along the length of a nanotube. The results presented here suggest that, for a given volume fraction, the longest nanotubes display significantly enhanced absorption, near-infrared fluorescence, and Raman scattering, which has important practical implications for potential applications that seek to exploit the unique optical characteristics of SWCNTs. PMID:17672462

  17. Structure and Characterization of Vertically Aligned Single-Walled Carbon Nanotube Bundles

    DOE PAGESBeta

    Márquez, Francisco; López, Vicente; Morant, Carmen; Roque-Malherbe, Rolando; Domingo, Concepción; Elizalde, Eduardo; Zamora, Félix

    2010-01-01

    Arrays of vertically aligned single-walled carbon nanotube bundles, SWCNTs, have been synthesized by simple alcohol catalytic chemical vapor deposition process, carried out at 800°C. The formed SWCNTs are organized in small groups perpendicularly aligned and attached to the substrate. These small bundles show a constant diameter of ca. 30 nm and are formed by the adhesion of no more than twenty individual SWCNTs perfectly aligned along their length.

  18. 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

  19. Below-gap excitation of semiconducting single-wall carbon nanotubes.

    PubMed

    Soavi, G; Grupp, A; Budweg, A; Scotognella, F; Hefner, T; Hertel, T; Lanzani, G; Leitenstorfer, A; Cerullo, G; Brida, D

    2015-10-29

    We investigate the optoelectronic properties of the semiconducting (6,5) species of single-walled carbon nanotubes by measuring ultrafast transient transmission changes with 20 fs time resolution. We demonstrate that photons with energy below the lowest exciton resonance efficiently lead to linear excitation of electronic states. This finding challenges the established picture of a vanishing optical absorption below the fundamental excitonic resonance. Our result points towards below-gap electronic states as an intrinsic property of semiconducting nanotubes. PMID:26488340

  20. Below-gap excitation of semiconducting single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Soavi, G.; Grupp, A.; Budweg, A.; Scotognella, F.; Hefner, T.; Hertel, T.; Lanzani, G.; Leitenstorfer, A.; Cerullo, G.; Brida, D.

    2015-10-01

    We investigate the optoelectronic properties of the semiconducting (6,5) species of single-walled carbon nanotubes by measuring ultrafast transient transmission changes with 20 fs time resolution. We demonstrate that photons with energy below the lowest exciton resonance efficiently lead to linear excitation of electronic states. This finding challenges the established picture of a vanishing optical absorption below the fundamental excitonic resonance. Our result points towards below-gap electronic states as an intrinsic property of semiconducting nanotubes.

  1. Dispersion and Purification of Single-Wall Carbon Nanotubes Using Carboxymethylcellulose

    NASA Astrophysics Data System (ADS)

    Takahashi, Teruo; Tsunoda, Katsunori; Yajima, Hirofumi; Ishii, Tadahiro

    2004-06-01

    We have developed a novel method for the purification of single-wall carbon nanotubes (SWNTs) that involves annealing in air and dispersing the SWNTs in an aqueous solution of carboxymethylcellulose (CMC). The purity of the resulting SWNTs was evaluated by analytical techniques such as electron microscopy, Raman spectroscopy, and thermogravimetric analysis (TGA). As a result, it was revealed that CMC functioned as an effective dispersion reagent in the exfoliation of the SWNT bundles and thereby, SWNTs with appreciably high quality were prepared.

  2. Intense photoluminescence from dried double-stranded DNA and single-walled carbon nanotube hybrid

    SciTech Connect

    Ito, M.; Kobayashi, T.; Ito, Y.; Hayashida, T.; Nii, D.; Umemura, K.; Homma, Y.

    2014-01-27

    Semiconducting single-walled carbon nanotubes (SWNTs) show near-infrared photoluminescence (PL) when they are individually isolated. This was an obstacle to use photonic properties of SWNTs on a solid surface. We show that SWNTs wrapped with DNA maintain intense PL under the dry conditions. SWNTs are well isolated individually by DNA even when the DNA-SWNT hybrids are agglomerated. This finding opens up application of SWNTs to photonic devices.

  3. 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.

  4. 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

  5. Single-walled carbon nanotubes growing radially from YC2 particles

    NASA Astrophysics Data System (ADS)

    Zhou, Dan; Seraphin, Supapan; Wang, Su

    1994-09-01

    In the primary soot produced by arc discharge using an yttrium carbide loaded anode, bundles of single-walled carbon nanotubes (SWT) are observed, protruding radially from YC2 particles coated with graphitic multilayers. The graphitic cages separating YC2 particle and SWT bundles fall into the narrow range of 10-20 layers. The morphology of the clusters suggests a two-step growth model: The radial SWT growth pattern is first initiated by catalytic action between the YC2 droplet and the carbon in the gas phase. Second, and upon cooling, the graphitic cage starts by segregating excess carbon from the YC2 bulk, arresting further growth of SWT.

  6. 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.

  7. Control of the Diameter and Chiral Angle Distributions during Production of Single-wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Nikolaev, Pavel; Holmes, William; Sosa, Edward; Boul, Peter; Arepalli, Sivaram; Yowell, Leonard

    2008-01-01

    Many applications of single wall carbon nanotubes (SWCNT), especially in microelectronics, will benefit from use of certain (n,m) nanotube types (metallic, small gap semiconductor, etc.). However, as produced SWCNT samples are polydispersed, with many (n,m) types present and typical approximate 1:2 metal/semiconductor ratio. It has been recognized that production of SWCNTs with narrow 'tube type populations' is beneficial for their use in applications, as well as for the subsequent sorting efforts. In the present work, SWCNTs were produced by a pulsed laser vaporization (PLV) technique. The nanotube type populations were studied with respect to the production temperature with two catalyst compositions: Co/Ni and Rh/Pd. The nanotube type populations were measured via photoluminescence, UV-Vis-NIR absorption and Raman spectroscopy. It was found that in the case of Co/Ni catalyst, decreased production temperature leads to smaller average diameter, exceptionally narrow diameter distribution, and strong preference toward (8,7) nanotubes. The other nanotubes present are distributed evenly in the 7-30 deg chiral angle range. In the case of Rh/Pd catalyst, a decrease in the temperature leads to a small decrease in the average diameter, with the chiral angle distribution skewed towards 30 o and a preference toward (7,6), (8,6) and (8,7) nanotubes. However, the diameter distribution remains rather broad. These results demonstrate that PLV production technique can provide at least partial control over the nanotube (n,m) populations. In addition, these results have implications for the understanding the nanotube nucleation mechanism in the laser oven.

  8. 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

  9. Translocation of Single-Stranded DNA Through Single-Walled Carbon Nanotubes

    SciTech Connect

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

    2009-01-01

    We report the fabrication of devices in which one single-walled carbon nanotube spans a barrier between two fluid reservoirs, enabling direct electrical measurement of ion transport through the tube. A fraction of the tubes pass anomalously high ionic currents. Electrophoretic transport of small single-stranded DNA oligomers through these tubes is marked by large transient increases in ion current and was confirmed by polymerase chain reaction analysis. Each current pulse contains about 10{sup 7} charges, an enormous amplification of the translocated charge. Carbon nanotubes simplify the construction of nanopores, permit new types of electrical measurements, and may open avenues for control of DNA translocation.

  10. Advances in NO2 sensing with individual single-walled carbon nanotube transistors

    PubMed Central

    Muoth, Matthias; Roman, Cosmin; Haluska, Miroslav; Hierold, Christofer

    2014-01-01

    Summary The charge carrier transport in carbon nanotubes is highly sensitive to certain molecules attached to their surface. This property has generated interest for their application in sensing gases, chemicals and biomolecules. With over a decade of research, a clearer picture of the interactions between the carbon nanotube and its surroundings has been achieved. In this review, we intend to summarize the current knowledge on this topic, focusing not only on the effect of adsorbates but also the effect of dielectric charge traps on the electrical transport in single-walled carbon nanotube transistors that are to be used in sensing applications. Recently, contact-passivated, open-channel individual single-walled carbon nanotube field-effect transistors have been shown to be operational at room temperature with ultra-low power consumption. Sensor recovery within minutes through UV illumination or self-heating has been shown. Improvements in fabrication processes aimed at reducing the impact of charge traps have reduced the hysteresis, drift and low-frequency noise in carbon nanotube transistors. While open challenges such as large-scale fabrication, selectivity tuning and noise reduction still remain, these results demonstrate considerable progress in transforming the promise of carbon nanotube properties into functional ultra-low power, highly sensitive gas sensors. PMID:25551046

  11. 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 ...

  12. Wrapping cytochrome c around single-wall carbon nanotube: engineered nanohybrid building blocks for infrared detection at high quantum efficiency

    E-print Network

    Gong, Youpin; Liu, Qingfeng; Wilt, Jamie Samantha; Gong, Maogang; Ren, Shenqiang; Wu, Judy

    2015-01-01

    Biomolecule cytochrome c (Cty c), a small molecule of a chain of amino acids with extraordinary electron transport, was helically wrapped around a semiconductive single-wall carbon nanotube (s-SWCNT) to form a molecular building block for uncooled...

  13. 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

  14. 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.

    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.

  15. Modulation of energy/electron transfer in gold nanoclusters by single walled carbon nanotubes and further consequences

    NASA Astrophysics Data System (ADS)

    Das, Tarasankar; Maity, Arnab; Mondal, Somen; Purkayastha, Pradipta

    2015-04-01

    Semiconductor or metallic character in single-walled carbon nanotubes (SWCNTs) is developed because of their chirality and diameter. Depending upon the extent of these characters in a particular sample of SWCNT, various electronic and mechanical applications are formulated. In this work we used protein protected red emitting gold nanoclusters (AuNCs) to enhance the metallic character in SWCNTs through electron transfer induced by photonic excitation. The AuNCs have been synthesized following a known protocol that generates Au+ protected Au0 clusters. Normal and carboxylic acid functionalized SWCNTs were obtained commercially for usage in the experiments. The non-functionalized SWCNTs facilitate intersystem electron transfer while the functionalized ones defer the phenomenon, which, in turn, affects the metallic character in the nanotubes. Steady state and time resolved fluorescence spectroscopy prove the dynamics and electrochemistry supports the intersystem electron transfer process.

  16. Atomic oxygen chemisorption on the sidewall of zigzag single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Margulis, Vl. A.; Muryumin, E. E.

    2007-01-01

    A theoretical approach is developed to study the chemisorption of a single oxygen atom on the outer surface of zigzag single-walled carbon nanotubes (ZSWCNTs). The adatom Green’s function, the charge transfer between the nanotubes and the chemisorbed O atom, and the adsorption energy ?Eads are calculated within the Anderson-Newns model, which takes account of Coulomb interaction between adsorbate electrons. Two different adsorption positions are considered, in which an oxygen atom forms a bridge between two nearest-neighbor carbon atoms: one is on top of an axial C-C bond (position I), and the other—on top of a zigzag C-C one (position II). According to our calculations carried out for a series of the ZSWCNTs (p,0) with p ranging from 9 to 18, the adsorption of a single O atom in both the above-mentioned positions is possible and equally probable from the energetic point of view as the corresponding adsorption energies, being negative, are almost identical. The absolute values of these energies generally fall into the range 1.1-2.7eV , larger ??Eads? values being associated with semiconducting tubes. For the latter ones, ?Eads is found to be practically independent of the nanotube radius R , whereas for metallic tubes ?Eads slightly decreases with increasing R , tending towards the “infinite” radius graphene case. The localized acceptor states created by the O adatom in the band gap of the semiconducting ZSWCNTs are found to be responsible for such a different behavior of ?Eads as a function of R for the two types of nanotubes (metallic and semiconducting), as well as for the lowering in ?Eads (by about 0.5eV ) for the semiconducting tubes as compared with the metallic ones. It is also shown that a fairly large charge transfer (of about 0.55 electron) to the O adatom occurs when it is chemisorbed on the outer surface of the ZSWCNTs, which suggests that their electronic transport properties can be significantly changed upon chemisorption of atomic oxygen.

  17. Structure-Processing-Property Interrelationships of Vapor Grown Carbon Nanofiber, Single-Walled Carbon Nanotube and Functionalized Single-Walled Carbon Nanotube - Polypropylene Nanocomposites

    NASA Astrophysics Data System (ADS)

    Radhakrishnan, Vinod Karumathil

    This dissertation describes the first use of a design of experiments approach to investigate the interrelationships between structure, processing, and properties of melt extruded polypropylene (PP) carbon nanomaterial composites. The effect of nanomaterial structure was evaluated by exploring the incorporation of vapor grown carbon nanofibers (VGCFs), or pristine or functionalized single-walled carbon nanotubes (SWNTs or C12SWNTs) in polypropylene, while the effect of processing was investigated by studying the influence of melt extrusion temperature, speed, and time. The nanomaterials and PP were combined by an initial mixing method prior to melt extrusion. The nanocomposite properties were characterized by a combination of morphological, rheological, and thermal methods. Preliminary investigations into the effects of the initial mixing method revealed that the distribution of nanomaterials obtained after the mixing had a considerable influence on the properties of the final melt extruded nanocomposite. Dry mixing (DM) resulted in minimal adhesion between nanomaterials and PP during initial mixing; the majority of nanomaterials descended to the bottom. Hot coagulation (HC) mixing resulted in extremely high degrees of interaction between the nanomaterials and PP chains. Rotary evaporation (RE) mixing resulted in nanomaterial distribution uniformity between that obtained from DM and HC. Employing design of experiments to investigate the effects of structure and processing conditions on melt extruded PP nanocomposite properties revealed several interesting effects. The effect of processing conditions varied depending on the degree of nanomaterial distribution in PP attained prior to melt processing. Increasing melt extrusion temperature increased the decomposition temperature (Td) of PP/C12SWNT obtained from HC mixing but decreased T d of PP/C12SWNT obtained from RE mixing. Higher melt extrusion screw speed, on the other hand, significantly improved the nanocomposite crystallization behavior in RE nanocomposites, while not being a major processing factor in HC nanocomposites. The variations in nanocomposite properties with processing conditions were the result of complex interactions between the degree of dispersion, polymer degradation, and stability of the nanocomposite microstructure effected by the nanomaterial structure and processing conditions. Most importantly, this investigation revealed that the optimum melt processing conditions to be employed varied depending on the materials being used and the property of interest.

  18. Photoinduced spontaneous free-carrier generation in semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Park, Jaehong; Reid, Obadiah G.; Blackburn, Jeffrey L.; Rumbles, Garry

    2015-11-01

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

  19. Photoinduced spontaneous free-carrier generation in semiconducting single-walled carbon nanotubes.

    PubMed

    Park, Jaehong; Reid, Obadiah G; Blackburn, Jeffrey L; Rumbles, Garry

    2015-01-01

    Strong quantum confinement and low dielectric screening impart single-walled carbon nanotubes with exciton-binding energies substantially exceeding kBT at room temperature. Despite these large binding energies, reported photoluminescence quantum yields are typically low and some studies suggest that photoexcitation of carbon nanotube excitonic transitions can produce free charge carriers. Here we report the direct measurement of long-lived free-carrier generation in chirality-pure, single-walled carbon nanotubes in a low dielectric solvent. Time-resolved microwave conductivity enables contactless and quantitative measurement of the real and imaginary photoconductance of individually suspended nanotubes. The conditions of the microwave conductivity measurement allow us to avoid the complications of most previous measurements of nanotube free-carrier generation, including tube-tube/tube-electrode contact, dielectric screening by nearby excitons and many-body interactions. Even at low photon fluence (approximately 0.05 excitons per ?m length of tubes), we directly observe free carriers on excitation of the first and second carbon nanotube exciton transitions. PMID:26531728

  20. Photoinduced spontaneous free-carrier generation in semiconducting single-walled carbon nanotubes

    PubMed Central

    Park, Jaehong; Reid, Obadiah G.; Blackburn, Jeffrey L.; Rumbles, Garry

    2015-01-01

    Strong quantum confinement and low dielectric screening impart single-walled carbon nanotubes with exciton-binding energies substantially exceeding kBT at room temperature. Despite these large binding energies, reported photoluminescence quantum yields are typically low and some studies suggest that photoexcitation of carbon nanotube excitonic transitions can produce free charge carriers. Here we report the direct measurement of long-lived free-carrier generation in chirality-pure, single-walled carbon nanotubes in a low dielectric solvent. Time-resolved microwave conductivity enables contactless and quantitative measurement of the real and imaginary photoconductance of individually suspended nanotubes. The conditions of the microwave conductivity measurement allow us to avoid the complications of most previous measurements of nanotube free-carrier generation, including tube–tube/tube–electrode contact, dielectric screening by nearby excitons and many-body interactions. Even at low photon fluence (approximately 0.05 excitons per ?m length of tubes), we directly observe free carriers on excitation of the first and second carbon nanotube exciton transitions. PMID:26531728

  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 Facile High-speed Vibration Milling Method to Water-disperse Single- walled Carbon Nanohorns

    SciTech Connect

    Shu, Chunying; Zhang, Jianfei; Sim, Jae Hyun; Burke, Brian; Williams, Keith A; Rylander, Nichole M; Campbell, Tom; Puretzky, Alexander A; Rouleau, Christopher M; Geohegan, David B; More, Karren Leslie; Esker, Alan R; Gibson, Harry W; Dorn, Harry C

    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.

  3. Diameter-selective solubilization of single-walled carbon nanotubes by reversible cyclic peptides.

    PubMed

    Ortiz-Acevedo, Alfonso; Xie, Hui; Zorbas, Vasiliki; Sampson, William M; Dalton, Alan B; Baughman, Ray H; Draper, Rockford K; Musselman, Inga H; Dieckmann, Gregg R

    2005-07-01

    We have utilized reversible cyclic peptides (RCPs)-peptides containing alternating l- and d-amino acids with N- and C-termini derivatized with thiol-containing groups allowing reversible peptide cyclization-to solubilize and noncovalently functionalize carbon single-walled nanotubes (SWNTs) in aqueous solution. Solubilization occurs through wrapping of RCPs around the circumference of a SWNT, followed by the formation of head-to-tail covalent bonds, yielding closed rings on the nanotubes. By controlling the length of the RCPs, we have demonstrated limited diameter-selective solubilization of the SWNTs as revealed by UV/vis/NIR and Raman spectroscopies, as well as atomic force microscopy. PMID:15984878

  4. Interaction of nucleic acid bases with single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Shukla, M. K.; Dubey, Madan; Zakar, Eugene; Namburu, Raju; Czyznikowska, Zaneta; Leszczynski, Jerzy

    2009-10-01

    Theoretical investigations at the M05-2X DFT level employing the 6-31G(d), 6-31G(d,p), 6-31+G(d,p) and cc-pVDZ basis sets show that all nucleic acid bases (NABs), guanine, adenine, cytosine, thymine and uracil form stable stacking complexes with the zigzag (7,0) single-walled carbon nanotube (SWCNT). The values of the BSSE corrected interaction energy suggested that among the bases guanine forms the most stable complex. The other bases generate complexes of similar stability with the considered SWCNT that are less stable than the guanine-SWCNT dimer.

  5. 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.

  6. Purification of single-wall carbon nanotubes by using ultrafine gold particles

    NASA Astrophysics Data System (ADS)

    Nihey, Fumiyuki; Mizoguti, Eiji; Yudasaka, Masako; Iijima, Sumio; Ichihashi, Toshinari; Nakamura, Kazuo

    2000-03-01

    The purification of single-wall carbon nanotubes (SWNTs) is needed to enable detailed characterization and some application of this material. We report a purification method utilizing ultrafine gold particles as catalysts to selectively oxidize carbonaceous impurities in SWNT soot. The ultrafine gold particles with a diameter of 20 nm were dispersed in the soot in combination with benzalkonium chloride as surfactant. Thermogravimetric analyses and electron microscopy observations revealed that oxidation occured at about 330^circC for carbonaceous impurities and at about 410^circC for SWNTs. This selective oxidation enabled us to purify SWNTs and make the quantitative analyses of SWNTs.

  7. On a Nanoscopically-Informed Shell Theory of Single-Wall Carbon Nanotubes

    E-print Network

    Chandrajit Bajaj; Antonino Favata; Paolo Podio-Guidugli

    2011-11-19

    This paper proposes a bottom-up sequence of modeling steps leading to a nanoscopically informed continuum, and as such macroscopic, theory of single-walled carbon nanotubes (SWCNTs). We provide a description of the geometry of the two most representative types of SWCNTs, armchair (A-) and zigzag (Z-), of their modules and of their elementary bond units. We believe ours to be the simplest shell theory that accounts accurately for the linearly elastic response of both A- and Z- CNTs. In fact, our theory can be shown to fit SWCNTs of whatever chirality; its main novel feature is perhaps the proposition of chirality-dependent concepts of effective thickness and effective radius.

  8. A new designed ? conjugated molecule for stable single walled carbon nanotube dispersion in aqueous medium.

    PubMed

    Nogueira, S L; Sahoo, S K; Jarrosson, T; Serein-Spirau, F; Lère-Porte, J-P; Moujaes, E A; Marletta, A; Santos, A P; Fantini, C; Furtado, C A; Silva, R A

    2016-02-15

    A molecule with a ? conjugated backbone built from aromatic thiophene and dialkoxyphenylene units and substituted imidazolium groups (TPO) is designed to obtain ultra-stable single walled carbon nanotube (SWCNT) dispersion in aqueous medium. The proposed mechanism of non-covalent interaction is accompanied by individualization of SWCNT and comprises of dominant nondisruptive ?-? and cation-? interaction between them and the TPO conjugated oligomer. The individualization of SWCNT and dispersibility and stability of the ultra-stable suspensions were estimated using high resolution transmission electron microscopy, UV-Visible-NIR absorption spectroscopy, Raman spectroscopy, photoluminescence and zeta potential measurement. Nuclear magnetic resonance data provides direct evidence toward possible cation-? interaction. PMID:26609931

  9. Extinction properties of single-walled carbon nanotubes: Two-fluid model

    SciTech Connect

    Moradi, Afshin

    2014-03-15

    The extinction spectra of a single-walled carbon nanotube are investigated, within the framework of the vector wave function method in conjunction with the hydrodynamic model. Both polarizations of the incident plane wave (TE and TM with respect to the x-z plane) are treated. Electronic excitations on the nanotube surface are modeled by an infinitesimally thin layer of a two-dimensional electron gas represented by two interacting fluids, which takes into account the different nature of the ? and ? electrons. Numerical results show that strong interaction between the fluids gives rise to the splitting of the extinction spectra into two peaks in quantitative agreement with the ? and ? + ? plasmon energies.

  10. Thermal buckling analysis of bridged single walled carbon nanotubes using molecular structural mechanics

    NASA Astrophysics Data System (ADS)

    Firouz-Abadi, R. D.; Badri-Kouhi, E.

    2015-03-01

    This paper is concerned with the stability analysis of bridged single walled carbon nanotubes (SWCNT) under temperature changes. A molecular structural mechanics model is utilized to investigate the free vibration frequencies and thermal buckling of SWCNT. In comparison with most of the previous studies, a temperature-variable thermal-expansion-coefficient is used that is negative under a certain temperature. Also thermal variation of Young's modulus of the CNTs is considered. Several studies are performed to investigate the critical temperature change due to heating and cooling of SWCNTs with different chiralities and slenderness ratios and the stability boundaries are determined.

  11. Nanobioconjugates of Candida antarctica lipase B and single-walled carbon nanotubes in biodiesel production.

    PubMed

    Bencze, László Csaba; Bartha-Vári, Judith H; Katona, Gabriel; To?a, Monica Ioana; Paizs, Csaba; Irimie, Florin-Dan

    2016-01-01

    Carboxylated single-walled carbon nanotubes (SWCNTCOOH) were used as support for covalent immobilization of Candida antarctica lipase B (CaL-B) using linkers with different lengths. The obtained nanostructured biocatalysts with low diffusional limitation were tested in batch mode in the ethanolysis of the sunflower oil. SWCNTCOOH-CaL-B proved to be a highly efficient and stable biocatalyst in acetonitrile (83.4% conversion after 4h at 35°C, retaining >90% of original activity after 10 cycles). PMID:26590760

  12. 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.

  13. Evaluation of the drag force on single-walled carbon nanotubes in rarefied gases.

    PubMed

    Wong, Ross Y M; Liu, Chong; Wang, Jun; Chao, Christopher Y H; Li, Zhigang

    2012-03-01

    The drag force on carbon nanotubes (CNTs) in dilute gases has been previously derived. However, the drag force formulae involve collision integrals, which are complex functions of the gas-CNT interaction potential. The unavailability of the collision integrals and interaction potential makes the application of the theoretical drag force laws impossible. In this work, we develop a potential model for the interaction between a gas and single-walled CNT. The collision integrals are then calculated based on the potential and empirical expressions are proposed. Finally, the drag force is computed directly through molecular dynamics simulations and compared with the theoretical predictions. PMID:22755052

  14. Molecule-induced quantum confinement in single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Hida, Akira; Ishibashi, Koji

    2015-04-01

    A method of fabricating quantum-confined structures with single-walled carbon nanotubes (SWNTs) has been developed. Scanning tunneling spectroscopy revealed that a parabolic confinement potential appeared when collagen model peptides were attached to both ends of an individual SWNT via the formation of carboxylic anhydrides. On the other hand, the confinement potential was markedly changed by yielding the peptide bonds between the SWNT and the collagen model peptides. Photoluminescence spectroscopy measurements showed that a type-II quantum dot was produced in the obtained heterostructure.

  15. Effects of ion beam heating on Raman spectra of single-walled carbon nanotubes

    SciTech Connect

    Hulman, Martin; Skakalova, Viera; Krasheninnikov, A. V.; Roth, S.

    2009-02-16

    Free standing films of single-wall carbon nanotubes were irradiated with energetic N{sup +} and C{sup 4+} ions. The observed changes in the Raman line shape of the radial breathing mode and the G band of the C{sup 4+} irradiated samples were similar to those found for a thermally annealed sample. We ascribe these changes to thermal desorption of volatile dopants from the initially doped nanotubes. A simple geometry of the experiment allows us to estimate the temperature rise by one-dimensional heat conductance equation. The calculation indicates that irradiation-mediated increase in temperature may account for the observed Raman spectra changes.

  16. Temperature Dependence of the Thermal Conductivity of Single Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Osman, Mohamed A.; Srivastava, Deepak

    2000-01-01

    The thermal conductivity of several single wall carbon nanotubes (CNT) has been calculated over a temperature range of 100-500 K using molecular dynamics simulations with Tersoff-Brenner potential for C-C interactions. In all cases, starting from similar values at 100K, thermal conductivities show a peaking behavior before falling off at higher temperatures. The peak position shifts to higher temperatures for nanotubes of larger diameter, and no significant dependence on the tube chirality is observed. It is shown that this phenomenon is due to onset of Umklapp scattering, which shifts to higher temperatures for nanotubes of larger diameter.

  17. On the charge transfer between single-walled carbon nanotubes and graphene

    SciTech Connect

    Rao, Rahul Pierce, Neal; Dasgupta, Archi

    2014-08-18

    It is important to understand the electronic interaction between single-walled carbon nanotubes (SWNTs) and graphene in order to use them efficiently in multifunctional hybrid devices. Here, we deposited SWNT bundles on graphene-covered copper and SiO{sub 2} substrates by chemical vapor deposition and investigated the charge transfer between them by Raman spectroscopy. Our results revealed that, on both copper and SiO{sub 2} substrates, graphene donates electrons to the SWNTs, resulting in p-type doped graphene and n-type doped SWNTs.

  18. Kinetics of reactive ion etching upon single-walled carbon nanotubes

    SciTech Connect

    Kato, Toshiaki; Hatakeyama, Rikizo

    2008-01-21

    The remarkable etching reaction of single-walled carbon nanotubes (SWNTs) has been observed in their growth of the parameter-controlled plasma chemical vapor deposition (CVD). The time evolution study of the SWNTs growth leads to establishing a growth equation which can completely express the growth kinetics of SWNTs in the plasma CVD. The growth equation is found to reveal that there are several key parameters which directly affect the etching reaction of SWNTs. Furthermore, such kinetics of the SWNT etching in plasmas can perfectly be explained with a reactive ion etching model.

  19. Finite length and solvent analysis effects on the squash mode of single walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    de Fréin, C.; Quirke, N.; Zerulla, D.

    2013-10-01

    Nanotube diameters (d) are usually characterized using the radial breathing mode d-1; the squash mode frequency (f) however is predicted to vary as d-2. We demonstrate using the MM+ forcefield that for lengths <9 nm the symmetric squash mode (SSM) and asymmetric squash mode (ASM) ((10,0) SWNT (single wall carbon nanotubes)) are non-degenerate with ?f ? 55 cm-1. In solution, the SWNT-water interaction upshifts the ASM by 20 cm-1 and the SSM by 10 cm-1. Such asymmetries could be used to simultaneously characterize the length and diameter of short nanotubes for applications including nanoresonators and biomedical probes.

  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. 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.

  2. 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.

  3. Synthesis and chemical modification of single-walled carbon nanotubes and inorganic nanowires

    NASA Astrophysics Data System (ADS)

    Zheng, Bo

    This dissertation describes the study of single-walled carbon nanotubes (SWNTs), inorganic nanowires, and carbon aerogels. A novel catalyst of iron/molybdenum nanoparticles supported on alumina aerogel was developed for CVD synthesis of SWNTs. Using this catalyst, the yield of SWNTs was enhanced by at least three times compared to previously reported best results. The highest yield of SWNTs was achieved when the reaction temperature was between 850°C and 900°C with CO (˜1000 sccm) as feeding gas. A combination of acid wash and mild oxidation processes was used to purify tire raw SWNT product. Transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) indicated that the majority (>90%) of the purified product was SWNTs. The purified SWNTs were fluorinated by diluted fluorine gas at 250°C. It was found that F-SWNTs could be recovered at an annealing temperature as low as 100°C. The thermal recovery behaviors of metallic and semiconducting SWNTs were very similar at annealing temperature ?150°C, as suggested by 2D UV-Vis-NIR correlation spectroscopy. F-SWNTs were also added into poly(ethylene oxide) (PEO) to form a PEO/F-SWNT composite. Mechanical properties measurements showed that the F-SWNTs significantly increased the strength of the resulting composite. A highly efficient method of SWNT synthesis on surfaces was also developed. It was found that the combination of carbon monoxide and hydrogen as a feeding gas greatly enhanced the surface growth of SWNTs. This method showed a large window of optimal HZ concentration (20%--80%) and synthesis temperature (800--900°C), so the result was very reproducible. In the second project, two novel methods of preparing silicon oxide and tungsten oxide nanowires, respectively, were developed. By using a millimeter-sized liquid gallium ball as a metal solvent at 920--940°C, bulk quantities of ultralong, uniform and well-aligned silicon oxide nanowires were synthesized. XPS and EDX indicated that the atomic ratio of Si to O in the nanowires was 1:1.5. On the other hand, isolated tungsten oxide nanowires were directly grown on tungsten tips and plates by a simple oxidation procedure at elevated temperature. These nanowire preparation techniques are simple, fast and economical. The third project focused on the fabrication of carbon aerogel. Resorcinol and furfural were polymerized in isopropanol using HCl as a catalyst and an organic gel was formed. This gel was dried under the supercritical condition of isopropanol, followed by carbonization at 900°C. Morphology study, surface area and resistance measurements indicated that the obtained carbon aerogel had similar properties to the one prepared under the supercritical condition of carbon oxide, which is a much longer process and requires much more energy.

  4. Replacement of Transparent Conductive Oxides by Single-Wall Carbon Nanotubes in Cu(In,Ga)Se2-Based Solar Cells

    SciTech Connect

    Contreras, M. A.; Barnes, T.; van de Lagemaat, J.; Rumbles, G.; Coutts, T. J.; Weeks, C.; Glatkowski, P.; Levitsky, I.; Peltola, J.; Britz, D. A.

    2007-01-01

    Thin films of single-wall carbon nanotubes were used as the transparent top electrical contact in Cu(In,Ga)Se{sub 2}- based solar cells. Specifically, we demonstrate that thin layers of carbon nanotubes in combination with insulating polymer layers can effectively replace the metal oxide layers typically used in polycrystalline thin-film solar cells. Replacing the standard n-type ZnO layer with a thin film of carbon nanotubes yielded energy conversion efficiencies up to 13%. The optical and electrical transport properties of the single-wall carbon nanotubes suggest that suitable applications for these materials include multiple-junction solar cells, thermophotovoltaics, and other applications benefiting from a p-type transparent conductor with high near-infrared transmission.

  5. Spectroelectrochemical properties of the single walled carbon nanotubes functionalized with polydiphenylamine doped with heteropolyanions

    SciTech Connect

    Smaranda, I.; Baibarac, M.; Baltog, I.; Mevellec, J.Y.; Lefrant, S.

    2013-01-15

    A combined chemical-electrochemical method was used for covalent functionalization of single-walled carbon nanotube (SWNT) with polydiphenylamine (PDPA) doped with heteropolyanions of H{sub 3}PMo{sub 12}O{sub 40}{center_dot}xH{sub 2}O. The functionalization process induces in Raman spectra of SWNTs the following changes: (i) an increase in relative intensity of the D band, accompanied a gradual up-shift of the G band in the case of the semiconducting tubes and a decrease in the relative intensity of band peaked at 1540 cm{sup -1} is remarked in the case of the metallic tubes; (ii) in the anti-Stokes Raman spectrum an increase in the relative intensity of Raman line of metallic tubes peaked at -1560 cm{sup -1} is remarked when the cycles number increases. The additional down-shift of the FTIR bands belonging to H{sub 3}PMo{sub 12}O{sub 40} heteropolyanions (at 881, 943 and 1055 cm{sup -1}) and PDPA (at 688, 736 and 1016 cm{sup -1}) originates in hindrance steric effects induced the covalent functionalization of SWNTs with polymer molecules. Using Raman scattering and FTIR spectroscopy we demonstrate that chemical polymerization of diphenylamine in the presence of H{sub 3}PMo{sub 12}O{sub 40}{center_dot}xH{sub 2}O and SWNTs results in a composite of the type blend based on PDPA in un-doped state and SWNTs doped with H{sub 3}PMo{sub 12}O{sub 40} heteropolyanions. - Graphical abstract: Stokes and anti-Stokes Raman spectra of the SWNTs before (a) and after electrochemical functionalization with PDPA doped with heteropolyanions by 5 (b) and 25 (c) voltammeter cycles. Highlights: Black-Right-Pointing-Pointer A chemical-electrochemical method is used to functionalization of SWNTs. Black-Right-Pointing-Pointer Functionalization of wall-side of tube is evidenced by anti-Stokes Raman studies. Black-Right-Pointing-Pointer FTIR spectra proves insertion of heteropolyanions in polydiphenylamine matrix. Black-Right-Pointing-Pointer FTIR spectra of polymer functionalized SWNTs reveal hindrance steric effects.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  7. Synthesis of single-walled carbon nanotubes by chemical vapor deposition using sodium chloride support

    NASA Astrophysics Data System (ADS)

    Teong Ooi, Jeremy Hor; Liu, Wei-Wen; Thota, Venugopal; Rahman Mohamed, Abdul; Chai, Siang-Piao

    2011-02-01

    Bundled single-walled carbon nanotubes (SWCNTs) together with multi-walled carbon nanotubes (MWCNTs) were directly grown on a water-soluble support catalyst that was prepared via sublimation of ferrocene on sodium chloride. The synthesis of nanotubes was carried out at a growth temperature of 700 °C in a combined methane and nitrogen environment of 1:1 volumetric ratio at a total flowrate of 80 ml/min for 1 h in a vertical reactor. Characterization techniques such as scanning electron microscope, transmission electron microscope, thermogravimetric analysis, and Raman spectroscopy were employed to study the carbon deposits. Transmission electron microscope shows the presence of SWCNTs with an average diameter of ca. 1.18 nm on the catalyst. The radial breathing mode (RBM) of Raman for shifts below 350 cm -1 further confirmed the presence of SWCNTs and the diameters were calculated to be 0.93, 1.36, 1.5 and 1.85 nm.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  10. 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

  11. Terahertz time-domain measurement of ballistic electron resonance in a single-walled carbon nanotube.

    PubMed

    Zhong, Zhaohui; Gabor, Nathaniel M; Sharping, Jay E; Gaeta, Alexander L; McEuen, Paul L

    2008-04-01

    Understanding the physics of low-dimensional systems and the operation of next-generation electronics will depend on our ability to measure the electrical properties of nanomaterials at terahertz frequencies ( approximately 100 GHz to 10 THz). Single-walled carbon nanotubes are prototypical one-dimensional nanomaterials because of their unique band structure and long carrier mean free path. Although nanotube transistors have been studied at microwave frequencies (100 MHz to 50 GHz), no techniques currently exist to probe their terahertz response. Here, we describe the first terahertz electrical measurements of single-walled carbon nanotube transistors performed in the time domain. We observe a ballistic electron resonance that corresponds to the round-trip transit of an electron along the nanotube with a picosecond-scale period. The electron velocity is found to be constant and equal to the Fermi velocity, showing that the high-frequency electron response is dominated by single-particle excitations rather than collective plasmon modes. These results demonstrate a powerful new tool for directly probing picosecond electron motion in nanostructures. PMID:18654503

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

    SciTech Connect

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

    2011-01-01

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

  13. Growth mechanism of single-walled carbon nanotube from catalytic reaction inside carbon nanotube template

    E-print Network

    Maruyama, Shigeo

    suggest that the DWNT formation from thermally annealed metallocene-encapsulating SWNT goes through formation of metal catalyst cluster, followed by SWNT precipitation at the root. The diameter of the inner SWNT is determined by the carbon/metal layered structure of the catalyst cluster, which gives rise

  14. Effects of single-walled carbon nanotubes on the bioavailability of PCBs in field-contaminated sediments

    EPA Science Inventory

    Adsorption of hydrophobic organic contaminants (HOCs) to black carbon is a well studied phenomenon. One emerging class of engineered black carbon materials are single-walled carbon nanotubes (SWNT). Little research has investigated the potential of SWNT to adsorb and sequester HO...

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

    E-print Network

    Tománek, David

    on the exact atomic positions. S0163-1829 97 07220-2 I. INTRODUCTION Carbon nanotubes, first discovered as a byElectronic structure of single-wall, multiwall, and filled carbon nanotubes D. O¨ stling, D. Toma-wall, multiwall, and filled carbon nanotubes using the local-density-functional formalism. In order to handle

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. In vivo MRI of single-wall carbon nanohorns through magnetite nanoparticle attachment

    NASA Astrophysics Data System (ADS)

    Miyawaki, Jin; Yudasaka, Masako; Imai, Hideto; Yorimitsu, Hideki; Isobe, Hiroyuki; Nakamura, Eiichi; Iijima, Sumio

    2006-03-01

    Superparamagnetic magnetite (SPM) is used as a contrast agent in magnetic resonance imaging (MRI). Thus, the SPM-attachment to carbon nanotubes (CNTs) will enable to visualize motional behaviors of CNTs in the living body through MRI. We found that the strong attachment of the SPM nanoparticles (ca. 6 nm size) to one type of CNTs, single-wall carbon nanohorns (SWNHs), could be achieved through a deposition of iron acetate clusters on SWNHs in ethanol at room temperature, followed by heat-treatment in Ar. In vivo MRI visualized that the SWNHs attached with the SPM nanoparticles accumulated in several organs of mice when injected into mice via tail veins. This simple method for the SPM-attaching on CNTs would facilitate the toxicity assessment of CNTs and the applications of CNTs in bioscience and biotechnology.

  1. Modulating diameter of single-walled carbon nanotubes in alcohol catalytic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Xiang, Rong; Cui, Kehang; An, Hua; Chen, Xiao; Chiashi, Shohei; Maruyama, Shigeo

    2015-03-01

    Modulating the diameter of a single walled carbon nanotube (SWNT) is essential for its applications in optical and electronic devices. We demonstrate that the average diameter of vertically aligned SWNTs can be successfully reduced from 2.5 to 1.2 nm by changing catalyst component ratio in a Co/Mo bimetallic system, no matter the catalyst is dip-coated or spray-coated onto a substrate. Meanwhile, the diameter can be further reduced after replacing the conventional ethanol carbon source by acetonitrile. Recently, Cu is found to be effective in reducing diameter in alcohol catalytic chemical vapor deposition, and sub-1-nm SWNTs are achieved using this novel Co/Cu combination. Diameter modulation is confirmed by Raman spectroscopy, optical absorption spectroscopy and transmission electron microscopy. The structure and element distribution in Co/Cu catalyst is also investigated.

  2. A theoretical study on the interaction of amphetamine and single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hafizi, Hamid; Najafi Chermahini, Alireza; Mohammadnezhad, Gholamhossein; Teimouri, Abbas

    2015-02-01

    The adsorption of 1-phenyl-2-aminopropane (amphetamine) on the (4,4), (5,5), (6,6), and (7,7) single-walled carbon nanotubes (SWCNTs) has been theoretically investigated. The molecule has been located in different modes including parallel, perpendicular, and oblique on the outer surface of carbon nanotubes. The physisorption of amphetamine onto SWCNT sidewall is thermodynamically favored; as a consequence, it modulates the electronic properties of pristine nanotube in the vicinity of Fermi region. The adsorption energies for the parallel and oblique modes found in the range of -1.13 to -1.88 and -1.27 to -2.01 kcal/mol, respectively. Projected density of states (PDOS) and frontier orbital analysis in the vicinity of Fermi level region suggest the electronic states to be contributed from SWCNT rather than amphetamine molecule.

  3. 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.

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

    E-print Network

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

    2013-01-01

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

  5. Confined propagation of covalent chemical reactions on single-walled carbon nanotubes.

    PubMed

    Deng, Shunliu; Zhang, Yin; Brozena, Alexandra H; Mayes, Maricris Lodriguito; Banerjee, Parag; Chiou, Wen-An; Rubloff, Gary W; Schatz, George C; Wang, YuHuang

    2011-01-01

    Covalent chemistry typically occurs randomly on the graphene lattice of a carbon nanotube because electrons are delocalized over thousands of atomic sites, and rapidly destroys the electrical and optical properties of the nanotube. Here we show that the Billups-Birch reductive alkylation, a variant of the nearly century-old Birch reduction, occurs on single-walled carbon nanotubes by defect activation and propagates exclusively from sp(3) defect sites, with an estimated probability more than 1,300 times higher than otherwise random bonding to the '?-electron sea'. This mechanism quickly leads to confinement of the reaction fronts in the tubular direction. The confinement gives rise to a series of interesting phenomena, including clustered distributions of the functional groups and a constant propagation rate of 18 ± 6 ?nm per reaction cycle that allows straightforward control of the spatial pattern of functional groups on the nanometre length scale. PMID:21750536

  6. 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.

  7. Energy Band Gap Study of Semiconducting Single Walled Carbon Nanotube Bundle

    NASA Technical Reports Server (NTRS)

    Elkadi, Asmaa; Decrossas, Emmanuel; El-Ghazaly, Samir

    2013-01-01

    The electronic properties of multiple semiconducting single walled carbon nanotubes (s-SWCNTs) considering various distribution inside a bundle are studied. The model derived from the proposed analytical potential function of electron density for na individual s-SWCNT is general and can be easily applied to multiple nanotubes. This work demonstrates that regardless the number of carbon nanotubes, the strong coupling occurring between the closet neighbors reduces the energy band gap of the bundle by 10%. As expected, the coupling is strongly dependent on the distance separating the s-SWCNTs. In addition, based on the developed model, it is proposed to enhance this coupling effect by applying an electric field across the bundle to significantly reduce the energy band gap of the bundle by 20%.

  8. Energy Band Gap Study of Semiconducting Single Walled Carbon Nanotube Bundle

    NASA Technical Reports Server (NTRS)

    Elkadi, Asmaa; Decrossas, Emmanuel; El-Ghazaly, Samir

    2013-01-01

    The electronic properties of multiple semiconducting single walled carbon nanotubes (s-SWCNTs) considering various distribution inside a bundle are studied. The model derived from the proposed analytical potential function of the electron density for an individual s-SWCNT is general and can be easily applied to multiple nanotubes. This work demonstrates that regardless the number of carbon nanotubes, the strong coupling occurring between the closest neighbours reduces the energy band gap of the bundle by 10%. As expected, the coupling is strongly dependent on the distance separating the s-SWCNTs. In addition, based on the developed model, it is proposed to enhance this coupling effect by applying an electric field across the bundle to significantly reduce the energy band gap of the bundle by 20%.

  9. Stabilization effect of single-walled carbon nanotubes on the functioning of photosynthetic reaction centers.

    PubMed

    Dorogi, Marta; Balint, Zoltan; Mikó, Csilla; Vileno, Bertrand; Milas, Mirko; Hernadi, Klara; Forró, Laszló; Varó, György; Nagy, Laszló

    2006-11-01

    The interaction between single-walled carbon nanotubes and photosynthetic reaction centers purified from purple bacterium Rhodobacter sphaeroides R-26 has been investigated. Atomic force microscopy studies provide evidence that reaction center protein can be attached effectively to the nanotubes. The typical diameter of the nanotube is 1-4 nm and 15 +/- 2 nm without and with the reaction centers, respectively. Light-induced absorption change measurements indicate the stabilization of the P+(Q(A)Q(B))- charge pair, which is formed after single saturating light excitation after the attachment to nanotubes. The separation of light-induced charges is followed by slow reorganization of the protein structure. The stabilization effect of light-initiated charges by the carbon nanotubes opens a possible direction of several applications, the most promising being in energy conversion and storage devices. PMID:17064097

  10. 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

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

    PubMed

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

    2012-03-01

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

  12. A parametric study of single-wall carbon nanotube growth by laser ablation

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram; Holmes, William A.; Nikolaev, Pavel; Hadjiev, Victor G.; Scott, Carl D.

    2004-01-01

    Results of a parametric study of carbon nanotube production by the double-pulse laser oven process are presented. The effect of various operating parameters on the production of single-wall carbon nanotubes (SWCNTs) is estimated by characterizing the nanotube material using analytical techniques, including scanning electron microscopy, transmission electron microscopy, thermo gravimetric analysis and Raman spectroscopy. The study included changing the sequence of the laser pulses, laser energy, pulse separation, type of buffer gas used, operating pressure, flow rate, inner tube diameter, as well as its material, and oven temperature. It was found that the material quality and quantity improve with deviation from normal operation parameters such as laser energy density higher than 1.5 J/cm2, pressure lower than 67 kPa, and flow rates higher than 100 sccm. Use of helium produced mainly small diameter tubes and a lower yield. The diameter of SWCNTs decreases with decreasing oven temperature and lower flow rates.

  13. 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

  14. 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.

  15. Separation of Single-Walled Carbon Nanotubes with DEP-FFF

    NASA Technical Reports Server (NTRS)

    Schmidt, Howard K.; Peng, Haiqing; Alvarez, Noe; Mendes, Manuel; Pasquali, Matteo

    2011-01-01

    A process using a modified dielectrophoresis device separates single-walled carbon nanotubes (SWNTs) according to their polarizability in electric fields. This depends on the size and dielectric constant of individual nanotubes and easily separates metallic from semiconducting nanotubes. Separation by length has also been demonstrated. Partial separation (enrichment) according to bandgap (which is linked to polarizability) has also been shown and can be improved to full separation of individual types of semiconducting SWNTs with better control over operational parameters and the length of SWNT starting material. This process and device can be scaled affordably to generate useful amounts of semiconducting SWNTs for electronic device development and production. In this study, a flow injection dielectrophoresis technique was used with a modified dielectrophoresis device. The length, width, and height of the modified chamber were 28, 2.5, and 0.025 cm, respectively. On the bottom of the chamber, there are two arrays of 50-m-wide, 2-m-thick gold electrodes, which are connected to an AC voltage generator and are alternately arranged so that every electrode is adjacent to two electrodes of the opposite polar. There is an additional plate electrode on the top of the chamber that is negatively biased. During the experiment, a syringe pump constantly pumps in the mobile phase, 1-percent sodium dodecylbenzene sulfonate (SDBS) solution, into the chamber. The frequency and voltage are set to 1 MHz and 10 V peak-to-peak, respectively. About 150 micro-L of SWNTs in 1- percent SDBS decanted solution are injected to the mobile phase through a septum near the entrance of the chamber. The flow rate of the mobile phase is set to 0.02 cu cm/min. The injected SWNTs sample flows through the chamber before it is lead into a fluorescence flow-through cell and collected for further analysis. The flow-through cell has three windows, thus allowing the fluorometer to collect fluorescence spectrum and visible absorption spectrums simultaneously. Dielectrophoresis field-flow fractionation (DEP-FFF) generally depends on interaction of a sedimentation force and DEP force for particle separation, and SWNTs are neutrally buoyant in water. In this innovation, the third electrode was added to create a sedimentation force based on DC electrophoresis. This makes this particular device applicable to separations on any neutrally buoyant particles in solution and a more general process for a broad range of nanomaterials sorting and separations.

  16. Thin-film transistors using DNA-wrapped semiconducting single-wall carbon nanotubes with selected chiralities

    NASA Astrophysics Data System (ADS)

    Kuwahara, Yuki; Nihey, Fumiyuki; Ohmori, Shigekazu; Saito, Takeshi

    2015-10-01

    Selected semiconducting chiralities, (7,5), (7,6), and (8,4), of DNA-wrapped single-wall carbon nanotubes (DNA-SWCNTs) were used for thin-film transistors (TFTs). Chirality separation was carried out by ion exchange chromatography (IEX) with the ssDNA of the (TAT)4 sequence. An on/off ratio of 3.8 × 106 with a carrier mobility of 11 cm2/(V·s) was successfully achieved in the fabricated SWCNT-TFTs. The comparison between the on/off ratios obtained before (101-102) and after IEX (104-107) indicated that the IEX separation process sufficiently improves the performance of SWCNT-TFTs because of the reducing metallic SWCNT pathways in the TFT channel.

  17. Direct current injection and thermocapillary flow for purification of aligned arrays of single-walled carbon nanotubes

    SciTech Connect

    Xie, Xu; Islam, Ahmad E.; Seabron, Eric; Dunham, Simon N.; Du, Frank; Lin, Jonathan; Wilson, William L.; Rogers, John A.; Wahab, Muhammad A.; Alam, Muhammad A.; Li, Yuhang; Tomic, Bojan; Huang, Jiyuan; Burns, Branden; Song, Jizhou; Huang, Yonggang

    2015-04-07

    Aligned arrays of semiconducting single-walled carbon nanotubes (s-SWNTs) represent ideal configurations for use of this class of material in high performance electronics. Development of means for removing the metallic SWNTs (m-SWNTs) in as-grown arrays represents an essential challenge. Here, we introduce a simple scheme that achieves this type of purification using direct, selective current injection through interdigitated electrodes into the m-SWNTs, to allow their complete removal using processes of thermocapillarity and dry etching. Experiments and numerical simulations establish the fundamental aspects that lead to selectivity in this process, thereby setting design rules for optimization. Single-step purification of arrays that include thousands of SWNTs demonstrates the effectiveness and simplicity of the procedures. The result is a practical route to large-area aligned arrays of purely s-SWNTs with low-cost experimental setups.

  18. Direct current injection and thermocapillary flow for purification of aligned arrays of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Xie, Xu; Wahab, Muhammad A.; Li, Yuhang; Islam, Ahmad E.; Tomic, Bojan; Huang, Jiyuan; Burns, Branden; Seabron, Eric; Dunham, Simon N.; Du, Frank; Lin, Jonathan; Wilson, William L.; Song, Jizhou; Huang, Yonggang; Alam, Muhammad A.; Rogers, John A.

    2015-04-01

    Aligned arrays of semiconducting single-walled carbon nanotubes (s-SWNTs) represent ideal configurations for use of this class of material in high performance electronics. Development of means for removing the metallic SWNTs (m-SWNTs) in as-grown arrays represents an essential challenge. Here, we introduce a simple scheme that achieves this type of purification using direct, selective current injection through interdigitated electrodes into the m-SWNTs, to allow their complete removal using processes of thermocapillarity and dry etching. Experiments and numerical simulations establish the fundamental aspects that lead to selectivity in this process, thereby setting design rules for optimization. Single-step purification of arrays that include thousands of SWNTs demonstrates the effectiveness and simplicity of the procedures. The result is a practical route to large-area aligned arrays of purely s-SWNTs with low-cost experimental setups.

  19. Mechanism of Synthesis of Ultra-Long Single Wall Carbon Nanotubes in Arc Discharge Plasma

    SciTech Connect

    Keidar, Michael

    2013-06-23

    In this project fundamental issues related to synthesis of single wall carbon nanotubes (SWNTs), which is relationship between plasma parameters and SWNT characteristics were investigated. Given that among plasma-based techniques arc discharge stands out as very advantageous in several ways (fewer defects, high flexibility, longer lifetime) this techniques warrants attention from the plasma physics and plasma technology standpoint. Both experimental and theoretical investigations of the plasma and SWNTs synthesis were conducted. Experimental efforts focused on plasma diagnostics, measurements of nanostructures parameters, and nanoparticle characterization. Theoretical efforts focused to focus on multi-dimensional modeling of the arc discharge and single wall nanotube synthesis in arc plasmas. It was demonstrated in experiment and theoretically that controlling plasma parameters can affect nanostucture synthesis altering SWNT properties (length and diameter) and leading to synthesis of new structures such as a few-layer graphene. Among clearly identified parameters affecting synthesis are magnetic and electric fields. Knowledge of the plasma parameters and discharge characteristics is crucial for ability to control synthesis process by virtue of both magnetic and electric fields. New graduate course on plasma engineering was introduced into curriculum. 3 undergraduate students were attracted to the project and 3 graduate students (two are female) were involved in the project. Undergraduate student from Historically Black University was attracted and participated in the project during Summer 2010.

  20. Sub-millimeter long single-walled carbon nanotubes synthesis by alcohol enclosed catalytic chemical vapor deposition

    E-print Network

    Maruyama, Shigeo

    , water, and acetaldehyde at CVD temperature. A possible mechanism for the increase of film thickness is suppression of carbon coating on catalysts by produced water, or the efficient reaction by the decomposedSub-millimeter long single-walled carbon nanotubes synthesis by alcohol enclosed catalytic chemical

  1. 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

  2. Gas Pressure Effect on Density of Horizontally Aligned Single-Walled Carbon Nanotubes Grown on Crystal Quartz Substrates

    E-print Network

    Maruyama, Shigeo

    Gas Pressure Effect on Density of Horizontally Aligned Single-Walled Carbon Nanotubes Grown performance FETs. In this study, we examined the effect of gas pressures on the growth process of horizontally grown by alcohol CVD method[5] using ethanol as a carbon source gas at different gas pressures. SWCNTs

  3. Elasticity of ideal single-walled carbon nanotubes via symmetry-adapted tight-binding objective modeling

    E-print Network

    Dumitrica,Traian

    Elasticity of ideal single-walled carbon nanotubes via symmetry-adapted tight-binding objective 2008; published online 25 July 2008 The elastic response for a large catalog of carbon nanotubes for the helical and angular symmetries exhibited by the elastically deformed nanotubes. The elasticity

  4. ADSORPTION OF TETRACYCLINE ON SINGLE-WALLED AND MULTI-WALLED CARBON NANOTUBES AS AFFECTED BY AQUEOUS SOLUTION CHEMISTRY

    E-print Network

    Alvarez, Pedro J.

    ADSORPTION OF TETRACYCLINE ON SINGLE-WALLED AND MULTI-WALLED CARBON NANOTUBES AS AFFECTED on the adsorption of tetracycline to carbon nanotubes. Specifically, the effects of ionic strength (NaCl and CaCl2) and presence of Cu2þ ion (7.5 mg/L) or dissolved soil or coal humic acids (50 mg/L) on adsorption

  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. Chemical engineering of the single-walled carbon nanotube-nylon 6 interface.

    PubMed

    Gao, Junbo; Zhao, Bin; Itkis, Mikhail E; Bekyarova, Elena; Hu, Hui; Kranak, Verina; Yu, Aiping; Haddon, Robert C

    2006-06-14

    We report an approach to the chemical engineering of the single-walled carbon nanotube (SWNT)-polymer interfacial interaction in a nylon 6 graft copolymer composite which is based on the degree of SWNT functionality. Continuous fibers are drawn from composites fabricated from the in situ polymerization of caprolactam with SWNTs possessing a range of carboxylic acid (SWNT-COOH) and amide (SWNT-CONH(2)) functionalities. Mechanical performance evaluation of the composite fibers shows that a high concentration of the carboxylic acid functional groups leads to a stronger SWNT-nylon interfacial interaction, as reflected in greater values of the Young's modulus and mechanical strength. Replacement of the COOH group by CONH(2) in the SWNT starting material changes the grafting polymerization chemistry, thereby leading to the covalent attachment of longer graft copolymer chains to the SWNTs, and alters the composite morphology while increasing the composite flexibility and toughness. PMID:16756303

  7. Selectivity of water-soluble proteins in single-walled carbon nanotube dispersions

    NASA Astrophysics Data System (ADS)

    Matsuura, Koji; Saito, Takeshi; Okazaki, Toshiya; Ohshima, Satoshi; Yumura, Motoo; Iijima, Sumio

    2006-10-01

    Proteins were screened by preparing dispersions of SWNTs to investigate the driving force of the interaction between single-walled carbon nanotubes (SWNTs) of mean diameter 1 nm and water-soluble proteins. Egg white lysozyme (LYS) and bovine serum albumin (BSA) dispersed SWNTs, whereas papain and pepsin could not. Far-UV circular dichroism spectra indicated that the LYS and BSA molecules that coat SWNT surfaces were partially denatured. From the amino acid composition, we ascribed the main driving force to the hydrophobic interactions between the side-wall of the SWNT and the inner hydrophobic domain exposed to the solvent during the three-dimensional change of the protein induced by sonication.

  8. Transport properties of single-walled carbon nanotube transistors after gamma radiation treatment

    NASA Astrophysics Data System (ADS)

    Vitusevich, S. A.; Sydoruk, V. A.; Petrychuk, M. V.; Danilchenko, B. A.; Klein, N.; Offenhäusser, A.; Ural, A.; Bosman, G.

    2010-03-01

    Single-walled carbon nanotube field-effect transistors (CNT-FETs) were characterized before and after gamma radiation treatment using noise spectroscopy. The results obtained demonstrate that in long channel CNT-FETs with a length of 10 ?m the contribution of contact regions can be neglected. Moreover, radiation treatment with doses of 1×106 and 2×106 rad allows a considerable decrease parallel to the nanotube parasitic conductivity and even the shift region with maximal conductivity to the voltage range of nearly zero gate voltage that improves the working point of the FETs. The Hooge parameters obtained before and after gamma radiation treatment with a dose of 1×106 rad are found to be about 5×10-3. The parameters are comparable with typical values for conventional semiconductors.

  9. Charge trapping in aligned single-walled carbon nanotube arrays induced by ionizing radiation exposure

    SciTech Connect

    Esqueda, Ivan S.; Cress, Cory D.; Che, Yuchi; Cao, Yu; Zhou, Chongwu

    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.

  10. Structural and mechanical properties of single-wall carbon nanotube fibers

    SciTech Connect

    Pichot, V.; Albouy, P. A.; Launois, P.; Badaire, S.; Zakri, C.; Poulin, P.

    2006-12-15

    We report quantitative experimental study correlating the structure and mechanical properties of fibers made from single-walled carbon nanotubes (SWNTs) and polyvinyl alcohol (PVA). A post-synthesis solvent drawing treatment is used to vary nanotube alignment, whose detailed understanding is a prerequisite for fiber development. Quantitative analysis of nanotube alignment within the fibers with different draw ratios is performed using x-ray scattering. The method is described in detail, and we also show that the improvement of nanotube alignment with draw ratio can be understood within a model of induced orientation at constant volume. Young's modulus and tensile strength increase with nanotube alignment. This is modeled using continuum mechanics in qualitative agreement with experiment, however quantitative differences show that nanotube alignment is not the only parameter controlling the fiber mechanical properties. We suggest that interaction between the SWNTs and PVA chains should also play a significant role.

  11. Single-walled carbon nanotube sensors for monitoring partial discharge induced dissociation of SF6.

    PubMed

    Jung, Sehun; Choi, Jaeboong; Kim, Youngjin; Lee, Jongchul; Chang, Yongmoo; Baik, Seunghyun

    2009-12-01

    We proposed to use a miniature single-walled carbon nanotube (SWNT) sensor, fabricated by alternating current dielectrophoresis, to detect dissociated and oxidized sulfur hexafluoride (SF6) gas species generated by partial discharge (PD) activity in a concealed chamber such as gas-insulated switchgear (GIS). The SWNT sensor did not react with pure SF6 gas but sensitively responded to the dissociated and oxidized SF6 species. Also, the SWNT sensor could be regenerated by purging with fresh air since the transduction was based on the physisorption of analytes. Therefore, the SWNT sensor is a promising device for the detection of the dissociated and oxidized SF6 species and for the monitoring of the PD activity inside GIS. PMID:19908783

  12. Adhesion energy of single wall carbon nanotube loops on various substrates

    SciTech Connect

    Li, Tianjun; Ayari, Anthony; Bellon, Ludovic

    2015-04-28

    The physics of adhesion of one-dimensional nano structures such as nanotubes, nano wires, and biopolymers on different substrates is of great interest for the study of biological adhesion and the development of nano electronics and nano mechanics. In this paper, we present force spectroscopy experiments of individual single wall carbon nanotube loops using a home-made interferometric atomic force microscope. Characteristic force plateaus during the peeling process allow the quantitative measurement of the adhesion energy per unit length on various substrates: graphite, mica, platinum, gold, and silicon. Moreover, using a time-frequency analysis of the deflection of the cantilever, we estimate the dynamic stiffness of the contact, providing more information on the nanotube configurations and its intrinsic mechanical properties.

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

    PubMed Central

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

    2015-01-01

    Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the ?-? stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwhile its forming time is related to helical angle. The simulated threshold of GNRs in SWCNT decreases with GNR width but increases with SWCNT diameter, and two formulas have come up in this study to estimate the quantity threshold for GNRs. It has been found that multilayered graphite is hard to be stripped in SWCNT because the special helical configuration with incompletely separated GNRs is metastable. This work provides a possibility to control the configuration of GNR@SWCNT. PMID:26374276

  14. Sensing Reversible Protein–Ligand Interactions with Single-Walled Carbon Nanotube Field-Effect Transistors

    PubMed Central

    2015-01-01

    We report on the reversible detection of CaptAvidin, a tyrosine modified avidin, with single-walled carbon nanotube (SWNT) field-effect transistors (FETs) noncovalently functionalized with biotin moieties using 1-pyrenebutyric acid as a linker. Binding affinities at different pH values were quantified, and the sensor’s response at various ionic strengths was analyzed. Furthermore, protein “fingerprints” of NeutrAvidin and streptavidin were obtained by monitoring their adsorption at several pH values. Moreover, gold nanoparticle decorated SWNT FETs were functionalized with biotin using 1-pyrenebutyric acid as a linker for the CNT surface and (±)-?-lipoic acid linkers for the gold surface, and reversible CaptAvidin binding is shown, paving the way for potential dual mode measurements with the addition of surface enhanced Raman spectroscopy (SERS). PMID:25126155

  15. Optical and thermal response of single-walled carbon nanotube-copper sulfide nanoparticle hybrid nanomaterials.

    PubMed

    Tseng, Yi-Hsuan; He, Yuan; Lakshmanan, Santana; Yang, Chang; Chen, Wei; Que, Long

    2012-11-16

    This paper reports the optical and thermal response of a single-walled carbon nanotube-copper sulfide nanoparticle (SWNT-CuS NP) hybrid nanomaterial and its application as a thermoelectric generator. The hybrid nanomaterial was synthesized using oleylamine molecules as the linker molecules between SWNTs and CuS NPs. Measurements found that the hybrid nanomaterial has significantly increased light absorption (up to 80%) compared to the pure SWNT. Measurements also found that the hybrid nanomaterial thin-film devices exhibit a clear optical and thermal switching effect, which can be further enhanced up to 10 ×  by asymmetric illumination of light and thermal radiation on the thin-film devices instead of symmetric illumination. A simple prototype thermoelectric generator enabled by the hybrid nanomaterials is demonstrated, indicating a new route for achieving thermoelectricity. PMID:23089651

  16. Laser images recording on aerosol-synthesized single-walled carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Mikheev, G. M.; Mikheev, K. G.; Anoshkin, I. V.; Nasibulin, A. G.

    2015-09-01

    It is shown that images on semitransparent conducting films of aerosol-synthesized single-walled carbon nanotubes (SWCNTs) can be recorded using focused low-power radiation of a He-Ne laser operating at a wavelength of 632.8 nm. Both free-standing films and those deposited on glass or polymer substrates can be used. Laser recording of images on the polymer-supported films is possible due to their transparency increased as a result of chemical reactions between iron nanoparticles encapsulated in SWCNTs and the products of local thermal decomposition of the polymer. Recording on the free-standing SWCNT films and those supported on glass substrates was performed upon acid treatment of the film surface.

  17. Improved conductivity of transparent single-wall carbon nanotube thin films via stable postdeposition functionalization

    NASA Astrophysics Data System (ADS)

    Parekh, Bhavin B.; Fanchini, Giovanni; Eda, Goki; Chhowalla, Manish

    2007-03-01

    A simple postdeposition method for improving the conductivity of transparent and conducting single-wall carbon nanotube (SWNT) thin films via exposure to nitric acid and thionyl chloride is reported. A systematic study on a range of films of variable density and from different commercial sources of SWNTs is performed. The functionalized films possess sheet resistances as low as that of indium tin oxide (ITO) (˜30?/?) albeit at lower transmittance (˜50%). At 80±5% transmittance, the functionalized films have resistance values ranging from 150to300?/?. The SWNT films, however, are more flexible than ITO. The stability of the functionalized films upon annealing and processing in solvents (water, methanol, and chloroform) is also reported.

  18. Detection of Sugar-Lectin Interactions by Multivalent Dendritic Sugar Functionalized Single-Walled Carbon Nanotubes

    E-print Network

    Vasu, K S; Bagul, R S; Jayaraman, N; Sood, A K; 10.1063/1.4739793

    2012-01-01

    We show that single walled carbon nanotubes (SWNT) decorated with sugar functionalized poly (propyl ether imine) (PETIM) dendrimer is a very sensitive platform to quantitatively detect carbohydrate recognizing proteins, namely, lectins. The changes in electrical conductivity of SWNT in field effect transistor device due to carbohydrate - protein interactions form the basis of present study. The mannose sugar attached PETIM dendrimers undergo charge - transfer interactions with the SWNT. The changes in the conductance of the dendritic sugar functionalized SWNT after addition of lectins in varying concentrations were found to follow the Langmuir type isotherm, giving the concanavalin A (Con A) - mannose affinity constant to be 8.5 x 106 M-1. The increase in the device conductance observed after adding 10 nM of Con A is same as after adding 20 \\muM of a non - specific lectin peanut agglutinin, showing the high specificity of the Con A - mannose interactions. The specificity of sugar-lectin interactions was chara...

  19. Adhesion energy of single wall carbon nanotube loops on various substrates

    NASA Astrophysics Data System (ADS)

    Li, Tianjun; Ayari, Anthony; Bellon, Ludovic

    2015-04-01

    The physics of adhesion of one-dimensional nano structures such as nanotubes, nano wires, and biopolymers on different substrates is of great interest for the study of biological adhesion and the development of nano electronics and nano mechanics. In this paper, we present force spectroscopy experiments of individual single wall carbon nanotube loops using a home-made interferometric atomic force microscope. Characteristic force plateaus during the peeling process allow the quantitative measurement of the adhesion energy per unit length on various substrates: graphite, mica, platinum, gold, and silicon. Moreover, using a time-frequency analysis of the deflection of the cantilever, we estimate the dynamic stiffness of the contact, providing more information on the nanotube configurations and its intrinsic mechanical properties.

  20. Induced hydroelectric energy generated by compressing a single-walled carbon nanotube hydrogel

    NASA Astrophysics Data System (ADS)

    Tan, Zhenquan; Yamamoto, Kazuhiro; Qiu, Nan; Hashishin, Takeshi; Ohara, Satoshi

    2014-07-01

    Using single-walled carbon nanotubes (SWCNTs) for energy harvesting and storage have attracted much attention recently because SWCNTs have supercapacity performance. In this paper, we report a simple electromechanical approach for the generation of induced electrical potential by the compression of a SWCNT-triggered sodium deoxycholate hydrogel. This hydrogel enhances the electrical potential generated under compression, and this is mainly because of the generation of hydroelectric power by the flow of water over the SWCNTs. The induced voltage was 63.1 mV upon the compression of a 4% SWCNT hydrogel to a compression ratio of 50%, which is superior to values reported previously. The enhancement in hydroelectric potential increased with SWCNT loading in the hydrogel and with the compression ratio because of an enhancement of the impact frequency between water molecules and the SWCNTs.

  1. Photophysical properties of zinc phthalocyanine-uridine single walled carbon nanotube--conjugates.

    PubMed

    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. PMID:25965170

  2. Functionalization of individual ultra-short single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ashcroft, Jared M.; Hartman, Keith B.; Mackeyev, Yuri; Hofmann, Cristina; Pheasant, Sean; Alemany, Lawrence B.; Wilson, Lon J.

    2006-10-01

    We report the functionalization of individual ultra-short (20-80 nm lengths) single-walled carbon nanotubes (US-tubes) via in situ Bingel cyclopropanation. Upon chemical reduction (K°/THF) of bundled US-tubes, the bundling forces are electrostatically overcome to yield single, negatively charged US-tubes in solution. These single US-tubes can then be functionalized with malonic acid bis-(3-tert-butoxycarbonylaminopropyl) ester using Bingel chemistry (CBr4/DBU) to yield 4-5 adducts nm-1, as determined by x-ray photoelectron spectroscopy (XPS). The derivatized US-tubes remain as individuals after functionalization and charge quenching. Thermogravimetric analysis (TGA) and solid-state NMR spectroscopy confirmed covalent attachment of the adducts and indicated tight wrapping of the adduct arms about the US-tubes. The resulting debundled and derivatized US-tubes serve as a prototype single-molecule-like 'capsule' for the containment and delivery of medically-useful payloads.

  3. Photoemission study of the electronic structure of azafullerene encapsulated single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yagi, Hajime; Tokumoto, Youji; Zenki, Masashi; Zaima, Takeyuki; Miyazaki, Takafumi; Rotas, Georgios; Tagmatarchis, Nikos; Iizumi, Yoko; Okazaki, Toshiya; Hino, Shojun

    2013-05-01

    We performed the ultraviolet photoemission spectroscopy study of single-walled carbon nanotubes (SWCNTs) encapsulating C59N. The work function of the C59N@SWCNT is estimated to be larger than that of the SWCNT. The ? states of the SWCNT shift toward the Fermi level upon encapsulation of C59N. The C59N pea spectrum is roughly similar to that of the (C59N)2, but some peaks shift. The results suggest a small charge transfer from the SWCNT to the C59N pea, which is in contrast to the previously reported n-type FET characteristics. This discrepancy is probably due to the difference in the molecular form of C59N.

  4. Novel Materials Containing Single-Wall Carbon Nanotubes Wrapped in Polymer Molecules

    NASA Technical Reports Server (NTRS)

    Smalley, Richard E.; O'Connell, Michael J.; Smith, Kenneth; Colbert, Daniel T.

    2009-01-01

    In this design, single-wall carbon nanotubes (SWNTs) have been coated in polymer molecules to create a new type of material that has low electrical conductivity, but still contains individual nanotubes, and small ropes of individual nanotubes, which are themselves good electrical conductors and serve as small conducting rods immersed in an electrically insulating matrix. The polymer is attached through weak chemical forces that are primarily non-covalent in nature, caused primarily through polarization rather than the sharing of valence electrons. Therefore, the electronic structure of the SWNT involved is substantially the same as that of free, individual (and small ropes of) SWNT. Their high conductivity makes the individual nanotubes extremely electrically polarizable, and materials containing these individual, highly polarizable molecules exhibit novel electrical properties including a high dielectric constant.

  5. Biointerfacial Property of Plasma-Treated Single-Walled Carbon Nanotube Film Electrodes for Electrochemical Biosensors

    NASA Astrophysics Data System (ADS)

    Hyub Kim, Joon; Lee, Jun-Yong; Jin, Joon-Hyung; Park, Eun Jin; Min, Nam Ki

    2013-01-01

    The single-walled carbon nanotube (SWCNT)-based thin film was spray-coated on the Pt support and functionalized using O2 plasma. The effects of plasma treatment on the biointerfacial properties of the SWCNT films were analyzed by cyclic voltammogram (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The plasma-functionalized (pf) SWCNT electrodes modified with Legionella pneumophila-specific probe DNA strands showed a much higher peak current and a smaller peak separation in differential pulse voltammetry and a lower charge transfer resistance, compared to the untreated samples. These results suggest that the pf-SWCNT films have a better electrocatalytic character and an electron transfer capability faster than the untreated SWCNTs, due to the fact that the oxygen-containing functional groups promote direct electron transfer in the biointerfacial region of the electrocatalytic activity of redox-active biomolecules.

  6. Plasma-Etching of Spray-Coated Single-Walled Carbon Nanotube Films for Biointerfaces

    NASA Astrophysics Data System (ADS)

    Kim, Joon Hyub; Lee, Jun-Yong; Min, Nam Ki

    2012-08-01

    We present an effective method for the batch fabrication of miniaturized single-walled carbon nanotube (SWCNT) film electrodes using oxygen plasma etching. We adopted the approach of spray-coating for good adhesion of the SWCNT film onto a pre-patterned Pt support and used O2 plasma patterning of the coated films to realize efficient biointerfaces between SWCNT surfaces and biomolecules. By these approaches, the SWCNT film can be easily integrated into miniaturized electrode systems. To demonstrate the effectiveness of plasma-etched SWCNT film electrodes as biointerfaces, Legionella antibody was selected as analysis model owing to its considerable importance to electrochemical biosensors and was detected using plasma-etched SWCNT film electrodes and a 3,3',5,5'-tetramethyl-benzidine dihydrochloride/horseradish peroxidase (TMB/HRP) catalytic system. The response currents increased with increasing concentration of Legionella antibody. This result indicates that antibodies were effectively immobilized on plasma-etched and activated SWCNT surfaces.

  7. Effects of electron exchange-correlation potential on electrostatic oscillations in single-walled carbon nanotubes

    SciTech Connect

    Khan, S. A. Hassan, Sunia

    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.

  8. Synthesis and characterization of long strands of nitrogen-doped single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Villalpando-Paez, F.; Zamudio, A.; Elias, A. L.; Son, H.; Barros, E. B.; Chou, S. G.; Kim, Y. A.; Muramatsu, H.; Hayashi, T.; Kong, J.; Terrones, H.; Dresselhaus, G.; Endo, M.; Terrones, M.; Dresselhaus, M. S.

    2006-06-01

    We describe the synthesis of N-doped single-walled carbon nanotubes (N-SWNTs), that agglomerate in bundles and form long strands (<10 cm), via the thermal decomposition of ferrocene/ethanol/benzylamine (FEB) solutions in an Ar atmosphere at 950 °C. The amount of benzylamine in the solution was varied from 0% to 26% by weight. Using Raman spectroscopy, we noted that as the N content is increased in the starting FEB solution, the growth of large diameter tubes is inhibited. We observed that the relative electrical conductivity of the strands increases with increasing nitrogen concentration. Thermogravimetric analysis (TGA) showed novel features for highly doped tubes that are related to chemical reactions on N sites.

  9. 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.

  10. Optical characterization of highly conductive single-wall carbon-nanotube transparent electrodes

    NASA Astrophysics Data System (ADS)

    Barnes, T. M.; van de Lagemaat, J.; Levi, D.; Rumbles, G.; Coutts, T. J.; Weeks, C. L.; Britz, D. A.; Levitsky, I.; Peltola, J.; Glatkowski, P.

    2007-06-01

    We report on a complete characterization of the optical dispersion properties of conducting thin films of single-wall carbon nanotubes (SWCNTs). The films studied exhibit sheet resistances between 50 and 1000?/sq and optical transparencies between 65% and 95% on glass and quartz substrates. These films have the potential to replace transparent conducting oxides in applications such as photovoltaics and flat-panel displays; however, their optical properties are not sufficiently well understood. The SWCNT films are shown to be hole conductors, potentially enabling their use as hole-selective contacts and allowing alternative device designs. The fundamental optical, morphological, and electrical characteristics of the films are presented here, and a phenomenological optical model that accurately describes the optical behavior of the films is introduced. Particular attention is paid to ellipsometry measurements and thorough evaluation of the reflection and absorption spectra of the films.

  11. Effects of Single Walled Carbon Nanotubes on the Electroluminescent Performance of Organic Light-emitting Diodes

    SciTech Connect

    Wong, S.S.; Shao, M.; Garrett, M.P.; Xu, X.; Ivanov, I.N.; Hu, B.

    2011-06-01

    Effects of single walled carbon nanotubes (SWNTs) on the electroluminescent performance of organic light-emitting diodes (OLEDs) have been investigated by mixing them in a hole-conducting layer and in a light-emitting layer in OLEDs. We found that SWNTs play different roles when used as polymer:SWNT composites in OLEDs. When used in a hole-conducting layer, SWNTs facilitate the charge transport in the transport layer and on the other hand they also act as the exciton quenching centers at the transporting/emitting interface provided their concentration is high enough. When used in a light-emitting layer, SWNTs act as an n-type dopant to increase electron transport in p-type electroluminescent film and subsequently improve the balancing degree of bipolar injection, leading to an enhancement in the electroluminescence efficiency.

  12. Molecular interactions on single-walled carbon nanotubes revealed by high-resolution transmission microscopy

    PubMed Central

    Umeyama, Tomokazu; Baek, Jinseok; Sato, Yuta; Suenaga, Kazu; Abou-Chahine, Fawzi; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

    2015-01-01

    The close solid-state structure–property relationships of organic ??aromatic molecules have attracted interest due to their implications for the design of organic functional materials. In particular, a dimeric structure, that is, a unit consisting of two molecules, is required for precisely evaluating intermolecular interactions. Here, we show that the sidewall of a single-walled carbon nanotube (SWNT) represents a unique molecular dimer platform that can be directly visualized using high-resolution transmission electron microscopy. Pyrene is chosen as the ??aromatic molecule; its dimer is covalently linked to the SWNT sidewalls by aryl addition. Reflecting the orientation and separation of the two molecules, the pyrene dimer on the SWNT exhibits characteristic optical and photophysical properties. The methodology discussed here—form and probe molecular dimers—is highly promising for the creation of unique models and provides indispensable and fundamental information regarding molecular interactions. PMID:26173983

  13. Nonlocal continuum model and molecular dynamics for free vibration of single-walled carbon nanotubes.

    PubMed

    Hu, Yan-Gao; Liew, K M; Wang, Q

    2011-12-01

    Free transverse, longitudinal and torsional vibrations of single-walled carbon nanotubes (SWCNTs) are investigated through nonlocal beam model, nonlocal rod model and verified by molecular dynamics (MD) simulations. The nonlocal Timoshenko beam model offers a better prediction of the fundamental frequencies of shorter SWCNTs, such as a (5, 5) SWCNT shorter than 3.5 nm, than local beam models. The nonlocal rod model is employed to study the longitudinal and torsional vibrations of SWCNT and found to enable a good prediction of the MD results for shorter SWCNTs. Nonlocal and local continuum models provide a good agreement with MD results for relatively longer SWCNTs, such as (5, 5) SWCNTs longer than 3.5 nm. The scale parameter in nonlocal beam and rod models is estimated by calibrations from MD results. PMID:22408916

  14. Passively Q-switching induced by the smallest single-walled carbon nanotubes

    SciTech Connect

    Xu, X. T.; Zhai, J. P.; Wang, J. S.; Chen, Y. P.; Yu, Y. Q.; Zhang, M.; Li, I. L.; Ruan, S. C.; Tang, Z. K.

    2014-04-28

    We report a passively Q-switched erbium-doped fiber laser (EDFL) by using the smallest single-walled carbon nanotubes (SWNTs) with a diameter of 0.3?nm as the saturable absorber. These small SWNTs are fabricated in the nanochannels of a ZnAPO-11 (AEL) single crystal. By inserting one of the AEL crystal into an EDFL cavity pumped by a 980?nm laser diode, stable passive Q-switching is achieved for a threshold pump power of 206.2 mW, and 4.73??s pulses with a repetition rate of 41.78?kHz and an average output power of 3.75 mW are obtained for a pump power of 406 mW.

  15. Fabrication of single-walled carbon nanohorns containing iodine and cesium

    NASA Astrophysics Data System (ADS)

    Cho, J. H.; Lim, S. T.; Huh, S. R.; Kim, G. H.

    2012-02-01

    Iodine and cesium atoms were encapsulated in single-walled carbon nanohorns (SWCNHs). Atom encapsulation was carried out with sequential plasma aided procedures which consisted of opening SWCNH tips with an oxygen plasma, atom insertion in an iodine-mixed or cesium-mixed argon plasma, and closing the open tip in an argon plasma. Results reveal that oxidation plays a role in the tip opening procedure, and capillary forces are the driving force for the permeation of the atoms through the open tip of the SWCNHs. The open tip of the atom inserted SWCNH can be closed under the ion irradiation. It demonstrated the fabrication process of encapsulating atoms in SWCNH by using the sequential plasma assisted processes.

  16. Non-radiative Exciton Decay in Single-walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Harrah, Mark; Swan, Anna

    2010-03-01

    Experiments have shown step-wise changes in the fluorescence intensity from single-walled carbon nanotubes [1,2]. It has been proposed that the underlying mechanism for the step-wise changes is diffusion-limited quenching of excitons at defects [1]. This property has been used to demonstrate single-molecule detection for biological applications [3]. We perform a Monte-Carlo simulation of nanotube fluorescence with a diffusion-limited quenching model. The fluorescence intensity is seen to depend on the mean-square distance between defects, implying a nonlinear dependence on the number of defects. The intensity for consecutive defect counts can overlap depending on the positions of the defects. [4pt] [1] Cognet, L. et al. Science 316, 1465-1468 (2007).[0pt] [2] Jin, H. et al. Nano Lett. 8, 4299-4304 (2008).[0pt] [3] Heller, D. A. et al. Nature Nanotech. 4, 114-120 (2009).

  17. Diameter Dependence of Lattice Thermal Conductivity of Single-Walled Carbon Nanotubes: Study from Ab Initio

    PubMed Central

    Yue, Sheng-Ying; Ouyang, Tao; Hu, Ming

    2015-01-01

    The effects of temperature, tube length, defects, and surface functionalization on the thermal conductivity (?) of single-walled carbon nanotubes (SWCNTs) were well documented in literature. However, diameter dependence of thermal conductivity of SWCNTs received less attentions. So far, diverse trends of the diameter dependence have been discussed by different methods and all the previous results were based on empirical interatomic potentials. In this paper, we emphasize to clarify accurate ? values of SWCNTs with different diameters and in-plane ? of graphene. All the studies were under the framework of anharmonic lattice dynamics and Boltzmann transport equation (BTE) based on first principle calculations. We try to infer the right trend of diameter dependent thermal conductivity of SWCNTs. We infer that graphene is the limitation as SWCNT with an infinite diameter. We analyzed the thermal conductivity contributions from each phonon mode in SWCNTs to explain the trend. Meanwhile, we also identify the extremely low thermal conductivity of ultra-thin SWCNTs. PMID:26490342

  18. 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.

  19. 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

  20. Thermal vibration of single-walled carbon nanotubes with quantum effects

    PubMed Central

    Wang, Lifeng; Hu, Haiyan

    2014-01-01

    The thermal vibration of a single-walled carbon nanotube (SWCNT) is investigated by using the models of Euler beam and Timoshenko beam with quantum effects taken into consideration when the law of energy equipartition is unreliable. The relation between temperature and the root of mean-squared (RMS) amplitude of thermal vibration at any cross section of the SWCNT is derived via the beam models in simply supported case and cantilevered case. The RMS amplitude of thermal vibration of SWCNT predicted by using Timoshenko beam is higher than that predicted by using Euler beam. The RMS amplitude of thermal vibration of an SWCNT predicted by the quantum theory is lower than that predicted by the law of energy equipartition. The quantum effect is more important for the thermal vibration of an SWCNT in the cases of higher-order modes, short length and low temperature. PMID:25104907

  1. Sound wave propagation in single-walled carbon nanotubes with initial axial stress

    NASA Astrophysics Data System (ADS)

    Heireche, H.; Tounsi, A.; Benzair, A.; Mechab, I.

    2008-07-01

    This paper studies the vibrational characteristics of single-walled carbon nanotubes (SWNTs) with initial axial loading based on the theory of nonlocal elasticity. The consistent equations of motion for the nonlocal Euler-Bernoulli and Timoshenko beam models are provided taking into account the initial axial stress. The small scale effect on CNT wave propagation dispersion relation is explicitly revealed for different CNT wave numbers and diameters by theoretical analyses and numerical simulations. In addition, the applicability of the two beam models is explored by numerical simulations. The research work reveals the significance of the effects of small scale, transverse shear deformation and rotary inertia on wave propagation in short SWCNTs with initial axial loading.

  2. Indium Oxide-Single-Walled Carbon Nanotube Composite for Ethanol Sensing at Room Temperature.

    PubMed

    Ellis, James E; Green, Uri; Sorescu, Dan C; Zhao, Yong; Star, Alexander

    2015-02-19

    Utilizing a sol-gel synthesis, indium oxide is grown on the surface of oxidized single-walled carbon nanotubes (SWCNT) to form a hybrid material with high conductivity and sensitivity toward certain organic vapors. The room-temperature sensing of dilute ethanol and acetone vapors on the surface of indium oxide/SWCNT hybrid material is studied using electrical conductance experiments in a nonoxidizing environment. Through testing of variously calcinated materials, it was observed that the degree of annealing greatly affects the material's response to acetone and ethanol, such that the intermediate calcination condition yields the best sensitivity. DFT simulations are used to study the interface between defective SWCNT and indium oxide, as well as the interaction between ethanol and acetone molecules with the indium oxide/SWCNT hybrid material. PMID:26262491

  3. Photoinduced transient mid-infrared absorption in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Murakami, Yoichi; Rice, William; Kono, Junichiro

    2007-03-01

    We have performed optical pump - mid-infrared (MIR) probe spectroscopy on single-walled carbon nanotubes (SWNTs). The second excitonic absorption band (E22) of (6,5) SWNTs was resonantly excited and the resulting photoinduced absorption was monitored in the MIR range (3.5 -- 5.5 ?m) in a time range up to several hundred ps. Carrageenan films containing individualized CoMoCAT SWNTs formed on sapphire substrates were used for the measurement. This sample is optically transparent in the ˜3.5 -- 6 ?m region, where the transition of E11 excitons from the lowest dark state (1g) to the second bright state (2u) is expected to be observed. Our preliminary data shows the existence of photoinduced absorption in the investigated range. The origin of the observed transient absorption will be discussed.

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

    PubMed Central

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

    2012-01-01

    This study presents a novel flexible strain sensor for real-time strain sensing. The material for strain sensing is single-walled carbon nanonets, grown using the alcohol catalytic chemical vapor deposition method, that were encapsulated between two layers of Parylene-C, with a polyimide layer as the sensing surface. All of the micro-fabrication was compatible with the standard IC process. Experimental results indicated that the gauge factor of the proposed strain sensor was larger than 4.5, approximately 2.0 times greater than those of commercial gauges. The results also demonstrated that the gauge factor is small when the growth time of SWCNNs is lengthier, and the gauge factor is large when the line width of the serpentine pattern of SWCNNs is small. PMID:22737007

  5. Predicting excitonic gaps of semiconducting single-walled carbon nanotubes from a field theoretic analysis

    SciTech Connect

    Konik, Robert M.; Sfeir, Matthew Y.; Misewich, James A.

    2015-02-17

    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. As a result, we 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.

  6. 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.

    2015-02-17

    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. Asmore »a result, we 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

  7. Preparation and Properties of Nanocomposites Prepared From Shortened, Functionalized Single-Walled Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Smith, J. G., Jr.; Delozier, D. M.; Watson, K. A.; Connell, J. W.; Yu, Aiping; Haddon, R. C.; Bekyarova, E.

    2006-01-01

    As part of a continuing materials development activity, low color space environmentally stable polymeric materials that possess sufficient electrical conductivity for electrostatic charge dissipation (ESD) have been investigated. One method of incorporating sufficient electrical conductivity for ESD without detrimental effects on other polymer properties of interest (i.e., optical and thermo-optical) is through the incorporation of single-walled carbon nanotubes (SWNTs). However, SWNTs are difficult to fully disperse in the polymer matrix. One means of improving dispersion is by shortening and functionalizing SWNTs. While this improves dispersion, other properties (i.e., electrical) of the SWNTs can be affected which can in turn alter the final nanocomposite properties. Additionally, functionalization of the polymer matrix can also influence nanocomposite properties obtained from shortened, functionalized SWNTs. The preparation and characterization of nanocomposites fabricated from a polyimide, both functionalized and unfunctionalized, and shortened, functionalized SWNTs will be presented.

  8. Fabrication of single-walled carbon nanohorns containing iodine and cesium

    SciTech Connect

    Cho, J. H.; Lim, S. T.; Huh, S. R.; Kim, G. H.

    2012-02-15

    Iodine and cesium atoms were encapsulated in single-walled carbon nanohorns (SWCNHs). Atom encapsulation was carried out with sequential plasma aided procedures which consisted of opening SWCNH tips with an oxygen plasma, atom insertion in an iodine-mixed or cesium-mixed argon plasma, and closing the open tip in an argon plasma. Results reveal that oxidation plays a role in the tip opening procedure, and capillary forces are the driving force for the permeation of the atoms through the open tip of the SWCNHs. The open tip of the atom inserted SWCNH can be closed under the ion irradiation. It demonstrated the fabrication process of encapsulating atoms in SWCNH by using the sequential plasma assisted processes.

  9. Enhanced electron field emission characteristics of single-walled carbon nanotube films by ultrasonic bonding

    NASA Astrophysics Data System (ADS)

    Liu, Xuan; Wu, Ying; Su, Yanjie; Zhao, Bo; Wang, Yarong; Liu, Chang; Zhang, Yafei

    2014-09-01

    A novel ultrasonic bonding process was used to fabricate the electron field emission cathode of single-walled nanotube film, which was deposited on an Al plate substrate by electrophoretic deposition. Electron field emission properties were improved remarkably after the cathode carbon nanotubes nanobonded with the Al substrate. Turn-on voltage showed a significant decrease and the emission current was much stabilized. This can be attributed to the reduction of the contact resistance in bonding area and easily moving electrons for field emission after ultrasonic bonding. In addition, the field emission performances of SWCNTs films formed at different bonding conditions were also studied. With a simple nano-bonding apparatus, this technique has low cost, and can be utilized for extensively roboticized fabrication of high performance field emission cathodes with short process time.

  10. 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.

  11. Diameter Dependence of Lattice Thermal Conductivity of Single-Walled Carbon Nanotubes: Study from Ab Initio

    NASA Astrophysics Data System (ADS)

    Yue, Sheng-Ying; Ouyang, Tao; Hu, Ming

    2015-10-01

    The effects of temperature, tube length, defects, and surface functionalization on the thermal conductivity (?) of single-walled carbon nanotubes (SWCNTs) were well documented in literature. However, diameter dependence of thermal conductivity of SWCNTs received less attentions. So far, diverse trends of the diameter dependence have been discussed by different methods and all the previous results were based on empirical interatomic potentials. In this paper, we emphasize to clarify accurate ? values of SWCNTs with different diameters and in-plane ? of graphene. All the studies were under the framework of anharmonic lattice dynamics and Boltzmann transport equation (BTE) based on first principle calculations. We try to infer the right trend of diameter dependent thermal conductivity of SWCNTs. We infer that graphene is the limitation as SWCNT with an infinite diameter. We analyzed the thermal conductivity contributions from each phonon mode in SWCNTs to explain the trend. Meanwhile, we also identify the extremely low thermal conductivity of ultra-thin SWCNTs.

  12. Attachment of Single-wall Carbon Nanotubes (SWNTs) on Platinum Surfaces by Self-Assembling Techniques

    NASA Technical Reports Server (NTRS)

    Rosario-Castro, Belinda I.; Cabrera, Carlos R.; Perez-Davis, Maria; Lebron, Marisabel; Meador, Michael

    2003-01-01

    Single-wall carbon nanotubes (SWNTs) are very interesting materials because of their morphology, electronic and mechanical properties. Its morphology (high length-to-diameter ratio) and electronic properties suggest potential application of SWNTs as anode material for lithium ion secondary batteries. The introduction of SWNTs on these types of sources systems will improve their performance, efficiency, and capacity to store energy. A purification method has been applied for the removal of iron and amorphous carbon from the nanotubes. Unpurified and purified SWNTs were characterized by transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). In order to attach carbon nanotubes on platinum electrode surfaces, a self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) was deposited over the electrodes. The amino-terminated SAM obtained was characterized by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), and Fourier-transforms infrared (FTIR) spectroscopy. Carbon nanotubes were deposited over the amino-terminated SAM by an amide bond formed between SAM amino groups and carboxylic acid groups at the open ends of the carbon nanotubes.This deposition was characterized using Raman spectroscopy and Scanning Electron microscopy (SEM).

  13. [Study on single-walled carbon nanotube thin film photoelectric device].

    PubMed

    Xie, Wen-bin; Zhu, Yong; Gong, Tian-cheng; Chen, Yu-lin; Zhang, Jie

    2015-01-01

    The single-walled carbon nanotube film photoelectric device was invented, and it can generate net photocurrent under bias voltage when it is illuminated by the laser. The influences of bias voltage, laser power and illuminating position on the net photocurrent were investigated. The experimental results showed that when the center of the film was illuminated, the photocurrent increased with the applied bias, but tended to saturate as the laser power increased. As the voltage and the laser power reached 0. 2 V and 22. 7 mW respectively, the photocurrent reached 0. 24 µA. When the voltage was removed, the photocurrent varied with the laser illuminating position on the film and its value was distributed symmetrically about the center of the device. The photocurrent reached maximum and almost zero respectively when the laser illuminated on two ends and the center of the film. Analysis proposes that the net photocurrent can be generated due to internal photoelectric effect when the device is under voltage and the laser illuminates on the center of the film. It can be also generated due to photo-thermoelectric effect when the device is under no voltage and the laser illuminates on the film, and the relation between the net photocurrent and the illuminating position was derived according to the nature of thermoelectric power of single-walled carbon nanotubes with the established temperature model, which coincides with experimental result. Two effects are the reasons for the generation and variety of the net photocurrent and they superimpose to form the result of the net photocurrent when the device is under general conditions of voltage and laser illuminating position. The device has potential applications in the areas of photovoltaic device and optical sensor for its characteristic. PMID:25993863

  14. Photoluminescence enhancement of aligned arrays of single-walled carbon nanotubes by polymer transfer

    NASA Astrophysics Data System (ADS)

    Schweiger, Manuel; Zakharko, Yuriy; Gannott, Florentina; Grimm, Stefan B.; Zaumseil, Jana

    2015-10-01

    The photoluminescence of as-grown, aligned single-walled carbon nanotubes (SWNTs) on quartz is strongly quenched and barely detectable. Here we show that transferring these SWNTs to another substrate such as clean quartz or glass increases their emission efficiency by up to two orders of magnitude. By statistical analysis of large nanotube arrays we show at what point of the transfer process the emission enhancement occurs and how it depends on the receiving substrate and the employed transfer polymer. We find that hydrophobic polystyrene (PS) as the transfer polymer results in higher photoluminescence enhancement than the more hydrophilic poly(methyl methacrylate) (PMMA). Possible mechanisms for this enhancement such as strain relief, disruption of the strong interaction of SWNTs with the substrate and localized emissive states are discussed.The photoluminescence of as-grown, aligned single-walled carbon nanotubes (SWNTs) on quartz is strongly quenched and barely detectable. Here we show that transferring these SWNTs to another substrate such as clean quartz or glass increases their emission efficiency by up to two orders of magnitude. By statistical analysis of large nanotube arrays we show at what point of the transfer process the emission enhancement occurs and how it depends on the receiving substrate and the employed transfer polymer. We find that hydrophobic polystyrene (PS) as the transfer polymer results in higher photoluminescence enhancement than the more hydrophilic poly(methyl methacrylate) (PMMA). Possible mechanisms for this enhancement such as strain relief, disruption of the strong interaction of SWNTs with the substrate and localized emissive states are discussed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05163k

  15. Pulsed ytterbium-doped fibre laser with a combined modulator based on single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Khudyakov, D. V.; Borodkin, A. A.; Lobach, A. S.; Vartapetov, S. K.

    2015-09-01

    This paper describes an all-normal-dispersion pulsed ytterbium-doped fibre ring laser mode-locked by a nonlinear combined modulator based on single-wall carbon nanotubes. We have demonstrated 1.7-ps pulse generation at 1.04 ?m with a repetition rate of 35.6 MHz. At the laser output, the pulses were compressed to 180 fs. We have examined an intracavity nonlinear modulator which utilises nonlinear polarisation ellipse rotation in conjunction with a saturable absorber in the form of a polymer-matrix composite film containing single-wall carbon nanotubes.

  16. Targeting single-walled carbon nanotubes for the treatment of breast cancer using photothermal therapy

    NASA Astrophysics Data System (ADS)

    Neves, Luis Filipe Ferreira

    To develop a therapeutic system with cancer cell selectivity, the present study evaluated a possible specific and localized tumor treatment. Phosphatidylserine (PS) exposure on the external face of the cell membrane is almost completely exclusive to cancer cells and endothelial cells in the tumor vasculature. The human protein annexin V is known to have strong calcium-dependent binding to anionic phospholipids such as PS. This protein was studied for targeting single-walled carbon nanotubes (SWNTs) to the vasculature of breast tumors. The synthesis of the protein annexin V, by a pET vector in Escherichia coli, constitutes the first phase of this study. Recombinant annexin V was purified from the cell lysate supernatant by immobilized metal affinity chromatography. The overall production of purified annexin V protein was 50 mg/L. The binding ability of the protein annexin V was evaluated by determining the dissociation constant when incubated with proliferating human endothelial cells in vitro. The dissociation constant, Kd, was measured to be 0.8 nM, indicating relatively strong binding. This value of Kd is within the range reported in the literature. Single-walled carbon nanotubes (SWNTs) were functionalized with annexin V using two intermediate linkers (containing FMOC and DSPE) resulting in stable suspensions. The SWNT and protein concentrations were 202 mg/L and 515 mg/L, respectively, using the linker with DSPE (average of nine preparations). The conjugation method that used the DSPE-PEG-maleimide linker allowed to successfully conjugate the SWNTs with final concentrations approximately five times higher than the linker containing FMOC. The conjugation method used has a non-covalent nature, and therefore the optical properties of the nanotubes were preserved. The conjugate was also visually observed using atomic force microscopy (AFM), allowing to verify the presence of the protein annexin V on the surface of the nanotubes, with an height ranging between 2.5 to 5.0 nm. Confocal microscopy was used to prove the binding of the conjugates to human endothelial cells grown in vitro. Proliferating endothelial cells were used to determine the optimal near-infrared (NIR) laser irradiation settings (energy density = 200 J/cm2), which would not induce cell cytotoxicity from the laser itself. A 2 hour incubation with the conjugate followed by a washing step and NIR irradiation (wavelength = 980 nm, power = 1 W/cm2, time = 200 seconds) was enough to induce significant cell death (?55 %), without significant damage to the control samples. Administration of the same conjugates i.v. in Balb/cJ female mice resulted in detectable accumulation of the SWNTs in the tumor tissues, with minimal retention in the kidneys 24 hours post-administration. A dosage of 0.82 mg/kg of SWNTs administered i.v. and followed one day later by a NIR irradiation (wavelength = 980 nm, power = 1 W/cm2, time = 175 seconds) led to complete disappearance of implanted 4T1 mouse mammary tumors for the majority of the animals from the treatment groups, within a few days. The combination of the photothermal therapy with a low dosage (50 mg/kg) of the immunoadjuvant cyclophosphamide, given 2 days before NIR irradiation, was also evaluated; this resulted in increased survival. Histological findings revealed the complete obliteration of the tumors treated from the original site, with complete regeneration of the skin epithelial layer and absence of cancer cells. In conclusion, this research was successful in demonstrating that SWNTs could be targeted to the tumor vasculature in vivo and then could be heated by NIR irradiation to completely kill mouse mammary tumors implanted in immune-competent mice. There is evidence that the co-administration of the immunostimulant cyclophosphamide caused increased survival of the mice. It is recommended that future work be directed to exploring methods to increase the concentration of the SWNT-annexin V conjugate in the tumor and to evaluate the co-administration of other immunostimulants, either alone or in combination.

  17. Threshold displacement energies in graphene and single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Merrill, Andrew; Cress, Cory D.; Rossi, Jamie E.; Cox, Nathanael D.; Landi, Brian J.

    2015-08-01

    The threshold displacement energy Ed has been determined for graphene and 216 different (n , m ) single-walled carbon nanotube chiralities, with 5 ?n ?20 and 0 ?m ?n , under several model conditions using classical molecular dynamics. The model conditions vary by particle (electron or carbon ion), empirical potential (two parametrizations of Tersoff [J. Tersoff, Phys. Rev. B 39, 5566 (1989), 10.1103/PhysRevB.39.5566; L. Lindsay and D. A. Broido, Phys. Rev. B 81, 205441 (2010), 10.1103/PhysRevB.81.205441] and one of Brenner et al. [D. W. Brenner, O. A. Shenderova, J. A. Harrison, S. J. Stuart, B. Ni, and S. B. Sinnott, J. Phys.: Condens. Matter 14, 783 (2002), 10.1088/0953-8984/14/4/312]), and momentum transfer direction (towards or away from the nanotube axis). For electron irradiation simulations, Ed exhibits a smoothly varying chirality dependence and a characteristic curvature influenced by the momentum transfer direction. Changing the empirical potential shifts the magnitude of Ed, but the trend is preserved for electron simulations. However, the perturbation in the knock-on dynamics introduced by the carbon ion leads to Ed trends that diverge from the equivalent electron simulation. Thus, the ion interaction has a non-negligible effect on the dynamics of the collision and leads to Ed values that can distinctly vary depending on the selected carbon nanostructure.

  18. Study of in vivo exposure of single-walled carbon nanotubes in mouse liver

    NASA Astrophysics Data System (ADS)

    Lyons, Lyndon L.

    Currently, few studies are available that have explored the role of carbon nanoparticles in liver toxicity. The susceptibility of the liver to nanoparticles rises from the inhalation exposure route often encountered during manufacturing and occupational exposure. Persons occupying these types of environmental setting are exposed to airborne nanoparticles less than 100nm, which have unobstructed access to most area of the lungs due to their size. Several reports have shown that single walled carbon nanotubes (SWCNTs) induce oxidative stress and pose the greatest cytotoxicity potential do to their size. Also, studies in mice indicate nanoparticles tend to accumulate in organs such as the spleen, kidney and liver, which is a major concern due to a lack of knowledge as to their fate. Single Wall Carbon Nanotubes (SWCNT's) are able to more easily penetrate through the cell membrane and display higher cell toxicity than Multi walled carbon nanotubes (MWCTs), opening the possibility for crossing various biological barriers within the body. Therefore effective occupational and environmental health risk assessments are significant in controlling the manufacture process of carbon nanotubes (CNTs). The present study was undertaken to determine the toxicity exhibited by SWCNT in mouse liver tissue as a model system. Mouse exposure during inhalation with and without SWCNT and reactive oxygen species (ROS) products were measured by change in fluorescence using dichloro fluorescein (DCF). The result showed no increase ROS on exposure of SWCNT in a dose and time dependent manner. Also, there is no reduction levels of glutathione (GSH) and super oxide dismutase (SOD), the antioxidant protective mechanism present in mouse liver cells upon SWCNT exposure. Lipid Peroxidation (LPO) and Lactate Dehydrogenase (LDH) assays indicated no tissue or protein damage. Additionally, Caspases --8 and --3 assays were conducted in order to understand the apoptotic signaling pathways initiated by oxidative stress. PEPCK and Hexokinase activity in mouse liver measured no hepatic glucokinase activity within the sensitivity of the assays. Based on the assays performed, the liver tolerated the SWCNT's 5mug dosage for 7 days, with no acute toxic effect. Although current tests and procedures may be appropriate to detect many risks associated with the use of these nanoparticles, it cannot be assumed that these assays will detect all potential risks. Given their limitations, specific emphasis should be on investigation in term of distribution in vivo both at the organ and cellular level using proteomics.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    We report a facile and scalable approach to synthesize single-walled carbon nanotubes (SWNTs) with selected diameter distribution by applying a magnetic field perpendicular to the electric field in the arc plasma region. It is found that this magnetic field-induced diameter-selectivity strategy enables the control of the SWNTs with different diameter distributions in different regions, and the diameter-selective efficiency could be enhanced by modifying the direction of magnetic field. Our results indicate that the motions of the catalysts with different particle sizes, positive carbon ions and electrons are significantly influenced by the magnetic field and electromagnetic force, resulting in the different nucleation and growth processes of SWNTs due to the collective interactions between the magnetic field and arc plasma. This approach would enable a viable route towards the synthesis of SWNTs with desired diameter through the tuning of arc parameters in the arc discharge process.We report a facile and scalable approach to synthesize single-walled carbon nanotubes (SWNTs) with selected diameter distribution by applying a magnetic field perpendicular to the electric field in the arc plasma region. It is found that this magnetic field-induced diameter-selectivity strategy enables the control of the SWNTs with different diameter distributions in different regions, and the diameter-selective efficiency could be enhanced by modifying the direction of magnetic field. Our results indicate that the motions of the catalysts with different particle sizes, positive carbon ions and electrons are significantly influenced by the magnetic field and electromagnetic force, resulting in the different nucleation and growth processes of SWNTs due to the collective interactions between the magnetic field and arc plasma. This approach would enable a viable route towards the synthesis of SWNTs with desired diameter through the tuning of arc parameters in the arc discharge process. Electronic supplementary information (ESI) available: Schematic diagram of SWNT sampling points, peak areas of S22 and M11 and relative ratios of S/M. See DOI: 10.1039/c2nr11783e

  20. Dispersion and characterization of arc discharge single-walled carbon nanotubes - towards conducting transparent films

    NASA Astrophysics Data System (ADS)

    Rösner, B.; Guldi, D. M.; Chen, J.; Minett, A. I.; Fink, R. H.

    2014-03-01

    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.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. Electronic supplementary information (ESI) available: EDS analyses of the catalyst materials, UV-Vis/NIR spectrum of an Iljin SWCNT dispersion, including the S11 transitions, and UV-Vis/NIR spectra evaluating the mass loss upon dispersion. See DOI: 10.1039/c3nr05788g

  1. Study of the surface chemistry and morphology of single walled carbon nanotube-magnetite composites

    NASA Astrophysics Data System (ADS)

    Marquez-Linares, F.; Uwakweh, O. N. C.; Lopez, N.; Chavez, E.; Polanco, R.; Morant, C.; Sanz, J. M.; Elizalde, E.; Neira, C.; Nieto, S.; Roque-Malherbe, R.

    2011-03-01

    The study of the morphologies of the single walled carbon nanotube (SWCNT), magnetite nanoparticles (MNP), and the composite based on them was carried with combined X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). These techniques together with thermogravimetric analyses (TGA) and diffuse reflectance infrared transform spectroscopy (DRIFTS) confirmed the production of pure single phases, and that the composite material consisted of MNP attached to the outer surface of the SWCNT. The Mössbauer spectroscopy (MS) research showed the presence of a large quantity of Lewis acid sites in the highly dispersed magnetite particles supported on the SWCNT outer surface. The DRIFTS carbon dioxide adsorption study of the composites revealed significant adsorption of carbon dioxide, fundamentally in the Lewis acid sites. Then, the Lewis acid sites were observed to be catalytically active. Further, the electron exchange between the Lewis acid sites and the basic or amphoteric adsorbed molecules could influence the magnetic properties of the magnetite. Consequently, together with this first ever use of MS in the study of Lewis acid sites, this investigation revealed the potential of the composites for catalytic and sensors applications.

  2. Functionalization of Single-Wall Carbon Nanotubes by Photo-Oxidation

    NASA Technical Reports Server (NTRS)

    Lebron-Colon, Marisabel; Meador, Michael A.

    2010-01-01

    new technique for carbon nanotube oxidation was developed based upon the photo-oxidation of organic compounds. The resulting method is more benign than conventional oxidation approaches and produces single-wall carbon nanotubes (SWCNTs) with higher levels of oxidation. In this procedure, an oxygen saturated suspension of SWNTs in a suitable solvent containing a singlet oxygen sensitizer, such as Rose Bengal, is irradiated with ultraviolet light. The resulting oxidized tubes are recovered by filtering the suspension, followed by washing to remove any adsorbed solvent and sensitizer, and drying in a vacuum oven. Chemical analysis by FT-infrared and x-ray photoelectron spectroscopy revealed that the oxygen content of the photo-oxidized SWCNT was 11.3 atomic % compared to 6.7 atomic % for SWCNT that had been oxidized by standard treatment in refluxing acid. The photo-oxidized SWCNT produced by this method can be used directly in various polymer matrixes, or can be further modified by chemical reactions at the oxygen functional groups and then used as additives. This method may also be suitable for use in oxidation of multiwall carbon nanotubes and graphenes.

  3. Poly(ethylene oxide) Crystallization in Single Walled Carbon Nanotube Based Nanocomposites: Kinetics and Structural Consequences

    SciTech Connect

    T Chatterjee; A Lorenzo; R Krishnamoorti

    2011-12-31

    The overall isothermal crystallization behavior of poly(ethylene oxide) (PEO) in single walled carbon nanotube (SWNT) based nanocomposites is studied with a focus on growth kinetics and morphological evolution of PEO using differential scanning calorimetry and in-situ small angle x-ray scattering measurements respectively. The characteristic time for crystallization of PEO increases due to the presence of lithium dodecyl sulfate (LDS) stabilized carbon nanotubes. Further, analysis of crystallization data using the Lauritzen-Hoffman regime theory of crystal growth shows the PEO chains stiffen in presence of LDS with an increased energy barrier associated with the nucleation and crystal growth, and the nanotubes further act as a barrier to chain transport or enhance the efficacy of the LDS action. The energy penalty and diffusional barrier to chain transport in the nanocomposites disrupt the crystalline PEO helical conformation. This destabilization leads to preferential growth of local nuclei resulting in formation of thinner crystal lamellae and suggests that the crystallization kinetics is strongly affected by the nucleation and crystal growth events. This study is particularly interesting considering the suppression of the PEO crystallinity in presence of small fraction of Lithium ion based surfactant and carbon nanotubes.

  4. Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics simulations

    SciTech Connect

    Shiomi, Junichiro; Maruyama, Shigeo

    2006-05-15

    Nonstationary heat conduction in a single-walled carbon nanotube was investigated by applying a local heat pulse with duration of subpicoseconds. The investigation was based on classical molecular dynamics simulations, where the heat pulse was generated as coherent fluctuations by connecting a thermostat to the local cell for a short duration. The heat conduction through the nanotube was observed in terms of spatiotemporal temperature profiles. Results of the simulations exhibit non-Fourier heat conduction where a distinct amount of heat is transported in a wavelike form. The geometry of carbon nanotubes allows us to observe such a phenomenon in the actual scale of the material. The resulting spatiotemporal profile was compared with the available macroscopic equations, the so-called non-Fourier heat conduction equations, in order to investigate the applicability of the phenomenological models to a quasi-one-dimensional system. The conventional hyperbolic diffusion equation fails to predict the heat conduction due to the lack of local diffusion. It is shown that this can be remedied by adopting a model with dual relaxation time. Further modal analyses using wavelet transformations reveal a significant contribution of the optical phonon modes to the observed wavelike heat conduction. The result suggests that, in carbon nanotubes with finite length where the long-wavelength acoustic phonons behave ballistically, even optical phonons can play a major role in the non-Fourier heat conduction.

  5. Optimization of single-walled carbon nanotube solubility by noncovalent PEGylation using experimental design methods

    PubMed Central

    Hadidi, Naghmeh; Kobarfard, Farzad; Nafissi-Varcheh, Nastaran; Aboofazeli, Reza

    2011-01-01

    In this study, noncovalent functionalization of single-walled carbon nanotubes (SWCNTs) with phospholipid-polyethylene glycols (Pl-PEGs) was performed to improve the solubility of SWCNTs in aqueous solution. Two kinds of PEG derivatives, ie, Pl-PEG 2000 and Pl-PEG 5000, were used for the PEGylation process. An experimental design technique (D-optimal design and second-order polynomial equations) was applied to investigate the effect of variables on PEGylation and the solubility of SWCNTs. The type of PEG derivative was selected as a qualitative parameter, and the PEG/SWCNT weight ratio and sonication time were applied as quantitative variables for the experimental design. Optimization was performed for two responses, aqueous solubility and loading efficiency. The grafting of PEG to the carbon nanostructure was determined by thermogravimetric analysis, Raman spectroscopy, and scanning electron microscopy. Aqueous solubility and loading efficiency were determined by ultraviolet-visible spectrophotometry and measurement of free amine groups, respectively. Results showed that Pl-PEGs were grafted onto SWCNTs. Aqueous solubility of 0.84 mg/mL and loading efficiency of nearly 98% were achieved for the prepared Pl-PEG 5000-SWCNT conjugates. Evaluation of functionalized SWCNTs showed that our noncovalent functionalization protocol could considerably increase aqueous solubility, which is an essential criterion in the design of a carbon nanotube-based drug delivery system and its biodistribution. PMID:21556348

  6. High-Temperature Transformation of Fe-Decorated Single-Wall Carbon Nanohorns to Nanooysters: A Combined Experimental and Theoretical Study

    SciTech Connect

    Chandrakumar, KRS; Puretzky, Alexander A; Rouleau, Christopher M; Readle, Jason D; Geohegan, David B; More, Karren Leslie; Krishnan, Veena G; Duscher, Gerd J M; Sumpter, Bobby G; Irle, Stephan; Morokuma, Keiji

    2013-01-01

    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 understand 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 typically localized near the edges where the two cones are joined together. 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 carbon shell surface area to metal nanoparticle volume. Therefore, both surface-reconstruction and dissolution precipitation models remain plausible for the synthesis of small and large nanooysters, respectively.

  7. Raising the performance of a 4 V supercapacitor based on an EMIBF4-single walled carbon nanotube nanofluid electrolyte.

    PubMed

    Kong, Chuiyan; Qian, Weizhong; Zheng, Chao; Yu, Yuntao; Cui, Chaojie; Wei, Fei

    2013-11-25

    Addition of a single walled carbon nanotube in ionic liquids of EMIBF4 produced a nanofluid with increased ionic conductivity. It, as the electrolyte, allowed the increase of the capacitance, energy density and cycling stability of a supercapacitor operated at 4 V. PMID:24104401

  8. Double-Stranded DNA Single-Walled Carbon Nanotube Hybrids for Optical Hydrogen Peroxide and Glucose Sensing

    E-print Network

    Chen, Liwei

    Double-Stranded DNA Single-Walled Carbon Nanotube Hybrids for Optical Hydrogen Peroxide and Glucose acid (DNA) reacted with either hydrogen peroxide H2O2 or glucose in the presence of the glucose oxidase the hydrogen peroxide. This study reinforces the potential of DNA-SWNT hybrids for use in immunoassays

  9. Template-Free Directional Growth of Single-Walled Carbon Nanotubes on a-and r-Plane Sapphire

    E-print Network

    Zhou, Chongwu

    Template-Free Directional Growth of Single-Walled Carbon Nanotubes on a- and r-Plane Sapphire Song of SWNTs using iron-film-coated sapphire substrates, but no orientation control and, hence, no ordered on miscut c-plane sapphire substrates;7 however, there is currently a lack of control over the miscut angle

  10. Changes in the Fluorescence Spectrum of Individual Single-Wall Carbon Nanotubes Induced by Light-Assisted Oxidation with Hydroperoxide

    E-print Network

    Maruyama, Shigeo

    Changes in the Fluorescence Spectrum of Individual Single-Wall Carbon Nanotubes Induced by Light, Tempaku-ku, Nagoya 468-8502, Japan Abstract Through fluorescence-spectrum measurements, we investigated that H2O2 was dissociated by absorbing the fluorescence light emitted from optically excited SWNTs, which

  11. Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect of Alignment and Selective Breakdown

    E-print Network

    generation electronics and sensors because of its unique electrical properties [1]. Typically, two differentFull Paper Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect The electrical transport and NH3 sensing properties of randomly oriented and aligned SWNT networks were presented

  12. Bioaccumulation and Toxicity of Single-Walled Carbon Nanotubes to Benthic Organisms at the Base of the Marine Food Chain

    EPA Science Inventory

    As the use of single-walled carbon nanotubes (SWNTs) increases over time, so does the potential for environmental release. This research aimed to determine the toxicity, bioavailability, and bioaccumulation of SWNTs in marine benthic organisms at the base of the food chain. The t...

  13. Thermal decomposition of ethanol and growth of vertically aligned single-walled carbon nanotubes by alcohol catalytic chemical vapor deposition

    E-print Network

    Maruyama, Shigeo

    Thermal decomposition of ethanol and growth of vertically aligned single-walled carbon nanotubes. In this study, we have investigated the thermal decomposition of ethanol at various temperatures, as well National Meeting, San Francisco, CA, September 10-14, 2006 1/1 PRES 29 - Thermal decomposition of ethanol

  14. 2,4,6-Trinitrotoluene (TNT) Chemical Sensing Based on Aligned Single-Walled Carbon Nanotubes and ZnO

    E-print Network

    Zhou, Chongwu

    candidates for building an electronic nose (e-nose) system.[6,7] Among these materials, semiconductor single-walled carbon nanotubes (SWNTs) are molecular-scale wires composed entirely of surface atoms, which should be ideal for the direct electrical detection and are expected to exhibit excellent sensitivity

  15. Direct synthesis of high-purity single-walled carbon nanotube mat on silicon and quartz substrates and their applications

    E-print Network

    Maruyama, Shigeo

    Direct synthesis of high-purity single-walled carbon nanotube mat on silicon and quartz substrates on the surface of silicon and quartz substrates was presented employing low-temperature alcohol CCVD method [1, 2 using thereby prepared blackened SWNT-synthesized quartz substrate. The obtained absorbance spectrum

  16. Decoration of Gold Nanoparticles on Surface-Grown Single-Walled Carbon Nanotubes for Detection of Every

    E-print Network

    Liu, Jie

    Decoration of Gold Nanoparticles on Surface-Grown Single-Walled Carbon Nanotubes for Detection) with gold nanoparticles of controlled size and interparticle distance. The density of the gold nanoparticles is determined by the density of seeds. Gold seeds are used for the SWCNT arrays grown on SiOx/Si substrates

  17. CVD Growth of Self-Organized Micro-Honeycomb Network Structure of Single-Walled Carbon Nanotubes for Photovoltaic Devices

    E-print Network

    Maruyama, Shigeo

    CVD Growth of Self-Organized Micro-Honeycomb Network Structure of Single-Walled Carbon Nanotubes of dye-sensitized solar cells. Here, we propose a self-organized micro-honeycomb network structure performance. The SWNT/n-Si heterojunction solar cell was built by placing the micro-honeycomb SWNTs network

  18. Investigations of single-wall carbon nanotube growth by time-restricted laser vaporization Alex A. Puretzky,1,2

    E-print Network

    Geohegan, David B.

    Investigations of single-wall carbon nanotube growth by time-restricted laser vaporization Alex A's within a high-temperature laser-vaporization LV reactor were measured and adjusted through in situ:YAG laser-vaporization conditions used in this study. These measurements permit the completion of a general

  19. 40 CFR 721.10277 - Single-walled and multi-walled carbon nanotubes (generic) (P-10-40).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10277 Single-walled and multi-walled carbon nanotubes (generic) (P-10-40). (a) Chemical substance and significant new uses subject to reporting. (1)...

  20. 40 CFR 721.10277 - Single-walled and multi-walled carbon nanotubes (generic) (P-10-40).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Single-walled and multi-walled carbon nanotubes (generic) (P-10-40). 721.10277 Section 721.10277 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  1. Sensitivity of Ammonia Interaction with Single-Walled Carbon Nanotube Bundles to the Presence of Defect Sites and

    E-print Network

    Borguet, Eric

    Sensitivity of Ammonia Interaction with Single-Walled Carbon Nanotube Bundles to the PresenceVersity, Atlanta, Georgia 30322 Received November 19, 2004; E-mail: eborguet@temple.edu Abstract: Ammonia cryogenic (94 K) and room (300 K) temperatures. At 94 K, vacuum- annealed SWNTs showed no detectable ammonia

  2. Ultrathin Films of Single-Walled Carbon Nanotubes for Electronics and Sensors: A Review of Fundamental and

    E-print Network

    Rogers, John A.

    Ultrathin Films of Single-Walled Carbon Nanotubes for Electronics and Sensors: A Review'' electronic technologies, such as spintronics,[44­47] molecular electronics,[48­53] quantum-dot cellular, such REVIEW www.advmat.de [*] Q. Cao, Prof. J. A. Rogers Department of Chemistry Department of Materials

  3. Dependence of Raman-active modes on the external voltage in single-wall carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Fanchini, Giovanni; Eda, Goki; Emrah Unalan, Husnu; Chhowalla, Manish

    2007-03-01

    We report on Raman measurements under the application of an external voltage in gap-cell devices made by transparent and conducting single-wall carbon nanotube (SWNT) thin films [1] Two different Raman excitation wavelengths (785 and 633 nm) were used. Application of voltage results in downshifts of the D and G modes and in reduction of their intensity. The intensities of the radial breathing modes increase with voltage in metallic SWNTs, while decreasing in semiconducting SWNTs. A model explaining the phenomenon in terms of both direct and indirect (Joule heating) effects of the field is proposed. Our work rules out the elimination of large amounts of metallic SWNTs in thin film transistors using high field pulses. Our results support the existence of Kohn anomalies in the Raman-active optical branches of metallic graphitic materials. Additional Raman measurements in SWNT thin film transistors at varying source-drain voltage and gate voltage will be presented as well. [1] G Fanchini, et al, submitted [2] S.Piscanec et al, PRL 93 (2004) 185503

  4. Pulmonary toxicity of single-wall carbon nanotubes in mice 7 and 90 days after intratracheal instillation

    NASA Technical Reports Server (NTRS)

    Lam, Chiu-Wing; James, John T.; McCluskey, Richard; Hunter, Robert L.

    2004-01-01

    Nanomaterials are part of an industrial revolution to develop lightweight but strong materials for a variety of purposes. Single-wall carbon nanotubes are an important member of this class of materials. They structurally resemble rolled-up graphite sheets, usually with one end capped; individually they are about 1 nm in diameter and several microns long, but they often pack tightly together to form rods or ropes of microscopic sizes. Carbon nanotubes possess unique electrical, mechanical, and thermal properties and have many potential applications in the electronics, computer, and aerospace industries. Unprocessed nanotubes are very light and could become airborne and potentially reach the lungs. Because the toxicity of nanotubes in the lung is not known, their pulmonary toxicity was investigated. The three products studied were made by different methods and contained different types and amounts of residual catalytic metals. Mice were intratracheally instilled with 0, 0.1, or 0.5 mg of carbon nanotubes, a carbon black negative control, or a quartz positive control and euthanized 7 d or 90 d after the single treatment for histopathological study of the lungs. All nanotube products induced dose-dependent epithelioid granulomas and, in some cases, interstitial inflammation in the animals of the 7-d groups. These lesions persisted and were more pronounced in the 90-d groups; the lungs of some animals also revealed peribronchial inflammation and necrosis that had extended into the alveolar septa. The lungs of mice treated with carbon black were normal, whereas those treated with high-dose quartz revealed mild to moderate inflammation. These results show that, for the test conditions described here and on an equal-weight basis, if carbon nanotubes reach the lungs, they are much more toxic than carbon black and can be more toxic than quartz, which is considered a serious occupational health hazard in chronic inhalation exposures.

  5. Polymer functionalized single walled carbon nanotubes mediated drug delivery of gliotoxin in cancer cells.

    PubMed

    Bhatnagar, Ira; Venkatesan, Jayachandran; Kiml, Se-Kwon

    2014-01-01

    During recent years, significant development has been achieved in carbon nanotube conjugated with polymer system for drug delivery system (DDS). In the present study, we have prepared functionalized single walled carbon nanotube conjugated with chitooligosaccharide (f-SWNT-COS) as a Drug Delivery System. In addition, drug Gliotoxin (GTX) and targeting molecules (Lysozyme, p53 and Folic acid) have been incorporated into f-SWNT-COS. f-SWNTs-COS-GTX-p53, f-SWNTs-COS-GTX-lysozyme, f-SWNTs-COS-GTX-FA have been physiochemically characterized for DDS. FT-IR, SEM and TEM analysis confirmed the formation of chemical interaction and polymer coating. FT-IR result clearly confirmed the interaction between f-SWNT and COS. The effective drug release was monitored against cervical cancer (HeLa) cells and Breast Cancer (MCF-7) cells and it was found that all the three drug delivery systems showed significant cytotoxicity. f-SWNTs-COS-GTX-p53 delivery vehicle and its effective cytotoxicity on HeLa cells was further checked with fluorescent activated cell sorter analysis. Our results suggest that the f-SWNTs-COS-GTX-p53 is the most effective delivery vehicle with a controlled release and enhanced cytotoxicity rendered through apoptosis in human cervical cancer (HeLa) cells. These systems can further be used for the delivery of other commercially available anti cancer drugs as well. PMID:24724504

  6. Separation and re-adhesion processes of two adhered single-walled carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Chiao; Ryan, Peter J.; McGruer, Nicol E.; Adams, George G.

    2014-03-01

    Carbon nanotubes are desirable components of nanoelectromechanical (NEM) devices due to their excellent mechanical and electrical properties. In this study, dielectrophoresis, a potential high-rate nanomanufacturing process, was used to assemble single-walled carbon nanotube (SWCNT) bundles suspended over a trench. The intent was to assemble a single SWCNT bundle between two electrodes. However, it was observed that when two or more SWCNT bundles assembled across the trench, the bundles were attached together in a portion of the suspended section. This study models the separation and re-adhesion processes of two adhered SWCNT bundles as their internal tensions are varied using an atomic force microscope (AFM) tip. Two devices were selected with distinct SWCNT bundles. Observation of the force-distance measurements through applying an AFM tip at the middle of the suspended SWCNT bundles, in conjunction with continuum mechanics modelling, allowed the work of adhesion between the two nanotube bundles to be determined. As the force was applied by the AFM tip, the tension induced in each bundle increases sufficiently to partially overcome the adhesion between the bundles, thereby decreasing the adhesive length. The adhesive length then recovers due to the decrease in the induced tension during the unloading process. The average value of the work of adhesion between two adhered SWCNT bundles was determined to be 0.37 J m-2 according to the experimental data and modelling results.

  7. Length- and defect-dependent fluorescence efficiencies of individual single-walled carbon nanotubes.

    PubMed

    Cherukuri, Tonya K; Tsyboulski, Dmitri A; Weisman, R Bruce

    2012-01-24

    Using near-infrared fluorescence videomicroscopy with spectrally selective excitation and imaging, more than 400 individual (10,2) single-walled carbon nanotubes (SWCNTs) have been studied in unsorted liquid dispersions. For each nanotube, the spatially integrated emission intensity was measured under controlled excitation conditions while its length was found either from direct imaging or from the diffusion coefficient computed by analyzing its Brownian motion trajectory. The studied nanotubes ranged in length from 170 to 5300 nm. For any length, a wide variation in emission intensities was observed. These variations are attributed to differing densities of nanotube imperfections that cause fluorescence quenching. The brightest nanotubes at each length (presumed near-pristine) show total emission nearly proportional to length. This implies a nearly constant fluorescence quantum yield and a constant absorption cross section per carbon atom, validating conventional Beer-Lambert analysis for finding concentrations of SWCNT species. Ensemble-averaged emission is also proportional to length, but at only ca. 40% of the near-pristine values. Further research is needed to investigate the extrinsic effects causing wide variation in quantum yields and assess their implications for SWCNT fluorimetry. PMID:22128755

  8. Enzyme-catalyzed Oxidation Facilitates the Return of Fluorescence for Single-Walled Carbon Nanotubes

    PubMed Central

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

    2013-01-01

    In this work, we studied enzyme-catalyzed oxidation of single-walled carbon nanotubes (SWCNTs) produced by the high-pressure carbon monoxide (HiPco) method. While oxidation via strong acids introduced defects sites on SWCNTs and suppressed their near-infrared (NIR) fluorescence, our results indicated that the fluorescence of SWCNTs was restored upon enzymatic oxidation, which provided new evidence that the reaction catalyzed by horseradish peroxidase (HRP) in the presence of H2O2 is mainly a defect-consuming step. These results were further supported by both UV-vis-NIR and Raman spectroscopy. Therefore, employing acid oxidation followed by HRP-catalyzed enzyme oxidation, shortened (< 300 nm in length) and NIR-fluorescent SWCNTs were produced. In contrast, when treated with myeloperoxidase (MPO), H2O2, and NaCl, the oxidized HiPco SWCNTs underwent complete oxidation (i.e. degradation). The shortened, NIR-fluorescent SWCNTs resulting from HRP-catalyzed oxidation of acid cut HiPco SWCNTs may find applications in cellular NIR imaging and drug delivery systems. PMID:23672715

  9. Wireless sensor array based on DNA decorated single-walled carbon nanotubes for gas monitoring

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Zhang, Yi; Dokmeci, Mehmet R.; Wang, Ming L.

    2012-04-01

    There is a growing interest in making sensors, optoelectronic and electronic devices with nanomaterials. Carbon nanotubes (CNTs) are unique materials due to their excellent electrical, mechanical and thermal properties, and also have good chemical stability. Single-walled carbon nanotubes (SWNTs) are formed by one atomic layer and have an extended ?-bonding configuration. The conductivity of SWNTs is sensitive to trace amount of molecules or ions attached onto their surfaces. CNTs have exceptionally high sensitivity and fast response and were utilized in numerous chemical and biological sensing applications for environmental monitoring. One of the present problems with SWNT sensors is their nonselective response to many analytes. SWNTs networks were assembled onto the microelectrodes by a low temperature, low cost Dielectrophoretic (DEP) assembly process. SsDNA of different sequences were used to functionalize the nanotubes and improved their response to the gas vapors dramatically. To reduce the undesirable response of SWNTs to interfering analytes, a wireless nanosensor array with six channels each functionalized with different molecules were developed to measure the resistances of six SWNT sensors simultaneously during exposure to gases. The responses of different DNA decorated SWNTs and bare SWNTs to toxic organics were measured simultaneously and displayed by a GUI interface. Development of this wireless sensor array enabled real-time gas monitoring with various DNA functionalized SWNTs from a distance.

  10. Solution-processed thin films for electronics from single-walled carbon nanotubes and graphene

    NASA Astrophysics Data System (ADS)

    Eda, Goki

    Single-walled carbon nanotubes (SWNTs) and graphene are sp 2 hybridized carbon nanostructures which exhibit extraordinary electronic properties arising from their unique energy dispersions and dimensionalities. A major issue preventing implementation of these materials into integrated electronic devices is the absence of large-scale controllable synthesis and subsequent manipulation. To circumvent this issue, solution processing of SWNTs and graphene has been proposed. Deposition of thin film networks allows the realization of a new class of materials that are useful for large-area or "macro-electronics" on flexible and inexpensive platforms. In this thesis, controllable and efficient solution-based deposition of SWNT and graphene thin film networks and their opto-electronic properties are investigated. Topics such as material dynamics in liquid, chemical structures, defects, morphology, and doping are studied utilizing various spectroscopy and microscopy analysis along with complementary electrical measurements. Further insight is provided through demonstrations of proof-of-principle thin film transistors, organic photovoltaics, and field emitters based on solution-processed SWNT and graphene thin films.

  11. Single-walled carbon nanotube interactions with HeLa cells

    PubMed Central

    Yehia, Hadi N; Draper, Rockford K; Mikoryak, Carole; Walker, Erin Kate; Bajaj, Pooja; Musselman, Inga H; Daigrepont, Meredith C; Dieckmann, Gregg R; Pantano, Paul

    2007-01-01

    This work concerns exposing cultured human epithelial-like HeLa cells to single-walled carbon nanotubes (SWNTs) dispersed in cell culture media supplemented with serum. First, the as-received CoMoCAT SWNT-containing powder was characterized using scanning electron microscopy and thermal gravimetric analyses. Characterizations of the purified dispersions, termed DM-SWNTs, involved atomic force microscopy, inductively coupled plasma – mass spectrometry, and absorption and Raman spectroscopies. Confocal microRaman spectroscopy was used to demonstrate that DM-SWNTs were taken up by HeLa cells in a time- and temperature-dependent fashion. Transmission electron microscopy revealed SWNT-like material in intracellular vacuoles. The morphologies and growth rates of HeLa cells exposed to DM-SWNTs were statistically similar to control cells over the course of 4 d. Finally, flow cytometry was used to show that the fluorescence from MitoSOX™ Red, a selective indicator of superoxide in mitochondria, was statistically similar in both control cells and cells incubated in DM-SWNTs. The combined results indicate that under our sample preparation protocols and assay conditions, CoMoCAT DM-SWNT dispersions are not inherently cytotoxic to HeLa cells. We conclude with recommendations for improving the accuracy and comparability of carbon nanotube (CNT) cytotoxicity reports. PMID:17956629

  12. Dynamic interactions between poly(3-hexylthiophene) and single-walled carbon nanotubes in marginal solvent.

    PubMed

    Luo, Yanqi; Santos, Franceska A; Wagner, Taylor W; Tsoi, Eric; Zhang, Shanju

    2014-06-01

    Interfacial interactions between conjugated polymers and carbon nanotubes are pivotal in determining the device performance of nanotube-based polymer electronic devices. Here, we report on interfacial structures and crystallization kinetics of poly(3-hexylthiophene) (P3HT) in the presence of single-walled carbon nanotubes (SWNTs) in anisole by means of transmission electron microscope (TEM) and ultraviolet-visible (UV-vis) absorption spectroscopy. Confined on SWNT surfaces, the P3HT forms nanofibril crystals perpendicular to the long axis of SWNTs. The equilibrium dissolution temperature of the P3HT crystals in anisole is determined to be 381 ± 10 K according to the Hoffman-Weeks extrapolation approach. Upon cooling, the polymer solution spontaneously undergoes a time-dependent chromism. Various kinetics factors such as crystallization temperature, concentration, and SWNT loading have been investigated. It is found that the growth rate (G) of the crystals scales with concentration (C) as G ? C(1.70±0.16). The Avrami model is utilized to analyze the nucleation mechanism and the Avrami exponents vary between 1.0 and 1.3. The Lauritzen-Hoffman theory is applied to study the chain-folding process. The fold surface free energy is calculated to be (5.28-11.9) × 10(-2) J m(-2). It is evident that the addition of 0.30 wt % SWNTs reduces the fold surface free energy by 55.6%. PMID:24856901

  13. Effect of single walled carbon nanotubes on the threshold voltage of dye based photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Manik, N. B.

    2016-01-01

    Carbon nanotubes are being widely used in organic photovoltaic (OPV) devices as their usage has been reported to enhance the device efficiency along with other related parameters. In this work we have studied the energy (Ec) effect of single walled carbon nanotubes (SWCNT) on the threshold voltage (Vth) and also on the trap states of dye based photovoltaic devices. SWCNT is added in a series of dyes such as Rose Bengal (RB), Methyl Red (MR), Malachite Green (MG) and Crystal Violet (CV). By analysing the steady state dark current-voltage (I-V) characteristics Vth and Ec is estimated for the different devices with and without addition of SWCNT. It is observed that on an average for all the dyes Vth is reduced by about 30% in presence of SWCNT. The trap energy Ec also reduces in case of all the dyes. The relation between Vth, Ec and total trap density is discussed. From the photovoltaic measurements it is seen that the different photovoltaic parameters change with addition of SWCNT to the dye based devices. Both the short circuit current density and fill factor are found to increase for all the dye based devices in presence of SWCNT.

  14. Nontrivial magnetoresistive behavior of a single-wall carbon nanotube with an attached molecular magnet

    NASA Astrophysics Data System (ADS)

    P?omi?ska, Anna; Weymann, Ireneusz

    2015-11-01

    The spin-resolved transport properties of a single-wall carbon nanotube quantum dot, with an attached single molecular magnet, are studied theoretically. With the aid of the real-time diagrammatic technique in the lowest-order perturbation expansion with respect to the tunnel coupling, the current, differential conductance, and the tunnel magnetoresistance (TMR) are determined in both the linear and nonlinear response regimes. It is shown that transport properties depend greatly on both the shell filling sequence of the carbon nanotube and the type of exchange interaction between the molecular magnet and nanotube. This results in highly nontrivial behavior of the TMR, which is especially visible in the low bias voltage regime. Depending on the gate voltage and parameters of the system, we find transport regimes where either a greatly enhanced or negative TMR develops. The mechanism leading to such behavior is associated with nonequilibrium spin accumulation, which builds up in the antiparallel magnetic configuration of the device. We show that it is crucial whether the spin accumulation occurs in the highest-weight spin states or in states with lower spin values. While in the former case it leads to enhanced TMR, in the latter case it may result in negative tunnel magnetoresistance. In addition, we analyze how the above effects depend on the magnitude of the molecular magnet's spin, and show that this dependence is generally nonmonotonic.

  15. Synthesis of single-walled carbon nanotubes and graphene composite in arc for ultracapacitors

    NASA Astrophysics Data System (ADS)

    Li, Jian; Cheng, Xiaoqian; Shashurin, Alexey; Keidar, Michael

    2012-10-01

    Arc discharge supported by the erosion of graphite anode is considered as one of the most practical and efficient methods to synthesize various carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene with minimal defects and large yield due to the relatively high synthesis temperature and eco-friendly growth mechanism. By introducing a non-uniform magnetic field during synthesis process, large-scale graphene and high-purity SWCNT can be obtained in one step. In addition, the yield of graphene can be controlled by external parameters, such as the type and pressure of buffer gas, the temperature of substrate, and so on. Possessing the properties of highly accessible surface area and good electrical conductivity, the composite of graphene and SWCNT are promising nanomaterials for the electrodes of ultracapacitor, which can store electric energy with high level of capacitance. In this work, we fabricated electrodes of ultracapacitor based on nanostructures composite by wire-wound rod coating method, characterized them by SEM, EDX and Raman spectroscopy, and tested the performance by a potentiostat/galvanostat.

  16. Synthesis, pharmacokinetics, and biological use of lysine-modified single-walled carbon nanotubes

    PubMed Central

    Mulvey, J Justin; Feinberg, Evan N; Alidori, Simone; McDevitt, Michael R; Heller, Daniel A; Scheinberg, David A

    2014-01-01

    We aimed to create a more robust and more accessible standard for amine-modifying single-walled carbon nanotubes (SWCNTs). A 1,3-cycloaddition was developed using an azomethine ylide, generated by reacting paraformaldehyde and a side-chain-Boc (tert-Butyloxycarbonyl)-protected, lysine-derived alpha-amino acid, H-Lys(Boc)-OH, with purified SWCNT or C60. This cycloaddition and its lysine adduct provides the benefits of dense, covalent modification, ease of purification, commercial availability of reagents, and pH-dependent solubility of the product. Subsequently, SWCNTs functionalized with lysine amine handles were covalently conjugated to a radiometalated chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). The 111In-labeled construct showed rapid renal clearance in a murine model and a favorable biodistribution, permitting utility in biomedical applications. Functionalized SWCNTs strongly wrapped small interfering RNA (siRNA). In the first disclosed deployment of thermophoresis with carbon nanotubes, the lysine-modified tubes showed a desirable, weak SWCNT-albumin binding constant. Thus, lysine-modified nanotubes are a favorable candidate for medicinal work. PMID:25228803

  17. Dynamics of fragmentation and multiple vacancy generation in irradiated single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Javeed, Sumera; Zeeshan, Sumaira; Ahmad, Shoaib

    2013-01-01

    The results from mass spectrometry of clusters sputtered from Cs+ irradiated single-walled carbon nanotubes (SWCNTs) as a function of energy and dose identify the nature of the resulting damage in the form of multiple vacancy generation. For pristine SWCNTs at all Cs+ energies, C2 is the most dominant species, followed by C3, C4 and C1. The experiments were performed in three stages: in the first stage, Cs+ energy E(Cs+) was varied. During the second stage, the nanotubes were irradiated continuously at E(Cs+) = 5 keV for 1,800 s. Afterwards, the entire sequence of irradiation energies was repeated to differentiate between the fragmentation patterns of the pristine and of heavily irradiated SWCNTs. The sputtering and normalized yields identify the quantitative and relative extent of the ion-induced damage by creating double, triple and quadruple vacancies; the single vacancies are least favored. Sputtering from the heavily irradiated SWCNTs occurs not only from the damaged and fragmented nanotubes, but also from the inter-nanotube structures that are grown due to the accumulation of the sputtered clusters. Similar irradiation experiments were performed with the multi-walled carbon nanotubes; the results confirmed the dominant C2 followed by C3, C4 and C1.

  18. Release characteristics of single-wall carbon nanotubes during manufacturing and handling

    NASA Astrophysics Data System (ADS)

    Ogura, I.; Kotake, M.; Hashimoto, N.; Gotoh, K.; Kishimoto, A.

    2013-04-01

    We investigated the release characteristics of single-wall carbon nanotubes (CNTs) synthesized by a pilot-scale plant. In addition to on-site aerosol measurements at the pilot-scale plant where the CNTs were synthesized, harvested, and packed, we conducted dustiness tests by vortex shaking and by transferring CNTs from one bowl to another. In the results of the on-site aerosol measurements, slight increases in the concentration were observed by aerosol monitoring instruments in the enclosure where CNTs were harvested and packed. In filter samples collected in this enclosure, micron-sized CNT clusters were observed by electron microscopy analysis. For samples collected outside the enclosure or during other processes, no CNTs were observed. The concentrations of elemental carbon at all locations were lower than the proposed occupational exposure limits of CNTs. The results of the dustiness tests revealed that submicron-sized particles were dominant in the number concentration measured by aerosol monitoring instruments, whereas micron-sized CNT clusters were mainly observed by electron microscopy analysis. The results of dustiness tests indicate that these CNTs have a low release characteristic. The lower drop impact of CNT clusters due to their lower bulk density resulted in lower CNT release from falling CNTs.

  19. The importance of an extensive elemental analysis of single-walled carbon nanotube soot

    PubMed Central

    Braun, Elizabeth I.; Pantano, Paul

    2014-01-01

    Few manufacturers provide elemental analysis information on the certificates of analysis of their single-walled carbon nanotube (SWCNT) soot products, and those who do primarily perform surface sensitive analyses that may not accurately represent the bulk properties of heterogeneous soot samples. Since the accurate elemental analysis of SWCNT soot is a requisite for exacting assessments of product quality and environmental health and safety (EH&S) risk, the purpose of this work was to develop a routine laboratory procedure for an extensive elemental analysis of SWCNT soot using bulk methods of analyses. Herein, a combination of carbon, hydrogen, nitrogen, sulfur, and oxygen (CHNS/O) combustion analyses, oxygen flask combustion/anion chromatography (OFC/AC), graphite furnace-atomic absorption spectroscopy (GF-AAS), and inductively coupled plasma-mass spectroscopy (ICP-MS) were used to generate a 77-element analysis of two as-received CoMoCAT® SWCNT soot products. Fourteen elements were detected in one product, nineteen in the other, and each data set was compared to its respective certificate of analysis. The addition of the OFC/AC results improved the accuracy of elements detected by GF-AAS and ICP-MS, and an assessment was performed on the results that concluded that the trace elemental impurities should not pose an EH&S concern if these soot products became airborne. PMID:25110357

  20. Synthesis, pharmacokinetics, and biological use of lysine-modified single-walled carbon nanotubes.

    PubMed

    Mulvey, J Justin; Feinberg, Evan N; Alidori, Simone; McDevitt, Michael R; Heller, Daniel A; Scheinberg, David A

    2014-01-01

    We aimed to create a more robust and more accessible standard for amine-modifying single-walled carbon nanotubes (SWCNTs). A 1,3-cycloaddition was developed using an azomethine ylide, generated by reacting paraformaldehyde and a side-chain-Boc (tert-Butyloxycarbonyl)-protected, lysine-derived alpha-amino acid, H-Lys(Boc)-OH, with purified SWCNT or C60. This cycloaddition and its lysine adduct provides the benefits of dense, covalent modification, ease of purification, commercial availability of reagents, and pH-dependent solubility of the product. Subsequently, SWCNTs functionalized with lysine amine handles were covalently conjugated to a radiometalated chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). The (111)In-labeled construct showed rapid renal clearance in a murine model and a favorable biodistribution, permitting utility in biomedical applications. Functionalized SWCNTs strongly wrapped small interfering RNA (siRNA). In the first disclosed deployment of thermophoresis with carbon nanotubes, the lysine-modified tubes showed a desirable, weak SWCNT-albumin binding constant. Thus, lysine-modified nanotubes are a favorable candidate for medicinal work. PMID:25228803

  1. Study of single walled carbon nanotube functionalization by means of surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ceponkus, Justinas; Velicka, Martynas; Pucetaite, Milda; Sablinskas, Valdas

    2015-09-01

    Raman spectroscopy is known to provide information about the quality of the single walled carbon nanotubes (SWCNT). The information is based on the intensity ratio of D and G spectral modes and the frequency of RBM modes. However due to resonance nature of Raman spectrum of the nanotubes this method is not suitable to detect functionalization of the nanotubes. Surface enhanced Raman spectroscopy (SERS) is known to enhance the Raman bands up to fourteen orders of magnitude. Preferable adsorption sites for small silver nanoparticles are expected to be the functional groups of SWCNT; therefore SERS technique allows detecting small amounts of functional groups despite strong resonance Raman from backbone of SWCNT. In this study functionalized nanotubes were dispersed in silver colloid and dried on the standard silver plate for Raman measurements. Spectra of SWCNT without colloid in the spectral range between 50 and 1800 cm-1 exhibit only four main spectral features: G, D, and RBM modes between 200 and 400 cm-1. Spectra of SWCNT with the colloid exhibit several additional spectral bands which do not belong to the colloid. These bands attributed to vibrations of C-O, C-C and O-H from the functional groups and the carbon atom of the SWCNT attached to the corresponding group. The bands associated with the vibrations involving O atom is an indication that silver nanoparticles interact with the functional group attached to SWCNT.

  2. Single-Walled Carbon Nanotubes Modulate the B- to A-DNA Transition

    PubMed Central

    2015-01-01

    We study the conformational equilibrium between B-to-A forms of ds-DNA adsorbed onto a single-walled carbon nanotube (SWNT) using free energy profile calculations based on all-atom molecular dynamics simulations. The potential of mean force (PMF) of the B-to-A transition of ds-DNA in the presence of an uncharged (10,0) carbon nanotube for two dodecamers with poly-AT or poly-GC sequences is calculated as a function of a root-mean-square-distance (?RMSD) difference metric for the B-to-A transition. The calculations reveal that in the presence of a SWNT DNA favors B-form DNA significantly in both poly-GC and poly-AT sequences. Furthermore, the poly-AT DNA:SWNT complex shows a higher energy penalty for adopting an A-like conformation than poly-GC DNA:SWNT by several kcal/mol. The presence of a SWNT on either poly-AT or poly-GC DNA affects the PMF of the transition such that the B form is favored by as much as 10 kcal/mol. In agreement with published data, we find a potential energy minimum between A and B-form DNA at ?RMSD ? ?1.5 Å and that the presence of the SWNT moves this minimum by as much as ?RMSD = 3 Å. PMID:25553205

  3. High field magneto-optical spectroscopy of semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Shaver, Jonah

    Single-walled carbon nanotubes (SWNTs) present an ideal system for study of one dimensional physics. Classically speaking, their long persistence lengths, i.e. the length over which they do not bend, result in rigid-rod-like behavior in the solution-phase. Quantum mechanically speaking, extreme confinement in the radial direction result in interesting properties for optically excited correlated electron-hole pairs, or excitons. In addition, their hollow crystalline structure presents a controllable way to modify the circumferential boundary conditions on their electronic wavefunctions resulting in changes to the electronic band structure via threading a magnetic field through the diameter. An applied magnetic field also aligns SWNTs due to their magnetic susceptibility anisotropy. We have measured the dynamic alignment properties of single-walled carbon nanotube (SWNT) suspensions in pulsed high magnetic fields through linear dichroism spectroscopy. Millisecond-duration pulsed high magnetic fields up to 55 T as well as microsecond-duration pulsed ultrahigh magnetic fields up to 166 T were used. Due to their anisotropic magnetic properties, SWNTs align in an applied magnetic field, and due to their anisotropic optical properties, aligned SWNTs show linear dichroism. The characteristics of their overall alignment depend on several factors, including the viscosity and temperature of the suspending solvent, the degree of anisotropy of nanotube magnetic susceptibilities, the nanotube length distribution, the degree of nanotube bundling, and the strength and duration of the applied magnetic field. In order to explain our data, we have developed a theoretical model based on the time-dependent Smoluchowski equation for rigid rods that accurately reproduces the salient features of the experimental data. We have also investigated excitons in SWNTs in stretch aligned polyacrylic acid films, direction of stretch (n?), through optical spectroscopy at low temperature (1.5 K) and high magnetic fields ( B) up to 55 T. The application of a magnetic field along the SWNT axis drastically increases the measured photoluminescence, by as much as a factor of 6, at low temperatures. To explain this we have developed a theoretical model based on field-dependent exciton band structure and the interplay of Coulomb interactions and the Aharonov-Bohm effect. This conclusively explains our data as the first experimental observation of dark excitons 5-10 meV below the bright excitons. In addition, utilizing two well-defined measurement geometries, n? || B and n? ? B, we provide unambiguous evidence that the photoluminescence energy and intensity are only sensitive to the B-component parallel to the tube axis.

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

    E-print Network

    Golovchenko, Jene A.

    in the center of self-supporting 0.5- m-thick Si3N4 mem- branes by optical lithography and lift off processing a suspended metallic nanotube grown directly on contacting metal electrodes with subsequent patterning­9 Interesting phenomena have been observed in su- perconducting metal nanowires prepared by using carbon

  5. New basic insight into reductive functionalization sequences of single walled carbon nanotubes (SWCNTs).

    PubMed

    Hof, Ferdinand; Bosch, Sebastian; Eigler, Siegfried; Hauke, Frank; Hirsch, Andreas

    2013-12-11

    The reactivity of reduced single walled carbon nanotubes (SWCNTs) (carbon nanotubides), prepared under strict inert conditions in a glovebox with respect to the covalent functionalization with hexyl iodide and subsequent exposure to ambient conditions (air, moisture), was systematically investigated by Raman, absorption, fluorescence, and IR spectroscopy as well as by TG/MS measurements. We have discovered that the alkylation does not lead to a complete discharging of the tubes since follow-up reactions with moisture still take place leading to mixed functionalized carbon nanotube derivatives containing H- and OH-addends (but no carboxylates) next to the hexyl groups. This was confirmed by the exposure of carbon nanotubides to ambient conditions. The degree of hexylation determined both under strict inert (ic) and ambient (ac) conditions increases with an increasing K:C ratio of the reduced SWCNT starting material. The presence of OH-groups covalently attached to the nanotubes was also confirmed by postfunctionalization reactions with 2-thiophenecarbonyl chloride, leading to the corresponding esters. Control experiments with KO2 give rise to the formation of the same oxygen functionalities. These combined findings allowed for the suggestions of a plausible reaction mechanism, describing all the observed reactions on the SWCNTs side walls. The amount of subsequent side reactions after the treatment of reduced SWCNTs with electrophiles is strongly influenced by the reduction potential of the electrophile, which is responsible for the extent of reoxidation. Incomplete quenching of negative charges allows stronger oxidants/electrophile (e.g., O2) to perform follow-up reactions. PMID:24256165

  6. Molecular Dynamics of Diffusive-Ballistic Heat Conduction in Single-Walled Carbon Nanotubes The University of Tokyo, Junichiro Shiomi, Shigeo Maruyama

    E-print Network

    Maruyama, Shigeo

    Molecular Dynamics of Diffusive-Ballistic Heat Conduction in Single-Walled Carbon Nanotubes of heat conduction characteristics of single-walled carbon nanotubes (SWNTs) is one of the primary issues towards their thermal and electric device applications. In this study, diffusive-ballistic heat conduction

  7. Thermal conductivity of single-walled carbon nanotubes Alexander V. Savin,1,2 Bambi Hu,3,4 and Yuri S. Kivshar1

    E-print Network

    Thermal conductivity of single-walled carbon nanotubes Alexander V. Savin,1,2 Bambi Hu,3,4 and Yuri 2009; published 30 November 2009 We study numerically the thermal conductivity of single-walled carbon of the methods employed and the potentials used, the character of the thermal conductivity depends crucially

  8. Effect of substrate on thermal conductivity of single-walled carbon nanotubes This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Effect of substrate on thermal conductivity of single-walled carbon nanotubes This article has been analyze numerically the thermal conductivity of single-walled carbon nanotubes placed on a flat rigid substrate. We demonstrate that the character of thermal conductivity depends crucially on the interaction

  9. Temperature dependent thermal conductivity increase of aqueous nanofluid with single walled carbon nanotube inclusions

    E-print Network

    Maruyama, Shigeo

    1 Temperature dependent thermal conductivity increase of aqueous nanofluid with single walled nanofluids, which we then thoroughly characterized by microscopic and spectroscopic methods. Electrical of the nanofluid was also found to increase with increasing temperature. Viscosity of the nanofluids showed

  10. Single-walled carbon nanotube based transparent immunosensor for detection of a prostate cancer biomarker osteopontin.

    PubMed

    Sharma, Abhinav; Hong, Seongkyeol; Singh, Renu; Jang, Jaesung

    2015-04-15

    Osteopontin (OPN) is involved in almost all steps of cancer development, and it is being investigated as a potential biomarker for a diagnosis and prognosis of prostate cancer. Here, we report a label-free, highly sensitive and transparent immunosensor based on single-walled carbon nanotubes (SWCNTs) for detection of OPN. A high density of COOH functionalized SWCNTs was deposited between two gold/indium tin oxide electrodes on a glass substrate by dielectrophoresis. Monoclonal antibodies specific to OPN were covalently immobilized on the SWCNTs. Relative resistance change of the immunosensors was measured as the concentration of OPN in phosphate buffer saline (PBS) and human serum was varied from 1 pg mL(-1) to 1 ?g mL(-1) for different channel lengths of 2, 5, and 10 ?m, showing a highly linear and reproducible behavior (R(2)>97%). These immunosensors were also specific to OPN against another test protein, bovine serum albumin, PBS and human serum, showing that a limit of detection for OPN was 0.3 pg mL(-1). This highly sensitive and transparent immunosensor has a great potential as a simple point-of-care test kit for various protein biomarkers. PMID:25818141

  11. Effect of the position of constriction on water permeation across a single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Wu, Linsong; Wu, Fengmin; Kou, Jianlong; Lu, Hangjun; Liu, Yang

    2011-06-01

    The transportation of water across a cell membrane facilitated by water channel proteins is fundamental to the normal water metabolism in all forms of life. It is understood that the narrow region in a water channel is responsible for gating or selectivity. However, the influence of the position of the narrow region on water transportation is still not thoroughly understood. By choosing a single-walled carbon nanotube (SWNT) as a simplified model and using molecular dynamics simulation, we have found that the water flux through the nanotube would change significantly if the narrow location moves away from the middle region along the tube. Simulation results show that the flux reaches the maximum when the deformation occurs in the middle part of nanotube and decreases as the deformation location moves toward the ends of the nanotube. However, the decrease of water flux is not monotonic and the flux gets the minimum near the ends. These interesting phenomena can be explained in terms of water-water interactions and water-SWNT interactions. It can be concluded that the regulation of water transportation through nanopores depends sensitively on the location of the narrow region, and these findings are helpful in devising high flux nanochannels and nanofiltration as well.

  12. Optical spectroscopy of single-walled carbon nanotubes in high magnetic fields

    NASA Astrophysics Data System (ADS)

    Zaric, Sasa

    Magnetic flux threading a single-walled carbon nanotube (SWNT) is predicted to influence its electronic structure through the Aharonov-Bohm (AB) effect, causing bandgap oscillations and absorption peaks splitting. In order to verify these predictions, near infrared (NIR) photoluminescence (PL) and visible-NIR absorption in the Voigt geometry were measured at room temperature in external magnetic field (B) up to 74 T. The used aqueous surfactant solubilized SWNT samples show excitonic interband absorption peaks coming from a range of nanotube chiralities present in the sample. At fields B > 30 T, PL peaks showed red shifts and changes in peak widths. Magneto-PL spectra were successfully simulated, demonstrating that the observed spectral changes can be understood in terms of magnetic alignment of SWNTs (due to their predicted anisotropy magnetic properties) and B dependent changes of the bandgap due to the AB effect. By using the measured B-induced nanotube alignment and the measured average length of nanotubes in the sample, we estimated SWNT magnetic anisotropy to be 1.4 x 10-5 emu/mol, consistent with theoretical predictions. At B > 55 T, clear absorption peak splittings were observed, with splitting rates of 1 meV/T in good agreement with theoretical predictions. Recent theory predicts a dark singlet exciton state (below the only bright singlet state) which brightens as B is applied. Our observation of two bright excitons at high B demonstrates that magnetic field is indeed capable of brightening dark excitons.

  13. Influence of exciton dimensionality on spectral diffusion of single-walled carbon nanotubes.

    PubMed

    Ma, Xuedan; Roslyak, Oleksiy; Wang, Feng; Duque, Juan G; Piryatinski, Andrei; Doorn, Stephen K; Htoon, Han

    2014-10-28

    We study temporal evolution of photoluminescence (PL) spectra from individual single-walled carbon nanotubes (SWCNTs) at cryogenic and room temperatures. Sublinear and superlinear correlations between fluctuating PL spectral positions and line widths are observed at cryogenic and room temperatures, respectively. We develop a simple model to explain these two different spectral diffusion behaviors in the framework of quantum-confined Stark effect (QCSE) caused by surface charges trapped in the vicinity of SWCNTs. We show that the wave function properties of excitons, namely, localization at cryogenic temperature and delocalization at room temperature, play a critical role in defining sub- and superlinear correlations. Room temperature PL spectral positions and line widths of SWCNTs coupled to gold dimer nanoantennas on the other hand exhibit sublinear correlations, indicating that excitonic emission mainly originates from nanometer range regions and excitons appear to be localized. Our numerical simulations show that such apparent localization of excitons results from plasmonic confinement of excitation and an enhancement of decay rates in the gap of the dimer nanoantennas. PMID:25251324

  14. Size reduction of 3D-polymer-coated single-walled carbon nanotubes by ultracentrifugation.

    PubMed

    Tsutsumi, Yusuke; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-12-14

    We describe a novel single-walled carbon nanotube (SWNT) cutting method without introducing any structural defects on the tubes; namely, the finding that simple ultracentrifugation at 600?000g for the SWNTs coated with a cross-linked polymer formed by poly(N-isopropylacrylamide) (PNIPAM) or the polyethylene glycol-carrying PNIPAM copolymer provides shortened (<200 nm) SWNTs, which was revealed by dynamic light scattering (DLS) and atomic force microscopy (AFM) measurements. The Raman and absorption measurements of the obtained SWNTs indicated that the graphitic structure and optical properties, such as characteristic absorption and photoluminescence in the near-IR region of the SWNTs, were almost unchanged even after the cutting. The obtained shortened SWNTs were individually solubilized in water and buffer solution due to the remaining cross-linked polymer structures on the SWNTs. The present method is very simple (only ultracentrifugation) and the yield is very high, which are the advantages in the preparation of many shortened isolated SWNTs with specific properties and functions that are applicable in many fields including bioapplications in vivo, such as imaging, NIR-hyperthermic treatment, photodynamic therapy, etc. PMID:26538202

  15. In-situ preparation and characterization of acid functionalized single walled carbon nanotubes with polyimide nanofibers.

    PubMed

    Dhakshnamoorthy, M; Ramakrishnan, S; Vikram, S; Kothurkar, Nikhil K; Rangarajan, Murali; Vasanthakumari, R

    2014-07-01

    Nanofiber composites (Polyimide/f-SWCNT) of Pyromellitic dianhydride, 4,4'-Oxydianiline, and 4,4'-(4,4'-isopropylidene diphenyl-1,1'-diyl dioxy) dianiline (PMDA-ODA/IDDA) and surface-functionalized single walled carbon nanotubes (f-SWCNT) were made by electrospinning a solution of poly(amic acid) (PAA) containing 0-2 wt% f-SWCNT followed by thermal imidization. X-ray photoelectron spectroscopy spectra verified the oxidation of SWCNT surface after acid treatment, and indicated possible hydrogen bonding interactions between the f-SWCNTs and polyamic acid. High-resolution scanning electron microscopy images showed the average diameter of nanofibers to be below 150 nm, and transmission electron microscopy images showed that SWCNTs were aligned inside the polymer nanofiber. In thermogravimetric analysis, all composites showed increased thermal stability with increasing f-SWCNT content compared to neat PI. Storage modulus also increased from 124 MPa to 229 MPa from neat PI to 2% f-SWCNT composite. PMID:24757974

  16. Blood oxidative stress generation after intraperitoneal administration of functionalized single-walled carbon nanotubes in rats.

    PubMed

    Clichici, Simona; Mocan, T; Filip, A; Biris, A; Simon, S; Daicoviciu, D; Decea, N; Parvu, A; Moldovan, R; Muresan, A

    2011-06-01

    Single-walled carbon nanotubes (SWCNTs) have been proposed for various medical applications. However, their safety for human administration has not been yet fully demonstrated. In vitro studies have pointed oxidative stress as a mechanism involved in their cytotoxic effects. In the present study we have evaluated the capacity of DNA functionalized SWCNTs to induce oxidative stress in blood after intraperitoneal (ip) administration in rats. The presence of SWCNTs in blood was confirmed by Raman spectroscopy 30 minutes after their ip administration. Oxidative stress parameters (malondialdehyde - MDA, protein carbonyls - PC, antioxidant capacity measured as hydrogen donating capacity - HD, sulfhydryl groups - SH, glutathione - GSH and nitrites - NO) were assessed in blood at 3, 6, 24, respectively, and 48 hours after ip injection. MDA, PC and NO exhibited a significant increase at 3-6 hours interval from exposure, followed by a recovery trend. The levels of HD reached a bottom level at 6 hours after administration, while SH strongly decreased at 3 hours interval and increased slightly up to 48 hours without attending the initial values. GSH level recorded an increasing tendency at the 3rd hour, an incomplete recovery process at 24 hours followed by a secondary significant increase following a 48-hour interval. Significant inverse correlations were obtained between the PC and SH levels and between the NO and HD values. In conclusion, the ip administration of DNA functionalized SWCNT in rats results in oxidative stress generation in plasma, with a transient pattern of evolution. PMID:21616782

  17. Infrared Responsivity of a Pyroelectric Detector with a Single-Wall Carbon Nanotube Coating

    SciTech Connect

    Theocharous, E.; Engtrakul, C.; Dillon, A. C.; Lehman, J.

    2008-08-01

    The performance of a 10 mm diameter pyroelectric detector coated with a single-wall carbon nanotube (SWCNT) was evaluated in the 0.8 to 20 {micro}m wavelength range. The relative spectral responsivity of this detector exhibits significant fluctuations over the wavelength range examined. This is consistent with independent absorbance measurements, which show that SWCNTs exhibit selective absorption bands in the visible and near-infrared. The performance of the detector in terms of noise equivalent power and detectivity in wavelength regions of high coating absorptivity was comparable with gold-black-coated pyroelectric detectors based on 50 {micro}m thick LiTaO{sub 3} crystals. The response of this detector was shown to be nonlinear for DC equivalent photocurrents >10{sup -9} A, and its spatial uniformity of response was comparable with other pyroelectric detectors utilizing gold-black coatings. The nonuniform spectral responsivity exhibited by the SWCNT-coated detector is expected to severely restrict the use of SWCNTs as black coatings for thermal detectors. However, the deposition of SWCNT coatings on a pyroelectric crystal followed by the study of the prominence of the spectral features in the relative spectral responsivity of the resultant pyroelectric detectors is shown to provide an effective method for quantifying the impurity content in SWCNT samples.

  18. Cytotoxicity Investigation on Cultured Human Blood Cells Treated with Single-Wall Carbon Nanotubes

    PubMed Central

    Zeni, Olga; Palumbo, Rosanna; Bernini, Romeo; Zeni, Luigi; Sarti, Maurizio; Scarfì, Maria Rosaria

    2008-01-01

    The single-wall carbon nanotubes (SWCNTs) are one of the new materials of emerging technologies. They are becoming increasingly studied for the possible applications in electronics, optics and biology. In particular, very promising fields of application are the development of optical biosensors and the intracellular drug delivery. Nevertheless, there is a paucity of information on their toxicological properties and on potential human health risk. In the present study the SWCNTs were investigated for the possible induction of toxicity in human blood cells. Cell growth, viability, apoptosis and metabolic activity were evaluated in proliferating human peripheral blood lymphocytes. In un-stimulated human leukocytes primary DNA damage was also evaluated. SWCNTs concentrations ranging from 1 to 50 ?g/ml were tested, and treatment duration varied from 6 to 72 h, in accordance with the biological target investigated. A statistically significant decrease in cell growth was found in cells treated with the highest concentrations (25 and 50 ?g/ml). Such decrease was not associated to cell death or apoptosis, but it was demonstrated to be related to a decrease in metabolic activity, as assessed by resazurin assay. Moreover, treatments of 6 h with SWCNTs concentrations of 1, 5 and 10 ?g/ml failed to induce primary DNA damage on the entire human leukocytes population.

  19. Random networks of single-walled carbon nanotubes promote mesenchymal stem cell's proliferation and differentiation.

    PubMed

    Lee, Jae-Hyeok; Shim, Wooyoung; Choolakadavil Khalid, Najeeb; Kang, Won-Seok; Lee, Minsu; Kim, Hyo-Sop; Choi, Je; Lee, Gwang; Kim, Jae-Ho

    2015-01-28

    Studies on the interaction of cells with single-walled carbon nanotubes (SWCNTs) have been receiving increasing attention owing to their potential for various cellular applications. In this report, we investigated the interactions between biological cells and nanostructured SWCNTs films and focused on how morphological structures of SWCNT films affected cellular behavior such as cell proliferation and differentiation. One directionally aligned SWCNT Langmuir-Blodgett (LB) film and random network SWCNT film were fabricated by LB and vacuum filteration methods, respectively. We demonstrate that our SWCNT LB and network film based scaffolds do not show any cytotoxicity, while on the other hand, these scaffolds promote differentiation property of rat mesenchymal stem cells (rMSCs) when compared with that on conventional tissue culture polystyrene substrates. Especially, the SWCNT network film with average thickness and roughness values of 95 ± 5 and 9.81 nm, respectively, demonstrated faster growth rate and higher cell thickness for rMSCs. These results suggest that systematic manipulation of the thickness, roughness, and directional alignment of SWCNT films would provide the convenient strategy for controlling the growth and maintenance of the differentiation property of stem cells. The SWCNT film could be an alternative culture substrate for various stem cells, which often require close control of the growth and differentiation properties. PMID:25546303

  20. Intracellular uptake, trafficking and subcellular distribution of folate conjugated single walled carbon nanotubes within living cells.

    PubMed

    Kang, Bin; Yu, De-Cai; Chang, Shu-Quan; Chen, Da; Dai, Yao-Dong; Ding, Yitao

    2008-09-17

    Herein we studied the uptake, trafficking and distribution of folate conjugated single walled carbon nanotubes (SWNTs) within living cells. SWNTs were noncovalently functionalized with chitosan and then linked with folate acid and fluorescence dye Alexa Fluor 488 (denoted FA-SWNTs). Hep G2 cells were cultured in vitro and incubated with FA-SWNTs at different levels. The FA-SWNTs exhibited a concentration-dependent uptake within Hep G2 cells, and Hep G2 cells were able to internalize FA-SWNTs via a folate receptor-mediated pathway. The distribution of nanotubes inside cells demonstrated that the FA-SWNTs only locate in the cytoplasm and not in nuclei, indicating the failure of transporting through the nuclear envelope. Transmission electron microscope (TEM) results showed the presence of FA-SWNTs in lysosomes and the discharge to extracellular space after incubation with nanotubes for 5 h. No obvious cellular death rate was observed when the concentration of nanotubes was below 50 µg ml(-1). However, cells with FA-SWNT uptake showed a concentration-dependent apoptosis. These discoveries might be helpful for understanding the interaction of SWNTs and living cells. PMID:21832540