Sample records for metallic single-wall carbon

  1. Separation of Metallic from Semiconducting Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Ralph Krupke; Frank Hennrich; Hilbert v. Löhneysen; Manfred M. Kappes

    2003-01-01

    We have developed a method to separate metallic from semiconducting single-walled carbon nanotubes from suspension using alternating current dielectrophoresis. Our method takes advantage of the difference of the relative dielectric constants of the two species with respect to the solvent, resulting in an opposite movement of metallic and semiconducting tubes along the electric field gradient. Metallic tubes are attracted toward

  2. Modeling electron transport in metallic single wall carbon nanotubes

    Microsoft Academic Search

    Ronald Cosby; Evan Wilson

    2010-01-01

    First principles atomistic calculations of electrical conductance for single-wall metallic carbon nanotubes on copper electrodes are described. Density functional theory and a non-equilibrium Green's function technique are used to calculate electronic structure and current-voltage characteristics. The computed effects of selected impurities and nanotube strains on the conductance are displayed and discussed. Progress in studying the impacts of copper-nanotube interface characteristics

  3. 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.

  4. Metal-assisted hydrogen storage on Pt-decorated single-walled carbon nanohorns

    E-print Network

    Geohegan, David B.

    Metal-assisted hydrogen storage on Pt-decorated single-walled carbon nanohorns Yun Liu a,b,*, Craig nanoparticles can assist in enhanced hydrogen storage on high-surface area supports are still under debate. Experimental mea- surements of metal-assisted hydrogen storage have been hampered by inaccurate estima- tion

  5. 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.

  6. Direct identification of metallic and semiconducting single-walled carbon nanotubes in scanning electron microscopy.

    PubMed

    Li, Jie; He, Yujun; Han, Yimo; Liu, Kai; Wang, Jiaping; Li, Qunqing; Fan, Shoushan; Jiang, Kaili

    2012-08-01

    Because of their excellent electrical and optical properties, carbon nanotubes have been regarded as extremely promising candidates for high-performance electronic and optoelectronic applications. However, effective and efficient distinction and separation of metallic and semiconducting single-walled carbon nanotubes are always challenges for their practical applications. Here we show that metallic and semiconducting single-walled carbon nanotubes on SiO(2) can have obviously different contrast in scanning electron microscopy due to their conductivity difference and thus can be effectively and efficiently identified. The correlation between conductivity and contrast difference has been confirmed by using voltage-contrast scanning electron microcopy, peak force tunneling atom force microscopy, and field effect transistor testing. This phenomenon can be understood via a proposed mechanism involving the e-beam-induced surface potential of insulators and the conductivity difference between metallic and semiconducting SWCNTs. This method demonstrates great promise to achieve rapid and large-scale distinguishing between metallic and semiconducting single-walled carbon nanotubes, adding a new function to conventional SEM. PMID:22730928

  7. 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

  8. Single-Walle 4. Single-Walled Carbon Nanotubes

    E-print Network

    Kono, Junichiro

    105 Single-Walle 4. Single-Walled Carbon Nanotubes Sebastien Nanot, Nicholas A. Thompson, Ji Single-walled carbon nanotubes (SWCNTs) are hol- low, long cylinders with extremely large aspect ratios their discovery, carbon nanotubes continue to surprise researchers with potential new applications and interesting

  9. 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.

  10. 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 .

  11. Bound excitons and optical absorption spectra of (10,10) metallic single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Deslippe, Jack; Spataru, Catalin; Louie, Steven

    2006-03-01

    Motivated by recent theoretical prediction of bound excitons [1] in small diameter metallic single-walled carbon nanotubes, we study the optical spectra of the larger diameter (10,10) metallic tube. We use an interacting-particle Green’s function approach which includes calculations of the quasiparticle excitation spectrum (within the GW approximation for the electron self energy) and the electron-hole excitation spectrum (within the Bethe-Salpeter formalism). We show that the (10,10) tube has important excitonic effects despite being a metal, due to the quasi-one dimensional nature of the carbon nanotubes. A bound exciton with binding energy of 60 meV is found, and the location of the excitonic peak in the optical spectrum is at 1.8 eV. [1] C. D. Spataru, S. Ismail-Beigi, L. X. Benedict, and S. G. Louie, Phys. Rev. Lett. 92, 077402 (2004).

  12. Selective electroless coating of palladium nanoparticles on metallic single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Feng, Yiyu; Lv, Peng; Zhang, Xuequan; Li, Yu; Feng, Wei

    2010-08-01

    The selective electroless coating of palladium (Pd) nanoparticles on metallic single-walled carbon nanotube (SWNT) was studied. The remarkable increase in conductivity of SWNT/Pd films up to fourfold higher than pure SWNT was due to p-type doping and Ohmic contact. Metallic behavior of SWNT/Pd-Field effect transistor (on/off ratio=1.2) was attributed to more hole carriers and no electrostatic barrier between nanotube and Pd. G-band and radial breathing mode in Raman indicates a definitive increase in the proportion of metallic SWNT. Results indicate Pd are selectively coated on metallic SWNT with more negative potential allowing for the electroless Pd2+ reduction.

  13. Graphitic electrical contacts to metallic single-walled carbon nanotubes using Pt electrodes.

    PubMed

    Kane, Alexander A; Sheps, Tatyana; Branigan, Edward T; Apkarian, V Ara; Cheng, Ming H; Hemminger, John C; Hunt, Steven R; Collins, Philip G

    2009-10-01

    We investigate electronic devices consisting of individual, metallic, single-walled carbon nanotubes contacted by Pt electrodes in a field effect transistor configuration, focusing on improvements to the metal-nanotube contact resistance as the devices are annealed in inert environments including ultrahigh vacuum. At moderate temperatures (T < 880 K), thermal processing results in high resistance contacts with thermally activated barriers. Higher temperatures (T > 880 K) achieve nearly transparent contacts. In the latter case, analytical surface measurements reveal the catalytic decomposition of hydrocarbons into graphene layers on the Pt surface, suggesting that improved electronic behavior is primarily due to the formation of an all-carbon nanotube-graphite interface rather than to the improvement of the nanotube-Pt one. PMID:19754066

  14. 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

  15. Is it possible to enhance Raman scattering of1 single-walled carbon nanotubes by metal particles2

    E-print Network

    Maruyama, Shigeo

    the possibility of using metal nano-particles to enhance the Raman2 scattering of single walled carbon nanotubes chemical4 vapor deposition (CVD). Particle position, metal type, film thickness, excitation5 wavelength the key structural parameters [5-7].10 Since the early stage of chemical vapor deposition (CVD) growth

  16. Potentiating toxicological interaction of single-walled carbon nanotubes with dissolved metals.

    PubMed

    Al-Shaeri, Majed; Ahmed, Dina; McCluskey, Fiona; Turner, Gavin; Paterson, Lynn; Dyrynda, Elisabeth A; Hartl, Mark G J

    2013-12-01

    The present study explored the ecotoxicology of single-walled carbon nanotubes (SWCNTs) and their likely interaction with dissolved metals, with a focus on the effect of in vivo exposure in marine mussels. Any nano-scale effects were negated by the tendency of uncoated SWCNTs to agglomerate in water, particularly with high ionic strength as is the case in estuarine and full-strength seawater. However, SWCNTs, in combination with natural organic matter, remained suspended in seawater for long enough to become available to filter-feeding mussels, leading to their concentration on and increased contact with gill epithelia during exposure. For the first time, the authors describe a potentiating toxicological effect, expressed as DNA strand breaks obtained using the comet assay, on divalent metals afforded by negatively charged SWCNT agglomerates in seawater at concentrations as low as 5?µg?L?¹. This is supported by the observation that SWCNTs alone were only toxic at concentrations ?100?µg?L?¹ and that the SWCNT-induced DNA damage was correlated with oxidative stress only in the absence of metals. If these laboratory experiments are confirmed in the natural environment, the present results will have implications for the understanding of the role of carbon nanotubes in environmental metal dynamics, toxicology, and consequently, regulatory requirements. PMID:23982896

  17. Metallic single-walled, carbon nanotube temperature sensor with self heating

    NASA Astrophysics Data System (ADS)

    Mohsin, K. M.; Banadaki, Y. M.; Srivastava, A.

    2014-04-01

    A metallic single-walled carbon nanotube (SWCNT) has been proposed as a highly sensitive temperature sensor with consideration of self-heating induced scattering. This sensor can be implemented to sense temperature spanning from 20º C to 400º C with high temperature coefficient of resistivity (TCR) ranging from 0.0035/ºC to 0.009/ ºC. Important aspect of this work is consideration of self-heating in SWCNT which was not considered in earlier carbon nanotube based temperature sensors. We have studied a metallic SWCNT over a silicon dioxide substrate and in between two metal contacts. Bias voltage of 0.1V has been applied in between these two contacts. For resistivity calculation, we have utilized one-dimensional semi-classical transport model assuming SWCNT is perfectly conducting. The heat flow equation has been solved assuming steady state flow of heat. We have also assumed that contact and substrate are in thermal equilibrium with the surroundings. Since self-heating significantly affects electro-thermal transport, incorporation of this phenomenon enables to design and model ambient temperature sensor accurately. We have studied CNT sensor with different lengths and chiralities. The results show that resistances of longest (3?m) and thinnest (9, 0) CNTs increase rapidly with temperature. For a 3?m long metallic SWCNT with chirality index (9, 0), TCR has the maximum value (~0.009/ ºC).

  18. 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

  19. Conversion of metallic single-walled carbon nanotube networks to semiconducting through electrochemical ornamentation.

    PubMed

    Asheghali, Darya; Vichchulada, Pornnipa; Lay, Marcus D

    2013-05-22

    Field-effect transistors (FETs) that incorporate single-walled carbon nanotube (SWNT) networks experience decreased on-off current ratios (I(on)/I(off)) due to the presence of metallic nanotubes. Herein, we describe a method to increase I(on)/I(off) without the need for either specialized SWNT growth methods or post growth processing steps to remove metallic nanotubes. SWNTs that were grown using conventional arc discharge methods were deposited from aqueous suspension. Then, the SWNTs in the network were decorated with Cu2O nanoparticles that acted as controllable valves that restricted current flow at positive gate voltages. This resulted in an unprecedented reduction in I(off), as the sub-10 nm sized nanoclusters acted as numerous tunable valves, providing greatly improved network sensitivity to gate voltages in the relatively small range of ±10 V, increasing I(on)/I(off) by up to 205-fold. Larger nanoclusters were found to increase the network conductivity but decrease I(on)/I(off). The ability to convert metallic SWNTs to semiconducting without removing them allows for enhanced I(on) and lower noise while still achieving greatly enhanced magnitudes of I(on)/I(off). PMID:23607878

  20. On the Preferential Growth of Metallic Single-Walled Carbon Nanotubes Thin Films

    NASA Astrophysics Data System (ADS)

    Harutyunyan, Avetik

    2010-03-01

    The lack of reasonably homogeneous single walled carbon nanotube (SWCNT) materials hinders their ubiquitous applications. There have been significant achievements in separating SWCNTs according to their conductivity and in enriching the distribution of nanotubes with a specific conductivity. Meanwhile, despite studies regarding direct control over carbon nanotube structure during growth, there is only a limited understanding of exactly what determines carbon nanotube chirality during catalytic growth and, thereby, the electronic structure of grown SWCNT. Here we report the results of the studies of growth of SWCNTs thin films from Fe nanocatalysts deposited onto a SiO2/Si support and in situ annealed in a He or Ar ambient that contains various ratios of H2 and H2O. Our investigations reveal that the variation of the noble gas ambient during thermal conditioning of the catalyst, in combination with oxidative and reductive species, alters the fraction of tubes with metallic conductivity from about 20% of the population to a maximum of 91%. The tubes have been identified based on Raman, photoluminescence and electrical (field effect transistor performance) characterizations by using special prepared reference sample. In situ environmental transmission electron microscopy observations of the SiO2 supported Fe nanocatalysts in H2O, H2/H2O, Ar/H2O and He/H2O gaseous environments reveal that presence of Ar in the ambient leads to significant coarsening of nanocatalysts with rounded surface morphology, while under He ambient the nanocatalyst is more faceted. Various scenarios such as adsorption and roughening induced morphology rearrangements of the catalyst particles and their relationships with grown tubes electronic structures will be presented.

  1. 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.

  2. Single-walled carbon nanotube electronics

    Microsoft Academic Search

    Paul L. McEuen; Michael S. Fuhrer; Hongkun Park

    2002-01-01

    Single-walled carbon nanotubes (SWNTs) have emerged as a very promising new class of electronic materials. The fabrication and electronic properties of devices based on individual SWNTs are reviewed. Both metallic and semiconducting SWNTs are found to possess electrical characteristics that compare favorably to the best electronic materials available. Manufacturability issues, however, remain a major challenge

  3. Semiconducting single wall carbon nanotubes inverstigated by

    E-print Network

    Maruyama, Shigeo

    Semiconducting single wall carbon nanotubes inverstigated by photoconductivity Electronique Fondamentale, University of Paris Sud 11, Orsay, France 3: Research Center for Photovoltaics Using semiconducting single wall carbon nanotubes with well defined chiral index (n,m), the photo

  4. Photo-physics of P3HT blended with highly enriched metallic and semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Holt, Josh; Mistry, Kevin; Ferguson, Andrew; Blackburn, Jeff

    2010-03-01

    Single-walled carbon nanotubes (SWNTs) possess unique properties that may potentially benefit photovoltaic (PV) devices, including high carrier mobilities, convenient work functions, and tunable optical transitions that span most of the solar spectrum. However, significant polydispersity in both diameter and electronic structure have hindered the realization of efficient PV cells incorporating SWNTs. In this presentation, we report the use of advanced techniques to separate single-walled carbon nanotubes (SWNTs) created by laser vaporization into highly enriched semiconducting and metallic species. The enriched SWNTs are then blended with regioregular poly(3-hexylthiophene) (P3HT) to serve as a model electron donor/acceptor system, analogous to systems typically used in organic PV devices. We investigate the photo-physical properties of charge generation and transfer using primarily time-resolved microwave conductivity (TRMC) and photoluminescence excitation spectroscopy and discuss the disparities between metallic vs semiconducting SWNT acceptors.

  5. Density functional theory investigation of the VIIIB transition metal atoms deposited on (5,5) single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Tabtimsai, Chanukorn; Ruangpornvisuti, Vithaya; Wanno, Banchob

    2013-03-01

    The binding of VIIIB transition metals i.e. Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, and Pt single atoms to single-walled carbon nanotube (SWCNT) was investigated using the density functional theory method. The B3LYP/LanL2DZ calculation shows that all these transition metal atoms have strong binding abilities to SWCNT. The binding abilities of these transition metals onto SWCNT are in following order: Os>Ru>Ir>Fe>Rh>Pt>Ni>Co>Pd. The Os single atom binding on SWCNT is the strongest binding of which the binding energy is -240.66 kcal/mol. The partial charge transfers from transition metal to SWCNT, density of states and energy gaps of metal atoms deposited on SWCNTs were analyzed and reported.

  6. Modification of conductive properties of (10, 0) zigzag single-walled carbon nanotubes (SWCNT) by alkali metals absorption

    NASA Astrophysics Data System (ADS)

    Hamadanian, Masood; Tavangar, Zahra; Noori, Banafsheh

    2014-11-01

    We have investigated the electronic and structural properties of (10, 0) zigzag single-walled carbon nanotubes (SWCNT) which have adsorbed different alkali metals (X: Li, Na, K, and Cs) and the hydrogen atom by using Density Functional Theory (DFT). It was discovered that among the alkali elements, Li atoms form the strongest bond with SWCNT. In addition, a significant shift was observed in the electronic state of alkali-adsorbed SWCNT compared to pristine SWCNT. Finally, it was proposed that due to showing excellent electronic structure, these modified nanotubes can be applied in new electronic devices, such as transistors, and field emission displays.

  7. Single wall carbon nanotube double quantum dot

    Microsoft Academic Search

    H. I. Jørgensen; K. Grove-Rasmussen; J. R. Hauptmann; P. E. Lindelof

    2006-01-01

    The authors report on two top-gate defined, coupled quantum dots in a semiconducting single wall carbon nanotube, constituting a tunable double quantum dot system. The single wall carbon nanotubes are contacted by titanium electrodes and gated by three narrow top-gate electrodes as well as a back gate. The authors show that a bias spectroscopy plot on just one of the

  8. Ferromagnetically Contacted Single-Wall Carbon Nanotubes

    E-print Network

    Nygård, Jesper

    Ferromagnetically Contacted Single-Wall Carbon Nanotubes Ane Jensen Ph.d. Thesis Department of Copenhagen April 2003 #12;#12;Ferromagnetically Contacted Single-Wall Carbon Nanotubes Abstract Ferromagnetic nanotubes (SWNTs), with the purpose of study spin-polarized transport under the unique conditions of- fered

  9. Carbon nanotubes Growth of Single-Walled Carbon Nanotubes from Sharp

    E-print Network

    Nordlund, Kai

    Carbon nanotubes Growth of Single-Walled Carbon Nanotubes from Sharp Metal Tips Julio A. Rodri Banhart* The nucleation and growth of single-walled carbon nanotubes is observed in situ in a transmission a region of high surface curvature, spontaneous nucleation and growth of single-walled carbon nanotubes

  10. 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.

  11. Electrophoretic analysis and separation of single-walled carbon nanotubes and metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoyou

    Electrophoresis has been widely used in biological science but has barely applied to nanomaterials. This study is to demonstrate the applications of electrophoresis to separation and analysis of nanomaterials based on size and shape. In an effort to purify arc-discharge single-walled carbon nanotubes (SWNTs), we developed a procedure to separate larger graphite-related materials from stable crude nanotubes suspension, which was subjected to electrophoretic separation in glass bead matrix and agarose gel. Three important components were well separated: purified SWNTs, short tubule carbon species, and fluorescent fragments. For the first time, electrophoresis has been successfully used to purify arc-discharge SWNTs. Moreover, the two classes of new nanomaterials: short tubule carbon and fluorescent fragments promise to be useful in their own right. The electrophoretic technique was extended to the separation of gold nanoparticles. First, column electrophoresis was demonstrated to separate nanospheres based on size. Next crude nanospheres were electrophoretically purified. The standard deviation of crude sample of 20% was narrowed to 3--4% of purified sample, indicative of substantial improvement in size distribution. Finally, the crude gold nanorod sample was separated into three components based on shape: spheres, platelets, and rods. Gel electrophoresis has demonstrated much higher resolution than conventional methods: multi-step centrifugation, size exclusion chromatography, etc. In spite of the fact that SERS activity is intimately associated with the size and shape of nanoparticles, there are rare reports on how to find the size and shape of nanoparticles with highest SERS activity. To achieve this goal, we have designed a procedure. First, crude silver nanoparticles with wide distribution in size and shape was synthesized and functionalized. Then gel electrophoresis was used to separate the nanoparticles into different colorful bands and each of them may correspond to the plasmon resonance scattering of the uniform nanoparticles in size and shape. It has been found the activity is very dependent on different sizes and shapes. Future work will find the absolute SERS intensity of each band after considering silver concentrations. A useful technique will be anticipated to sensor the SERS activity based on size and shape of nanoparticles.

  12. 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.

  13. Long-term colloidal stability and metal leaching of single wall carbon nanotubes: effect of temperature and extracellular polymeric substances.

    PubMed

    Adeleye, Adeyemi S; Keller, Arturo A

    2014-02-01

    Long term (90 day) stability, aggregation kinetics in the presence and absence of natural organic materials (NOM), and metal leaching of five commercial single wall carbon nanotubes (SWCNTs) in waters (e.g. freshwater, seawater, stormwater, wastewater, and groundwater) were studied, as well as the effect of temperature on SWCNT stability and metal leaching. Zeta (?) potential of SWCNT decreased in magnitude with increase in temperature. In wastewater, SWCNT sedimented from the water column to below detectable levels after 30 days when kept at 40 °C, but at 20 °C 19% suspension was still observed after the same exposure time. Addition of 0.1 mg-C L(-1) EPS shifted the critical coagulation concentration (CCC) of SRNOM-stabilized SWCNT from 15 mM to 54 mM NaCl via additional electrostatic and possibly steric stabilization. Attachment efficiencies (?) of SWCNT in waters ranged from ?0.001 in DI with 10 mg L(-1) SRNOM to 1 in seawater. However, sedimentation of SWCNT in seawater (and other high ionic strength conditions) was not as fast as expected due to improved buoyancy and/or drag. Purified forms of SWCNTs exhibited better dispersibility and stability in most waters, but as expected, the total metal leached out was higher in the raw variants. Metal leaching from CNT in these studies was controlled by metal and water chemistries, CNT pretreatment, leachable metal fraction, exposure time, and presence of NOM. PMID:24342047

  14. 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.

  15. Stability, metal leaching, photoactivity and toxicity in freshwater systems of commercial single wall carbon nanotubes.

    PubMed

    Bennett, Samuel W; Adeleye, Adeyemi; Ji, Zhaoxia; Keller, Arturo A

    2013-08-01

    Carbon nanotubes (CNTs) are exciting new materials that have been intensively researched and are becoming increasingly used in consumer products. With rapid growth in production and use of CNTs in many applications, there is the potential for emissions to the environment and thus research is needed to assess the risks associated with CNTs in the environment. Here we show that commercial CNTs differ in their stability, photoactivity, metal leachate, and toxicity to freshwater algae. The behavior between raw and purified variants of the CNTs differs considerably; for example purified CNTs are generally more photoactive, producing singlet oxygen and superoxide, while raw CNTs show little or no photoactivity. Residual metal catalysts differ based on synthesis method used to prepare CNTs and thus may be comprised of elements with varying degrees of toxic potential. Influenced by pH and other constituents of the natural waters, our work shows that metals can leach out from all the commercial CNTs studied, even purified versions, albeit at different levels in many natural waters. As much as 10% of the total residual nickel leached from a purified CNT after 72 h. Aqueous concentrations of molybdenum leached from a different purified CNT were nearly 0.060 mg L(-1) after 72 h. With little sample preparation, CNTs are dispersible in most freshwaters and stable for several days. Not all tested CNTs were toxic; for those CNTs that did induce toxicity we show that photoactivity, not metal leaching, contributes to the toxicity of commercial CNTs to freshwater algae, with growth rates significantly reduced by as much as 200%. PMID:23591109

  16. Separation of single-walled carbon nanotubes into metallic and semiconducting groups: a simple and large-scale method

    NASA Astrophysics Data System (ADS)

    Lu, Jing; Maeda, Y.

    2006-03-01

    Separation of a large number of single-walled carbon nanotubes (SWNTs) into groups each with specifically metallic and semiconducting properties is an extremely important task for technology application. Even though effective methods (1, 2) have been devised, they suffer from drawbacks such as either the yield is low (3) or expense is high (4). In this work, we study the problem from a theoretical approach, we notice that based on the first principles calculations the binding strengths of methylamine to the semiconducting [13, 0] SWNT are only 36˜61% of that to the metallic [7, 7] SWNT, which suggests that the amines is much more attractive toward the pure metallic than the semiconducting SWNTs. Therefore starting from as-prepared SWNTs and with the assistance of amines, we achieved SWNTs with enriched metallic properties over semiconducting in a convenient and large-scale manner. References: (1) D. Chattopadhyay, L. Galeska, F. Papadimitrakopoulos, Journal of the American Chemical Society 125, 3370 (MAR 19, 2003). (2) H. P. Li et al., Journal of the American Chemical Society 126, 1014 (FEB 4, 2004). (3) R. Krupke, F. Hennrich, H. von Lohneysen, M. Kappes, SCIENCE 301, 344 (JUL 18, 2003). (4) M. Zheng et al., Science 302, 1545 (NOV 28, 2003).

  17. Hydrogenation of single-walled carbon nanotubes

    E-print Network

    Anton Nikitin; Hirohito Ogasawara; David Mann; Reinhard Denecke; Zhiyong Zhang; Hongjie Dai; KJ Cho; Anders Nilsson

    2005-10-14

    Towards the development of a useful mechanism for hydrogen storage, we have studied the hydrogenation of single-walled carbon nanotubes with atomic hydrogen using core-level photoelectron spectroscopy and x-ray absorption spectroscopy. We find that atomic hydrogen creates C-H bonds with the carbon atoms in the nanotube walls and such C-H bonds can be com-pletely broken by heating to 600 oC. We demonstrate approximately 65+/-15 at % hydrogenation of carbon atoms in the single-walled carbon nanotubes which is equivalent to 5.1+/-1.2 weight % hydrogen capacity. We also show that the hydrogenation is a reversible process.

  18. 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 ...

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Electrochemical and In-situ Studies of Alkali Metal Doping in Single Wall Carbon Nanotubes

    Microsoft Academic Search

    Agnes Claye

    2000-01-01

    Electrochemistry has proven to be extremely useful for the study of guest-host systems, in particular carbon-based intercalation compounds. Not only does it provide essential information about thermodynamics and kinetics, but it also offers accurate control of guest stoichiometry, which is difficult to achieve through other doping methods. Perhaps more importantly, in-situ electrochemical experiments afford continuous and reversible composition control, and

  6. Absorption spectroscopy of individual single-walled carbon nanotubes

    E-print Network

    Boyer, Edmond

    Absorption spectroscopy of individual single-walled carbon nanotubes Stéphane Berciaud,a Laurent-walled carbon nanotubes (SWNTs) lead to heterogeneous samples containing mixtures of metallic and semiconducting species with a variety of lengths and defects. Optical detection at the single nanotube level should thus

  7. Fluorination of single-wall carbon nanotubes

    Microsoft Academic Search

    E. T. Mickelson; C. B. Huffman; A. G. Rinzler; R. E. Smalley; R. H. Hauge; J. L. Margrave

    1998-01-01

    Purified single-wall carbon nanotubes (SWNTs) were fluorinated at several different temperatures. Product stoichiometries were determined and electron microscopy was used to verify whether or not the fluorination was destructive of the tubes. SWNTs fluorinated at three different temperatures were then defluorinated using hydrazine. Raman spectroscopy and resistance measurements were utilized to verify whether or not the products of the defluorination

  8. Assessing The Hydrogen Adsorption Capacity Of Single-Wall Carbon Nanotube / Metal Composites

    NASA Astrophysics Data System (ADS)

    Heben, Michael J.; Dillon, Anne C.; Gilbert, Katherine E. H.; Parilla, Philip A.; Gennett, Thomas; Alleman, Jeffrey L.; Hornyak, G. Louis; Jones, Kim M.

    2003-07-01

    Carefully controlled and calibrated experiments indicate a maximum capacity for adsorption of hydrogen on SWNTs is ˜8 wt% under room temperature and pressure conditions. Samples displaying this maximum value were prepared by sonicating purified SWNTs in a dilute nitric acid solution with a high-energy probe. The process cuts the SWNT into shorter segments and introduces a Ti-6Al-4V alloy due to the disintegration of the ultrasonic probe. The Ti-6Al-4V alloy is a well-known metal hydride and its contribution to the measured hydrogen uptake was accounted for in order to assess the amount of hydrogen stored on the SWNT fraction. The principal purpose of this paper is to present key details associated with the measurement procedures in order to illustrate the degree of rigor with which the findings were obtained.

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

    SciTech Connect

    Lukaszczuk, Pawel, E-mail: plukaszczuk@zut.edu.pl [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin (Poland)] [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin (Poland); Ruemmeli, Mark H.; Knupfer, Martin [Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden (Germany)] [Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20, 01069 Dresden (Germany); Kalenczuk, Ryszard J.; Borowiak-Palen, Ewa [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin (Poland)] [West Pomeranian University of Technology, Institute of Chemical and Environment Engineering, ul. Pulaskiego 10, 70-322 Szczecin (Poland)

    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.

  10. Electrochemical and In-situ Studies of Alkali Metal Doping in Single Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Claye, Agnes

    2000-03-01

    Electrochemistry has proven to be extremely useful for the study of guest-host systems, in particular carbon-based intercalation compounds. Not only does it provide essential information about thermodynamics and kinetics, but it also offers accurate control of guest stoichiometry, which is difficult to achieve through other doping methods. Perhaps more importantly, in-situ electrochemical experiments afford continuous and reversible composition control, and eliminate the need for glove box transfer. We have used in-situ and ex-situ electrochemical techniques to study the structural and electronic properties of Li/SWNT and K/SWNT compounds. In this paper we review their thermodynamic properties, investigated by cyclic voltammetry and galvanometry. More specifically, we demonstrate 1) the ability to reversibly dope SWNT with Li and K; and 2) the absence of phase transformations as a function of composition, in contrast to intercalation in graphite, polyacetylene and solid C_60. We present the effect of alkali doping on the structure of SWNT, as studied by in-situ X-ray diffraction. We show the changes in electronic transport properties as a function of doping level through in-situ resistivity, in-situ electron spin resonance, and electrochemical impedance spectroscopy. All three techniques show that the bulk resistance of SWNT decreases continuously as a function of doping level, confirming the charge transfer between dopant and host. We use in-situ conduction electron spin resonance to elucidate the electronic structure of doped SWNT. The spin relaxation rate is discussed in terms of the Elliot-Yafet mechanism (A. Claye et al., contributed abstract). Finally, we use electrochemical impedance spectroscopy to study kinetics and alkali doping mechanisms in SWNT. The properties described above are compared and contrasted to those of graphite intercalation compounds and doped conjugated polymers.

  11. Electrostriction in single-walled carbon nanotubes

    Microsoft Academic Search

    Khalil El-Hami; Kazumi Matsushige

    2005-01-01

    Single-walled carbon nanotube (SWCNT) is an electrostrictive material. A significant electrostriction strain was found in semi-conductor SWCNT as a consequence of its carbon atoms’ vibration under an applied electric field. The use of the conductive atomic force microscopy (AFM) combined with lock-in amplifier operating at the second harmonic (2?), facilitated the determination of the experimental electrostriction coefficient (Ce) of about

  12. Molecular discriminators using single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Tamoghna; Dasgupta, Anjan Kr; Ranjan Ray, Nihar; Sarkar, Sabyasachi

    2012-09-01

    The interaction between single wall carbon nanotubes (SWNTs) and amphiphilic molecules has been studied in a solid phase. SWNTs are allowed to interact with different amphiphilic probes (e.g. lipids) in a narrow capillary interface. Contact between strong hydrophobic and amphiphilic interfaces leads to a molecular restructuring of the lipids at the interface. The geometry of the diffusion front and the rate and the extent of diffusion of the interface are dependent on the structure of the lipid at the interface. Lecithin having a linear tail showed greater mobility of the interface as compared to a branched tail lipid like dipalmitoyl phosphatidylcholine, indicating the hydrophobic interaction between single wall carbon nanotube core and the hydrophobic tail of the lipid. Solid phase interactions between SWNT and lipids can thus become a very simple but efficient means of discriminating amphiphilic molecules in general and lipids in particular.

  13. Viscoelasticity of Single Wall Carbon Nanotube Suspensions

    Microsoft Academic Search

    L. A. Hough; M. F. Islam; P. A. Janmey; A. G. Yodh

    2004-01-01

    We investigate the viscoelastic properties of an associating rigid rod network: aqueous suspensions of surfactant stabilized single wall carbon nanotubes (SWNTs). The SWNT suspensions exhibit a rigidity percolation transition with an onset of solidlike elasticity at a volume fraction of 0.0026; the percolation exponent is 2:3 ? 0:1. At large strain, the solidlike samples show volume fraction dependent yielding. We

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

    E-print Network

    pyrolytic graphite (HOPG), in single wall carbon nanotube (SWNT) bundles, and in isolated SWNTs. We foundSecond-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

  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. Fluorination of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Mickelson, E. T.; Huffman, C. B.; Rinzler, A. G.; Smalley, R. E.; Hauge, R. H.; Margrave, J. L.

    1998-10-01

    Purified single-wall carbon nanotubes (SWNTs) were fluorinated at several different temperatures. Product stoichiometries were determined and electron microscopy was used to verify whether or not the fluorination was destructive of the tubes. SWNTs fluorinated at three different temperatures were then defluorinated using hydrazine. Raman spectroscopy and resistance measurements were utilized to verify whether or not the products of the defluorination were in fact SWNTs. It has been determined that the bulk of the SWNTs survive the fluorination process at temperatures up to 325°C and that hydrazine can be employed as an effective defluorinating agent to regenerate the unfluorinated starting material.

  18. Solar synthesis of single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Alvarez, L.; Guillard, T.; Anglaret, E.; Sauvajol, J. L.; Bernier, P.; Flamant, G.; Olalde, G.; Laplaze, D.; Martinez, M. T.; Benito, A.; Maser, W. K.

    1999-09-01

    We discuss here the influence of some synthesis parameters in the production of single wall carbon nanotubes (SWNT) with a 2 kW solar furnace at the Odeillo Institute. We first study the specific role of catalysts like nickel or cobalt on the SWNT formation process. SEM and TEM pictures show significant differences in the yield of production and suggest different growth mechanisms. Furthermore, we report Raman spectra for samples produced using lanthanium or sulfur as catalysts. These samples provide very striking results in the low frequency range (in term of distribution in diameter) with a good correlation with the graphite-like modes region.

  19. Electron Spin in Single Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Lindelof, P. E.; Borggreen, J.; Jensen, A.; Nygård, J.; Poulsen, P. R.

    2003-10-01

    We review aspects of electrical transport in metallic single wall carbon nanotubes (SWCNT) related to the spin of the conductance electrons. For large contact resistances, R ? h/2e2, a SWCNT exhibits Coulomb blockade, and transmission can only occur, when a gate voltage leads to an energy degeneracy for two different numbers of electrons in the SWCNT. The Coulomb blockade gate voltage change is directly proportional to the addition energy for single electron tunnelling. In certain ideal cases every second of the populated electronic states has a higher addition energy, indicating that two spindegenerate electrons are roomed at each orbital state. A low addition energy therefore corresponds to approaching an even number of electrons. The odd-even alternation can be checked in a magnetic field, since then the odd additional electron may enter in one of two Zeeman states. If the high resistance contact is a tunnel junction, the transmission reflects the density of states. This leads to a direct detection of the so-called Luttinger liquid state of the electrons. Ferromagnetic contacts to the SWCNT leads to a conductance which depends on the orientation of the magnetic domains in the contacts. The magnetoresistance effect can be much larger than expected from a simple spin-valve phenomenon. For any intermediate normal metal (Au) contact resistances, R ˜ h/2e2, the Coulomb blockade may still separate the single electron states in the SWCNT with odd and even numbers of electrons. However, at the lowest temperatures the transmission only shows Coulomb blockade for even number of electrons. In the situations with odd number of electrons a coherent tunnelling process dominates. This shortage of the blockade is rooted in the Kondo states formed in the two Au electrodes by exchange interaction due to the spin state in the SWCNT. This tunnelling process is a result of a net spin on the SWCNT and consequently a spin degeneracy. A triplet state is forced into degeneracy with the singlet state in a suitable magnetic field. The situation in a magnetic field is particularly simple in a SWCNT, in contrast to conventional quantum dots, because the tiny diameter of the SWCNT practically speaking precludes orbital effects.

  20. Electron Spin in Single Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Lindelof, P. E.; Borggreen, J.; Jensen, A.; Nygård, J.; Poulsen, P. R.

    We review aspects of electrical transport in metallic single wall carbon nanotubes (SWCNT) related to the spin of the conductance electrons. For large contact resistances, R?h/2e2, a SWCNT exhibits Coulomb blockade, and transmission can only occur, when a gate voltage leads to an energy degeneracy for two different numbers of electrons in the SWCNT. The Coulomb blockade gate voltage change is directly proportional to the addition energy for single electron tunnelling. In certain ideal cases every second of the populated electronic states has a higher addition energy, indicating that two spindegenerate electrons are roomed at each orbital state. A low addition energy therefore corresponds to approaching an even number of electrons. The odd-even alternation can be checked in a magnetic field, since then the odd additional electron may enter in one of two Zeeman states. If the high resistance contact is a tunnel junction, the transmission reflects the density of states. This leads to a direct detection of the so-called Luttinger liquid state of the electrons. Ferromagnetic contacts to the SWCNT leads to a conductance which depends on the orientation of the magnetic domains in the contacts. The magnetoresistance effect can be much larger than expected from a simple spin-valve phenomenon. For any intermediate normal metal (Au) contact resistances, Rh/2e2, the Coulomb blockade may still separate the single electron states in the SWCNT with odd and even numbers of electrons. However, at the lowest temperatures the transmission only shows Coulomb blockade for even number of electrons. In the situations with odd number of electrons a coherent tunnelling process dominates. This shortage of the blockade is rooted in the Kondo states formed in the two Au electrodes by exchange interaction due to the spin state in the SWCNT. This tunnelling process is a result of a net spin on the SWCNT and consequently a spin degeneracy. A triplet state is forced into degeneracy with the singlet state in a suitable magnetic field. The situation in a magnetic field is particularly simple in a SWCNT, in contrast to conventional quantum dots, because the tiny diameter of the SWCNT practically speaking precludes orbital effects.

  1. 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.

  2. Electron transport through metallic single wall carbon nanotubes with adsorbed NO2 and NH3 molecules: A first-principles study

    NASA Astrophysics Data System (ADS)

    Sivasathya, S.; Thiruvadigal, D. John; Mathi Jaya, S.

    2014-08-01

    In this Letter, variations in the transport characteristics of metallic single wall carbon nanotubes (SWCNTs) due to the absorption of NO2 and NH3 molecules on the surface are investigated using the Landauer formalism combined with the non-equilibrium Green's function techniques and ab initio electronic structure obtained using density functional theory (DFT). The electronic structure, charge distribution, transmission spectrum and I-V characteristics of the SWCNT are significantly changed on adsorption which is reflected in the conductance and transport characteristics of the SWCNT. Thus, we conclude that these systems can be used in CNT based NO2 and NH3 gas sensors.

  3. Optically active single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Peng, Xiaobin; Komatsu, Naoki; Bhattacharya, Sumanta; Shimawaki, Takanori; Aonuma, Shuji; Kimura, Takahide; Osuka, Atsuhiro

    2007-06-01

    The optical, electrical and mechanical properties of single-walled carbon nanotubes (SWNTs) are largely determined by their structures, and bulk availability of uniform materials is vital for extending their technological applications. Since they were first prepared, much effort has been directed toward selective synthesis and separation of SWNTs with specific structures. As-prepared samples of chiral SWNTs contain equal amounts of left- and right-handed helical structures, but little attention has been paid to the separation of these non-superimposable mirror image forms, known as optical isomers. Here, we show that optically active SWNT samples can be obtained by preferentially extracting either right- or left-handed SWNTs from a commercial sample. Chiral `gable-type' diporphyrin molecules bind with different affinities to the left- and right-handed helical nanotube isomers to form complexes with unequal stabilities that can be readily separated. Significantly, the diporphyrins can be liberated from the complexes afterwards, to provide optically enriched SWNTs.

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

    E-print Network

    Mintmire, John W.

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

  5. Coherent Lattice Vibrations in Single-Walled Carbon Nanotubes

    E-print Network

    Kono, Junichiro

    Coherent Lattice Vibrations in Single-Walled Carbon Nanotubes Yong-Sik Lim,, Ki-Ju Yee,§ Ji-Hee Kim-walled carbon nanotubes corresponding to the radial breathing mode (RBM) using ultrashort laser pulses. Because electronic and vibrational dynamics in real time.2,3 Single- walled carbon nanotubes (SWNTs

  6. Breakdown of metallic single-wall carbon nanotube paths by NiO nanoparticle point etching for high performance thin film transistors.

    PubMed

    Li, Shisheng; Sakurai, Shunsuke; Futaba, Don N; Hata, Kenji

    2015-01-28

    A selective and highly local etching of the metallic single-wall carbon nanotube (SWCNT) was demonstrated by using a NiO nanoparticle (NP) point etching technique. Following the NiO NP point etching at temperatures ranging from 250 to 350 °C, the current on/off ratios of the SWCNT field effect transistors (FETs) increased over 50-fold from ?10 s to ?10(4). Furthermore, the unavoidable drop in on-state current due to the reduction in current paths could be minimized to within one order of magnitude. Atomic force microscopy and Raman spectroscopy studies supported the view that the improvement in FET performance was attributed to the efficient and localized etching of metallic SWCNT paths solely around the NiO NPs, resulting in minimal damage to the semiconducting SWCNT networks. PMID:25492495

  7. Breakdown of metallic single-wall carbon nanotube paths by NiO nanoparticle point etching for high performance thin film transistors

    NASA Astrophysics Data System (ADS)

    Li, Shisheng; Sakurai, Shunsuke; Futaba, Don N.; Hata, Kenji

    2015-01-01

    A selective and highly local etching of the metallic single-wall carbon nanotube (SWCNT) was demonstrated by using a NiO nanoparticle (NP) point etching technique. Following the NiO NP point etching at temperatures ranging from 250 to 350 °C, the current on/off ratios of the SWCNT field effect transistors (FETs) increased over 50-fold from ~10 s to ~104. Furthermore, the unavoidable drop in on-state current due to the reduction in current paths could be minimized to within one order of magnitude. Atomic force microscopy and Raman spectroscopy studies supported the view that the improvement in FET performance was attributed to the efficient and localized etching of metallic SWCNT paths solely around the NiO NPs, resulting in minimal damage to the semiconducting SWCNT networks.

  8. Elastic wave velocities in single-walled carbon nanotubes

    Microsoft Academic Search

    Chunyu Li; Tsu-Wei Chou

    2006-01-01

    This paper reports an atomistic simulation of single-walled carbon nanotubes subjected to harmonic waves, using the molecular structural mechanics method and normal mode superposition. The velocities of longitudinal, transverse, and torsional waves propagating in single walled carbon nanotubes are obtained. The results indicate that the longitudinal wave velocity is roughly twice as much as that of torsional wave. The velocity

  9. Simulations of nanosensors based on single walled carbon nanotubes

    E-print Network

    Adler, Joan

    Simulations of nanosensors based on single walled carbon nanotubes Polina Pine1, Yuval E. Yaish2. The potential of single-walled carbon nanotubes as mass sensors is examined. The change in mass leads to proportional changes in the nanotube vibrational frequencies, which are monitored during atomistic simulations

  10. Quantum rotation of hydrogen in single-wall carbon nanotubes

    E-print Network

    Yildirim, Taner

    Quantum rotation of hydrogen in single-wall carbon nanotubes C.M. Brown a,b , T. Yildirim b , D containing single-wall carbon nanotubes. These materials have attracted considerable interest recently due the ortho±para conversion of physisorbed hydrogen in a nanotube containing soot loaded with hydrogen. From

  11. Manipulation and Imaging of Individual Single-Walled Carbon Nanotubes

    E-print Network

    Manipulation and Imaging of Individual Single-Walled Carbon Nanotubes with an Atomic Force Microscope** By Henk W. C. Postma, Allard Sellmeijer, and Cees Dekker* Carbon nanotubes[1] have attracted-walled nanotubes,[3±5] the prototype single-walled tubes are much more difficult to study since their diameter

  12. Electrowetting devices with transparent single-walled carbon nanotube electrodes

    E-print Network

    Gruner, George

    - parent to be seen or observed, requiring transparent and elec- trically conducting substrates. Indium tin. Transparent and conducting films made of randomly dis- tributed single-walled carbon nanotubes SWCNTs haveElectrowetting devices with transparent single-walled carbon nanotube electrodes Liangbing Hu

  13. Environmental effects on photoluminescence of single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    Chapter X Environmental effects on photoluminescence of single-walled carbon nanotubes Yutaka Ohno to characterize single-walled carbon nanotubes (SWNTs). In particular, photoluminescence (PL) and the excitation with the practical examples. 2. Optical transition and photoluminescence in SWNTs 2.1 Density of states and optical

  14. Thermochemistry of fluorinated single wall carbon nanotubes.

    PubMed

    Bettinger, H F; Kudin, K N; Scuseria, G E

    2001-12-26

    The gradient corrected Perdew-Burke-Ernzerhof density functional in conjunction with a 3-21G basis set and periodic boundary conditions was employed to investigate the geometries and energies of C(2)F fluorinated armchair single wall carbon nanotubes (F-SWNT's) with diameters ranging from 16.4 to 4.2 A [(12,12) to (3,3)] as well as a C(2)F graphene sheet fluorinated on one side only. Using an isodesmic equation, we find that the thermodynamic stability of F-SWNT's increases with decreasing tube diameter. On the other hand, the mean bond dissociation energies of the C-F bonds increase as the tubes become thinner. The C-F bonds in the (5,5) F-SWNT's are about as strong as those in graphite fluoride (CF)(n)() and are also covalent albeit slightly (<0.04 A) stretched. Whereas a fluorine atom is found not to bind covalently to the concave surface of [60]fullerene, endohedral covalent binding is possible inside a (5,5) SWNT despite a diameter similar to that of the C(60) cage. PMID:11749543

  15. Optically active single-walled carbon nanotubes.

    PubMed

    Peng, Xiaobin; Komatsu, Naoki; Bhattacharya, Sumanta; Shimawaki, Takanori; Aonuma, Shuji; Kimura, Takahide; Osuka, Atsuhiro

    2007-06-01

    The optical, electrical and mechanical properties of single-walled carbon nanotubes (SWNTs) are largely determined by their structures, and bulk availability of uniform materials is vital for extending their technological applications. Since they were first prepared, much effort has been directed toward selective synthesis and separation of SWNTs with specific structures. As-prepared samples of chiral SWNTs contain equal amounts of left- and right-handed helical structures, but little attention has been paid to the separation of these non-superimposable mirror image forms, known as optical isomers. Here, we show that optically active SWNT samples can be obtained by preferentially extracting either right- or left-handed SWNTs from a commercial sample. Chiral 'gable-type' diporphyrin molecules bind with different affinities to the left- and right-handed helical nanotube isomers to form complexes with unequal stabilities that can be readily separated. Significantly, the diporphyrins can be liberated from the complexes afterwards, to provide optically enriched SWNTs. PMID:18654308

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    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 × 105.

  18. 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, E-mail: yanagi-kazuhiro@tmu.ac.jp [Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 (Japan); Oyane, Ayako [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8562 (Japan); Naitoh, Yasuhisa [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8564 (Japan)

    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}.

  19. 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.

  20. 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

  1. Liquid crystal behavior of single wall carbon nanotubes

    Microsoft Academic Search

    M. Bravo-Sanchez; Trevor J. Simmons; M. A. Vidal

    2010-01-01

    Single wall carbon nanotubes are dispersed in water with the water-soluble polymer polyvinylpyrrolidone and the surfactant sodium dodecylbenzene sulfonate, and then deposited by evaporative deposition onto degeneratively-doped silicon wafer substrates. These deposits were examined by scanning electron microscopy, which revealed highly-ordered arrays of large single wall carbon nanotube bundles. Various solution concentrations were prepared and deposition conditions were varied to

  2. Laser-Irradiation-Induced Enrichment of Metallic Single-Walled Carbon Nanotubes from As-Synthesized Nanotubes Individually Dispersed in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Koji; Kumazawa, Akira; Tajima, Isamu; Uchida, Katsumi; Ishii, Tadahiro; Yajima, Hirofumi

    2012-10-01

    In the present study, we developed a novel technique for the enrichment of metallic (m-) single-walled carbon nanotubes (SWNTs) from as-synthesized SWNTs that are individually dispersed in carboxymethylcellulose (CMC) aqueous solution by irradiation with a nanosecond-pulsed optical parametric oscillator (OPO) laser with wavelength tunability. The 507 nm laser irradiation in the m-SWNT first-transition band (M11) resulted in the collapse of both m- and semiconducting (s-) SWNTs. In contrast, the irradiation with a laser with a wavelength (778 or 989 nm) corresponding to the typical absorption peaks in the s-SWNT second (S22)- or first (S11)-transition bands caused a preferential collapse of s-SWNTs, resulting in enriched m-SWNTs of high purity and in large quantity. The present m-SWNT collection technique can be generalized for various SWNT dispersion systems using different dispersing agents. The OPO laser irradiation discussed in this study is a promising technique for the selective separation of dispersed m-SWNTs.

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

    SciTech Connect

    Weeks, C.; Peltola, J.; Levitsky, I.; Glatkowski, P.; van de Lagemaat, J.; Rumbles, G.; Barnes, T.; Coutts, T.

    2006-01-01

    Transparent and electrically conductive coatings and films have a variety of uses in the fast-growing field of optoelectronic applications. Transparent electrodes typically include semiconductive metal oxides such as indium tin oxide (ITO), and conducting polymers such as poly(3,4-ethylenedioxythiophene), doped and stabilized with poly(styrenesulfonate) (PEDOT/PSS). In recent years, Eikos, Inc. has conceived and developed technologies to deliver novel alternatives using single-wall carbon nanotubes (SWNT). These technologies offer products having a broad range of conductivity, excellent transparency, neutral color tone, good adhesion, abrasion resistance as well as mechanical robustness. Additional benefits include ease of ambient processing and patterning capability. This paper reports our recent findings on achieving 2.6% and 1.4% efficiencies on nonoptimized organic photovoltaic cells employing SWNT as a transparent electrode.

  4. 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.

  5. Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes

    E-print Network

    Kono, Junichiro

    Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes Qi Zhang, Erik resonance is expected to occur in metallic and doped semiconducting carbon nanotubes in the terahertz conductivity peak commonly observed for carbon nanotube ensembles remains controversial. Here we present

  6. The role of Li and Ni metals in the adsorbate complex and their effect on the hydrogen storage capacity of single walled carbon nanotubes coated with metal hydrides, LiH and NiH 2

    Microsoft Academic Search

    V. J. Surya; K. Iyakutti; N. Venkataramanan; H. Mizuseki; Y. Kawazoe

    2010-01-01

    In this first principles study based on density functional theory, we report the hydrogen storage capability of (5, 5) single walled carbon nanotubes coated with Lithium hydride and Nickel hydride. The paper brings out the role of lightweight Li atom and heavy Ni atom in binding the respective hydrides and hydrogen molecules with the single walled carbon nanotubes. The investigation

  7. Single-walled carbon nanotube–amylopectin complexes

    Microsoft Academic Search

    Leszek Stobinski; Piotr Tomasik; Cheng-Yi Lii; Hua-Han Chan; Hong-Ming Lin; Hsiang-Lin Liu; Chun-Tao Kao; Kun-Sheng Lu

    2003-01-01

    Single-walled carbon nanotubes (SWCNTs) are wetted in aqueous solution of pure potato and waxy corn amylopectins. Formation of weak sorption complexes of amylopectins on carbon nanotubes is postulated based on the micro-Raman spectra, differential scanning calorimetric and thermogravimetric studies as well as scanning electron micrographs and atomic force microscope images. Under an influence of ultrasounds bundles of SWCNTs disintegrated much

  8. Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes

    E-print Network

    Dekker, Cees

    Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes B. J. LeRoy,a) S. G-wall carbon nanotubes that are freely suspended over a trench. The nanotubes were grown by chemical vapor on the freestanding portions of the nanotubes. Spatially resolved spectroscopy on the suspended portion of both

  9. Electrochemical and Raman measurements on single-walled carbon nanotubes

    E-print Network

    Nabben, Reinhard

    Electrochemical and Raman measurements on single-walled carbon nanotubes M. Stoll a,*, P performed on a carbon nanotube mat as a working electrode using different salt solutions. The gravimetric capacitance of the nanotube material was estimated and its effective surface area was de- termined in a purely

  10. Nucleation of Single-Walled Carbon Nanotubes X. Fan,1,2,* R. Buczko,1,3,4

    E-print Network

    Pennycook, Steve

    Nucleation of Single-Walled Carbon Nanotubes X. Fan,1,2,* R. Buczko,1,3,4 A. A. Puretzky,5,1 D. B-668 Warsaw, Poland 4 Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 5; published 9 April 2003) The nucleation pathway for single-wall carbon nanotubes on a metal surface

  11. 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.

  12. Temperature dependent thermal conductivity increase of aqueous nanofluid with single walled carbon nanotube inclusions

    E-print Network

    Maruyama, Shigeo

    carbon nanotube inclusions Sivasankaran Harish1 , Kei Ishikawa1 , Erik Einarsson1, 2 , Shinya Aikawa1 of water seeded with single-walled carbon nanotubes (SWCNT) synthesized using the alcohol catalytic and metallic oxides. These predominantly include copper, copper oxide, aluminum, aluminum oxide, zinc oxide

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

    E-print Network

    Maruyama, Shigeo

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

  14. Electrochemical investigation of single-walled carbon nanotubes for hydrogen storage

    Microsoft Academic Search

    N Rajalakshmi; K. S Dhathathreyan; A Govindaraj; B. C Satishkumar

    2000-01-01

    Electrodes made of purified and open single walled carbon nanotubes behave like metal hydride electrodes in Ni–MH batteries, showing high electrochemical reversible charging capacity up to 800 mAh g?1 corresponding to a hydrogen storage capacity of 2.9 wt% compared to known AB5, AB2 metal hydride electrodes.

  15. Helicity Selective Separation of Zeolite-supported Single-walled Carbon Nanotubes Synthesized from

    E-print Network

    Maruyama, Shigeo

    1 Helicity Selective Separation of Zeolite-supported Single-walled Carbon Nanotubes Synthesized on metal supported Zeolite.10,11 Purification and helicity selective separation of SWNTs is still an important challenge. Two methods for purification, removal of metal catalysts and Zeolite, of SWNTs produced

  16. 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.

  17. 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.

  18. Improving quality of single-walled carbon nanotube networks

    Microsoft Academic Search

    Alberto Ansaldo; D. R. Robotic; Marco Chiarolini; Ermanno Di Zitti; Sandesh Jaybhaye

    2009-01-01

    Single-walled carbon nanotubes (SWCNTs) are one of the most interesting alternatives to indium tin oxide for the fabrication of transparent conductive films. SWCNT percolating networks have been produced by a variety of different methods, mainly by spraying or filtration of solutions, but, unfortunately, suspending CNTs in liquid requires the use of ultrasound and surfactants. While sonication reduces bundling, it increases

  19. Elastic properties of single-walled carbon nanotubes

    Microsoft Academic Search

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

    2000-01-01

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

  20. Optical properties of single-wall carbon nanotubes

    Microsoft Academic Search

    H. Kataura; Y. Kumazawa; Y. Maniwa; I. Umezu; S. Suzuki; Y. Ohtsuka; Y. Achiba

    1999-01-01

    Four kinds of single-wall carbon nanotubes (SWNTs) with different diameter distribution have been synthesized and optical absorption spectra have been measured. Three large absorption bands due to the optical transitions between spike-like density of states, characteristics of SWNTs, were observed from infrared to visible region. Comparing with the calculated energy band, it has been concluded that the first and the

  1. 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…

  2. Green luminescence from triphenylphosphine functionalized single-wall carbon nanotubes

    Microsoft Academic Search

    Rima Paul; P. Kumbhakar; A. K. Mitra

    2011-01-01

    In a simple wet chemical process, purified single-wall carbon nanotubes (SWCNTs) are treated with triphenylphosphine (Ph3P) at room temperature. The functionalized material is characterized by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. HRTEM micrograph clearly reveals that triphenylphosphine nanocrystals of nearly uniform size are attached to the surfaces of

  3. High Weight Fraction Surfactant Solubilization of Single-Wall Carbon

    E-print Network

    Islam, Mohammad F.

    High Weight Fraction Surfactant Solubilization of Single-Wall Carbon Nanotubes in Water M. F. Islam processing schemes, has been facilitated by surfactants and polymers14,15,34-36 (with sodium dodecyl sulfate, SDS, the most widely used surfactant), by polymer wrapping,37,38 and by chemical modification.33

  4. Individually Suspended Single-Walled Carbon Nanotubes in Various Surfactants

    Microsoft Academic Search

    Valerie C. Moore; Michael S. Strano; Erik H. Haroz; Robert H. Hauge; Richard E. Smalley; Judith Schmidt; Yeshayahu Talmon

    2003-01-01

    Individual single-walled carbon nanotubes (SWNTs) have been suspended in aqueous media using various anionic, cationic, nonionic surfactants and polymers. The surfactants are compared with respect to their ability to suspend individual SWNTs and the quality of the absorption and fluorescence spectra. For the ionic surfactants, sodium dodecylbenzene sulfonate (SDBS) gives the most well resolved spectral features. For the nonionic systems,

  5. Electronic Raman Scattering On Individual Semiconducting Single Walled Carbon Nanotubes

    PubMed Central

    Chen, Xi; Zhu, Bairen; Zhang, Anmin; Zeng, Hualing; Zhang, Qingming; Cui, Xiaodong

    2014-01-01

    We report experimental measurements of electronic Raman scattering by electrons (holes) in individual single-walled carbon nanotubes (SWNTs) under resonant conditions. The Raman scattering at low frequency range reveals a single particle excitation feature. And the dispersion of electronic structure around the center of Brillouin zone of a semiconducting SWNT (14, 13) is extracted. PMID:25095891

  6. Theoretical study on the combined systems of peanut-shaped carbon nanotubes encapsulated in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Guo; Huang, Yuanhe

    2012-10-01

    The combined systems of peanut-shaped carbon nanotubes encapsulated in both semiconducting and metallic single-walled carbon nanotubes are investigated by using self-consistent field crystal orbital method based on the density functional theory. The investigation indicates that the interaction between the two constituents is mainly contributed by the ? orbitals. The encapsulation does not change the semiconducting or metallic nature of the single-walled carbon nanotubes, but significantly changes the band dispersion and decreases the frontier band width of the metallic one. The carrier mobility and mean free path of the metallic single-walled carbon nanotube increase greatly after the encapsulation. The calculated mobilities have the order of 103 cm2 V-1 s-1 for both of the semiconducting and metallic double-walled carbon nanotubes.

  7. Fluctuation theory of single-walled carbon nanotube formation

    NASA Astrophysics Data System (ADS)

    Vosel, Sergey V.; Onischuk, Andrei A.; Purtov, Peter A.; Nasibulin, Albert G.

    2013-11-01

    In the framework of classical fluctuation theory an analytical formula is derived for the reversible work of formation of just detached carbon cap on the surface of catalyst nanoparticle (NP). This cap is considered as single walled carbon nanotube (SWCNT) formation center. The work of cap formation depends on the source carbon chemical potential ?C. Using the derived formula for this work an expression for the rate of SWCNT formation is determined. From this expression the SWCNT diameter distributions can be obtained. The obtained distributions have sharp maxima. It is found that the modal SWCNT diameter dm increases weakly with ?C being in the narrow window of 1.0 < dm < 1.8 nm when changing the source carbon chemical potential in a wide range. The determined diameter distributions proved to be in a good agreement with the typical values of the SWCNT diameters as experimentally measured in the chemical vapor deposition process. The increase of dm is accompanied by the increase of the distribution width ?d. The selectivity dm/?d is a function of ?C, the higher values of ?C the worse selectivity is observed. Although the value of the SWCNT formation rate I cannot be calculated precisely the relationship between I and the system parameters, such as the NP radius RS, can be obtained. This relationship is derived for the solid-liquid-solid system. To determine the function I(RS) for nanotubes of a certain diameter d, formulas for catalyst/amorphous carbon mutual solubilities as functions of NP radius are derived in the framework of the rigorous Gibbs theory of interface. Using the derived formulas an expression giving the dependence I(RS) is obtained. The expression predicts an increase of I with the radius RS. The estimations carried out for the metal/carbon interface surface tension of 1000 mN/m show that the SWCNT formation rate increases by a few orders of magnitude with the radius increase from 1 to 10 nm.

  8. Mechanically interlocked single-wall carbon nanotubes.

    PubMed

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

    2014-05-19

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

  9. Comparison of influence of incorporated 3d-, 4d- and 4f-metal chlorides on electronic properties of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Kharlamova, M. V.

    2013-06-01

    In the present work, the channels of single-walled carbon nanotubes were filled with melts of ZnCl2, CdCl2, and TbCl3 by a capillary method with subsequent slow cooling. The detailed study of electronic structure of filled nanotubes was performed using Raman, optical absorption, and X-ray photoelectron spectroscopy. The obtained data are in mutual agreement and it proves that the filling of carbon nanotube channels with all these salts leads to the charge transfer from nanotube walls to the incorporated compounds, thus acceptor doping of nanotubes takes place. It was found out that encapsulated terbium chloride has the largest influence on the electronic properties of carbon nanotubes.

  10. 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.

  11. 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.

  12. 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.

  13. Synthesis and Electronic Transport in Known Chirality Single Wall Carbon Nanotubes

    E-print Network

    Hone, James

    Synthesis and Electronic Transport in Known Chirality Single Wall Carbon Nanotubes Bhupesh Chandra;ABSTRACT Synthesis and Electronic Transport in Known Chirality Single Wall Carbon Nanotubes Bhupesh Chandra Carbon nanotubes are intriguing new materials with extraordinary electrical properties originating from

  14. 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.

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

    SciTech Connect

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

    2007-01-01

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

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

    SciTech Connect

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

    2007-01-01

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

  17. Quantitative optical imaging of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Herman, Lihong H.

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

  18. Probing Scattering in Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Rosenblatt, Sami

    2005-03-01

    Transport measurements and atomic force microscopy were used to study electron scattering rates in metallic single-walled carbon nanotubes. From scaling of the resistance of the same nanotube with length in the low and high bias regimes, the mean free paths for both regimes are inferred. The observed scattering rates are consistent with calculations for acoustic phonon scattering at low biases and zone boundary/optical phonon scattering at high biases. We have also developed techniques to probe the high frequency transport properties of nanotube transistors. We have used the nanotube transistor as a microwave mixer operating at frequencies up to 50 GHz. The long-term goal is to directly measure the fundamental excitations and scattering rates. The author would like to acknowledge Ji-Yong Park, Yuval Yaish, Vera Sazonova, Xinjian Zhou, Hao Lin, Hande Ustunel, Stephan Braig, T.A. Arias, Piet W. Brower, Sandip Tiwari and Paul L. McEuen of Cornell University for their contributions to this work.

  19. 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-level post processing. The chip was fabricated using the AMI 0.5µm CMOS Technology. An electroless zincation process was performed over the Aluminum assembly electrodes (Metal 3 of CMOS technology) to clean

  20. Fe-catalyzed single-walled carbon nanotube synthesis within a flame environment

    Microsoft Academic Search

    RANDALL L. VANDER WAL

    2002-01-01

    Flame synthesis of single walled carbon nanotubes (SWNT) is demonstrated using Fe nanoparticles [introduced by nebulization of an iron (III) nitrate salt solution] within a pyrolysis flame configuration. The roles of the nebulized solution solvent, metal nitrate concentration, pyrolysis flame gas composition, and the surrounding flame gas composition are interpreted as reflecting suitable concentrations of reactants without excessive pyrolysis products

  1. One-dimensional N2 gas inside single-walled carbon nanotubes Christian Kramberger1*

    E-print Network

    Maruyama, Shigeo

    One-dimensional N2 gas inside single-walled carbon nanotubes Christian Kramberger1* , Theerapol: Christian.Krambergerer-Kaplan@univie.ac.at (C. Kramberger) #12;vicinity of their innermost walls. [5 containing 0.01 wt.% of the respective metal species. After reducing the dip-coated substrate under flowing

  2. Influence of Zeolite Catalyst Supports on the Synthesis of Single-Walled Carbon Nanotubes

    E-print Network

    Maruyama, Shigeo

    1 Influence of Zeolite Catalyst Supports on the Synthesis of Single-Walled Carbon Nanotubes; catalytic CVD; metal catalyst; Zeolite ABSTRACT: Choice of the catalyst support is an important factor) method. Zeolites, which are a class of microporous crystalline material, have also been known

  3. Single-walled carbon nanotube-silicon nitride composites

    Microsoft Academic Search

    Erica Lorrane Corral

    2005-01-01

    Colloidal processing methods were developed in order to disperse highly concentrated 1.0, 2.0, and 6.0 vol% single-walled carbon nantoube (SWNT)-Si 3N4 aqueous composite suspensions. Interparticle pair potentials were developed between individual Si3N4 particles and SWNT bundles by coating them with cationic surfactant molecules of cetyltrimethylammonium bromide (CTAB). Zeta potential, viscosity, and sedimentation measurements were conducted on SWNTs and Si3N4 particle

  4. 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.

  5. Single-wall carbon nanotube\\/conjugated polymer photovoltaic devices

    Microsoft Academic Search

    E. Kymakis; G. A. J. Amaratunga

    2002-01-01

    We report the optoelectronic properties occurring in single-walled carbon nanotubes (SWNTs)-conjugated polymer, poly(3-octylthiophene) composites. Composite films were drop or spin cast from a solution on indium-tin oxide (ITO) and quartz substrates and studied using absorption spectroscopy and electrical characterization methods. Diodes (Al\\/polymer-nanotube composite\\/ITO) with a low nanotube concentration (<1%) show photovoltaic behavior, with an open circuit voltage of 0.7-0.9 V.

  6. Individual single-wall carbon nanotubes as quantum wires

    Microsoft Academic Search

    Sander J. Tans; Michel H. Devoret; Hongjie Dai; Andreas Thess; Richard E. Smalley; L. J. Geerligs; Cees Dekker

    1997-01-01

    Carbon nanotubes have been regarded since their discovery1 as potential molecular quantum wires. In the case of multi-wall nanotubes, where many tubes are arranged in a coaxial fashion, the electrical properties of individual tubes have been shown to vary strongly from tube to tube2,3, and to be characterized by disorder and localization4. Single-wall nanotubes5,6 (SWNTs) have recently been obtained with

  7. Field emission from single-wall carbon nanotube films

    Microsoft Academic Search

    Jean-Marc Bonard; Jean-Paul Salvetat; Thomas Stöckli; Walt A. de Heer; László Forró; André Châtelain

    1998-01-01

    We report on the field emission properties of single-wall carbon nanotube films, with emphasis on current-versus-voltage (I-V) characteristics and current stability. The films are excellent field emitters, yielding current densities higher than 10 mA cm-2 with operating voltages that are far lower than for other film emitters, but show a significant degradation of their performances with time. The observed deviations

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

    PubMed

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

    2014-07-14

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

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

    Microsoft Academic Search

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

    2006-01-01

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

  10. Electrochemically Functionalized Single-Walled Carbon Nanotube Ting Zhang,a

    E-print Network

    polymer, Polyaniline, Electrochemical functionalization, Gas sensor, Nanosensor DOI: 10.1002/elanFull Paper Electrochemically Functionalized Single-Walled Carbon Nanotube Gas Sensor Ting Zhang using single-walled carbon nanotubes (SWNT) electrochemically functionalized with polyaniline (PANI

  11. Cross-polarized absorption of single-walled carbon nanotubes by photoluminescence

    E-print Network

    Maruyama, Shigeo

    Cross-polarized absorption of single-walled carbon nanotubes by photoluminescence excitation@photon.t.u-tokyo.ac.jp Photoluminescence excitation (PLE) spectroscopy of single-walled carbon nanotubes (SWNTs) have been ex- tensively

  12. Photoluminescence from independently aligned single-walled carbon nanotubes by cross-polarized excitation

    E-print Network

    Maruyama, Shigeo

    Photoluminescence from independently aligned single-walled carbon nanotubes by cross, photoluminescence (PL) of single-walled carbon nanotubes (SWNTs) has been intensively investigated by polarized photoluminescence excitation (PLE) spectroscopy of 2-dimentionally aligned individual nanotubes

  13. Photoluminescence studies of cross-polarized absorption of single-walled carbon nanotubes Shigeo Maruyama

    E-print Network

    Maruyama, Shigeo

    Photoluminescence studies of cross-polarized absorption of single-walled carbon nanotubes Shigeo-8656, Japan Though our previous studies of photoluminescence (PL) of single-walled carbon nanotubes (SWNTs

  14. Vibrational modes and thermal transformation of purified single walled carbon nanotubes

    Microsoft Academic Search

    Un Jeong Kim

    2006-01-01

    Vibrational modes of single-walled carbon nanotubes (SWNTs) and graphitic nanoribbons (GNRs) were studied using Raman scattering and\\/or Fourier Transform Infrared Spectroscopies, Variations in a three-step purification scheme to remove amorphous carbon and residual catalyst were studied: (step 1) Oxidation, (step 2) Acid Reflux, and (step 3) Thermal Annealing were found to remove most amorphous carbon (oxidation step) and residual metal

  15. 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

  16. physica status solidi, 27 August 2012 Reduction of single-walled carbon

    E-print Network

    Maruyama, Shigeo

    physica status solidi, 27 August 2012 Reduction of single-walled carbon nanotube diameter to sub Published online XXXX Key words: Single-walled carbon nanotube, vertically aligned, diameter control@photon.t.u-tokyo.ac.jp, Phone: +81-3-5841-6421, Fax: +81-3-5800-6983 Vertically aligned single-walled carbon nanotube arrays

  17. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 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...

  18. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 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...

  19. 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...

  20. 40 CFR 721.10156 - Single-walled carbon nanotubes (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 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...

  1. Self-Assembled Micro-Honeycomb Network of Single-Walled Carbon Nanotubes for Solar Cells

    E-print Network

    Maruyama, Shigeo

    1 Self-Assembled Micro-Honeycomb Network of Single-Walled Carbon Nanotubes for Solar Cells KehangW/cm² FF: 73% PCE: 10.02% KEYWORDS: Single-walled carbon nanotube, nanotube-Si solar cell, self-3-5800-6983. #12;2 ABSTRACT We propose a water vapor treatment to direct the formation of single-walled carbon

  2. Air-Stable High-Efficiency Solar Cells Using Improved Single-Walled Carbon Nanotube Films

    E-print Network

    Maruyama, Shigeo

    1 Air-Stable High-Efficiency Solar Cells Using Improved Single-Walled Carbon Nanotube Films Kehang-3-5800-6983. #12;2 ABSTRACT We present the single-walled carbon nanotube/silicon (SWNT/Si) solar cells approaching front contact KEYWORDS: Single-walled carbon nanotube, solar cell, high efficiency, stability, SWNT

  3. Single-Walled Carbon Nanotubes of Controlled Diameter and Bundle Size and Their Field Emission Properties

    E-print Network

    Resasco, Daniel

    Single-Walled Carbon Nanotubes of Controlled Diameter and Bundle Size and Their Field Emission: June 8, 2005 Field emission studies were conducted on as-produced CoMoCAT single-walled carbon nanotube electron emitter. By adjusting the catalytic synthesis conditions, single-walled carbon nanotubes (SWNT

  4. Field Emission Properties of Single-Walled Carbon Nanotubes with a Variety of Emitter-Morphologies

    E-print Network

    Maruyama, Shigeo

    1 Field Emission Properties of Single-Walled Carbon Nanotubes with a Variety of Emitter@chemsys.t.u-tokyo.ac.jp Field emission properties of single-walled carbon nanotubes (SWNTs), which have been prepared through: single-walled carbon nanotube, field emission, alcohol catalytic chemical vapor deposition, ethanol

  5. Optical Characterization and Applications of Single Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Strano, Michael S.

    2005-03-01

    Recent advances in the dispersion and separation of single walled carbon nanotubes have led to new methods of optical characterization and some novel applications. We find that Raman spectroscopy can be used to probe the aggregation state of single-walled carbon nanotubes in solution or as solids with a range of varying morphologies. Carbon nanotubes experience an orthogonal electronic dispersion when in electrical contact that broadens (from 40 meV to roughly 80 meV) and shifts the interband transition to lower energy (by 60 meV). We show that the magnitude of this shift is dependent on the extent of bundle organization and the inter-nanotube contact area. In the Raman spectrum, aggregation shifts the effective excitation profile and causes peaks to increase or decrease, depending on where the transition lies, relative to the excitation wavelength. The findings are particularly relevant for evaluating nanotube separation processes, where relative peak changes in the Raman spectrum can be confused for selective enrichment. We have also used gel electrophoresis and column chromatography conducted on individually dispersed, ultrasonicated single-walled carbon nanotubes to yield simultaneous separation by tube length and diameter. Electroelution after electrophoresis is shown to produce highly resolved fractions of nanotubes with average lengths between 92 and 435 nm. Separation by diameter is concomitant with length fractionation, and nanotubes that have been cut shortest also possess the greatest relative enrichments of large-diameter species. The relative quantum yield decreases nonlinearly as the nanotube length becomes shorter. These findings enable new applications of nanotubes as sensors and biomarkers. Particularly, molecular detection using near infrared (n-IR) 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. Carbon nanotubes have a tunable n-IR emission that responds to changes in the local dielectric function but remains stable to permanent photobleaching. We report the synthesis and successful testing of solution phase, near-infrared sensors, with ?-D-glucose sensing as a model system, using single walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules. New types of non-covalent functionalization using electron withdrawing molecules are shown to provide sites for transferring electrons in and out of the nanotube. We also show two distinct mechanisms of signal transduction -- fluorescence quenching and charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.

  6. Aligned arrays of single walled carbon nanotubes for transparent electronics

    NASA Astrophysics Data System (ADS)

    Du, Frank; Rogers, John A.

    2013-06-01

    Single walled carbon nanotubes have garnered substantial interest in the electronic materials research community due to their unparalleled intrinsic electrical properties. In addition, their mechanical robustness and thin geometries make SWNTs ideal candidates for transparent electronics. Aligned arrays of SWNTs grown via chemical vapor deposition (CVD) on quartz enable device uniformity and wafer scale integration with existing commercial semiconductor processing methods. A crucial roadblock in incorporation of SWNTs in commercial electronics has been the co-existence of metallic and semiconducting SWNTs. Demanding device metrics in high performance and complex integrated electrical devices, sensors, and other applications dictate the necessity of pristine, purely semiconducting arrays of SWNTs. By exploiting a novel process in nanoscale flow of thin film organic coatings, we have demonstrated a method to purify as-grown aligned arrays to produce such as result. Comparison with single nanotube statistics, characterization using a novel thermal scanning probe microscopy technique, as well as corroboration with thermal modeling validated the result. Thin film field effect transistors exhibiting mobilities exceeding ~1000cm2/Vs and on/off ratios exceeding 10,000 were fabricated using the purified semiconducting SWNTs. This manuscript reviews some of these results, which represent the first successful demonstration of purification of aligned arrays of SWNTs, in a robust and scalable scheme that allows integration of aligned arrays into complex, high performance electrical devices. We separately also describe new results on the advanced development of soft lithography techniques with the ability to transfer print aligned arrays of SWNTs onto transparent substrates after synthesis and processing, thereby completing a direct pathway to achieve complex, high performance, and highly integrated transparent SWNTs electronics, sensors, or other devices.

  7. Nano-aggregates of single-walled graphitic carbon nano-horns

    Microsoft Academic Search

    S. Iijima; M. Yudasaka; R. Yamada; S. Bandow; K. Suenaga; F. Kokai; K. Takahashi

    1999-01-01

    We have found a new type of carbon particle produced by the CO2 laser ablation of carbon at room temperature without a metal catalyst. The product has a powder form of graphitic particles with a uniform size of about 80 nm. An individual particle is composed of an aggregate of many horn-shaped sheaths of single-walled graphene sheets, which we named

  8. Curvature Effect on the Band Structure and Optical Properties of Single Wall Carbon Nanotubes

    Microsoft Academic Search

    Shu Kin Lok; Bingshen Wang; Weikun Ge

    2001-01-01

    The electronic structure and optical properties of single-wall carbon nanotubes (SWCN's) have been studied using a nearest-neighbor empirical tight-binding model. Hybridization of the sigma, pi, pi and sigma^* states of the graphene network is shown to be as important as zone-folding effects in determining the metallicity of small radius carbon nanotubes. The energy dispersion relations are further used to calculate

  9. Electrochemical nitration of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Yubing; Malhotra, Sanjay V.; Owens, Frank J.; Iqbal, Zafar

    2005-05-01

    Electrochemical nitration of self-assembled single wall carbon nanotube (SWNT) sheets with -NO 2 groups is reported. A SWNT sheet, used as the working electrode in 6 M aqueous solution of potassium nitrite, was anodically oxidized to form -NO 2 groups on the SWNTs. Attenuated-total-reflection Fourier-transform infrared and micro-Raman spectroscopy showed the presence of chemisorbed -NO 2 groups consistent with transmission electron microscope images of the nanotube bundles after functionalization. Approximately 13% weight loss attributed to C-NO 2 bond breaking was measured by thermogravimetry, corresponding to an endothermic dissociation process measured by differential thermal analysis with an onset temperature near 425 °C.

  10. Optical anisotropy in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yoo, Seongwoo; Jung, Yongmin; Lee, Dong Soo; Han, Won-Taek; Oh, Kyunghwan; Murakami, Y.; Edamura, T.; Maruyama, Shigeo

    2005-12-01

    Optical anistropy at optical communication wavelength was observed in films of vertically aligned single-walled carbon nanotubes (SWNTs). We report the control of both the polarization state and transmission of incoming light at 1550 nm by azimuthal and axial tilting of SWNT film about its aligned axis. The experiments reveal that the polarization state of light is susceptible to the azimuthal angle of the aligned direction of a SWNT having semiconductor characteristics and the intensity of the output beam after SWNT film shows cosine function dependence on the axial tilting angle.

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

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; Hedberg, James; Miyahara, Yoichi; Grutter, Peter; Ishibashi, Koji

    2014-12-01

    Two coupled single wall carbon nanotube quantum dots in a multiple quantum dot system were characterized by using a low temperature scanning gate microscopy (SGM) technique, at a temperature of 170 mK. The locations of single wall carbon nanotube quantum dots were identified by taking the conductance images of a single wall carbon nanotube contacted by two metallic electrodes. The single electron transport through single wall carbon nanotube multiple quantum dots has been observed by varying either the position or voltage bias of a conductive atomic force microscopy tip. Clear hexagonal patterns were observed in the region of the conductance images where only two sets of overlapping conductance rings are visible. The values of coupling capacitance over the total capacitance of the two dots, {{C}m}/{{C}1(2)} have been extracted to be 0.21 ˜ 0.27 and 0.23 ˜ 0.28, respectively. In addition, the interdot coupling (conductance peak splitting) has also been confirmed in both conductance image measurement and current–voltage curves. The results show that a SGM technique enables spectroscopic investigation of coupled quantum dots even in the presence of unexpected multiple quantum dots.

  12. A green access to highly pure single-walled carbon nanotubes by taurocholate-assistant dispersion and centrifugation

    Microsoft Academic Search

    Yongfu Lian

    2009-01-01

    Raw single-walled carbon nanotubes produced by arc discharge were oxidized in the air to eliminate amorphous carbon, and then dispersed in the aqueous solution of sodium taurocholate supersonically. Thus obtained stable dispersion was subjected to centrifugation, and the metal catalysts and varying carbon impurities were separated with carbon nanotubes. The efficiency of the above procedure was confirmed by scanning electron

  13. 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).

  14. Binding of Nucleobases with Single-Walled Carbon Nanotubes

    E-print Network

    Anindya Das; A. K. Sood; Prabal K. Maiti; Mili Das; R. Varadarajan; C. N. R. Rao

    2007-09-19

    We have calculated the binding energy of various nucleobases (guanine (G), adenine (A), thymine (T) and cytosine (C)) with (5,5) single-walled carbon nanotubes (SWNTs) using ab-initio Hartre-Fock method (HF) together with force field calculations. The gas phase binding energies follow the sequence G $>$ A $>$ T $>$ C. We show that main contribution to binding energy comes from van-der Wall (vdW) interaction between nanotube and nucleobases. We compare these results with the interaction of nucleobases with graphene. We show that the binding energy of bases with SWNTs is much lower than the graphene but the sequence remains same. When we include the effect of solvation energy (Poisson-Boltzman (PB) solver at HF level), the binding energy follow the sequence G $>$ T $>$ A $>$ C $>$, which explains the experiment\\cite{zheng} that oligonucleotides made of thymine bases are more effective in dispersing the SWNT in aqueous solution as compared to poly (A) and poly (C). We also demonstrate experimentally that there is differential binding affinity of nucleobases with the single-walled carbon nanotubes (SWNTs) by directly measuring the binding strength using isothermal titration (micro) calorimetry. The binding sequence of the nucleobases varies as thymine (T) $>$ adenine (A) $>$ cytosine (C), in agreement with our calculation.

  15. Single-Walled Carbon Nanotube / Semicrystalline Polymer Composite Fibers

    NASA Astrophysics Data System (ADS)

    Haggenmueller, Reto; Fischer, John E.; Winey, Karen I.

    2002-03-01

    Single-walled carbon nanotubes (SWNTs) have demonstrated far superior mechanical, thermal and electrical properties relative to carbon fibers. Similar properties are expected for polymer/SWNT nanocomposites. We have produced SWNT-thermoplastic composites with extraordinary alignment of the nanotubes via melt processing followed by fiber melt spinning. The improved mechanical properties depend on the alignment of the nanotubes, which is controlled by the draw ratio of the composite fibers. Alignment of the nanotubes seems to reduce the electrical conductivity, because the percolation threshold of the one-dimensional conductors is reduced for straight, aligned nanotubes. Semicrystalline polyethylene and various nylons are used as the matrix and the mechanical, electrical properties are measured. The effect of the nanotubes on the crystallinity and the melting point are determined. A key factor of the composite performance is the dispersion of the nanotubes in the polymer matrix, the characterization of which is explored.

  16. Translocation events in a single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  17. Absolute Absorptivity of Single-walled Carbon Nanotubes Employing a Pyroelectric Detector

    Microsoft Academic Search

    Katherine Hurst; Anne Dillon; John Lehman

    2007-01-01

    Optical properties are important for determining fundamental characteristics of carbon single-walled nanotube (SWNT) samples including purity, chirality, and tube diameter. Previously, we have estimated the volume fraction of metallic versus semiconducting tubes for highly purified SWNT bucky-paper on a pyroelectric detector from spectral responsivity measurements and an effective medium approximation to determine the dielectric function (1). Pyroelectric detector-based measurements are

  18. High-Field Electrical Transport in Single-Wall Carbon Nanotubes

    Microsoft Academic Search

    Zhen Yao; Charles L. Kane; Cees Dekker

    2000-01-01

    Using low-resistance electrical contacts, we have measured the intrinsic high-field transport properties of metallic single-wall carbon nanotubes. Individual nanotubes appear to be able to carry currents with a density exceeding 109 A\\/cm2. As the bias voltage is increased, the conductance drops dramatically due to scattering of electrons. We show that the current-voltage characteristics can be explained by considering optical or

  19. Acoustic Analysis of Single-Walled Carbon Nanotube-based Vacuum Sensor

    Microsoft Academic Search

    Yi Zhang; Hang Guo

    2007-01-01

    In this paper, the acoustic wave propagation of single walled carbon nanotube (SWCNT) is investigated with a look into their applications in vacuum sensors at the microscale. First, the carbon nanotube in fixed-free is simulated by a continuum elastic shell modeling to analyze to the wave propagation of single walled carbon nanotubes. The sensing principle of the single-walled carbon nanotube-based

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

    Microsoft Academic Search

    Aravind Vijayaraghavan

    2005-01-01

    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

  1. Molecular Imaging with Single-Walled Carbon Nanotubes

    PubMed Central

    Hong, Hao; Gao, Ting; Cai, Weibo

    2011-01-01

    Nanoparticle-based molecular imaging has emerged as an interdisciplinary field which involves physics, chemistry, engineering, biology, and medicine. Single-walled carbon nanotubes (SWCNTs) have unique properties which make them suitable for applications in a variety of imaging modalities, such as magnetic resonance, near-infrared fluorescence, Raman spectroscopy, photoacoustic tomography, and radionuclide-based imaging. In this review, we will summarize the current state-of-the-art of SWCNTs in molecular imaging applications. Multifunctionality is the key advantage of nanoparticles over traditional approaches. Targeting ligands, imaging labels, therapeutic drugs, and many other agents can all be integrated into the nanoparticle to allow for targeted molecular imaging and molecular therapy by encompassing many biological and biophysical barriers. A multifunctional, SWCNT-based nanoplatform holds great potential for clinical applications in the future. PMID:21754949

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  3. Nanoscale vibrational analysis of single-walled carbon nanotubes.

    PubMed

    Anderson, Neil; Hartschuh, Achim; Cronin, Steve; Novotny, Lukas

    2005-03-01

    We use near-field Raman imaging and spectroscopy to study localized vibrational modes along individual, single-walled carbon nanotubes (SWNTs) with a spatial resolution of 10-20 nm. Our approach relies on the enhanced field near a laser-irradiated gold tip which acts as the Raman excitation source. We find that for arc-discharge SWNTs, both the radial breathing mode (RBM) and intermediate frequency mode (IFM) are highly localized. We attribute such localization to local changes in the tube structure (n, m). In comparison, we observe no such localization of the Raman active modes in SWNTs grown by chemical vapor deposition (CVD). The direct comparison between arc-discharge and CVD-grown tubes allows us to rule out any artifacts induced by the supporting substrate. PMID:15725008

  4. 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.

  5. Efficient spectrofluorimetric analysis of single-walled carbon nanotube samples.

    PubMed

    Rocha, John-David R; Bachilo, Sergei M; Ghosh, Saunab; Arepalli, Sivaram; Weisman, R Bruce

    2011-10-01

    A new method and instrumentation are described for rapid compositional analysis of single-walled carbon nanotube (SWCNT) samples. The customized optical system uses multiple fixed-wavelength lasers to excite NIR fluorescence from SWCNTs individualized in aqueous suspensions. The emission spectra are efficiently captured by a NIR spectrometer with InGaAs multichannel detector and then analyzed by a computer program that consults a database of SWCNT spectral parameters. The identities and relative abundances of semiconducting SWCNTs species are quickly deduced and displayed in graphs and tables. Results are found to be consistent with those based on manual interpretation of full excitation-emission scans from a conventional spectrofluorometer. The new instrument also measures absorption spectra using a broadband lamp and multichannel spectrometers, allowing samples to be automatically characterized by their emission efficiencies. The system provides rapid data acquisition and is sensitive enough to detect the fluorescence of a few picograms of SWCNTs in ~50 ?L sample volumes. PMID:21866945

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

    NASA Astrophysics Data System (ADS)

    Island, J. O.; Tayari, V.; Yi?en, S.; McRae, A. C.; Champagne, A. R.

    2011-12-01

    We describe a method to fabricate clean suspended single-wall carbon nanotube (SWCNT) transistors hosting a single quantum dot ranging in length from a few 10 s of nm down to ?3 nm. We first align narrow gold bow-tie junctions on top of individual SWCNTs and suspend the devices. We then use a feedback-controlled electromigration to break the gold junctions and expose nm-sized sections of SWCNTs. We measure electron transport in these devices at low temperature and show that they form clean and tunable single-electron transistors. These ultra-short suspended transistors offer the prospect of studying THz oscillators with strong electron-vibron coupling.

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

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

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

  8. Phonon sidebands of photoluminescence in single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yu, Guili; Liang, Qifeng; Jia, Yonglei; Dong, Jinming

    2010-01-01

    The multiphonon-assisted photoluminescence (PL) of the single wall carbon nanotubes (SWNTs) have been studied by solving the Schrödinger equation, showing a set of phonon sidebands, both the Stokes and anti-Stokes lines, which are induced by the longitudinal optical phonon and radial breathing mode phonon. All the calculated results are in a good agreement with the recent experimental PL spectra of the SWNTs [F. Plentz, H. B. Ribeiro, A. Jorio, M. S. Strano, and M. A. Pimenta, Phys. Rev. Lett. 95, 247401 (2005)] and J. Lefebvre and P. Finnie, Phys. Rev. Lett. 98, 167406 (2007)]. In addition, it is very interesting to find in the calculated PL several additional phonon sidebands with rather weak intensities, which are caused by the exciton's coupling with two kinds of phonons, and expected to be observed in future experiments.

  9. Vertical semiconducting single-walled carbon nanotube Schottky diode

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan

    2014-07-01

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

  10. 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.

  11. Generalizing thermodynamic properties of bulk single-walled carbon nanotubes

    PubMed Central

    Rodriguez, Kenneth R.; Nanney, Warren A.; A. Maddux, Cassandra J.; Martínez, Hernán L.

    2014-01-01

    The enthalpy and Gibbs free energy thermodynamical potentials of single walled carbon nanotubes were studied of all types (armchairs, zig-zags, chirals (n>m), and chiral (n

  12. 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.

  13. 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.

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

    E-print Network

    Wang, Lihong

    Single-walled carbon nanotubes as a multimodal- thermoacoustic and photoacoustic-contrast agent, Missouri 63130 Abstract. We have developed a novel carbon nanotube-based con- trast agent for both thermoacoustic and photoacoustic tomography. In comparison to deionized water, single-walled carbon nanotubes ex

  15. Growth and characterization of high-density mats of single-walled carbon nanotubes for interconnects

    E-print Network

    Nabben, Reinhard

    limit of copper, 6 106 A cm-2 . Carbon nanotubes are one of the few possible materials that can carryGrowth and characterization of high-density mats of single-walled carbon nanotubes 22 October 2008 We grow high-density, aligned single wall carbon nanotube mats for use

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

    E-print Network

    Maruyama, Shigeo

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

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

    E-print Network

    Zhong, Zhaohui

    Unexpected Hole Transfer Leads to High Efficiency Single-Walled Carbon Nanotube Hybrid Photovoltaic photovoltaics. KEYWORDS Carbon nanotube, P3HT, hybrid photovoltaics, hole acceptor I n organic photovoltaic1 photovoltaics, including heterojunction devices be- tween one-dimensional systems of single-walled carbon

  18. 50 (2013-5) Single-walled Carbon Nanotubes-Silicon Heterojunction Solar Cells

    E-print Network

    Maruyama, Shigeo

    50 (2013-5) - Single-walled Carbon Nanotubes-Silicon Heterojunction Solar Cells. of Tokyo, Bunkyo-ku, Tokyo 113-8656 Single-walled carbon nanotube (SWNT)-silicon heterojunction solar cells with the water vapor and nitric acid treatments. Key Words : Carbon Nanotube, Solar Cell, Silicon, Heterojunction

  19. Ultra-high-yield growth of vertical single-walled carbon nanotubes: Hidden roles of hydrogen

    E-print Network

    Zhang, Guangyu

    Ultra-high-yield growth of vertical single-walled carbon nanotubes: Hidden roles of hydrogen to afford large-scale, highly reproducible, ultra-high-yield growth of vertical single-walled carbon been developed to grow vertically aligned multiwalled carbon nanotubes, growth of ver- tical single

  20. Purification and characterization of zeolite-supported single-walled carbon nanotubes catalytically synthesized from

    E-print Network

    Maruyama, Shigeo

    Purification and characterization of zeolite-supported single-walled carbon nanotubes catalytically complete removal of zeolite particles and Fe/Co catalysts from raw single-walled carbon nanotubes (SWNTs-scale production of quasi-aligned multi-walled carbon nanotube bundles on zeolite by CCVD, in which acetylene

  1. Tip-enhanced Raman scattering on single-wall carbon nanotubes Niculina Peica, Christian Thomsen, Janina Maultzsch

    E-print Network

    Nabben, Reinhard

    Tip-enhanced Raman scattering on single-wall carbon nanotubes Niculina Peica, Christian Thomsen and the sample. BACKGROUND AND MOTIVATION TERS - metal coated AFM tip in intermittent contact with the sample Metals 103 (1999) 2555. 4. V. N. Popov, L. Henrard, P. Lambin Phys. Rev. B 72 (2005) 035436. 5. N. Peica

  2. Radiation effects in single-walled carbon nanotube papers

    NASA Astrophysics Data System (ADS)

    Cress, Cory D.; Schauerman, Christopher M.; Landi, Brian J.; Messenger, Scott R.; Raffaelle, Ryne P.; Walters, Robert J.

    2010-01-01

    The effects of ionizing radiation on the temperature-dependent conductivity of single-walled carbon nanotube (SWCNT) papers have been investigated in situ in a high vacuum environment. Irradiation of the SWCNT papers with 4.2MeV alpha particles results in a steady decrease in the SWCNT paper conductivity, resulting in a 25% reduction in room temperature conductivity after a fluence of 3×1012 alpha particles/cm2. The radiation-induced temperature-dependent conductivity modification indicates that radiation damage causes an increase in the effective activation barrier for tunneling-like conductivity and a concomitant increase in wavefunction localization of charge carriers within individual SWCNTs. The spatial defect generation within the SWCNT paper was modeled and confirms that a uniform displacement damage dose was imparted to the paper. This allows the damage coefficient (i.e., differential change in conductivity with fluence) for alpha particles, carbon ions, and protons to be compared with the corresponding nonionizing energy loss (NIEL) of the incident particle. The resulting nonlinear relationship with NIEL between these parameters is distinct from the more typical linear response observed in many bulk semiconductors and superconductors and indicates that localized radiation damage in the SWCNT papers has a greater impact than distributed damage. Although SWCNT papers behave largely as a bulk material with properties that are a convolution of the underlying SWCNT distribution, the radiation response appears to be largely dominated by degradation in the preferred one-dimensional conduction within these two-dimensionally confined nanostructures.

  3. MINIMAL INFLAMMOGENICITY OF PRISTINE SINGLE-WALL CARBON NANOTUBES

    PubMed Central

    TOYOKUNI, SHINYA; JIANG, LI; KITAURA, RYO; SHINOHARA, HISANORI

    2015-01-01

    ABSTRACT Carbon nanotubes (CNTs) are a novel synthetic material comprising only carbon atoms. Based on its rigidity, its electrical and heat conductivity and its applicability to surface manufacturing, this material is expected to have numerous applications in industry. However, due to the material’s dimensional similarity to asbestos fibers, its carcinogenicity was hypothesized during the last decade, and indeed, we have shown that multi-wall CNTs (MWCNTs) of 50 nm in diameter are potently carcinogenic to mesothelial cells after intraperitoneal injection. Additionally, we suggested that inflammogenicity after intraperitoneal injection can predict mesothelial carcinogenesis. However, few data have been published on the intraperitoneal inflammogenicity of single-wall CNTs (SWCNTs). Here, we conducted a series of studies on SWCNTs using both intraperitoneal injection into rats and MeT5A mesothelial cells. Intraperitoneal injection of 10 mg SWCNTs caused no remarkable inflammation in the abdominal cavity, and the exposure of MeT5A cells to up to 25 ?g/cm2 SWCNTs did not alter proliferation. MWCNTs of 50 nm in diameter were used as a positive control, and tangled MWCNTs of 15 nm in diameter were used as a negative control. The results suggest that SWCNTs are a low-risk material with respect to mesothelial carcinogenesis. PMID:25797984

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  5. 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.

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

    SciTech Connect

    Kharlamova, M. V., E-mail: mv.kharlamova@gmail.com [Moscow State University (Russian Federation); Niu, J. J. [Drexel University, Department of Materials Science and Engineering (United States)

    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.

  7. Transparent flexible organic thin-film transistors that use printed single-walled carbon nanotube electrodes

    E-print Network

    Rogers, John A.

    Transparent flexible organic thin-film transistors that use printed single-walled carbon nanotube; published online 15 March 2006 Electrodes based on printed networks of single-walled carbon nanotubes SWNTs are integrated with ultrathin layers of the organic semiconductor pentacene to produce bendable, transparent thin

  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. Record High Efficiency Single-Walled Carbon Nanotube/Silicon p-n Junction Solar Cells

    E-print Network

    Reed, Mark

    Record High Efficiency Single-Walled Carbon Nanotube/Silicon p-n Junction Solar Cells Yeonwoong: Carrier transport characteristics in high-efficiency single-walled carbon nanotubes (SWNTs)/silicon (Si-n homojunction Si solar cells. KEYWORDS: CNT/Si solar cell, hybrid solar cell, photovoltaics, high efficiency

  10. The strength of the radial-breathing mode in single-walled carbon nanotubes

    E-print Network

    Nabben, Reinhard

    The strength of the radial-breathing mode in single-walled carbon nanotubes M. Machón , S. Reich of the absolute Raman cross section of the radial breathing mode (RBM) of single-walled carbon nanotubes. We compare our calculations to measurements of the absolute Raman cross section of individual nanotubes

  11. Organic Solvent Dispersions of Single-Walled Carbon Nanotubes: Toward Solutions of Pristine Nanotubes

    E-print Network

    Ben-Yakar, Adela

    LETTERS Organic Solvent Dispersions of Single-Walled Carbon Nanotubes: Toward Solutions of Pristine Nanotubes Kevin D. Ausman, Richard Piner, Oleg Lourie, and Rodney S. Ruoff* Department of Physics/dispersion of pristine single-walled carbon nanotubes (SWCNTs). Five solvents, all featuring high electron pair donicity

  12. Role of Catalysts in the Surface Synthesis of Single-Walled Carbon Nanotubes

    E-print Network

    Liu, Jie

    Role of Catalysts in the Surface Synthesis of Single-Walled Carbon Nanotubes Weiwei Zhou, Lei Ding the role of catalysts in the surface growth of single-walled carbon nanotubes (SWNTs) by reviewing recent progress in the surface synthesis of SWNTs. Three effects of catalysts on surface synthesis are studied

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

    E-print Network

    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

  14. Silica Supported Single-Walled Carbon Nanotubes as a Modifier in Polyethylene Composites

    E-print Network

    Resasco, Daniel

    Silica Supported Single-Walled Carbon Nanotubes as a Modifier in Polyethylene Composites Neal D. Mc.interscience.wiley.com). ABSTRACT: Composites have been made from single- wall carbon nanotubes in a polyethylene (PE) matrix: additives; composites; conducting polymers; nanocomposites; polyethylene INTRODUCTION Polyethylene (PE

  15. 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

  16. CNT-Si heterojunction solar cell with single-walled carbon nanotubes Shigeo Maruyama

    E-print Network

    Maruyama, Shigeo

    CNT-Si heterojunction solar cell with single-walled carbon nanotubes Shigeo Maruyama Department.photon.t.u-tokyo.ac.jp/~maruyama/index.html Single-walled carbon nanotubes (SWNTs) with outstanding electronic, optical, mechanical, and thermal solar cells. We proposed a water vapor treatment to build up SWNTs to a self-assembled micro

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

    E-print Network

    Maruyama, Shigeo

    Controlled Growth of Single-Walled Carbon Nanotubes for CNT-Si heterojunction solar cell Shigeo@photon.t.u-tokyo.ac.jp http://www.photon.t.u-tokyo.ac.jp/~maruyama/index.html Single-walled carbon nanotubes (SWNTs two different SWNT assemblies for SWNT-Si heterojuction solar cells. We proposed a water vapor

  18. CNT-SI HETEROJUNCTION SOLAR CELLS WITH STRUCTURE-CONTROLLED SINGLE-WALL CARBON NANOTUBE FILMS

    E-print Network

    Maruyama, Shigeo

    CNT-SI HETEROJUNCTION SOLAR CELLS WITH STRUCTURE- CONTROLLED SINGLE-WALL CARBON NANOTUBE FILMS@photon.t.u-tokyo.ac.jp Single-walled carbon nanotubes (SWNTs) with outstanding electronic, optical, mechanical, and thermal solar cells. We proposed a water-vapor treatment to build up SWNTs to a self-assembled micro- honeycomb

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

    E-print Network

    Maruyama, Shigeo

    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-Walled Carbon Nanotubes by Kehang CUI Presented to GRADUATE SCHOOL OF ENGINEERING, THE UNIVERSITY OF TOKYO

  20. ACCVD Growth of Vertically Aligned Single-Walled Carbon Nanotubes on a Quartz Substrate

    E-print Network

    Maruyama, Shigeo

    ACCVD Growth of Vertically Aligned Single-Walled Carbon Nanotubes on a Quartz Substrate Shigeo: maruyama@photon.t.u-tokyo.ac.jp Vertically aligned single-walled carbon nanotubes (SWNTs) up to 5 microns of CVD growth of vertically aligned SWNTs [2], hydrogen gas was supplied only during the heating-up stage

  1. 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 of vertically aligned single-walled carbon nanotubes (SWNTs) with a few micron thickness were grown by catalytic CVD was essential for generating dense enough SWNTs with vertical alignment. Vertical alignment

  2. 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

  3. Molecular Dynamics Simulation of Hydrogen Storage with Single Walled Carbon Nanotubes Shigeo MARUYAMA1,2

    E-print Network

    Maruyama, Shigeo

    Molecular Dynamics Simulation of Hydrogen Storage with Single Walled Carbon Nanotubes * Shigeo-8656 The hydrogen storage mechanism of SWNTs was studied through molecular dynamics simulations. Assuming the simple : Molecular Dynamics Method, Hydrogen Storage, Single Walled Carbon Nanotubes, Lennard-Jones, Adsorption

  4. Strength of radial breathing mode in single-walled carbon nanotubes M. Machn,1

    E-print Network

    Nabben, Reinhard

    Strength of radial breathing mode in single-walled carbon nanotubes M. Machón,1 S. Reich,2 H. Telg Me-ph of the radial breathing mode in single-walled carbon nanotubes depends strongly on tube scattering intensity. We show measured resonance Raman profiles of the radial breathing mode which support

  5. 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.

  6. Carrier transport properties in single-walled carbon nanotubes studied by photoluminescence spectroscopy

    E-print Network

    Maruyama, Shigeo

    Carrier transport properties in single-walled carbon nanotubes studied by photoluminescence. We have investigated the photoluminescence (PL) of in individual single-walled carbon nanotubes-field dependence of PL intensity. Time-resolved photoluminescence of SWNTs dispersed in surfactant solution has

  7. Polarized Raman and Photoluminescence Characterization of Vertically Aligned Single-Walled Carbon Nanotubes

    E-print Network

    Maruyama, Shigeo

    Polarized Raman and Photoluminescence Characterization of Vertically Aligned Single-Walled Carbon and photoluminescence studies were employed to characterize vertically aligned single-walled carbon nanotubes (VA with the typical photoluminescence measurement setup using Xe lamp excitation. These higher order Raman scatterings

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

    PubMed

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

    2015-03-11

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

  9. 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.

  10. Bulk Mechanical Properties of Single Walled Carbon Nanotube Electrodes

    NASA Astrophysics Data System (ADS)

    Giarra, Matthew; Landi, Brian; Cress, Cory; Raffaelle, Ryne

    2007-03-01

    The unique properties of single walled carbon nanotubes (SWNTs) make them especially well suited for use as electrodes in power devices such as lithium ion batteries, hydrogen fuel cells, solar cells, and supercapacitors. The performances of such devices are expected to be influenced, at least in part, by the mechanical properties of the SWNTs used in composites or in stand alone ``papers.'' Therefore, the elastic moduli and ultimate tensile strengths of SWNT papers were measured as functions of temperature, SWNT purity, SWNT length, and SWNT bundling. The SWNTs used to produce the papers were synthesized in an alexandrite laser vaporization reactor at 1100^oC and purified using conventional acid-reflux conditions. Characterization of the SWNTs was performed using SEM, BET, TGA, and optical and Raman spectroscopy. The purified material was filtered and dried to yield papers of bundled SWNTs which were analyzed using dynamic mechanical analysis (DMA). It was observed that the mechanical properties of acid-refluxed SWNT papers were significantly improved by controlled thermal oxidation and strain-hardening. Elastic moduli of SWNT papers were measured between 3 and 6 GPa. Ultimate (breaking) tensile stresses were measured between 45 and 90 MPa at 1-3% strain. These results and their implications in regard to potential applications in power devices will be discussed.

  11. Nonlinear resonances of a single-wall carbon nanotube cantilever

    NASA Astrophysics Data System (ADS)

    Kim, I. K.; Lee, S. I.

    2015-03-01

    The dynamics of an electrostatically actuated carbon nanotube (CNT) cantilever are discussed by theoretical and numerical approaches. Electrostatic and intermolecular forces between the single-walled CNT and a graphene electrode are considered. The CNT cantilever is analyzed by the Euler-Bernoulli beam theory, including its geometric and inertial nonlinearities, and a one-mode projection based on the Galerkin approximation and numerical integration. Static pull-in and pull-out behaviors are adequately represented by an asymmetric two-well potential with the total potential energy consisting of the CNT elastic energy, electrostatic energy, and the Lennard-Jones potential energy. Nonlinear dynamics of the cantilever are simulated under DC and AC voltage excitations and examined in the frequency and time domains. Under AC-only excitation, a superharmonic resonance of order 2 occurs near half of the primary frequency. Under both DC and AC loads, the cantilever exhibits linear and nonlinear primary and secondary resonances depending on the strength of the excitation voltages. In addition, the cantilever has dynamic instabilities such as periodic or chaotic tapping motions, with a variation of excitation frequency at the resonance branches. High electrostatic excitation leads to complex nonlinear responses such as softening, multiple stability changes at saddle nodes, or period-doubling bifurcation points in the primary and secondary resonance branches.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  13. 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

  14. Endohedral Motions Inside Capped Single-Walled Carbon Nanotubes

    SciTech Connect

    Cioslowski, Jerzy (Florida State University) [Florida State University; Rao, Niny (Florida State University) [Florida State University; Pernal, Katarzyna (Uniwersytet Szczecinski) [Uniwersytet Szczecinski; Moncrieff, David (Florida State University) [Florida State University

    2003-03-08

    B3LYP/6-311G* electronic structure calculations reveal that the dependence of the complexation energy E{sub cmpl}(z) on the longitudinal displacement z of the guest in endohedral complexes of the Na{sup +} cation with capped [5,5] armchair single-walled carbon nanotubes stems from an interplay between the polarization of the host by the electric field of the guest and the guest-host steric repulsion. Overall, E{sub cmpl}(z) is characterized by the presence of a periodic pattern of local minima and maxima that reflect the discrete nature of the tube and of a pair of global minima located at fixed distances from the tube termini. Because of the large barrier height/zero-point energy ratio, the endohedral motion of the Na{sup +} cation at T = 0 [K] is largely confined to a surface that internally follows the contour of the tube. Vibrations perpendicular to the surface give rise to transitions in the vicinity of 100 [cm{sup -1}], whereas the unimpeded motions within the surface result in a plethora of transitions with onsets as low as 0.1 [cm{sup -1}].

  15. Endohedral Motions Inside Capped Single-Walled Carbon Nanotubes

    SciTech Connect

    Cioslowski, Jerzy; Rao, Niny; Pernal, Katarzyna; Moncrieff, David

    2003-03-08

    B3LYP/6-311G* electronic structure calculations reveal that the dependence of the complexation energy Ecmpl(z) on the longitudinal displacement z of the guest in endohedral complexes of the Na1cation with capped [5,5] armchair single-walled carbon nanotubes stems from an interplay between the polarization of the host by the electric field of the guest and the guest-host steric repulsion. Overall, Ecmpl(z) is characterized by the presence of a periodic pattern of local minima and maxima that reflect the discrete nature of the tube and of a pair of global minima located at fixed distances from the tube termini. Because of the large barrier height/zero-point energy ratio, the endohedral motion of the Na1 cation at T=0 [K] is largely confined to a surface that internally follows the contour of the tube. Vibrations perpendicular to the surface give rise to transitions in the vicinity of 100 [cm-1], whereas the unimpeded motions within the surface result in a plethora of transitions with onsets as low as 0.1 [cm-1].

  16. Ultrafast pump probe spectroscopy of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhu, Zipeng

    This dissertation is mainly focused on the femtosecond pump probe spectroscopy of the (6, 5) single wall carbon nanotubes (SWNTs). There are three advantages in this experiment, first, we upgrade the optical parametric amplifier (OPA) in the laser system to allow automatic wavelength tuning of the OPA; second, we tune the excitation wavelength continuously across the E22 exciton resonance of the (6, 5) tube to examine the dynamics at the E11 and E22 states; third, we use highly purified chirality enriched SWNT samples. These advantages allow us to obtain the spectroscopy with unprecedented details, which greatly help to improve our understanding of the two fundamental issues in SWNT pump probe spectroscopy, for the excited state dynamics, we are able to separate a short time dynamics from a long time dominant 1D diffusion process in the (6, 5) tube and relate this short time process to the carrier dynamics on the E11 state; for the photoinduced absorption, we are able to compare it with the phonon sideband features in the photoluminescence excitation spectrum and propose a new mechanism for its origin, the phonon assisted carrier scattering to the E11 states.

  17. A Single-Walled Carbon Nanotube Network Gas Sensing Device

    PubMed Central

    Wang, Li-Chun; Tang, Kea-Tiong; Teng, I-Ju; Kuo, Cheng-Tzu; Ho, Cheng-Long; Kuo, Han-Wen; Su, Tseng-Hsiung; Yang, Shang-Ren; Shi, Gia-Nan; Chang, Chang-Ping

    2011-01-01

    The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT) networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD). The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3. PMID:22164044

  18. Radiation effects in single-walled carbon nanotube papers

    SciTech Connect

    Cress, Cory D.; Messenger, Scott R.; Walters, Robert J. [Electronics Science and Technology Division, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Schauerman, Christopher M.; Raffaelle, Ryne P. [NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, New York 14623 (United States); Landi, Brian J. [NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, New York 14623 (United States); Department of Chemical and Biomedical Engineering, Rochester Institute of Technology, Rochester, New York 14623 (United States)

    2010-01-15

    The effects of ionizing radiation on the temperature-dependent conductivity of single-walled carbon nanotube (SWCNT) papers have been investigated in situ in a high vacuum environment. Irradiation of the SWCNT papers with 4.2 MeV alpha particles results in a steady decrease in the SWCNT paper conductivity, resulting in a 25% reduction in room temperature conductivity after a fluence of 3x10{sup 12} alpha particles/cm{sup 2}. The radiation-induced temperature-dependent conductivity modification indicates that radiation damage causes an increase in the effective activation barrier for tunneling-like conductivity and a concomitant increase in wavefunction localization of charge carriers within individual SWCNTs. The spatial defect generation within the SWCNT paper was modeled and confirms that a uniform displacement damage dose was imparted to the paper. This allows the damage coefficient (i.e., differential change in conductivity with fluence) for alpha particles, carbon ions, and protons to be compared with the corresponding nonionizing energy loss (NIEL) of the incident particle. The resulting nonlinear relationship with NIEL between these parameters is distinct from the more typical linear response observed in many bulk semiconductors and superconductors and indicates that localized radiation damage in the SWCNT papers has a greater impact than distributed damage. Although SWCNT papers behave largely as a bulk material with properties that are a convolution of the underlying SWCNT distribution, the radiation response appears to be largely dominated by degradation in the preferred one-dimensional conduction within these two-dimensionally confined nanostructures.

  19. Single-walled carbon nanotubes for spintronic and photovoltaic applications

    Microsoft Academic Search

    Christopher Ali Merchant

    2009-01-01

    Electron transport in carbon nanotubes (CNTs) is studied as it relates to both spintronic and photovoltaic devices. First, a new spintronic device is studied which we refer to as a spin diode. The spin diode consists of a single carbon nanotube quantum dot with one ferromagnetic and one normal-metal lead. Spin-dependent rectification of the current is observed for one direction

  20. 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.

  1. Optical heating and temperature determination of core-shell gold nanoparticles and single-walled carbon nanotube microparticles.

    PubMed

    Yashchenok, Alexey; Masic, Admir; Gorin, Dmitry; Inozemtseva, Olga; Shim, Bong Sup; Kotov, Nicholas; Skirtach, Andre; Möhwald, Helmuth

    2015-03-01

    The real-time temperature measurement of nanostructured materials is particularly attractive in view of increasing needs of local temperature probing with high sensitivity and resolution in nanoelectronics, integrated photonics, and biomedicine. Light-induced heating and Raman scattering of single-walled carbon nanotubes with adsorbed gold nanoparticles decorating silica microparticles are reported, by both green and near IR lasers. The plasmonic shell is used as nanoheater, while the single-walled carbon nanotubes are Raman active and serve as a thermometer. Stokes and Anti-Stokes Raman spectra of single-walled carbon nanotubes serve to estimate the effective light-induced temperature rise on the metal nanoparticles. The temperature rise is constant with time, indicating stability of the adsorption density. The effective temperatures derived from Stokes and Anti-Stokes intensities are correlated with those measured in a heating stage. The resolution of the thermal experiments in our study was found to be 5-40 K. PMID:25367373

  2. 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

  3. Semi-Crystalline Polymer based Single Walled Carbon Nanotube Nanocomposites

    NASA Astrophysics Data System (ADS)

    Mitchell, Cynthia; Krishnamoorti, Ramanan

    2004-03-01

    The reinforcement of polymers with nanometer scale inorganic materials has stimulated much scientific and technological interest because, when compared to traditional composites, nanocomposites exhibit improved thermal, mechanical and physical properties at much lower particle loading. Development of single walled carbon nanotube (SWNT) based polymer nanocomposites is attractive because of the possibility of combining the extraordinary array of properties of SWNTs with the light-weight character of polymers to develop unique and tailorable materials. Important areas of concern in the development of SWNT composites are ensuring homogeneity of dispersion, good interfacial compatibility with the polymeric matrix and the exfoliation of the ropes and bundles. Several strategies for developing well-dispersed SWNT polymer nanocomposites have been undertaken in the current research and we demonstrate the development of well dispersed SWNT nanocomposites with poly(e-caprolactone) (PCL). PCL is a model, low melting analog of nylon-6, an important commercial material, and additionally is a biocompatible and biodegradable crystalline polymer. Compatibility between PCL and SWNT is anticipated based on the fact that the monomer e-caprolactone disperses SWNTs effectively. Preparation of the composites was accomplished by in-situ polymerization and also by solution blending a model polymer with functionalized or unfunctionalized SWNTs. Composites were characterized extensively utilizing UV- Vis - NearIR spectroscopy, FTIR, DSC, X-ray scattering and diffraction, AFM, melt state rheology and electrical conductivity. Controlling the interactions by covalently linking the polymer to the nanotube or by use of a dispersing aid before the introduction of the polymer and the extensive characterization of the resulting system could lead to the development of structure property relationships that would be beneficial to the tailoring of ultra lightweight materials with exceptional mechanical and physical properties.

  4. Carbonyl group generation on single-wall carbon nanotubes with nitric acid: A theoretical description

    NASA Astrophysics Data System (ADS)

    Da Silva, Antônio M.; Dos Santos, Hélio F.; Giannozzi, Paolo

    2013-09-01

    The initial steps of single-wall carbon nanotube (SWNT) oxidation in nitric acid were studied using a (6,6) supercell with a mono-vacancy defect and employing spin-polarised density functional theory. According to our results, the geometric changes that occur during the process are significantly localised around the vacancy. The carbonyl group generation does not change the metallic nature of the nanosystem. Vibrational thermal corrections calculated using full and partial Hessian vibrational analysis indicated a small contribution to the reaction energy. An overall favourable oxidation pathway is proposed and includes an initial NO2+ exothermic electrophilic attack followed by an endothermic oxaziridine formation.

  5. 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.

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

    PubMed

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

    2014-09-10

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Single-wall carbon nanotubes as attractive toughening agents in alumina-based nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhan, Guo-Dong; Kuntz, Joshua D.; Wan, Julin; Mukherjee, Amiya K.

    2003-01-01

    The extraordinary mechanical, thermal and electrical properties of carbon nanotubes have prompted intense research into a wide range of applications in structural materials, electronics, chemical processing and energy management. Attempts have been made to develop advanced engineering materials with improved or novel properties through the incorporation of carbon nanotubes in selected matrices (polymers, metals and ceramics). But the use of carbon nanotubes to reinforce ceramic composites has not been very successful; for example, in alumina-based systems only a 24% increase in toughness has been obtained so far. Here we demonstrate their potential use in reinforcing nanocrystalline ceramics. We have fabricated fully dense nanocomposites of single-wall carbon nanotubes with nanocrystalline alumina (Al2O3) matrix at sintering temperatures as low as 1,150 °C by spark-plasma sintering. A fracture toughness of 9.7 MPa m½, nearly three times that of pure nanocrystalline alumina, can be achieved.

  12. 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.

  13. 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.

  14. Ultrashort single-walled carbon nanotubes in a lipid bilayer as a new nanopore sensor

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Yang, Chun; Zhao, Kai; Li, Jingyuan; Wu, Hai-Chen

    2013-12-01

    An important issue in nanopore sensing is to construct stable and versatile sensors that can discriminate analytes with minute differences. Here we report a means of creating nanopores that comprise ultrashort single-walled carbon nanotubes inserted into a lipid bilayer. We investigate the ion transport and DNA translocation through single-walled carbon nanotube nanopores and find that our results are fundamentally different from previous studies using much longer single-walled carbon nanotubes. Furthermore, we utilize the new single-walled carbon nanotube nanopores to selectively detect modified 5-hydroxymethylcytosine in single-stranded DNA, which may have implications in screening specific genomic DNA sequences. This new nanopore platform can be integrated with many unique properties of carbon nanotubes and might be useful in molecular sensing such as DNA-damage detection, nanopore DNA sequencing and other nanopore-based applications.

  15. 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

  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. Binding of hydroxylated single-walled carbon nanotubes to two hemoproteins, hemoglobin and myoglobin.

    PubMed

    Wang, Yan-Qing; Zhang, Hong-Mei; Cao, Jian

    2014-12-01

    Herein, we studied the binding interactions between hydroxylated single-walled carbon nanotubes and hemoglobin and myoglobin by the use of multi-spectral techniques and molecular modeling. The ultraviolet-vis absorbance and circular dichroism spectral results indicated that the binding interactions existed between hydroxylated single-walled carbon nanotubes and hemoglobin/myoglobin. These binding interactions partially affected the soret/heme bands of hemoglobin and myoglobin. The secondary structures of hemoproteins were partially destroyed by hydroxylated single-walled carbon nanotubes. Fluorescence studies suggested that the complexes formed between hydroxylated single-walled carbon nanotubes and hemoglobin/myoglobin by hydrogen bonding, hydrophobic, and ?-? stacking interactions. In addition, molecular modeling analysis well supported the experimental results. PMID:25313539

  18. 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 ...

  19. Fermi-Energy-Dependent Structural Deformation of Chiral Single-Wall Carbon Nanotubes

    E-print Network

    Vieira, Bruno G.?M.

    In this work, we use an extended tight-binding approach for calculating the Fermi-energy dependence of the structural deformation of chiral single-wall carbon nanotubes (SWNTs). We show that, in general, nanotube strains ...

  20. 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 ...

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

    E-print Network

    Heller, Daniel Alan

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

  2. Chirality dependence of coherent phonon amplitudes in single-wall carbon nanotubes

    E-print Network

    Dresselhaus, Mildred

    We simulate the ultrafast dynamics of laser-induced coherent phonons in single-wall carbon nanotubes (SWNTs). In particular, we examine the coherent phonon amplitude of the radial breathing mode (RBM) as a function of ...

  3. OH and COOH functionalized single walled carbon nanotubes-reinforced alumina ceramic nanocomposites

    Microsoft Academic Search

    Ali Can Zaman; Cem B. Üstünda?; Figen Kaya; Cengiz Kaya

    Alumina ceramics reinforced with 1wt.% single-walled carbon nanotube (SWCNT) were fabricated via spark plasma sintering (SPS) of composite powders containing carboxyl (COOH) or hydroxyl (OH) group functionalized single-walled carbon nanotubes. The samples were SPS’ed at 1600°C under 50MPa pressure for holding time of 5min and at a heating rate of 4°C\\/s. The effects of CNT addition having different surface functional

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

    Microsoft Academic Search

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

    2003-01-01

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

  5. 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.

  6. Xenon adsorption on defected single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Jalili, S.; Vaez, A.

    2007-04-01

    Molecular dynamics (MD) simulation is used to compute the adsorption isotherms of xenon (Xe) gas on defected open ended single-walled nanotubes (o-SWNT). We perform a simulation based on a many-body interatomic Brenner potential with a two-body interatomic Lennard-Jones (LJ) potential. Adsorption isotherms of Xe on (10, 10) o-SWNT for several temperatures, between 95 and 130 K, are measured. Adsorption coverage, isosteric heat, and binding energy were calculated at various temperatures and pressures and compared with the same properties for the perfect (10, 10) o-SWNT. It is shown that adsorption occurs both inside and outside of an o-SWNTs.

  7. 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

  8. Influence of the growth conditions on the defect density of single-walled carbon nanotubes

    E-print Network

    Paris-Sud XI, Université de

    to determine experimental conditions allowing the preparation of samples free of pyrolytic carbon1 Influence of the growth conditions on the defect density of single-walled carbon nanotubes manuscript, published in "Carbon 50 (2012) 2407" DOI : 10.1016/j.carbon.2012.01.055 #12;2 ABSTRACT

  9. Improved efficiency of smooth and aligned single walled carbon nanotube/silicon hybrid solar cells

    E-print Network

    Reed, Mark

    Improved efficiency of smooth and aligned single walled carbon nanotube/silicon hybrid solar cells for many next generation solar cell devices including CNT/polymer, carbon/polymer, and all carbon solar as a platform for many next generation solar cell devices including CNT/polymer,11 carbon/polymer,12,13 and all

  10. Atomistic nucleation and growth mechanism for single-wall carbon nanotubes on catalytic nanoparticle surfaces.

    PubMed

    Wang, Jian-Tao; Chen, Changfeng; Ohno, Kaoru; Wang, Enge; Chen, Xiao-Long; Wang, Ding-Sheng; Mizuseki, Hiroshi; Kawazoe, Yoshiyuki

    2010-03-19

    We demonstrate an atomistic nucleation and growth mechanism for single-wall carbon nanotubes (SWNTs) on catalytic nanoparticle surfaces based on a core-shell model. We show by ab initio calculations that strain relief between the metal core and carbon shell plays a crucial role in facilitating the hexagonal tubular growth. The incipient nucleation begins with the formation of a hemispherical fullerene cap by a size-selected core-shell bonding process which is followed by a repeated phase-separating growth mode with increasing energetic stability via periodic pulsatile strain relief along the tubular growth pathway. These results provide an excellent account for experimental observations and shed new light on the origin and underlying dynamics of SWNT growth. PMID:20173247

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

    PubMed

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

    2014-10-01

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

  12. 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.

  13. Synthesis and characterization of platinum nanoparticles on single-walled Carbon nanotube "nanopaper" support

    NASA Astrophysics Data System (ADS)

    Bromberg, Malka R.; Patlolla, Anitha; Segal, Rebecca; Feldman, Yishai; Wang, Qi; Iqbal, Zafar; Frenkel, Anatoly I.

    2009-11-01

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

  14. Near-infrared photoresponse in single walled carbon nanotube/polymer composite films

    NASA Astrophysics Data System (ADS)

    Sarker, Biddut K.; Arif, M.; Khondaker, Saiful I.

    2010-03-01

    We present a near-infrared photoresponse study of single-walled carbon nanotube/poly(3-hexylthiophene)-block-polystyrene polymer (SWCNT/P3HT-b-PS) composite films for different loading ratios of SWCNT in the polymer matrix. Compared to the pure SWCNT film, the photoresponse [(light current -- dark current)/dark current] is much larger in the SWCNT/polymer composite films. The photoresponse is up to 157% when SWCNTs are embedded in P3HT-b-PS while for a pure SWCNT film it is only 40%. We also show that the photocurrent strongly depends on the position of the laser spot with maximum photocurrent occurring at the metal--film interface. We explain the photoresponse due to exciton dissociations and charge carrier separation caused by a Schottky barrier at the metallic electrode - SWCNT interface

  15. Improving photovoltaic properties by incorporating both single walled carbon nanotubes and functionalized multiwalled carbon nanotubes

    Microsoft Academic Search

    Ishwor Khatri; Sudip Adhikari; Hare Ram Aryal; Tetsuo Soga; Takashi Jimbo; Masayoshi Umeno

    2009-01-01

    Single-walled carbon nanotubes (SWCNTs) and functionalized multiwalled carbon nanotubes (f-MWCNTs) are introduced together for photovoltaic application in a poly(3-octylthiophene)\\/n-Si heterojunction solar cell. The performance of the device was improved by manyfold by the incorporation of both SWCNTs and f-MWCNTs. The open circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and power conversion efficiency (?) were 0.44 V,

  16. Gas-phase catalytic growth of single-walled carbon nanotubes from carbon monoxide

    Microsoft Academic Search

    Pavel Nikolaev; Michael J Bronikowski; R. Kelley Bradley; Frank Rohmund; Daniel T Colbert; K. A Smith; Richard E Smalley

    1999-01-01

    Single-walled carbon nanotubes (SWNTs) have been produced in a gas-phase catalytic process. Catalysts for SWNT growth form in situ by thermal decomposition of iron pentacarbonyl in a heated flow of carbon monoxide at pressures of 1–10 atm and temperatures of 800–1200°C. The SWNT yield and diameter distribution can be varied by controlling the process parameters, and SWNTs as small as

  17. The separation and substrate independent organization of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Debjit D.

    Learning how to separate, purify and manipulate single wall carbon nanotubes (SWNTs) presents a unique challenge in material science. The processing-related difficulties of these long nano-fibers stem from their high aspect ratio, rigidity and the profound hydrophobic attractions along their tubular walls. Shortening them into discrete segments, with lengths from tens to hundreds of nanometers, presents a viable methodology to alleviate the shape-induced intractability. The thesis presents a route for the length fractionation of shortened-S WNTs, and most importantly provides a venue by which substantial separation of single wall carbon nanotubes (SWNTs) according to type (metallic versus semiconducting) has been achieved for HiPco and laser-ablated SWNTs. Herein I argue that stable dispersions of SWNTs with octadecylamine (ODA) in tetrahydrofuran (THF) originate from the physisorption and organization of ODA along the SWNT sidewalls in addition to the originally proposed zwitterion model. Furthermore, the reported affinity of amine groups for semiconducting SWNTs, as opposed to their metallic counterparts contributes additional stability to the physisorbed ODA. This provides a venue for the selective precipitation of metallic SWNTs upon increasing dispersion concentration, as indicated by Raman investigations. In addition, the thesis provides a novel metal-assisted self-organization of these nanosized objects into nano-forest geometries with dense perpendicular surface grafting, and demonstrates that such nanosized objects hold significant promise for the development of nanoscale sensors. Additionally, this dissertation provides a method for the complete elimination of catalytic impurities from SWNTs. Electrochemical actuators using such purified SWNTs have been characterized.

  18. Identifying individual single-walled and double-walled carbon nanotubes by atomic force microscopy.

    PubMed

    DeBorde, Tristan; Joiner, J Caleb; Leyden, Matthew R; Minot, Ethan D

    2008-11-01

    We show that the number of concentric graphene cylinders forming a carbon nanotube can be found by squeezing the tube between an atomic force microscope tip and a silicon substrate. The compressed height of a single-walled nanotube (double-walled nanotube) is approximately two (four) times the interlayer spacing of graphite. Measured compression forces are consistent with the predicted bending modulus of graphene and provide a mechanical signature for identifying individual single-walled and double-walled nanotubes. PMID:18811211

  19. Flexible thermoelectric rubber polymer composites based on single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Nakano, Motohiro; Nonoguchi, Yoshiyuki; Nakashima, Takuya; Kawai, Tsuyoshi

    2015-04-01

    Flexible polymer composite materials are advantageous for future thermoelectrics. In this paper we report the controlled dispersion of single-walled carbon nanotubes into an elastic polymer matrix for efficient thermoelectric power generation capability. Optimized rubber composites with a 30 wt % loading level of single-walled carbon nanotubes showed a 15 µW m?1 K?2 thermoelectric power factor, comparable to those of non-elastic carbon nanotube sheets, and larger than those of flexible composite films based on carbon nanotubes.

  20. A Timoshenko beam model for vibration analysis of chiral single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Boumia, Lakhdar; Zidour, Mohamed; Benzair, Abdelnour; Tounsi, Abdelouahed

    2014-05-01

    In this paper, dynamic properties of a single-walled carbon nanotube (SWCNT) with small scale effects are studied. Based on the nonlocal continuum theory and the Timoshenko beam model, the equations of motion are derived. The influences of scale coefficients, the vibrational mode number, the chirality of carbon nanotube and the aspect ratio on the vibrational characteristics of the SWCNTs are discussed. Results indicate significant dependence of natural frequencies on the chirality of single-walled carbon, the small-scale parameter, the vibrational mode number and the aspect ratio. These findings are important in mechanical design considerations of devices that use carbon nanotubes.

  1. 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.

  2. 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.

  3. Elastic properties and pressure-induced phase transitions of single-walled carbon nanotubes

    E-print Network

    Nabben, Reinhard

    Elastic properties and pressure-induced phase transitions of single-walled carbon nanotubes S-walled carbon nanotubes under hydrostatic pressure by first-princi- ples calculations. The circular tubes of carbon nanotubes has been studied with a variety of experimental techniques. Most of these studies seemed

  4. Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes

    E-print Network

    Boyer, Edmond

    Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes Jared J. Crochet@lanl.gov KEYWORDS: carbon nanotube, exciton, dephasing, transport, exchange interaction Abstract We present measurements of S1 exciton transport in (6,5) carbon nanotubes at room tem- perature in a colloidal environment

  5. POLARIZED RAMAN MEASUREMENTS IN ZEOLITE-GROWN SINGLE-WALL CARBON NANOTUBES

    E-print Network

    Nabben, Reinhard

    POLARIZED RAMAN MEASUREMENTS IN ZEOLITE-GROWN SINGLE-WALL CARBON NANOTUBES J. Maultzsch*, P. M, Hardenbergstr. 36, D-10623 Berlin, E-Mail: janina@physik.tu-berlin.de The Raman spectra of carbon nanotubes able to grow carbon nanotubes inside the channels of an AlPO4 zeolite crystal [1]. The directions

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  7. Self-aligned growth of single-walled carbon nanotubes using optical near-field effects

    NASA Astrophysics Data System (ADS)

    Xiong, W.; Zhou, Y. S.; Mahjouri-Samani, M.; Yang, W. Q.; Yi, K. J.; He, X. N.; Liou, S. H.; Lu, Y. F.

    2009-01-01

    Self-aligned growth of ultra-short single-walled carbon nanotubes (SWNTs) was realized by utilizing optical near-field effects in a laser-assisted chemical vapor deposition (LCVD) process. By introducing the optical near-field effects, bridge structures containing single suspended SWNT channels were successfully fabricated through the LCVD process at a relatively low substrate temperature. Raman spectroscopy and I-V analyses have been carried out to characterize the SWNT-bridge structures. Numerical simulations using a high-frequency structure simulator revealed that significant enhancement of local heating occurs at metallic electrode tips under laser irradiation; it is about one order of magnitude higher than that in the rest of the electrodes. This technique suggests a novel approach to in situ low-temperature fabrication of SWNT-based devices in a precisely controlled manner, based on the nanoscale heating enhancement induced by the optical near-field effects.

  8. Self-aligned growth of single-walled carbon nanotubes using optical near-field effects.

    PubMed

    Xiong, W; Zhou, Y S; Mahjouri-Samani, M; Yang, W Q; Yi, K J; He, X N; Liou, S H; Lu, Y F

    2009-01-14

    Self-aligned growth of ultra-short single-walled carbon nanotubes (SWNTs) was realized by utilizing optical near-field effects in a laser-assisted chemical vapor deposition (LCVD) process. By introducing the optical near-field effects, bridge structures containing single suspended SWNT channels were successfully fabricated through the LCVD process at a relatively low substrate temperature. Raman spectroscopy and I-V analyses have been carried out to characterize the SWNT-bridge structures. Numerical simulations using a high-frequency structure simulator revealed that significant enhancement of local heating occurs at metallic electrode tips under laser irradiation; it is about one order of magnitude higher than that in the rest of the electrodes. This technique suggests a novel approach to in situ low-temperature fabrication of SWNT-based devices in a precisely controlled manner, based on the nanoscale heating enhancement induced by the optical near-field effects. PMID:19417270

  9. Length-dependent plasmon resonance in single-walled carbon nanotubes.

    PubMed

    Morimoto, Takahiro; Joung, Soon-Kil; Saito, Takeshi; Futaba, Don N; Hata, Kenji; Okazaki, Toshiya

    2014-10-28

    The optical response of single-walled carbon nanotubes (SWCNTs) to far-infrared (FIR) radiation was systematically studied using various SWCNTs with different tube-length distributions. The observed peak position in the FIR spectra linearly scaled with the inverse of tube length irrespective of diameter, which is consistent with the dispersion relation predicted by the one-dimensional plasmon resonance model. The effects of chemical doping on the FIR spectra of the separated metallic and semiconducting SWCNTs clearly indicate that the motion of plasmons in the electronic band structures is primarily responsible for the optical response in these spectral regions. The observed absorption peaks are naturally sensitive to the presence of defects on the tube wall and correlated with the electric resistance, suggesting that the plasmons resonate with the current path length of the SWCNTs. PMID:25283493

  10. Three-dimensional polymeric structures of single-wall carbon nanotubes

    SciTech Connect

    Lian, Chao-Sheng; Wang, Jian-Tao, E-mail: wjt@aphy.iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-05-28

    We explore by ab initio calculations the possible crystalline phases of polymerized single-wall carbon nanotubes (P-SWNTs) and determine their structural, elastic, and electronic properties. Based on direct cross-linking and intertube sliding-assisted cross-linking mechanisms, we have identified a series of stable three-dimensional polymeric structures for the zigzag nanotubes up to (10,0). Among proposed P-SWNT phases, the structures with favorable diamond-like sp{sup 3} intertube bonding configuration and small tube cross-section distortion are found to be the most energetically stable ones. These polymeric crystalline phases exhibit high bulk and shear moduli superior to SWNT bundles, and show metallic or semiconducting properties depending on the diameter of constituent tubes. We also propose by hydrostatic pressure simulations that the intertube sliding between van der Waals bonded nanotubes may be an effective route to promote the polymerization of SWNTs under pressure.

  11. Three-dimensional polymeric structures of single-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Lian, Chao-Sheng; Wang, Jian-Tao

    2014-05-01

    We explore by ab initio calculations the possible crystalline phases of polymerized single-wall carbon nanotubes (P-SWNTs) and determine their structural, elastic, and electronic properties. Based on direct cross-linking and intertube sliding-assisted cross-linking mechanisms, we have identified a series of stable three-dimensional polymeric structures for the zigzag nanotubes up to (10,0). Among proposed P-SWNT phases, the structures with favorable diamond-like sp3 intertube bonding configuration and small tube cross-section distortion are found to be the most energetically stable ones. These polymeric crystalline phases exhibit high bulk and shear moduli superior to SWNT bundles, and show metallic or semiconducting properties depending on the diameter of constituent tubes. We also propose by hydrostatic pressure simulations that the intertube sliding between van der Waals bonded nanotubes may be an effective route to promote the polymerization of SWNTs under pressure.

  12. Three-dimensional polymeric structures of single-wall carbon nanotubes.

    PubMed

    Lian, Chao-Sheng; Wang, Jian-Tao

    2014-05-28

    We explore by ab initio calculations the possible crystalline phases of polymerized single-wall carbon nanotubes (P-SWNTs) and determine their structural, elastic, and electronic properties. Based on direct cross-linking and intertube sliding-assisted cross-linking mechanisms, we have identified a series of stable three-dimensional polymeric structures for the zigzag nanotubes up to (10,0). Among proposed P-SWNT phases, the structures with favorable diamond-like sp(3) intertube bonding configuration and small tube cross-section distortion are found to be the most energetically stable ones. These polymeric crystalline phases exhibit high bulk and shear moduli superior to SWNT bundles, and show metallic or semiconducting properties depending on the diameter of constituent tubes. We also propose by hydrostatic pressure simulations that the intertube sliding between van der Waals bonded nanotubes may be an effective route to promote the polymerization of SWNTs under pressure. PMID:24880313

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

    PubMed Central

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

    2012-01-01

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

  14. Scaling properties in transistors that use aligned arrays of single-walled carbon nanotubes.

    PubMed

    Ho, Xinning; Ye, Lina; Rotkin, Slava V; Cao, Qing; Unarunotai, Sakulsuk; Salamat, Shuaib; Alam, Muhammad A; Rogers, John A

    2010-02-10

    Recent studies and device demonstrations indicate that horizontally aligned arrays of linearly configured single-walled carbon nanotubes (SWNTs) can serve as an effective thin film semiconductor material, suitable for scalable use in high-performance transistors. This paper presents the results of systematic investigations of the dependence of device properties on channel length, to reveal the role of channel and contact resistance in the operation. The results indicate that, for the range of channel lengths and SWNT diameters studied here, source and drain contacts of Pd yield transistors with effectively Ohmic contacts that exhibit negligible dependence of their resistances on gate voltage. For devices that use Au, modulation of the resistance of the contacts represents a significant contribution to the response. Extracted values of the mobilities of the semiconducting SWNTs and the contact resistances associated with metallic and semiconducting SWNTs are consistent with previous reports on single tube test structures. PMID:20050675

  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. Reinforcing mechanisms of single-walled carbon nanotube-reinforced polymer composites.

    PubMed

    Li, Xiaodong; Gao, Hongsheng; Scrivens, Wally A; Fei, Dongling; Xu, Xiaoyou; Sutton, Michael A; Reynolds, Anthony P; Myrick, Michael L

    2007-07-01

    The reinforcing mechanisms of single-walled carbon nanotube-reinforced epoxy composites were studied by micromechanics models. The modeling results obtained from both Halpin-Tsai and Mori-Tanaka models are in good agreement with the experimental results. It has been found that these two models are also applicable to other single-walled carbon nanotube-reinforced, amorphous-polymer composites, given the existence of efficient load transfer. The reinforcing mechanisms that work in polymer-carbon nanotube composites were studied. The reasons responsible for the low mechanical property enhancement of single-walled carbon nanotube in polymer composites were discussed in conjunction with the effective fiber length concept, interface between nanotube bundles and the matrix, properties of the reinforcements and matrix, bundle effects, bundle curvature, and alignment. PMID:17663245

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  20. Cesium encapsulation in single-walled carbon nanotubes via plasma ion irradiation: Application to junction formation and ab initio investigation

    Microsoft Academic Search

    G.-H. Jeong; A. A. Farajian; R. Hatakeyama; T. Hirata; T. Yaguchi; K. Tohji; H. Mizuseki; Y. Kawazoe

    2003-01-01

    Using an approach different from the conventional vapor doping methods, Cs positive ions in a magnetized-plasma column are irradiated upon a negatively biased substrate which is covered with dispersed single-walled carbon nanotubes (SWNTs). The Cs ions are evidently observed inside SWNTs by the Z-contrast method in scanning transmission electron microscopy, demonstrating the formation of alkali-metal encapsulating SWNTs. Ab initio band

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

    Microsoft Academic Search

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

    1999-01-01

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

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

    E-print Network

    Li, Mo

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

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

    SciTech Connect

    Mu, Weihua, E-mail: whmu@mit.edu, E-mail: muwh@itp.ac.cn [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Kavli Institute for Theoretical Physics China, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Cao, Jianshu, E-mail: jianshu@mit.edu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Singapore-MIT Alliance for Research and Technology (SMART), Singapore 138602 (Singapore); Ou-Yang, Zhong-can [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Kavli Institute for Theoretical Physics China, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Singapore-MIT Alliance for Research and Technology (SMART), Singapore 138602 (Singapore); Center for Advanced Study, Tsinghua University, Beijing 100084 (China)

    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. Protective roles of single-wall carbon nanotubes in ultrasonication-induced DNA base damage.

    PubMed

    Petersen, Elijah J; Tu, Xiaomin; Dizdaroglu, Miral; Zheng, Ming; Nelson, Bryant C

    2013-01-28

    The overall level of ultrasonication-induced DNA damage is reduced in the presence of single-wall carbon nanotubes (SWCNTs), particularly for DNA lesions formed by one-electron reduction of intermediate radicals. The protective role of SWCNTs observed in this work suggests a contrary view to the general idea that carbon nanotubes have damaging effects on biomolecules. PMID:22987483

  6. 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

  7. 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

  8. 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

  9. Hydrogen adsorption and cohesive energy of single-walled carbon nanotubes

    Microsoft Academic Search

    Y. Ye; C. C. Ahn; C. Witham; B. Fultz; J. Liu; A. G. Rinzler; D. Colbert; K. A. Smith; R. E. Smalley

    1999-01-01

    Hydrogen adsorption on crystalline ropes of carbon single-walled nanotubes (SWNT) was found to exceed 8 wt. %, which is the highest capacity of any carbon material. Hydrogen is first adsorbed on the outer surfaces of the crystalline ropes. At pressures higher than about 40 bar at 80 K, however, a phase transition occurs where there is a separation of the

  10. Structure-Dependent Fluorescence Efficiencies of Individual Single-Walled Carbon Nanotubes

    E-print Network

    Boyer, Edmond

    1 Structure-Dependent Fluorescence Efficiencies of Individual Single-Walled Carbon Nanotubes Dmitri, F-33405 France AUTHOR EMAIL ADDRESS: weisman@rice.edu RECEIVED DATE #12;2 ABSTRACT: Single-nanotube fluorimetric intensities. KEYWORDS: SWNT, carbon nanotubes, fluorescence, microscopy, spectroscopy, emission

  11. Origin of the high-energy Raman modes in single-wall carbon nanotubes

    E-print Network

    Nabben, Reinhard

    Origin of the high-energy Raman modes in single-wall carbon nanotubes J. Maultzsch, C. Thomsen, S nanotubes. Similar to the disorder-induced D mode, the high-energy modes are deter- mined by double of the first-order high-energy Raman modes in carbon nanotubes has been a puzzling question since the first

  12. Computational analysis of binding free energies between peptides and single-walled carbon nanotubes

    Microsoft Academic Search

    Y. Cheng; G. R. Liu; Z. R. Li; C. Lu

    2006-01-01

    Coating carbon nanotubes (CNTs) with peptides can solubilize the nanotubes in water solvent. To explore the utilization of CNTs in solvent and the affinities of CNTs for different peptides, binding free energies of peptides to single-walled carbon nanotubes (SWCNTs) are calculated and analyzed. The interactions between different peptides and SWCNTs are simulated using molecular dynamics (MD) methods. The binding free

  13. Random Networks and Aligned Arrays of Single-Walled Carbon Nanotubes for Electronic Device Applications

    E-print Network

    Rogers, John A.

    that could find utility in areas such as flexible electronics, RF analog devices and others that mightRandom Networks and Aligned Arrays of Single-Walled Carbon Nanotubes for Electronic Device complement the capabilities of established systems. KEYWORDS Carbon nanotubes, electronic devices, thin

  14. 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

  15. 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.

  16. Fluorescence quenching of dyes covalently attached to single-walled carbon nanotubes.

    PubMed

    Chiu, Cheuk Fai; Dementev, Nikolay; Borguet, Eric

    2011-09-01

    The development of chromophore-carbon nanotube hybrids requires efficient and accurate methods to investigate their photophysical properties. Using the ability of the fluorescence labeling of surface species (FLOSS) technique to determine the density of covalently attached dyes to the surface of single-walled carbon nanotubes (SWCNTs), the luminescence of dye-SWCNT hybrids was quantitatively studied with two chromophores: dansyl hydrazine (DH) and panacyl bromide (PB). The fluorescence intensity of PB-SWCNT hybrids was reduced by 20-80% compared to that of free PB. A strong positive correlation between the degree of quenching and the residual metal impurity content in the SWCNT sample suggests that quenching of fluorescence of PB in PB-SWCNTs may be caused by the metal impurities and not by SWCNTs. On the contrary, the intensity of fluorescence of DH-SWCNT hybrids was reduced by almost 2 orders of magnitude compared to free DH, independent of the residual metal content in the SWCNT sample, suggesting that quenching of fluorescence in DH-SWCNT hybrids might occur via charge transfer from DH chromophores to SWCNTs, and revealing the potential of DH-SWCNT hybrids for solar light harvesting applications. PMID:21766814

  17. Single walled carbon nanotube growth and chirality dependence on catalyst composition

    NASA Astrophysics Data System (ADS)

    Orbaek, Alvin W.; Owens, Andrew C.; Crouse, Christopher C.; Pint, Cary L.; Hauge, Robert H.; Barron, Andrew R.

    2013-09-01

    Vertical arrays of single walled carbon nanotubes (VA-SWNTs) were grown using bi-metallic nanoparticle pro-catalysts. Iron oxide particles were doped with varying quantities of first row transition metals (Mn, Co, Ni, and Cu) for a comparative study of the growth of nanotubes. VA-CNT samples were verified using scanning electron microscopy, and characterized using resonance Raman spectroscopy. The length of the VA-CNTs is used as a measure of catalyst activity: the presence of dopants results in a change in the CNT length and length distribution. Cross correlation of the Raman spectra reveal variations in the distribution of radial breathing mode peaks according to the pro-catalyst composition. The formation of various chirality nanotubes is constant between repetitive runs with a particular catalyst, but may be controlled by the identity and concentration of the metal dopants within the iron catalyst. These results demonstrate that the composition of the catalyst is a major driving force toward type selective growth of nanotubes.Vertical arrays of single walled carbon nanotubes (VA-SWNTs) were grown using bi-metallic nanoparticle pro-catalysts. Iron oxide particles were doped with varying quantities of first row transition metals (Mn, Co, Ni, and Cu) for a comparative study of the growth of nanotubes. VA-CNT samples were verified using scanning electron microscopy, and characterized using resonance Raman spectroscopy. The length of the VA-CNTs is used as a measure of catalyst activity: the presence of dopants results in a change in the CNT length and length distribution. Cross correlation of the Raman spectra reveal variations in the distribution of radial breathing mode peaks according to the pro-catalyst composition. The formation of various chirality nanotubes is constant between repetitive runs with a particular catalyst, but may be controlled by the identity and concentration of the metal dopants within the iron catalyst. These results demonstrate that the composition of the catalyst is a major driving force toward type selective growth of nanotubes. Electronic supplementary information (ESI) available: Example of the protocol for fitting and normailizing the Raman data set. See DOI: 10.1039/c3nr03142j

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    Microsoft Academic Search

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    We investigated the adsorption of hydrogen peroxide molecules on Fe-filled single-walled carbon nanotubes (SWNTs) based on density functional theory (DFT) calculations. The adsorption possibilities for the hydrogen peroxide molecule were tested by finding the minimum energy as a function of distance of the molecule from the Fe-filled SWNT. Stable structures were obtained by optimizing the hydrogen peroxide (H2O2) as it was adsorbed on to the Fe-filled SWNT. This study may serve as an initial investigation into the possibility of Fe-filled single-walled carbon nanotubes (SWNTs) as catalyst material for the proton exchange membrane fuel cell (PEMFC).

  1. Low-temperature growth of single-wall carbon nanotubes inside nano test tubes

    Microsoft Academic Search

    Hidetsugu Shiozawa; S. Ravi P. Silva; Zheng Liu; Kazu Suenaga; Hiromichi Kataura; Christian Kramberger; Rudolf Pfeiffer; Hans Kuzmany; Thomas Pichler

    2010-01-01

    From nano-test tube chemistry we determine details of low temperature\\u000a growth of carbon nanotubes. Single-walled carbon nanotubes of various\\u000a diameters are grown at different temperatures from a Pt organometallic\\u000a precursor encapsulated inside template single-walled tubes. At the low\\u000a temperature limits where the reactions are slower and milder, the\\u000a inner-tube diameters are optimally determined by the outer-tube\\u000a diameter. The growth temperature

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

    PubMed

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

    2009-02-11

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

  3. Photoexcitation of the triplet exciton in single wall carbon nanotubes

    E-print Network

    Santos, Tiffany S.

    The carbon nanotube photoexcitation spectrum is dominated by excitonic transitions, rather than interband transitions between continuum states. There are eight distinct excitonic transitions (four singlet and four triplet), ...

  4. 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.

  5. 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.

  6. 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 ...

  7. Anharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine structure spectroscopy analysis

    E-print Network

    , multiwalled carbon nanotubes MWCNTs , and highly oriented pyrolytic graphite HOPG was achieved by meansAnharmonicity in single-wall carbon nanotubes as evidenced by means of extended energy loss fine A comparative study of the structure of free-standing parallel bundles of single-wall carbon nanotubes SWCNTs

  8. Self-Assembled Micro-Honeycomb Network of Single-Walled Carbon Nanotubes for Heterojunction Solar Cells

    E-print Network

    Maruyama, Shigeo

    Self-Assembled Micro-Honeycomb Network of Single-Walled Carbon Nanotubes for Heterojunction Solar@photon.t.u-tokyo.ac.jp Keywords: Self-assembly, micro-honeycomb network, single-walled carbon nanotubes, heterojunction solar cell-walled carbon nanotube (SWNT) and inferior performance of macro-scale SWNT devices is hindering its widespread

  9. Self-Assembled Micro-Honeycomb Network of Single-Walled Carbon Nanotubes for Heterojunction Solar Cell

    E-print Network

    Maruyama, Shigeo

    Self-Assembled Micro-Honeycomb Network of Single-Walled Carbon Nanotubes for Heterojunction Solar@photon.t.u-tokyo.ac.jp) Various forms of nano-carbon films such as random network of single-walled carbon nanotubes (SWNTs), vertically aligned SWNT (VA-SWNTs) and graphene have been examined for SWNT/Si heterojunction solar cells

  10. Can trans-polyacetylene be formed on single-walled carbon-doped boron nitride nanotubes?

    PubMed

    Chen, Ying; Wang, Hong-xia; Zhao, Jing-xiang; Cai, Qing-hai; Wang, Xiao-guang; Wang, Xuan-zhang

    2012-07-01

    Recently, the grafting of polymer chains onto nanotubes has attracted increasing attention as it can potentially be used to enhance the solubility of nanotubes and in the development of novel nanotube-based devices. In this article, based on density functional theory (DFT) calculations, we report the formation of trans-polyacetylene on single-walled carbon-doped boron nitride nanotubes (BNNTs) through their adsorption of a series of C(2)H(2) molecules. The results show that, rather than through [2 + 2] cycloaddition, an individualmolecule would preferentially attach to a carbon-doped BNNT via "carbon attack" (i.e., a carbon in the C(2)H(2) attacks a site on the BNNT). The adsorption energy gradually decreases with increasing tube diameter. The free radical of the carbon-doped BNNT is almost completely transferred to the carbon atom at the end of the adsorbed C(2)H(2) molecule. When another C(2)H(2) molecule approaches the carbon-doped BNNT, it is most energetically favorable for this C(2)H(2) molecule to be adsorbed at the end of the previously adsorbed C(2)H(2) molecule, and so on with extra C(2)H(2) molecules, leading to the formation of polyacetylene on the nanotube. The spin of the whole system is always localized at the tip of the polyacetylene formed, which initiates the adsorption of the incoming species. The present results imply that carbon-doped BNNT is an effective "metal-free" initiator for the formation of polyacetylene. PMID:22271098

  11. A generalized kinetic model for the formation and growth of single-walled metal oxide nanotubes

    E-print Network

    Nair, Sankar

    , is critical in order to predict and control key properties such as the length distribution and concentrationA generalized kinetic model for the formation and growth of single-walled metal oxide nanotubes G mechanisms. c The model successfully predicts the results of changing the growth conditions. a r t i c l e i

  12. 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.

  13. 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

  14. Raman and IR Spectroscopy of Chemically-Processed Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Furtado, C. A.; Kim, U. J.

    2005-03-01

    We have used IR and Raman spectroscopy to study the evolution of the vibrational spectrum of bundled single-walled carbon nanotubes (SWNTs) during the purification process needed to remove metal catalyst and amorphous carbon from arc-derived soot and after high temperature annealing. We have carried out a systematic study to define the different outcomes stemming from different purification protocols, e.g., DO, DO/HCl, DO/HNO3, H2O2, H2O2/HCl, where the first step is either dry oxidation (DO) in flowing air or wet oxidation in refluxing H2O2 to remove amorphous carbon. The second step is an acid reflux step to remove the residual growth catalyst (Ni-Y). Using IR transmission through thin films of nanotubes, we resolve structure due to functional groups, which are present in the as-prepared material (e.g., -COC-), and groups added through the chemical processing (e.g., -COOH, -OH). After high temperature vacuum annealing at 1100^oC, most of oxygen-containing groups were removed. ^This work was supported, in part, by the NSF NIRT program (DMR- 0304178).

  15. Single walled carbon nanotube growth and chirality dependence on catalyst composition.

    PubMed

    Orbaek, Alvin W; Owens, Andrew C; Crouse, Christopher C; Pint, Cary L; Hauge, Robert H; Barron, Andrew R

    2013-10-21

    Vertical arrays of single walled carbon nanotubes (VA-SWNTs) were grown using bi-metallic nanoparticle pro-catalysts. Iron oxide particles were doped with varying quantities of first row transition metals (Mn, Co, Ni, and Cu) for a comparative study of the growth of nanotubes. VA-CNT samples were verified using scanning electron microscopy, and characterized using resonance Raman spectroscopy. The length of the VA-CNTs is used as a measure of catalyst activity: the presence of dopants results in a change in the CNT length and length distribution. Cross correlation of the Raman spectra reveal variations in the distribution of radial breathing mode peaks according to the pro-catalyst composition. The formation of various chirality nanotubes is constant between repetitive runs with a particular catalyst, but may be controlled by the identity and concentration of the metal dopants within the iron catalyst. These results demonstrate that the composition of the catalyst is a major driving force toward type selective growth of nanotubes. PMID:23974219

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

    NASA Astrophysics Data System (ADS)

    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.

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

    Microsoft Academic Search

    Hai M. Duong; Dimitrios V. Papavassiliou; Kieran J. Mullen; Brian L. Wardle

    The present work is a systematic numerical study of the thermal properties of single walled carbon nanotubes (SWNTs) in suspensions. A computational model, based on the simulation of the random movement of Brownian thermal walkers in aqueous and in oil suspensions of SWNTs, was used to investigate the effect of the SWNT aspect ratio, weight fraction and of the interfacial

  18. Electrical And Thermal Coatings From A Single-Walled Carbon Nanotube (SWCNT)\\/Polymer Composite

    Microsoft Academic Search

    Gerard T. Caneba; Jay Axland

    2004-01-01

    Single-walled carbon nanotubes (SWCNTs) are uniquely suitable as lightweight electrically and thermally conductive materials. However, due to their tendency to agglomerate into fiber bundles and relatively weak adhesion to other materials, it has always been a challenge to process these materials for various applications. Solvents and additives with relatively strong specific intermolecular forces were proposed to be required to effect

  19. Manganese Peroxidase Degrades Pristine but Not Surface-Oxidized (Carboxylated) Single-Walled Carbon Nanotubes

    E-print Network

    Alvarez, Pedro J.

    Manganese Peroxidase Degrades Pristine but Not Surface-Oxidized (Carboxylated) Single-Walled Carbon ligninolytic enzymes: lignin perox- idase, manganese peroxidase (MnP), and laccase. Only MnP was capable peroxidase (HRP) in the presence of 40 M H2O2 and proposed that the reactive oxygen species (ROS) generated

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

    E-print Network

    Resasco, Daniel

    nanotubes can withstand a current 1 000 times higher than copper or silver. The thermal conductivity of SWNTs is also extremely high; higher than diamond or copper. Such properties suggest that nanotubesComposites of Single-Walled Carbon Nanotubes and Styrene-Isoprene Copolymer Latices Mai L. P. Ha

  1. Flexible, transparent single-walled carbon nanotube transistors with graphene electrodes

    Microsoft Academic Search

    Sukjae Jang; Houk Jang; Youngbin Lee; Daewoo Suh; Seunghyun Baik; Byung Hee Hong; Jong-Hyun Ahn

    2010-01-01

    This paper reports a mechanically flexible, transparent thin film transistor that uses graphene as a conducting electrode and single-walled carbon nanotubes (SWNTs) as a semiconducting channel. These SWNTs and graphene films were printed on flexible plastic substrates using a printing method. The resulting devices exhibited a mobility of ~ 2 cm2 V - 1 s - 1, On\\/Off ratio of

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

    SciTech Connect

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

    2009-01-01

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

  3. 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

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

    E-print Network

    Kim, Philip

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

  5. Thermal conductance of the junction between single-walled carbon nanotubes

    E-print Network

    McGaughey, Alan

    Thermal conductance of the junction between single-walled carbon nanotubes Lin Hu and Alan J. H. Mc held together by van der Waals interactions.2,3 For a CNT aerogel in vacuum at a tempera- ture of 300 K

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

    E-print Network

    Maruyama, Shigeo

    effect gives rise to the long-time heat flux correlation.11) More recently, the length dependenceMolecular 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

  7. Photophysical comparative study of amylose and polyvinyle pyrrolidone / single walled carbon nanotubes complex.

    E-print Network

    Paris-Sud XI, Université de

    Photophysical comparative study of amylose and polyvinyle pyrrolidone / single walled carbon : pierre.m.bonnet@univ-bpclermont.fr ABSTRACT: Progressive addition of hydroxypropylated amylose (Am structures of (a): PVP; (b): Hydroxypropylated amylose (AmH). The circle shows the hydroxypropyl side group

  8. Large-scale purification of single-wall carbon nanotubes: process, product, and characterization

    Microsoft Academic Search

    A. G. Rinzler; J. Liu; H. Dai; P. Nikolaev; C. B. Huffman; F. J. Rodríguez-Macías; P. J. Boul; A. H. Lu; D. Heymann; D. T. Colbert; R. S. Lee; J. E. Fischer; A. M. Rao; P. C. Eklund; R. E. Smalley

    1998-01-01

    We describe, in detail, a readily scalable purification process capable of handling single-wall carbon nanotube (SWNT) material in large batches. Characterization of the resulting material by SEM, TEM, XRD, Raman scattering, and TGA shows it to be highly pure. Resistivity measurements on freestanding mats of the purified tubes are also reported. We also report progress in scaling up SWNT production

  9. 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 ...

  10. 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...

  11. 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 vapor deposition (ACCVD),2) many groups achieved this morphology of nanotubes by several tricks in CVD as for the CVD condition (i.e., 0 to 0.03 kPa). During this heat treatment, Fe formed into a nanoparticle

  12. Processing, spinning, and fabrication of continuous fibers of single-walled carbon nanotubes

    Microsoft Academic Search

    Richard Delane Booker

    2010-01-01

    Single-walled carbon nanotubes (SWNTs) show great promise for use in a wide range of applications. One of the most promising avenues for attaining these applications is the dispersion of SWNTs at high concentrations in superacids and processing into macroscopic articles such as fibers or films. Fibers spun from SWNT\\/superacid dispersions indicate that the morphology of the starting SWNT material influences

  13. 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.

  14. 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 from temperatures of 20­400 K. Based on the real and imaginary parts of the microwave conductivity films are promising as a type of transparent microwave shielding material. By combining their data

  15. 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

  16. On the Applicability of Single-Walled Carbon Nanotubes as VLSI Interconnects

    Microsoft Academic Search

    Navin Srivastava; Hong Li; Franz Kreupl; Kaustav Banerjee

    2009-01-01

    This paper presents a comprehensive study of the applicability of single-walled carbon nanotubes (SWCNTs) as interconnects in nanoscale integrated circuits. A detailed analysis of SWCNT interconnect resistance (considering its dependence on all physical parameters, as well as factors affecting the contact resistance), the first full 3-D capacitance simulations of SWCNT bundles for realistic very large scale integration (VLSI) interconnect dimensions,

  17. Alignment and Alignment Modulation of Single Wall Carbon Nanotubes Using Lyotropic Chromonic Liquid Crystals

    Microsoft Academic Search

    M. F. Islam; I. I. Smalyukh; O. D. Lavrentovich; A. G. Yodh

    2006-01-01

    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

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

    Microsoft Academic Search

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

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

  19. 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 ...

  20. The elastic modulus of single-wall carbon nanotubes: a continuum analysis incorporating interatomic potentials

    Microsoft Academic Search

    P. Zhang; Y. Huang; P. H. Geubelle; P. A. Klein; K. C. Hwang

    2002-01-01

    A nanoscale continuum theory is established to directly incorporate interatomic potentials into a continuum analysis without any parameter fitting. The theory links interatomic potentials and atomic structure of a material to a constitutive model on the continuum level. The theory is applied to study the linear elastic modulus of a single-wall carbon nanotube. The Young's modulus predicted by this nanoscale

  1. 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 sensing mechanism of hybrid gold-SWNT nanostructures toward hydrogen sulfide was investigated using field charac- teristics show that the gold nanoparticles at the surface of SWNTs acted as nano

  2. 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 sensitive conducto- metric gas nanosensors for H2S can be synthesized by electrodepositing gold allowed for tuning of the size and number of gold nanoparticles deposited. The best H2S sensing

  3. Scaling Properties in Transistors That Use Aligned Arrays of Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Xinning Ho; Lina Ye; Slava V. Rotkin; Qing Cao; Sakulsuk Unarunotai; Shuaib Salamat; Muhammad A. Alam; John A. Rogers

    2010-01-01

    Recent studies and device demonstrations indicate that horizontally aligned arrays of linearly configured single-walled carbon nanotubes (SWNTs) can serve as an effective thin film semiconductor material, suitable for scalable use in high-performance transistors. This paper presents the results of systematic investigations of the dependence of device properties on channel length, to reveal the role of channel and contact resistance in

  4. Growth process of vertically aligned single-walled carbon nanotubes Erik EINARSSON, Tadao EDAMURA, Yoichi MURAKAMI,

    E-print Network

    Maruyama, Shigeo

    Growth process of vertically aligned single-walled carbon nanotubes * Erik., The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan The growth process of vertically aligned activity must be developed in order to realize large-scale production of vertically aligned SWNT films. Key

  5. 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

  6. Gas-Surface Energy Exchange in Collisions of Helium Atoms with Aligned Single-Walled Carbon

    E-print Network

    Maruyama, Shigeo

    1 Gas-Surface Energy Exchange in Collisions of Helium Atoms with Aligned Single-Walled Carbon #12;2 ABSTRACT Since gas flows in micro/nano devices are dominated by the interaction of gas molecules accommodation of gas molecules on surfaces. The scattering of gas molecules on quartz surfaces covered with VA

  7. Molecular Dynamics Simulation of Hydrogen Storage with Single Walled Carbon Nanotubes

    E-print Network

    Maruyama, Shigeo

    Molecular Dynamics Simulation of Hydrogen Storage with Single Walled Carbon Nanotubes Shigeo MARUYAMA #12;The hydrogen storage mechanism of SWNTs was studied through molecular dynamics simulations,12) Fig. 6 Hydrogen storage inside each SWNT #12;Table 1 Potential parameters between SWNTs Tube d0 [Ã?

  8. 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

  9. Excitonic effects on radial breathing mode intensity of single wall carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    Excitonic effects on radial breathing mode intensity of single wall carbon nanotubes Kentaro Satoa- culate resonance Raman intensity for radial breathing mode as a function of diameter and chiral angle. Excitonic effect of resonance Raman intensities for the radial breath- ing mode is enhanced by the curvature

  10. Optical Characterizations and Electronic Devices of Nearly Pure (10,5) Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Li Zhang; Xiaomin Tu; Kevin Welsher; Xinran Wang; Ming Zheng; Hongjie Dai

    2009-01-01

    It remains an elusive goal to achieve high performance single-walled carbon nanotube (SWNTs) field effect transistors (FETs) comprised of only single chirality SWNTs. Many separation mechanisms have been devised and various degrees of separation demonstrated, yet it is still difficult to reach the goal of total fractionation of a given nanotube mixture into its single chirality components. Chromatography has been

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

    Microsoft Academic Search

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

    2011-01-01

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

  12. 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 ...

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

    E-print Network

    Maruyama, Shigeo

    Society of America OCIS codes: (260.5430) Polarization; (240.0310) Thin films, (060.2340) Fiber optics components I. Introduction Single-walled carbon nano-tubes (SWCNTs) have been the subject of focused multi as saturable absorbers in mode locking of erbium doped silica fiber lasers have been reported[2,3]. Control

  14. Diameter-Controlled Growth of Single-Walled Carbon Nanotubes by Using Nano-diamond Particles

    E-print Network

    Maruyama, Shigeo

    Diameter-Controlled Growth of Single-Walled Carbon Nanotubes by Using Nano-diamond Particles Shohei with smaller diameter attract attention. Here, we perform CVD growth by using nano-diamond particles As the catalyst particles, nano-diamond particles were used. The diamond particles were dispersed in ethanol

  15. Zeolite Surface as a Catalyst Support Material for Synthesis of Single-Walled Carbon Nanotubes

    E-print Network

    Maruyama, Shigeo

    1 Zeolite Surface as a Catalyst Support Material for Synthesis of Single-Walled Carbon Nanotubes support material. Although zeolite has been frequently used as a catalyst support material for the synthesis of SWNTs, detailed surface properties of previously employed zeolites, and thus their role

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

    E-print Network

    Maruyama, Shigeo

    Photoluminescence intermittency in an individual single-walled carbon nanotube at room temperature-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan ABSTRACT We described the photoluminescence (PL) properties physical properties.1-3 Recently, photoluminescence (PL) signals were observed from micelle

  17. Spectral features due to dark exciton in photoluminescence map of single-walled carbon nanotubes

    E-print Network

    Maruyama, Shigeo

    Spectral features due to dark exciton in photoluminescence map of single-walled carbon nanotubes-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan Features in Photoluminescence Map of SWNTs Over the past seven years photoluminescence (PL) spectroscopy has emerged as an important characterization tool

  18. Bright Band Gap Photoluminescence from Unprocessed Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    J. Lefebvre; Y. Homma; P. Finnie

    2003-01-01

    Unprocessed single-walled carbon nanotubes suspended in air at room temperature emit bright, sharply peaked band gap photoluminescence. This is in contrast with measurements taken from nanotubes lying on the flat surface for which no luminescence was detected. Each individual nanotube has a luminescence peak of similar linewidth (˜13 meV), with different species emitting at various different wavelengths spanning at least

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

    E-print Network

    Maruyama, Shigeo

    1 Identification of excitonic phonon sideband by photoluminescence spectroscopy of single studied photoluminescence (PL) and resonant Raman scatterings of single-walled carbon nanotubes (SWNTs frequency by the square-root of the mass ratio 12/13. By comparing photoluminescence excitation (PLE

  20. Gas detection mechanism for single-walled carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Boyd, Anthony; Dube, Isha; Fedorov, Georgy; Paranjape, Makarand; Barbara, Paola

    2011-03-01

    We study field-effect transistors fabricated with carbon nanotube (CNT) networks to determine whether the gas sensing mechanism is due to molecules adsorbed on the nanotubes, or changes at the interface between the nanotubes and the contacts. Our previous work showed that in devices made with isolated CNT, the response to nitrogen dioxide was mainly due to the contact interfaces [1]. Here, we focus on CNT networks and use SU-8 layers patterned with e-beam lithography to passivate the contact interfaces, while leaving the network exposed. We look to investigate possible differences in sensing mechanism for devices made with isolated tubes versus networks. [4pt] [1] J. Zhang, A. Boyd, A. Tselev, M. Paranjape, and P. Barbara, Mechanism of NO2 detection in carbon nanotube field effect transistor chemical sensors, Applied Physics Letters 88, 123112-123115 (2006)

  1. A new theory about single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Tsai, Yao Yang; Fang, Shih Chung

    2014-07-01

    Since carbon nanotubes were discovered, till now no definitive formulation for computing the shear modulus of them was presented. To develop a theoretically rigorous and mathematically elegant expression for the shear modulus, thus, we initially propound a new small-strain theory in which merely small strain will arise when small-diameter carbon nanotubes are formed and thereby conclude the total potential energy including bond elongation and bond angle variation will suffice and the utilization of Quantum Mechanics and certain far complicated potential functions is unnecessary. Then based on it, a closed-form expression derived entirely from the "definition" of shear modulus, which was never published in all other literature, will be evolved. It should be noted that previously there was only one formula by which the shear moduli for all carbon nanotubes with diverse diameters and configurations could be predicted. By comparing the values calculated by the expression in this paper with those reckoned from the article mentioned above, it is obvious that both classes of quantities are similar to each other. It should also be noted that because the expression in this paper is the first (really having no precedent in related study fields) to be derived entirely according to the definition of shear modulus, perhaps this paper can be used as a useful theoretical tool for further study.

  2. Single wall carbon nanotube supports for portable direct methanol fuel cells.

    PubMed

    Girishkumar, G; Hall, Timothy D; Vinodgopal, K; Kamat, Prashant V

    2006-01-12

    Single-wall and multiwall carbon nanotubes are employed as carbon supports in direct methanol fuel cells (DMFC). The morphology and electrochemical activity of single-wall and multiwall carbon nanotubes obtained from different sources have been examined to probe the influence of carbon support on the overall performance of DMFC. The improved activity of the Pt-Ru catalyst dispersed on carbon nanotubes toward methanol oxidation is reflected as a shift in the onset potential and a lower charge transfer resistance at the electrode/electrolyte interface. The evaluation of carbon supports in a passive air breathing DMFC indicates that the observed power density depends on the nature and source of carbon nanostructures. The intrinsic property of the nanotubes, dispersion of the electrocatalyst and the electrochemically active surface area collectively influence the performance of the membrane electrode assembly (MEA). As compared to the commercial carbon black support, single wall carbon nanotubes when employed as the support for anchoring the electrocatalyst particles in the anode and cathode sides of MEA exhibited a approximately 30% enhancement in the power density of a single stack DMFC operating at 70 degrees C. PMID:16471506

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

    NASA Astrophysics Data System (ADS)

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

    2001-03-01

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

  4. 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.

  5. Controlled CVD Growth of Single-Walled Carbon Nanotubes and Application to CNT-Si Heterojunction Solar Cells

    E-print Network

    Maruyama, Shigeo

    Controlled CVD Growth of Single-Walled Carbon Nanotubes and Application to CNT-Si Heterojunction Solar Cells Shigeo Maruyama Department of Mechanical Engineering, The University of Tokyo 113 reaction process in CVD growth of single-walled carbon nanotubes (SWNTs) will be discussed with diameter

  6. Improved CNT-Si heterojunction solar cell with structured single-walled carbon nanotubes Shigeo Maruyama1

    E-print Network

    Maruyama, Shigeo

    Improved CNT-Si heterojunction solar cell with structured single-walled carbon nanotubes Shigeo maruyama@photon.t.u-tokyo.ac.jp Single-walled carbon nanotubes (SWNTs) with outstanding electronic, optical-Si heterojuction solar cells. We proposed a water vapor treatment to build up SWNTs to a self-assembled micro

  7. Controlled Growth of Single-Walled Carbon Nanotubes and Application to CNT-Si Heterojunction Solar Cells

    E-print Network

    Maruyama, Shigeo

    Controlled Growth of Single-Walled Carbon Nanotubes and Application to CNT-Si Heterojunction Solar process in CVD growth of single-walled carbon nanotubes (SWNTs) will be discussed with diameter controlled assembly of SWNTs for SWNT-Si heterojunction solar cells will be discussed. We found the reversible

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

    E-print Network

    Maruyama, Shigeo

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

  9. Synthesis of Single-Walled Carbon Nanotubes from Defined Surface of Silicalite-1 Zeolite and their Photoluminescence Characterizations

    E-print Network

    Maruyama, Shigeo

    Synthesis of Single-Walled Carbon Nanotubes from Defined Surface of Silicalite-1 Zeolite-0011, Japan 3 Dept. of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan Zeolites (MFI-type) zeolite for supporting catalysts for the growth of single-walled carbon nanotubes (SWNTs

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

    SciTech Connect

    Thekkethala, Joe Francis; Sathian, Sarith P., E-mail: sarith@nitc.ac.in [Computational Nanotechnology Laboratory, School of Nano Science and Technology, National Institute of Technology Calicut, Kozhikode, Kerala - 673601 (India)

    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.

  11. 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.

  12. Resonant ablation of single-wall carbon nanotubes by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Arutyunyan, N. R.; Komlenok, M. S.; Kononenko, V. V.; Pashinin, V. P.; Pozharov, A. S.; Konov, V. I.; Obraztsova, E. D.

    2015-01-01

    The thin 50?nm film of bundled arc-discharge single-wall carbon nanotubes was irradiated by femtosecond laser pulses with wavelengths 675, 1350 and 1745?nm corresponding to the absorption band of metallic nanotubes E11M, to the background absorption and to the absorption band of semiconducting nanotubes E11S, respectively. The aim was to induce a selective removal of nanotubes of specific type from the bundled material. Similar to conducted thermal heating experiments, the effect of laser irradiation results in suppression of all radial breathing modes in the Raman spectra, with preferential destruction of the metallic nanotubes with diameters less than 1.26?nm and of the semiconducting nanotubes with diameters 1.36?nm. However, the etching rate of different nanotubes depends on the wavelength of the laser irradiation. It is demonstrated that the relative content of nanotubes of different chiralities can be tuned by a resonant laser ablation of undesired nanotube fraction. The preferential etching of the resonant nanotubes has been shown for laser wavelengths 675?nm (E11M) and 1745?nm (E11S).

  13. 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

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

    NASA Astrophysics Data System (ADS)

    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.

    2014-11-01

    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.

  15. Explaining the Purification of Single-Walled Carbon Nanotubes by 248 nanometer UV Light

    Microsoft Academic Search

    Abram van der Geest; Katherine Hurst; John Lehman; Mark Lusk

    2009-01-01

    It has been experimentally observed that amorphous carbon is removed from as-prepared, bulk, single-walled carbon nanotubes by illumination with 248 nm (5 eV) UV light. The process via which this occurs, though, has not yet been rigorously identified. We use a combination of experiments and modeling to explain how localized surface plasmon pairs can be induced at the surfaces of

  16. Catalytic nanoreactors in continuous flow: hydrogenation inside single-walled carbon nanotubes using supercritical CO2.

    PubMed

    Chamberlain, Thomas W; Earley, James H; Anderson, Daniel P; Khlobystov, Andrei N; Bourne, Richard A

    2014-05-25

    One nanometre wide carbon nanoreactors are utilised as the reaction vessel for catalytic chemical reactions on a preparative scale. Sub-nanometre ruthenium catalytic particles which are encapsulated solely within single-walled carbon nanotubes offering a unique reaction environment are shown to be active when embedded in a supercritical CO2 continuous flow reactor. A range of hydrogenation reactions were tested and the catalyst displayed excellent stability over extended reaction times. PMID:24496498

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

    Microsoft Academic Search

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

    1997-01-01

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

  18. Polarization switching using single-walled carbon nanotubes grown on epitaxial ferroelectric thin films

    NASA Astrophysics Data System (ADS)

    Paruch, P.; Posadas, A.-B.; Dawber, M.; Ahn, C. H.; McEuen, P. L.

    2008-09-01

    We have directly grown single-walled carbon nanotubes on epitaxial BaTiO3 thin films, fabricating prototype carbon nanotube-ferroelectric devices. We demonstrate polarization switching using the nanotube as a local electric field source and compare the results to switching with an atomic force microscopy tip. The observed variation of domain growth rates in the two cases agrees with the changes in electric field intensity at the ferroelectric surface.

  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. Water-Assisted Highly Efficient Synthesis of Impurity-Free Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Kenji Hata; Don N. Futaba; Kohei Mizuno; Tatsunori Namai; Motoo Yumura; Sumio Iijima

    2004-01-01

    We demonstrate the efficient chemical vapor deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water. Water-stimulated enhanced catalytic activity results in massive growth of superdense and vertically aligned nanotube forests with heights up to 2.5 millimeters that can be easily separated from the catalysts, providing nanotube material with carbon purity above

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

    Microsoft Academic Search

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

    2006-01-01

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

  2. Single-walled carbon nanotube formation on iron oxide catalysts in diffusion flames

    Microsoft Academic Search

    Chad J. Unrau; Richard L. Axelbaum; Phil Fraundorf

    2010-01-01

    Single-walled carbon nanotubes (SWCNTs) are shown to grow rapidly on iron oxide catalysts on the fuel side of an inverse ethylene\\u000a diffusion flame. The pathway of carbon in the flame is controlled by the flame structure, leading to formation of SWCNTs free\\u000a of polycyclic aromatic hydrocarbons (PAH) or soot. By using a combination of oxygen-enrichment and fuel dilution, fuel oxidation

  3. Hydrogen Storage in Single-Walled Carbon Nanotubes at Room Temperature

    Microsoft Academic Search

    C. Liu; Y. Y. Fan; M. Liu; H. T. Cong; H. M. Cheng; M. S. Dresselhaus

    1999-01-01

    Masses of single-walled carbon nanotubes (SWNTs) with a large mean diameter of about 1.85 nanometers, synthesized by a semicontinuous hydrogen arc discharge method, were employed for hydrogen adsorption experiments in their as-prepared and pretreated states. A hydrogen storage capacity of 4.2 weight percent, or a hydrogen to carbon atom ratio of 0.52, was achieved reproducibly at room temperature under a

  4. Thermal Properties of Metal-Coated Vertically-Aligned Single Wall Nanotube Films M. Panzer, G. Zhang, D. Mann, X. Hu, E. Pop, H. Dai, and K. E. Goodson

    E-print Network

    Zhang, Guangyu

    to thermal expansion mismatch and thermal cycling. The thermal conductivity of individual single wall CNTsThermal Properties of Metal-Coated Vertically-Aligned Single Wall Nanotube Films M. Panzer, G to their extraordinarily high thermal conductivities, carbon nanotubes (CNTs) are promising for use in advanced thermal

  5. Doping of single-walled carbon nanotubes controlled via chemical transformation of encapsulated nickelocene

    NASA Astrophysics Data System (ADS)

    Kharlamova, Marianna V.; Sauer, Markus; Saito, Takeshi; Sato, Yuta; Suenaga, Kazu; Pichler, Thomas; Shiozawa, Hidetsugu

    2015-01-01

    Controlled doping of carbon nanotubes is elemental for their electronic applications. Here we report an approach to tune the polarity and degree of doping of single-walled carbon nanotubes via filling with nickelocene followed by encapsulated reactions. Using Raman, photoemission spectroscopy and transmission electron microscopy, we show that nickelocene molecules transform into nickel carbides, nickel and inner carbon nanotubes with reaction temperatures as low as 250 °C. The doping efficiency is determined for each chemical component. Synchronous charge transfer among the molecular components allows bipolar doping of the carbon nanotubes to be achieved in a broad range of +/-0.0012 e- per carbon.

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

    SciTech Connect

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

    2008-01-01

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

  7. Exposure to Carbon Nanotube Material: Aerosol Release During the Handling of Unrefined Single-Walled Carbon Nanotube Material

    Microsoft Academic Search

    Andrew D. Maynard; Paul A. Baron; Michael Foley; Anna A. Shvedova; Elena R. Kisin; Vincent Castranova

    2004-01-01

    Carbon nanotubes represent a relatively recently discovered allotrope of carbon that exhibits unique properties. While commercial interest in the material is leading to the development of mass production and handling facilities, little is known of the risk associated with exposure. In a two-part study, preliminary investigations have been carried out into the potential exposure routes and toxicity of single-walled carbon

  8. 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.

  9. Controlled-growth of single-walled carbon nanotubes using optical near-field effects

    NASA Astrophysics Data System (ADS)

    Xiong, W.; Zhou, Y. S.; Mahjouri-Samani, M.; Yang, W. Q.; Yi, K. J.; He, X. N.; Lu, Y. F.

    2009-02-01

    Controlled growth of self-aligned single-walled carbon nanotubes (SWNTs) was realized using optical near-field effects in a laser-assisted chemical vapor deposition (LCVD) process. Electronic devices containing ultrashort suspended SWNT channels were successfully fabricated at relatively low substrate temperatures. According to the numerical simulations using High Frequency Structure Simulator (HFSS), significant local-heating enhancement occurred at electrode tip apexes under laser irradiation, which was about ten times higher than the rest part of the electrodes. Experimental results revealed that the localized heating enhancement at the electrode tip apexes significantly stimulates the growth of SWNTs at a significantly reduced substrate temperature compared with the conventional LCVD process. The near-field enhancement dependence on metallic film thickness and laser polarization was investigated through numerical simulation using HFSS, which provided a guideline for further optimization of maximum near-field enhancement. This technique suggests a viable laser-based strategy for fabricating SWNT-based devices at relatively low substrate temperatures in a precisely controlled manner using the nanoscale optical near-field effects, which paves the way for the mass production of SWNT-based devices using expanded laser beams.

  10. High electrical conductance enhancement in Au-nanoparticle decorated sparse single-wall carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    McAndrew, Calum F.; Baxendale, Mark

    2013-08-01

    We report high electrical conductance enhancement in sparse single-walled carbon nanotube networks by decoration with Au nanoparticles. The optimized hybrid network exhibited a sheet resistance of 650 ? sq-1, 1/1500 of the resistance of the host undecorated network, with a negligible optical transmission penalty (>90% transmittance at 550 nm wavelength). The electrical transport at room temperature in the host and decorated networks was dominated by two-dimensional variable range hopping. The high conductance enhancement was due to positive charge transfer from the decorating Au nanoparticles in intimate contact with the host network causing a Fermi energy shift into the high density of states at a van Hove singularity and enhanced electron delocalization relative to the host network which beneficially modifies the hopping parameters in such a way that the network behaves as an integral whole. The effect is most pronounced when the nanoparticle diameter is comparable to the electron mean free path in the bulk material at room temperature and there is minimum nanoparticle agglomeration. For higher than optimal values of nanoparticle coverage or nanoparticle diameter, the conductance enhancement is countered by metallic inclusions in the current pathways that are of higher resistance than the variable range hopping-controlled elements.

  11. A plasmon absorption model for a super-lattice of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Markes, M. E.; Williams, P. F.

    2006-03-01

    Several years ago one of us (P. F. Williams*) developed a self-consistent dielectric response model for one-dimensional metals at high frequency using a tight-binding approximation. At the time this model was found useful in a study of the single-particle excitations and plasmon dispersion curves of tetrathiofulvalene-tetracyano-quinodimethane (TTF-TCNQ). This paper is a report of work in progress to extend this model to arrays of single-walled carbon nanotubes. First the quasi one-dimensional model is extended to represent free electrons confined to the surfaces of cylindrical shells arranged in a 2-D square array. The collective electronic excitations of this system are characterized by a frequency and wavelength dependent complex dielectric constant obtained using the method of self-consistent fields in the random phase approximation. Progress in extending the model to arrays of shells with surface structure will also be discussed. *P. F. Williams and A. N. Bloch, Phys. Rev. B, 10, 1097 (1974)

  12. Real-time observation of nonlinear coherent phonon dynamics in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Gambetta, A.; Manzoni, C.; Menna, E.; Meneghetti, M.; Cerullo, G.; Lanzani, G.; Tretiak, S.; Piryatinski, A.; Saxena, A.; Martin, R. L.; Bishop, A. R.

    2006-08-01

    Single-walled carbon nanotubes (SWNTs) are ?-conjugated, quasi-one-dimensional structures consisting of rolled-up graphene sheets that, depending on their chirality, behave as semiconductors or metals; owing to their unique properties, they enable groundbreaking applications in mechanics, nanoelectronics and photonics. In semiconducting SWNTs, medium-sized excitons (3-5nm) with large binding energy and oscillator strength are the fundamental excitations; exciton wavefunction localization and one-dimensionality give rise to a strong electron-phonon coupling, the study of which is crucial for the understanding of their electronic and optical properties. Here we report on the use of resonant sub-10-fs visible pulses to generate and detect, in the time domain, coherent phonons in SWNT ensembles. We observe vibrational wavepackets for the radial breathing mode (RBM) and the G mode, and in particular their anharmonic coupling, resulting in a frequency modulation of the G mode by the RBM. Quantum-chemical modelling shows that this effect is due to a corrugation of the SWNT surface on photoexcitation, leading to a coupling between longitudinal and radial vibrations.

  13. Is it possible to dope single-walled carbon nanotubes and graphene with sulfur?

    PubMed

    Denis, Pablo A; Faccio, Ricardo; Mombru, Alvaro W

    2009-03-01

    Herein, we investigate sulfur substitutional defects in single-walled carbon nanotubes (SWCNTs) and graphene by using first-principles calculations. The estimated formation energies for the (3,3), (5,5), and (10,0) SWCNTs and graphene lie between 0.9 and 3.8 eV, at sulfur concentrations of 1.7-4 atom %. Thus, from a thermodynamic standpoint, sulfur doping is not difficult. Indeed, these values can be compared with that of 0.7 eV obtained for a nitrogen-doped (5,5) SWCNT. We suggest that it may be possible to introduce sulfur into the SWCNT framework by employing sulfur-containing heterocycles. Our simulations indicate that sulfur doping can modify the electronic structure of the SWCNTs and graphene, depending on the sulfur content. In the case of graphene, sulfur doping can induce different effects: the doped sheet can be a small-band-gap semiconductor, or it can have better metallic properties than the pristine sheet. Thus, S-doped graphene may be a smart choice for constructing nanoelectronic devices, since it is possible to modulate the electronic properties of the sheet by adjusting the amount of sulfur introduced. Different synthetic routes to produce sulfur-doped graphene are discussed. PMID:19189365

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

    SciTech Connect

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

    2010-01-01

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

  15. Covalent functionalization of single-walled carbon nanotubes through attachment of aromatic diisocyanate molecules from first principles

    NASA Astrophysics Data System (ADS)

    Goclon, Jakub; Kozlowska, Mariana; Rodziewicz, Pawel

    2015-01-01

    We performed first-principle calculations of the covalent functionalization of metallic (6,0) and semiconducting (10,0) single-walled carbon nanotubes (SWCNTs) with aromatic diisocyanate molecules, namely, 4,4?-methylene diphenyl diisocyanate (MDI) and toluene-2,4-diisocyanate (TDI). The corresponding binding energies of the attached molecules were scrutinized. We analyzed the changes in the electronic band structure of SWCNTs caused by the amide bond formation after the functionalization process. Furthermore, the MDI-MDI and TDI-TDI mutual interactions on the nanotube surface were investigated.

  16. Helicity-dependent single-walled carbon nanotube alignment on graphite for helical angle and handedness recognition

    PubMed Central

    Chen, Yabin; Shen, Ziyong; Xu, Ziwei; Hu, Yue; Xu, Haitao; Wang, Sheng; Guo, Xiaolei; Zhang, Yanfeng; Peng, Lianmao; Ding, Feng; Liu, Zhongfan; Zhang, Jin

    2013-01-01

    Aligned single-walled carbon nanotube arrays provide a great potential for the carbon-based nanodevices and circuit integration. Aligning single-walled carbon nanotubes with selected helicities and identifying their helical structures remain a daunting issue. The widely used gas-directed and surface-directed growth modes generally suffer the drawbacks of mixed and unknown helicities of the aligned single-walled carbon nanotubes. Here we develop a rational approach to anchor the single-walled carbon nanotubes on graphite surfaces, on which the orientation of each single-walled carbon nanotube sensitively depends on its helical angle and handedness. This approach can be exploited to conveniently measure both the helical angle and handedness of the single-walled carbon nanotube simultaneously at a low cost. In addition, by combining with the resonant Raman spectroscopy, the (n,m) index of anchored single-walled carbon nanotube can be further determined from the (d,?) plot, and the assigned (n,m) values by this approach are validated by both the electronic transition energy Eii measurement and nanodevice application. PMID:23892334

  17. POPULATION ANALYSIS OF DIFFERENT CHIRALITIES IN THE (8,8) & (9,9) FAMILIES IN ARMCHAIR-ENRICHED SINGLE-WALLED CARBON NANOTUBE

    E-print Network

    Mellor-Crummey, John

    resistivity than that of copper. In order to identify the (8,8) & (9,9) family of nanotubes with resonant-ENRICHED SINGLE-WALLED CARBON NANOTUBE SAMPLES VIA RESONANT RAMAN SPECTROSCOPY A. Jeng1 , H. Sugahara2 , P. Yu3 the metallic and semiconductor nanotubes in mixed samples by determining the vibrational and rotational modes

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

    PubMed

    Mashapa, Matete G; Ray, Suprakas Sinha

    2010-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    E-print Network

    Gruner, George

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

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

    E-print Network

    Golovchenko, Jene A.

    Coulomb blockade in suspended Si3N4-coated single-walled carbon nanotubes H. B. Peng and J. A in the center of self-supporting 0.5- m-thick Si3N4 mem- branes by optical lithography and lift off processing the gap area between the electrodes all the way through the Si3N4 membranes. Figure 1(a) illustrates

  2. Rheology and Phase Behavior of Single Wall Carbon Nanotube / Strong Acid Systems

    NASA Astrophysics Data System (ADS)

    Pasquali, Matteo; Davis, Virginia A.; Ericson, Lars M.; Smalley, Richard E.; Winey, Karen I.

    2002-03-01

    Assessing potential routes to single wall carbon nanotube fiber production requires an understanding of the rheological properties of the dispersions involved. SWNT have been successfully dispersed in strong acids at a wide range of concentrations (0.1 - 10wt%) for fiber production. These SWNT/acid systems exhibit interesting phase behavior analogous to rigid-rod polymer molecule systems, including a liquid crystalline phase. In addition, rheometry experiments reveal the SWNT dispersions to be highly shear-thinning power law liquids.

  3. Thermal conductivity and interfacial resistance in single-wall carbon nanotube epoxy composites

    Microsoft Academic Search

    M. B. Bryning; D. E. Milkie; M. F. Islam; J. M. Kikkawa; A. G. Yodh

    2005-01-01

    We report thermal conductivity measurements of purified single-wall carbon nanotube (SWNT) epoxy composites prepared using suspensions of SWNTs in N-N-Dimethylformamide (DMF) and surfactant stabilized aqueous SWNT suspensions. Thermal conductivity enhancement is observed in both types of composites. DMF-processed composites show an advantage at SWNT volume fractions between phi~0.001 to 0.005. Surfactant processed samples, however, permit greater SWNT loading and exhibit

  4. Thermal conductivity and interfacial resistance in single-wall carbon nanotube epoxy composites

    Microsoft Academic Search

    M. B. Bryning; D. E. Milkie; M. F. Islam; J. M. Kikkawa; A. G. Yodh

    2005-01-01

    We report thermal conductivity measurements of purified single-wall carbon nanotube (SWNT) epoxy composites prepared using suspensions of SWNTs in N-N-Dimethylformamide (DMF) and surfactant stabilized aqueous SWNT suspensions. Thermal conductivity enhancement is observed in both types of composites. DMF-processed composites show an advantage at SWNT volume fractions between ??0.001 to 0.005. Surfactant processed samples, however, permit greater SWNT loading and exhibit

  5. Photosensitization of nonlinear scattering and photoacoustic emission from single-walled carbon nanotubes

    Microsoft Academic Search

    I.-Yin Sandy Lee; Tomomi Matsuo; Honoh Suzuki

    2008-01-01

    Enhancement of laser-induced nonlinear scattering has been observed from an aqueous suspension of single-walled carbon nanotubes (SWCNTs) doped with near-infrared dye chromophores. The underlying mechanism involves cavitation triggered by optical heating and bubble pulsation, which are further enhanced by the dye adsorbed on SWCNT surfaces, resulting in the scattering enhancement and a modification of the accompanying photoacoustic waveform. These photosensitizing

  6. Sample-specific and ensemble-averaged magnetoconductance of individual single-Wall carbon nanotubes

    Microsoft Academic Search

    H. T. Man; A. F. Morpurgo

    2005-01-01

    We discuss magnetotransport measurements on individual single-wall carbon\\u000ananotubes with low contact resistance, performed as a function of temperature\\u000aand gate voltage. We find that the application of a magnetic field\\u000aperpendicular to the tube axis results in a large magnetoconductance of the\\u000aorder of e^2\\/h at low temperature. We demonstrate that this magnetoconductance\\u000aconsists of a sample-specific and of

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  8. Transparent flexible organic thin-film transistors that use printed single-walled carbon nanotube electrodes

    Microsoft Academic Search

    Qing Cao; Zheng-Tao Zhu; Maxime G. Lemaitre; Ming-Gang Xia; Moonsub Shim; John A. Rogers

    2006-01-01

    Electrodes based on printed networks of single-walled carbon nanotubes (SWNTs) are integrated with ultrathin layers of the organic semiconductor pentacene to produce bendable, transparent thin-film transistors on plastic substrates. The physical and structural properties of the SWNTs lead to the remarkably good electrical contacts with the pentacene. Optical transmittances of ~70%, device mobilities >0.5 cm2 V-1 s-1, ON\\/OFF ratios >105

  9. Hydrodynamic assembly of conductive nanomesh of single-walled carbon nanotubes using biological glue.

    PubMed

    Lee, Ki-Young; Byeon, Hye-Hyeon; Jang, Chaun; Choi, Jee-Hyun; Choi, In-Suk; Jung, Younginha; Kim, Woong; Chang, Joonyeon; Yi, Hyunjung

    2015-02-01

    A hydrodynamic phenomenon is used to assemble a large-scale conductive nanomesh of single-walled carbon nanotubes (SWNTs) with exceptional control of the nanostructure. This is accomplished by a biological material with nanoscale features and a strong binding affinity toward SWNTs. The biological material also presents a unique glue effect for the assembly. Unprecedented material characteristics are observed for the nanomesh. PMID:25504593

  10. (Single-Walled Carbon Nanotubes, SWNTs) CVD Smalley HiPco [1,2

    E-print Network

    Maruyama, Shigeo

    (Single-Walled Carbon Nanotubes, SWNTs) (n, m) SWNTs CVD Smalley HiPco [1,2] CVD) EnergySeparation(eV) 488 nm 514.5 nm 633 nm Intensity(arb.units) Raman Shift (cm ­1 ) (c) HiPco (b Electric furnace Pressure gauge Vacuum pump Quartz boat Ar/H2 Ar or Ethanol tank Hot bath Ethanol tank Hot

  11. Single-walled carbon nanotube transistors fabricated by advanced alignment techniques utilizing CVD growth and dielectrophoresis

    Microsoft Academic Search

    S. Kim; Y. Xuan; P. D. Ye; Saeed Mohammadi; S. W. Lee

    2008-01-01

    Single-walled carbon nanotube field effect transistors (SWNT-FETs) are fabricated by two different alignment techniques. The first technique is based on direct synthesis of an aligned SWNTs array on quartz wafer using chemical vapor deposition. The transistor with three SWNTs and atomic layer deposited (ALD) Al2O3 gate oxide shows a contact resistance of 280K?, a maximum on-current of ?7?A, and a

  12. Electrical transport through single-wall carbon nanotube-anodic aluminum oxide-aluminum heterostructures

    Microsoft Academic Search

    Jarmo Kukkola; Aatto Rautio; Giovanni Sala; Flavio Pino; Géza Tóth; Anne-Riikka Leino; Jani Mäklin; Heli Jantunen; Antti Uusimäki; Krisztián Kordás; Eduardo Gracia; Mauricio Terrones; Andrey Shchukarev; Jyri-Pekka Mikkola

    2010-01-01

    Aluminum foils were anodized in sulfuric acid solution to form thick porous anodic aluminum oxide (AAO) films of thickness ~6 µm. Electrodes of carboxyl-functionalized single-wall carbon nanotube (SWCNT) thin films were inkjet printed on the anodic oxide layer and the electrical characteristics of the as-obtained SWCNT-AAO-Al structures were studied. Nonlinear current-voltage transport and strong temperature dependence of conduction through the

  13. Processing of fullerene-single wall carbon nanotube complex for bulk heterojunction photovoltaic cells

    Microsoft Academic Search

    Cheng Li; Somenath Mitra

    2007-01-01

    A fullerene-single wall carbon nanotube (C60-SWCNT) complex is used as a component of the photoactive layer in bulk heterojunction photovoltaic cells. This complex synthesized by microwave-assisted reaction takes advantage of the electron accepting feature of C60 and the high electron transport capability of SWCNTs. In this paper, quantum efficiency enhancement by increasing light absorption and by bringing about appropriate morphological

  14. Polymer functionalized n-type single wall carbon nanotube photovoltaic devices

    Microsoft Academic Search

    Zhongrui Li; Viney Saini; Enkeleda Dervishi; Vasyl P. Kunets; Jianhui Zhang; Yang Xu; Alexandru R. Biris; Gregory J. Salamo; Alexandru S. Biris

    2010-01-01

    Photovoltaic conversion was achieved from high-density p-n heterojunctions formed between polymer functionalized n-type single wall carbon nanotubes (SWNTs) and underlying p-type Si substrate. Functionalization of SWNTs by amine-rich polymers results in the evolution of tubes from p-type to n-type, and the polyethylene imine (PEI) functionalized SWNT film can serve as both photogeneration sites and a charge carrier collecting\\/transport layer. Photoremoval

  15. Encapsulation of cesium inside single-walled carbon nanotubes by plasma-ion irradiation method

    Microsoft Academic Search

    Goo-Hwan Jeong; A. A. Farajian; Takamichi Hirata; Rikizo Hatakeyama; Kazuyuki Tohji; T. M. Briere; Hiroshi Mizuseki; Yoshiyuki Kawazoe

    2003-01-01

    Positive Cs ions are irradiated to a negatively biased substrate, which is covered with the dispersed single-walled carbon nanotubes (SWNTs) and immersed in the Cs plasma. Field emission type transmission electron microscopy (FE-TEM) and Z-contrast technique by scanning TEM (STEM) are used for the precise observation. FE-TEM gives high resolved images of structurally modified SWNTs such as irreversible bending of

  16. Elastic and Shear Moduli of Single-Walled Carbon Nanotube Ropes

    Microsoft Academic Search

    Jean-Paul Salvetat; G. Andrew D. Briggs; Jean-Marc Bonard; Revathi R. Bacsa; Andrzej J. Kulik; Thomas Stöckli; Nancy A. Burnham; László Forró

    1999-01-01

    Carbon nanotubes are believed to be the ultimate low-density high-modulus fibers, which makes their characterization at nanometer scale vital for applications. By using an atomic force microscope and a special substrate, the elastic and shear moduli of individual single-walled nanotube (SWNT) ropes were measured to be of the order of 1 TPa and 1 GPa, respectively. In contrast to multiwalled

  17. Directed assembly of high density single-walled carbon nanotube patterns on flexible polymer substrates

    Microsoft Academic Search

    Xugang Xiong; Chia-Ling Chen; Peter Ryan; Ahmed A. Busnaina; Yung Joon Jung; Mehmet R. Dokmeci

    2009-01-01

    We report an effective technique for the controlled assembly of single-walled carbon nanotubes (SWNTs) and demonstrate organized high density network architectures on soft polymeric substrates. We utilize the surface energy differential between a plasma treated (hydrophilic) parylene-C surface and a photoresist (hydrophobic) surface to create microscale patterns of SWNT networks on a 10 µm thick parylene-C substrate. The large scale

  18. A Novel Three Dimensional Field Effect Transistor Based on Single-Walled Carbon Nanotubes

    Microsoft Academic Search

    Selvapraba Selvarasah; Prashanth Makaram; Chia-Ling Chen; Huiyan Pan; Ahmed Busnaina; Mehmet R. Dokmeci

    2008-01-01

    We present the design, fabrication and testing of a novel three dimensional (3D) Field Effect Transistor based on Single-Walled Carbon Nanotubes (SWNTs). Three Dimensional SWNT transistors are realized utilizing low temperature Dielectrophoretic (DEP) assembly. A 1mum thick conformal Parylene-C (poly-para-xylylene) layer is utilized as the gate dielectric with a non-local top gate electrode around the conducting channel. The preliminary results

  19. Assembly of untreated single-walled carbon nanotubes at a liquid–liquid interface

    Microsoft Academic Search

    Jun Matsui; Kohei Yamamoto; Tokuji Miyashita

    2009-01-01

    Untreated single-walled carbon nanotubes (SWCNTs) were assembled at a liquid–liquid interface to form an ultrathin film. The SWCNTs were dispersed into water using sodium dodecyl sulfate (SDS) as a solubilizing agent. Then, hexane was added to the dispersion to create a liquid–liquid interface. The SWCNTs were assembled at the interface to form a smooth ultrathin film when ethanol was added

  20. 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

  1. Measurement of optical second-harmonic generation from an individual single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Huttunen, M. J.; Herranen, O.; Johansson, A.; Jiang, H.; Mudimela, P. R.; Myllyperkiö, P.; Bautista, G.; Nasibulin, A. G.; Kauppinen, E. I.; Ahlskog, M.; Kauranen, M.; Pettersson, M.

    2013-08-01

    We show that optical second-harmonic generation (SHG) can be observed from individual single-walled carbon nanotubes (SWCNTs) and, furthermore, allows imaging of individual tubes. Detailed analysis of our results suggests that the structural non-centrosymmetry, as required for SHG, arises from the non-zero chiral angle of the SWCNT. SHG thus has potential as a fast, non-destructive and simple method for imaging of individual nanomolecules and for probing their chiral properties.

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

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

  3. Plasmon excitation in single wall carbon nanotubes by penetrating charged particles

    NASA Astrophysics Data System (ADS)

    Segui, Silvina; Mowbray, Duncan J.; Gervasoni, Juana L.; Miškovi?, Zoran L.; Arista, Néstor R.

    2012-11-01

    In this work we study the excitation of plasmons due to the incidence of a charged particle passing through a single wall carbon nanotube. We use a quantized hydrodynamic, in which the ? and ? electrons characteristic of these carbonaceous structures are depicted as two interacting 2-dimensional fluids, to calculate the average number of plasmons excited. We analyze the contribution of the different plasmon modes in a variety of configurations, and study the energy lost by the incident particle.

  4. Rectifying behaviors introduced by nitrogen-vacancy complex in spiral chirality single walled carbon nanotube device

    NASA Astrophysics Data System (ADS)

    Cheng, Caiping; Hu, Huifang; Wei, Yan; Zhang, Zhaojin; Wang, Xiaowei; Zhao, Juan; Peng, Ping

    2013-08-01

    By applying nonequilibrium Green's functions in combination with density-functional theory, the effects of nitrogen-vacancy complex on electronic transport properties are investigated in spiral chirality single walled carbon nanotube device. The results show that rectifying behaviors can be tuned by introducing the complex defects with vacancy and nitrogen atoms. Moreover, current-voltage characteristics and negative differential conductance behavior can also be observed in this model. The mechanisms for these interesting phenomena are suggested.

  5. DFT calculations of KI crystals formed within single-walled carbon nanotubes

    Microsoft Academic Search

    Emma L. Sceats; Malcolm L. H. Green; Angus I. Kirkland; Jennifer C. Green

    2008-01-01

    Density functional theory calculations are used to obtain structures for KI crystals formed within single-walled carbon nanotubes. The predicted structures are compared with experimental specimen exit plane wavefunctions restored from focal series of high-resolution electron microscope images. These comparisons show good agreement between the calculated structure for KI@(12,12). The calculations also predict that surface rumples invert as the crystal becomes

  6. Photon-drag effect in single-walled carbon nanotube films.

    PubMed

    Mikheev, Gennady M; Nasibulin, Albert G; Zonov, Ruslan G; Kaskela, Antti; Kauppinen, Esko I

    2012-01-11

    We observed an interaction of single-walled carbon nanotube films with obliquely incident nanosecond laser radiation in visible and infrared regions generating unipolar voltage pulses replicating the shape of the laser pulses. The photoelectric signal significantly depends on the laser polarization and has maximum value at the laser beam incidence angle of ±65° and at the film thickness of 350 nm. The results are explained in the framework of the photon-drag effect. PMID:22112234

  7. 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. [Department of Physics, Tokyo University of Science, Tokyo 162-8601 (Japan)

    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.

  8. Electrochemical and vibrational properties of single-walled carbon nanotubes in hydrochloric acid solutions

    Microsoft Academic Search

    S. Lefrant; M. Baibarac; I. Baltog; T. Velula; J. Y. Mevellec; O. Chauvet

    2005-01-01

    Raman spectroscopy and cyclic voltammetry (CV) are used for the investigation of the oxidation–reduction processes of single-wall carbon nanotubes (SWNTs) films in an HCl 0.5 M solution. In the potential ranges (+100; +800) and (0; +1500) mV vs. saturated calomel electrode (SCE), the oxidation–reduction reactions of SWNT films, in both aqueous and semi-aqueous HCl 0.5M solutions, are reversible and irreversible,

  9. 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.

  10. Electrospun single-walled carbon nanotube\\/polyvinyl alcohol composite nanofibers: structure property relationships

    Microsoft Academic Search

    Minoo Naebe; Tong Lin; Mark P. Staiger; Liming Dai; Xungai Wang

    2008-01-01

    Polyvinyl alcohol (PVA) nanofibers and single-walled carbon nanotube (SWNT)\\/PVA composite nanofibers have been produced by electrospinning. An apparent increase in the PVA crystallinity with a concomitant change in its main crystalline phase and a reduction in the crystalline domain size were observed in the SWNT\\/PVA composite nanofibers, indicating the occurrence of a SWNT-induced nucleation crystallization of the PVA phase. Both

  11. Selective synthesis and device applications of semiconducting single-walled carbon nanotubes using isopropyl alcohol as feedstock.

    PubMed

    Che, Yuchi; Wang, Chuan; Liu, Jia; Liu, Bilu; Lin, Xue; Parker, Jason; Beasley, Cara; Wong, H-S Philip; Zhou, Chongwu

    2012-08-28

    The development of guided chemical vapor deposition (CVD) growth of single-walled carbon nanotubes provides a great platform for wafer-scale integration of aligned nanotubes into circuits and functional electronic systems. However, the coexistence of metallic and semiconducting nanotubes is still a major obstacle for the development of carbon-nanotube-based nanoelectronics. To address this problem, we have developed a method to obtain predominantly semiconducting nanotubes from direct CVD growth. By using isopropyl alcohol (IPA) as the carbon feedstock, a semiconducting nanotube purity of above 90% is achieved, which is unambiguously confirmed by both electrical and micro-Raman measurements. Mass spectrometric study was performed to elucidate the underlying chemical mechanism. Furthermore, high performance thin-film transistors with an on/off ratio above 10(4) and mobility up to 116 cm(2)/(V·s) have been achieved using the IPA-synthesized nanotube networks grown on silicon substrate. The method reported in this contribution is easy to operate and the results are highly reproducible. Therefore, such semiconducting predominated single-walled carbon nanotubes could serve as an important building block for future practical and scalable carbon nanotube electronics. PMID:22849386

  12. 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.

  13. 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

  14. Effective and efficient purification of single-wall carbon nanotubes based on hydrogen treatment

    NASA Astrophysics Data System (ADS)

    Sheng, Leimei; Shi, Lei; An, Kang; Yu, Liming; Ando, Yoshinori; Zhao, Xinluo

    2011-01-01

    A simple, effective and efficient purification method for single-wall carbon nanotubes (SWCNTs) prepared by hydrogen arc discharge has been developed. Hydrogen treatment has been used to remove the amorphous carbon and graphene sheets encapsulating Fe catalyst nanoparticles. The exposed Fe nanoparticles can be easily dissolved in concentrated hydrochloric acid. Carbon content higher than 99 wt.% can be achieved. The small SWCNTs with a diameter of 0.9 nm are found to survive during the purification processes. This new purification method enables us to obtain purified SWCNTs with high-crystallinity and without obvious damage.

  15. 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.

  16. Debundling and dissolution of single-walled carbon nanotubes in amide solvents.

    PubMed

    Furtado, C A; Kim, U J; Gutierrez, H R; Pan, Ling; Dickey, E C; Eklund, Peter C

    2004-05-19

    Wet chemical methods involving ultrasound and amide solvents were used to purify and separate large bundles of single-walled carbon nanotubes (SWNTs) into individual nanotubes that could then be transported to silicon or mica substrates. The SWNTs studied were produced by the arc-discharge process. Dry oxidation was used in an initial step to remove amorphous carbon. Subsequently, two acid purification schemes were investigated (HCl- and HNO(3)-reflux) to remove the metal growth catalyst (Ni-Y). Finally, ultrasonic dispersion of isolated tubes into either N,N-dimethylformamide (DMF) or N-methyl-2-pyrrolidone (NMP) was carried out. Raman scattering, atomic force microscopy (AFM), and electron microscopy were used to study the evolution of the products. Raman scattering was used to probe possible wall damage during the chemical processing. We found that both HCl and HNO(3) could be used to successfully remove the Ni-Y below approximately 1 wt %. However, the HNO(3)-reflux produced significant wall damage (that could be reversed by vacuum annealing at 1000 degrees C). In the dispersion step, both amide solvents (DMF and NMP) produced a high degree of isolated tubes in the final product, and no damage during this dispersion step was observed. HNO(3)-refluxed tubes were found to disperse the best into the amide solvents, perhaps because of significant wall functionalization. AFM was used to study the filament diameter and length distributions in the final product, and interesting differences in these distributions were observed, depending on the chemical processing route. PMID:15137775

  17. Electrical percolation thresholds of semiconducting single-walled carbon nanotube networks in field-effect transistors.

    PubMed

    Jang, Ho-Kyun; Jin, Jun Eon; Choi, Jun Hee; Kang, Pil-Soo; Kim, Do-Hyun; Kim, Gyu Tae

    2015-02-25

    With the advances in the separation and purification of carbon nanotubes (CNTs), the use of highly pure metallic or semiconducting CNTs has practical merit in electronics applications. When highly pure CNTs are applied in various fields, CNT networks are preferred to individual CNTs. In such cases, the presence of an electrical path becomes crucial in the network. In this study, we report on the electrical percolation thresholds of semiconducting single-walled carbon nanotube (s-SWCNT) networks, and their electrical characteristics in field-effect transistors (FET). Using the Monte Carlo method, s-SWCNT networks were randomly generated in the channels defined by the source-drain electrodes of the FET. On the basis of percolation theory, the percolation thresholds of s-SWCNT networks were obtained at different channel lengths (2, 6, and 10 ?m) by generating random s-SWCNT networks 100 times. The network density corresponding to the electrical percolation threshold was theoretically gained at each channel length. As a result, the network densities at the percolation thresholds for the channel lengths of 2, 6, and 10 ?m were 6.8, 9.0, and 9.9 tube ?m(-2), respectively. In addition, SPICE calculations were performed for each s-SWCNT network, constituting an electrical path between the source and the drain electrodes of the FET. In all channel lengths, the on/off ratio of the s-SWCNT networks was enhanced with increasing network density. Finally, we found a power law relationship between the on/off ratio of the s-SWCNT networks and the network density at the percolation threshold. PMID:25673219

  18. Unique Toxicological Behavior from Single-Wall Carbon Nanotubes Separated via Selective Adsorption on Hydrogels.

    PubMed

    Clar, Justin G; Gustitus, Sarah A; Youn, Sejin; Silvera Batista, Carlos A; Ziegler, Kirk J; Bonzongo, Jean Claude J

    2015-03-17

    Over the past decade, extensive research has been completed on the potential threats of single-wall carbon nanotubes (SWCNTs) to living organisms upon release to aquatic systems. However, these studies have focused primarily on the link between adverse biological effects in exposed test organisms on the length, diameter, and metallic impurity content of SWCNTs. In contrast, few studies have focused on the bioeffects of the different SWCNTs in the as-produced mixture, which contain both metallic (m-SWCNT) and semiconducting (s-SWCNT) species. Using selective adsorption onto hydrogels, high purity m-SWCNT and s-SWCNT fractions were produced and their biological impacts determined in dose-response studies with Pseudokirchneriella subcapitata as test organism. The results show significant differences in the biological responses of P. subcapitata exposed to high purity m- and s-SWCNT fractions. Contrary to the biological response observed using SWCNTs separated by density gradient ultracentrifugation, it is found that the high-pressure CO conversion (HiPco) s-SWCNT fraction separated by selective adsorption causes increased biological impact. These findings suggest that s-SWCNTs are the primary factor driving the adverse biological responses observed from P. subcapitata cells exposed to our as-produced suspensions. Finally, the toxicity of the s-SWCNT fraction is mitigated by increasing the concentration of biocompatible surfactant in the suspensions, likely altering the nature of surfactant coverage along SWCNT sidewalls, thereby reducing potential physical interaction with algal cells. These findings highlight the need to couple sample processing and toxicity response studies. PMID:25710331

  19. 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.

  20. Thin single-wall BN-nanotubes formed inside carbon nanotubes

    PubMed Central

    Nakanishi, Ryo; Kitaura, Ryo; Warner, Jamie H.; Yamamoto, Yuta; Arai, Shigeo; Miyata, Yasumitsu; Shinohara, Hisanori

    2013-01-01

    We report a high yield synthesis of single-wall boron nitride nanotubes (SWBNNTs) inside single-wall carbon nanotubes (SWCNTs), a nano-templated reaction, using ammonia borane complexes (ABC) as a precursor. Transmission electron microscope (TEM), high angle annular dark field (HAADF)-scanning TEM (STEM), electron energy loss spectra (EELS) and high resolution EELS mapping using aberration-corrected TEM system clearly show the formation of thin SWBNNTs inside SWCNTs. We have found that the yield of the SWBNNT formation is high and that the most of ABC molecules decompose and fuse to form the thin BNNTs at a temperature of 1,673?K having a narrow diameter distribution of 0.7 ± 0.1?nm. Optical absorption measurements suggest that the band gap of the thin SWBNNTs is about 6.0?eV, which provide the ideal insulator nanotubes with very small diameters. PMID:23459405

  1. Impact energy dependence of defect formation in single-walled carbon nanotubes

    SciTech Connect

    Zhang, Chao [Beijing Normal University; Mao, Fei [Beijing Normal University; Zhang, Fenf-Shou [Beijing Normal University; Zhang, Yanwen [ORNL

    2012-01-01

    By employing atomistic simulations based on empirical potential and density-functional theory, we study the irradiation of single-walled carbon nanotubes with a carbon ion. According to different impact locations on the surface of the nanotube, the incident threshold energies of defects formation are predicted to be 19, 35 and 45 eV, respectively. Moreover, the displacement threshold energy is investigated by using the collision dynamical method, and a reasonable value 17.59 eV is clarified by eliminating the thermal effect induced by the collision. Finally, the formation energy of a single vacancy is calculated by the ab initio method.

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

    SciTech Connect

    Liu, Haitao [Columbia University; He, Jin [Arizona State University; Tang, Jinyao [Columbia University; Liu, Hao [Arizona State University; Pang, Pei [Arizona State University; Cao, Di [Arizona State University; Krstic, Predrag S [ORNL; Joseph, Sony nmn [ORNL; Lindsay, Stuart [Arizona State University; Nuckolls, Colin [Columbia University

    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.

  3. Structure of single-wall carbon nanotubes purified and cut using polymer

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Yudasaka, M.; Koshio, A.; Jabs, C.; Ichihashi, T.; Iijima, S.

    2002-01-01

    Following on from our previous report that a monochlorobenzene solution of polymethylmethacrylate is useful for purifying and cutting single-wall carbon nanotubes (SWNTs) and thinning SWNT bundles, we show in this report that polymer and residual amorphous carbon can be removed by burning in oxygen gas. The SWNTs thus obtained had many holes (giving them a worm-eaten look) and were thermally unstable. Such severe damage caused by oxidation is unusual for SWNTs; we think that they were chemically damaged during ultrasonication in the monochlorobenzene solution of polymethylmethacrylate.

  4. 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

  5. Electronic Structure and Field-Emission Characteristics of Open-Ended Single-Walled Carbon Nanotubes

    SciTech Connect

    Zhou, Gang; Duan, Wenhui; Gu, Binglin

    2001-08-27

    The field-emission mechanism of open-ended single-walled carbon nanotubes (SWNTs) is studied. Owing to electronic effects that directly alter the bonding mode and remarkably influence the work function, an open-ended SWNT has much better field-emission properties than a closed SWNT; owing to geometrical effects that slightly influence the work function and the amplification factor, an open-ended SWNT with relaxation has higher threshold voltage and higher current density compared to one without relaxation. It is suggested that adjusting the localized electronic states of the emitting regions, by electronic and geometrical means, could improve the field-emission properties of carbon nanotubes.

  6. Quantitative assessment of the effect of purity on the properties of single wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Matsumoto, Naoyuki; Chen, Guohai; Yumura, Motoo; Futaba, Don N.; Hata, Kenji

    2015-03-01

    We quantitatively demonstrate the importance of high purity for the application of single wall carbon nanotubes (SWCNTs), materials solely composed of one surface, by examining the effects of carbon impurities on the electrical, thermal, and mechanical properties of both as-grown SWCNT forests and processed buckypaper. While decreases in properties were expected, our results showed the extreme sensitivity of SWCNT properties to carbonaceous impurities either through scattering in the individual SWCNTs or an inhibition of the ability to form inter-SWCNT junctions. Each property showed a nonlinear decrease (as high as 40%) with the addition of low levels of carbon impurities (~15 wt%), which demonstrates that purity is as important as the crystalline structure.We quantitatively demonstrate the importance of high purity for the application of single wall carbon nanotubes (SWCNTs), materials solely composed of one surface, by examining the effects of carbon impurities on the electrical, thermal, and mechanical properties of both as-grown SWCNT forests and processed buckypaper. While decreases in properties were expected, our results showed the extreme sensitivity of SWCNT properties to carbonaceous impurities either through scattering in the individual SWCNTs or an inhibition of the ability to form inter-SWCNT junctions. Each property showed a nonlinear decrease (as high as 40%) with the addition of low levels of carbon impurities (~15 wt%), which demonstrates that purity is as important as the crystalline structure. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07618d

  7. 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

  8. Carbon nanotunnels form from single-walled carbon nanotubes interacting with a diamond (100)-(2 X 1) surface.

    SciTech Connect

    Horner, D. A.; Sternberg, M.; Zapol, P.; Curtiss, L. A. (Center for Nanoscale Materials); ( MSD); (North Central Coll.)

    2011-08-01

    A quantum chemical study of the interaction of (5,5), (7,7), (9,9) and (8,0) single-walled carbon nanotubes with a clean (100)-(2 x 1) diamond surface is reported. Stable structures with covalent bonds at the interface were found for carbon nanotubes oriented parallel or perpendicular to the dimer rows on the reconstructed (100) surface. The binding energy of the most stable (5,5) nanotube-diamond structure is 1.7 eV/{angstrom}, and is attributed to strong covalent bonds formed between the carbon nanotube and the diamond surface. The structure of the nanotube is distorted by adsorption on the surface such that it adopts a tunnel-like geometry. Two other nanotunnel geometries were found for the (5,5) nanotube, with binding energies of 1.39 and 1.09 eV/{angstrom}. In the most stable (5,5) nanotube-diamond structure the interaction between the nanotube and the diamond surface produces a 0.6 eV band gap near the Fermi level, but the metallic character of the nanotube is maintained in the two other, less strongly bound nanotunnel structures. No charge transfer occurs between the diamond surface and the nanotunnels in any of the three orientations. Binding energies decrease with increases in tube diameter, to the extent that one of the three nanotunnel structures is not formed by (9,9) carbon nanotubes.

  9. Spray deposition of steam treated and functionalized single-walled and multi-walled carbon nanotube films for supercapacitors.

    PubMed

    Zhao, Xin; Chu, Bryan T T; Ballesteros, Belén; Wang, Weiliang; Johnston, Colin; Sykes, John M; Grant, Patrick S

    2009-02-11

    Steam purified, carboxylic and ester functionalized single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) films with homogeneous distribution and flexible control of thickness and area were fabricated on polymeric and metallic substrates using a modified spray deposition technique. By employing a pre-sprayed polyelectrolyte, the adhesion of the carbon nanotube (CNT) films to the substrates was significantly enhanced by electrostatic interaction. Carboxylic and ester functionalization improved electrochemical performance when immersed in 0.1 M H(2)SO(4) and the specific capacitance reached 155 and 77 F g(-1) for carboxylic functionalized SWNT and MWNT films respectively. Compared with existing techniques such as hot pressing, vacuum filtration and dip coating, the ambient pressure spray deposition technique is suggested as particularly well suited for preparing CNT films at large scale for applications including providing electrodes for electrochemical supercapacitors and paper batteries. PMID:19417393

  10. Advanced Characterization and Optical Properties of Single-Walled Carbon Nanotubes and Graphene Oxide

    NASA Astrophysics Data System (ADS)

    Naumov, Anton Viatcheslavovich

    Photophysical, electronic, and compositional properties of single-walled carbon nanotubes (SWCNTs) and bulk nanotube samples were investigated together with graphene oxide photoluminescence. First, we studied the effect of external electric fields on SWCNT photoluminescence. Fields of up to 107 V/m caused dramatic, reversible decreases in emission intensity. Quenching efficiency was proportional to the projection of the field on the SWCNT axis, and showed inverse correlation with optical band gap. The magnitude of the effect was experimentally related to exciton binding energy, as consistent with a proposed field-induced exciton dissociation model. Further, the electronic composition of various SWCNT samples was studied. A new method was developed to measure the fraction of semiconducting nanotubes in as- grown or processed samples. SWCNT number densities were compared in images from near-IR photoluminescence (semiconducting species) and AFM (all species) to compute the semiconducting fraction. The results provide important information about SWCNT sample compositions that can guide controlled growth methods and help calibrate bulk characterization techniques. The nature of absorption backgrounds in SWCNT samples was also studied. A number of extrinsic perturbations such as extensive ultrasonication, sidewall functionalization, amorphous carbon impurities, and SWCNT aggregation were applied and their background contributions quantified. Spectral congestion backgrounds from overlapping absorption bands were assessed with spectral modeling. Unlike semiconducting nanotubes, metallic SWCNTs gave broad intrinsic absorption backgrounds. The shape of the metallic background component and its absorptivity coefficient were determined. These results can be used to minimize and evaluate SWCNT absorption backgrounds. Length dependence of SWCNT optical properties was investigated. Samples were dispersed by ultrasonication or shear processing, and then length-fractionated by gel electrophoresis or controlled ultrasonication shortening. Fractions from both methods showed no significant absorbance variations with SWCNT length. The photoluminescence intensity increased linearly with length, and the relative quantum yield gradually increased, approaching a limiting value. Finally, a strong pH dependence of graphene oxide photoluminescence was observed. Sharp and structured excitation/emission features resembling the spectra of molecular fluorophores were obtained in basic conditions. Based on the observed pH-dependence and quantum calculations, these spectral features were assigned to quasi-molecular fluorophores formed by the electronic coupling of oxygen-containing addends with nearby graphene carbon atoms.

  11. 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

  12. Chiral angle dependence of resonance window widths in (2n+m) families of single-walled carbon nanotubes

    E-print Network

    Hsieh, Ya-Ping

    Raman spectra of isolated single-walled carbon nanotubes (SWNTs) were obtained for a wide range of laser excitation energies to study the resonance excitation window of the radial breathing mode feature for members of ...

  13. 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 ...

  14. The study of synthesis and functionalized single-walled carbon nanotubes with amide group

    NASA Astrophysics Data System (ADS)

    Abjameh, Reza; Moradi, Omid; Amani, Javad

    2014-06-01

    This study includes of syntheses and characteristics functionalized single-walled carbon nanotubes (SWCNTs) with amide group using thionyl chloride and NH3. First SWCNTs in H2SO4 and HNO3, solved and the solution obtained ultrasound was to reach the equilibrium temperature to functionalization of carboxylate single-walled carbon nanotubes (SWCNT-COOH). Then using thionyl chloride with (SOCl2) and DMF the mixture was refluxing. SWCNT-COCl was obtained from the previous step with ammonia (NH3), and DMF as solvent, and the mixture was refluxing. The black solid obtained was placed overnight in the oven to dry. Carbon nanotubes were expected at this stage to have a functional group CONH2. All new chemical bonding products were identified by FT-IR and observations using scanning electron microscopy (SEM) were confirmed. SWCNT-COOH functionalized carbon nanotubes have a relatively smooth surface and thin Stowe and the SEM image of the SWCNT-NH2; a thin layer of hope is clearly placed on the surface of SWCNT-COOH and its diameter is increased.

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

  16. The effect of surface heterogeneity on the mechanical properties of single wall carbon nanotube carpets

    NASA Astrophysics Data System (ADS)

    Maldonado, E. C.; Roth, M. W.

    2010-03-01

    The results presented and discussed involve Material Point Method (MPM) simulations of single wall carbon nanotube (SWNT) carpets with varying surface heterogeneity. Specifically, we use deterministic MPM simulations to explore the effect of the degree of randomness of the SWNT array on peeling and adhesive properties as well as the degree clumping of the carpets acting under the constraint of guided motion of the carpet substrate. The bulk elastic properties of the tubes and substrate are taken into account and the system's behavior is characterized through calculations involving dynamics and energetics.

  17. 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.

  18. 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.

  19. The behavior of benzene confined in a single wall carbon nanotube.

    PubMed

    Fomin, Yury D; Tsiok, Elena N; Ryzhov, Valentin N

    2015-05-01

    We present the molecular dynamics study of benzene molecules confined into the single wall carbon nanotube. The local structure and orientational ordering of benzene molecules are investigated. It is found that the molecules mostly group in the middle distance from the axis of the tube to the wall. The molecules located in the vicinity of the wall demonstrate some deviation from planar shape. There is a tilted orientational ordering of the molecules which depends on the location of the molecule. It is shown that the diffusion coefficient of the benzene molecules is very small at the conditions we report here. © 2015 Wiley Periodicals, Inc. PMID:25753740

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

    NASA Astrophysics Data System (ADS)

    Rao, Rahul; Pierce, Neal; Dasgupta, Archi

    2014-08-01

    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 SiO2 substrates by chemical vapor deposition and investigated the charge transfer between them by Raman spectroscopy. Our results revealed that, on both copper and SiO2 substrates, graphene donates electrons to the SWNTs, resulting in p-type doped graphene and n-type doped SWNTs.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Clair, Sylvain; Shin, Hyung-Joon; Kim, Yousoo; Kawai, Maki

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

    di Bartolomeo, A.; Yang, Y.; Rinzan, M. B. M.; Boyd, A. K.; Barbara, P.

    2010-11-01

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

  4. Translocation of single-wall carbon nanotubes through solid-state nanopores.

    PubMed

    Hall, Adam R; Keegstra, Johannes M; Duch, Matthew C; Hersam, Mark C; Dekker, Cees

    2011-06-01

    We report the translocation of individual single-wall carbon nanotubes (SWNTs) through solid-state nanopores. Single-strand DNA oligomers are used to both disperse the SWNTs in aqueous solution and to provide them with a net charge, allowing them to be driven through the nanopores by an applied electric field. The resulting temporary interruptions in the measured nanopore conductance provide quantitative information on the diameter and length of the translocated nanotubes at a single-molecule level. Furthermore, we demonstrate that the technique can be utilized to monitor bundling of SWNT in solution by using complementary nucleotides to induce tube-tube agglomeration. PMID:21574581

  5. Magnetic response of single-walled carbon nanotubes induced by an external magnetic field.

    PubMed

    Kibalchenko, Mikhail; Payne, Mike C; Yates, Jonathan R

    2011-01-25

    Using first-principles density functional calculations, magnetically induced currents are obtained for zigzag single-walled carbon nanotubes. Clear differences and trends in current flow are observed between the different nanotube families. In particular, for a magnetic field applied along the tube axis, the current response of the ? = 0 infinite nanotubes is paramagnetic, whereas for ? = 1 and 2 nanotubes, the response is diamagnetic. The results are used to predict and interpret the significant changes in NMR properties for small molecules encapsulated inside a tube. PMID:21171576

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

    NASA Astrophysics Data System (ADS)

    Kim, Duckjong; Li, Cheng Ai; Choi, Kwang-Min

    2015-01-01

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

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    Song, Li; Ma, Wenjun; Ren, Yan; Zhou, Weiya; Xie, Sishen; Tan, Pingheng; Sun, Lianfeng

    2008-03-01

    The temperature-dependent Raman frequency shift in single-walled carbon nanotube (SWCNT) rings in the range of 80-550K is investigated. We observe that the frequency decreases with increasing temperature for all Raman peaks of the nanotube rings. Furthermore, compared to the nanotubes with linear structure, the temperature coefficients of the radial breathing mode and G-mode frequencies of the nanotube rings are much smaller, which means the nanotube rings have more stable thermal ability. We attribute the better thermal stability to the high bending strain energy along the nanotube rings induced by the sidewall curvature.

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

    PubMed

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

    2009-10-01

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

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

    SciTech Connect

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Basic Sciences, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)] [Department of Basic Sciences, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)

    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.

  11. 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.

  12. 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.

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

    SciTech Connect

    Shu, Chunying [Virginia Polytechnic Institute and State University (Virginia Tech); Zhang, Jianfei [Virginia Polytechnic Institute and State University (Virginia Tech); Sim, Jae Hyun [Virginia Polytechnic Institute and State University (Virginia Tech); Burke, Brian [University of Virginia, Charlottesville; Williams, Keith A [University of Virginia, Charlottesville; Rylander, Nichole M [Virginia Polytechnic Institute and State University (Virginia Tech); Campbell, Tom [Virginia Polytechnic Institute and State University (Virginia Tech); Puretzky, Alexander A [ORNL; Rouleau, Christopher M [ORNL; Geohegan, David B [ORNL; More, Karren Leslie [ORNL; Esker, Alan R [Virginia Polytechnic Institute and State University (Virginia Tech); Gibson, Harry W [Virginia Polytechnic Institute and State University (Virginia Tech); Dorn, Harry C [Virginia Polytechnic Institute and State University (Virginia Tech)

    2010-01-01

    A high-speed vibration milling (HSVM) method was applied to synthesize water dispersible single- walled carbon nanohorns (SWNHs). Highly reactive free radicals (HOOCCH2CH2 ) produced from an acyl peroxide under HSVM conditions react with hydrophobic SWNHs to produce a highly water dispersible derivative (f-SWNHs), which has been characterized in detail by spectroscopic and microscopic techniques together with thermogravimetric analysis (TGA) and dynamic light scatter- ing (DLS). The carboxylic acid functionalized, water-dispersible SWNHs material are versatile precursors that have potential applications in the biomedical area.

  14. Structure and properties of polyacrylonitrile\\/single wall carbon nanotube composite films

    Microsoft Academic Search

    Huina Guo; T. V. Sreekumar; Tao Liu; Marilyn Minus; Satish Kumar

    2005-01-01

    Polyacrylonitrile (PAN)\\/single wall carbon nanotube (SWNT) composite films have been processed with unique combination of tensile strength (103MPa), modulus (10.9GPa), electrical conductivity (1.5×104S\\/m), dimensional stability (coefficient of thermal expansion 1.7×10?6\\/°C), low density (1.08g\\/cm3), solvent resistance, and thermal stability. PAN molecular motion above the glass transition temperature (Tg) in the composite film is significantly suppressed, resulting in high PAN\\/SWNT storage modulus

  15. Vibrational analysis of thermal oscillations of single-walled carbon nanotubes under axial strain

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    The first four flexural vibrational modes of single-walled carbon nanotubes (SWCNTs) of various lengths under different axial strains were studied using atomistic molecular dynamics within the framework of the Brenner interatomic potential and Fourier analysis. The simulated results are in excellent agreement with the Timoshenko beam model, which includes the effect of both rotary inertia and of shearing deformation. From the crossing points of the simulation data with the expected resonance frequencies of the unstrained tubes an upper limit for the effective SWCNT thickness is found (?0.1 nm), with no adjustable parameters. This partially resolves Yakobson's paradox concerning scattered estimates for nanotube width.

  16. Fabrication of entangled single-wall carbon nanotube films as nanoporous junctions for ion concentration polarization

    NASA Astrophysics Data System (ADS)

    Kim, Bumjoo; Heo, Joonseong; Kwon, Hyukjin J.; Kim, Intae; An, Taechang; Lim, Geunbae

    2015-03-01

    Ion concentration polarization (ICP) is a distinctive electrochemical phenomenon that occurs near an ion-exchange membrane with an applied DC electric field, generating a significant concentration gradient in back and forth on the membrane. To date, however, there have been only a few attempts to introduce unconventional materials for ion transport in micro–nanofluidic systems. Here, we describe the development of a novel ICP system using an entangled single-wall carbon nanotube (SWNT) film as an ion-selective membrane instead of a Nafion membrane, for investigating the detailed relationship between electrical properties, i.e., ionic conductance through nanojunctions, and nonlinear electrokinetic behavior.

  17. Determination of the single wall carbon nanotube opening ratio by means of rare gas adsorption

    NASA Astrophysics Data System (ADS)

    Arab, M.; Picaud, F.; Ramseyer, Ch.; Babaa, M.-R.; Valsaque, F.; McRae, E.

    2006-05-01

    When single wall carbon nanotubes are mechanically or chemically cut, the ratio between opened and closed tubes after treatment is difficult to determine. We propose a new way to characterize this using rare gas adsorption. We compare theoretical calculations and experimental results performed on both closed and opened nanotube bundles. Plateau height analysis allows extracting the tube density in the bundles. Secondly, upon exposure to Kr or Xe, the adsorption isotherms obtained for closed and opened tube samples differ substantially due to the presence of different adsorption sites and thus can help to evaluate the efficiency of the opening method.

  18. Inkjet printing of aligned single-walled carbon-nanotube thin films

    NASA Astrophysics Data System (ADS)

    Takagi, Yuki; Nobusa, Yuki; Gocho, Shota; Kudou, Hikaru; Yanagi, Kazuhiro; Kataura, Hiromichi; Takenobu, Taishi

    2013-04-01

    We report a method for the inkjet printing of aligned single-walled carbon-nanotube (SWCNT) films by combining inkjet technology with the strong wettability contrast between hydrophobic and hydrophilic areas based on the patterning of self-assembled monolayers. Both the drying process control using the strong wettability boundary and the coffee-stain effect strongly promote the aggregation of SWCNTs along the contact line of a SWCNT ink droplet, thereby demonstrating our achievement of inkjet-printed aligned SWCNT films. This method could open routes for developing high-performance and environmentally friendly SWCNT printed electronics.

  19. 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.

  20. Energy Spectrum and Optical Properties of Single-Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Murzashev, A. I.; Shadrin, E. O.

    2013-12-01

    The energy spectrum and the optical absorption spectra of single-wall carbon nanotubes with chiralities (5,5), (10,0), (9,0), (12,0), and (15,0) is calculated within the framework of the Shubin-Wonsowskii-Hubbard model taking into account distant (adjacent to the nearest) interstitial electron transfer. It is demonstrated that all of them, irrespective of the chirality, are narrow-gap semiconductors with a gap of ~0.1 eV that coincides with the available experimental data. The optical absorption spectra are also in good agreement with the experimentally measured spectra.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  3. 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.

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

    SciTech Connect

    Rao, Rahul, E-mail: rrao@honda-ri.com; Pierce, Neal; Dasgupta, Archi [Honda Research Institute USA, Columbus, Ohio 43212 (United States)

    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.

  5. Temperature dependence of the Raman spectra of single-wall carbon H. D. Li, K. T. Yue,a)

    E-print Network

    Wang, Zhong L.

    of carbonaceous materials including carbon fiber,4 highly ori- ented pyrolytic graphite HOPG ,5 disordered carbonTemperature dependence of the Raman spectra of single-wall carbon nanotubes H. D. Li, K. T. Yue-wall carbon nanotubes SWCNTs were measured at different temperatures by varying the incident laser power

  6. Pt-Fe catalyst nanoparticles supported on single-wall carbon nanotubes: Direct synthesis and electrochemical performance for methanol oxidation

    NASA Astrophysics Data System (ADS)

    Ma, Xiaohui; Luo, Liqiang; Zhu, Limei; Yu, Liming; Sheng, Leimei; An, Kang; Ando, Yoshinori; Zhao, Xinluo

    2013-11-01

    Single-wall carbon nanotubes (SWCNTs) supported Pt-Fe nanoparticles have been prepared by one-step hydrogen arc discharge evaporation of carbon electrode containing both Pt and Fe metal elements. The formation of SWCNTs and Pt-Fe nanoparticles occur simultaneously during the evaporation process. High-temperature hydrogen treatment and hydrochloric acid soaking have been carried out to purify and activate those materials in order to obtain a new type of Pt-Fe/SWCNTs catalyst for methanol oxidation. The Pt-Fe/SWCNTs catalyst performs much higher electrocatalytic activity for methanol oxidation, better stability and better durability than a commercial Pt/C catalyst according to the electrochemical measurements, indicating that it has a great potential for applications in direct methanol fuel cells.

  7. Electrochemical gating of individual single-wall carbon nanotubes observed by electron transport measurements and resonant Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Cronin, S. B.; Barnett, R.; Tinkham, M.; Chou, S. G.; Rabin, O.; Dresselhaus, M. S.; Swan, A. K.; Ünlü, M. S.; Goldberg, B. B.

    2004-03-01

    Metal electrodes patterned lithographically on top of individual single-wall carbon nanotubes are used to gate the nanotubes with respect to a reference electrode in an electrolyte drop. The gating is found to have a dramatic effect on both the Raman spectra and electron transport of the nanotubes. Current through metallic nanotubes is found to increase sharply with electrochemical gate voltage, indicating that the Fermi energy reaches valence and conduction band van Hove singularities. Using resonant confocal micro-Raman spectroscopy, we observe a 9 cm-1 upshift of the tangential mode vibrational frequency, as well as a 90% decrease in intensity, by applying 1 V between an individual nanotube and a silver reference electrode in a dilute H2SO4 solution. The mechanisms for the shifts of the Raman mode frequencies are discussed on the basis of changes in the lattice constant of heavily charged nanotubes.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao; Song, Yan-Rong

    2014-06-01

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

  9. Single-walled metal-organic nanotube built from a simple synthon.

    PubMed

    Adarsh, Nayarassery N; Dîrtu, Marinela M; Naik, Anil D; Léonard, Alexandre F; Campagnol, Nicolo; Robeyns, Koen; Snauwaert, Johan; Fransaer, Jan; Su, Bao Lian; Garcia, Yann

    2015-03-01

    A conformationally flexible triazole-carboxylic acid ligand derived from an L-amino acid, namely, 4?H-1,2,4-triazol-4-yl-acetic acid (?HGlytrz), has been exploited to synthesize a structurally diverse and functionally intriguing metal-organic framework with CuSiF6 . The crystal structure reveals a novel single-walled metal-organic nanotube (SWMONT), namely, {[Cu3 (?3 -OH)(H2 O)3 (Glytrz)3 ]?SiF6 ?8?H2 O?X}? (1), (where X=disordered lattice water molecules) having a pore size as large as zeolites. Compound 1 was synthesized as crystals, as powder, or as layers by precipitation/electrodeposition. Mercury intrusion porosimetry demonstrates the ability of this material to store metallic mercury, after a pressure treatment, contrary to previous literature examples. PMID:25601611

  10. Chemical vapor deposition growth of single-walled carbon nanotubes with controlled structures for nanodevice applications.

    PubMed

    Chen, Yabin; Zhang, Jin

    2014-08-19

    Single-walled carbon nanotubes (SWNTs), a promising substitute to engineer prospective nanoelectronics, have attracted much attention because of their superb structures and physical properties. The unique properties of SWNTs rely sensitively on their specific chiral structures, including the diameters, chiral angles, and handedness. Furthermore, high-performance and integrated circuits essentially require SWNT samples with well-aligned arrays, of single conductive type and of pure chirality. Although much effort has been devoted to chemical vapor deposition (CVD) growth of SWNTs, their structure control, growth mechanism, and structural characterizations are still the primary obstacles for the fabrication and application of SWNT-based nanodevices. In this Account, we focus on our established CVD growth methodology to fulfill the requirements of nanodevice applications. A rational strategy was successfully exploited to construct complex architectures, selectively enrich semiconducting (s) or metallic (m) SWNTs, and control chirality. First, well-aligned and highly dense SWNT arrays are beneficial for nanodevice integration. For the directed growth mode, anisotropic interactions between the SWNTs and the crystallographic structure of substrate are crucial for their growth orientation. Just as crystals possess various symmetries, SWNTs with controlled geometries have the corresponding turning angles. Their complex architectures come from the synergetic effect of lattice and gas flow directed modes. Especially, the aligned orientations of SWNTs on graphite are chirality-selective, and their chiral angles, handedness, and (n,m) index have been conveniently and accurately determined. Second, UV irradiation and sodium dodecyl sulfate (SDS) washing-off methods have been explored to selectively remove m-SWNTs, leaving only s-SWNT arrays on the surface. Moreover, the UV-assisted technique takes the advantages of low cost and high efficiency and it directly produces a high ratio of s-SWNT arrays. We also designed a smart scotch tape to sort out the s-SWNTs and m-SWNTs from the as-grown mixture with 3-aminopropyl-triethoxysilane and triethoxyphenylsilane as glues, respectively. This is analogous to the mechanical exfoliation of a graphene sheet. Third, the obtained SWNT intramolecular junctions obtained by temperature-mediated CVD indicate that temperature can seriously affect the SWNT's chirality during its growth. Importantly, the cloning method can validate the chirality-controlled growth of SWNTs, and the cloning efficiency is significantly improved on a quartz surface. Well-aligned SWNT arrays with a high density and controlled structures are highly desirable for carbon nanoelectronics. We hope that the advanced methodology used here will promote their controlled preparation and provide insights into the growth mechanism of SWNTs. PMID:24926610

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

    SciTech Connect

    Smaranda, I. [National Institute of Materials Physics, Lab. Optical Processes in Nanostructured Materials, P.O. Box MG-7, Bucharest R077125 (Romania); Baibarac, M., E-mail: barac@infim.ro [National Institute of Materials Physics, Lab. Optical Processes in Nanostructured Materials, P.O. Box MG-7, Bucharest R077125 (Romania); Baltog, I. [National Institute of Materials Physics, Lab. Optical Processes in Nanostructured Materials, P.O. Box MG-7, Bucharest R077125 (Romania); Mevellec, J.Y.; Lefrant, S. [Institut des Materiaux 'Jean Rouxel', 2 rue de la Houssiniere, B.P. 32229, F-44322 Nantes (France)

    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.

  12. Van Der Waals Interaction between Two Parallel Radially Deformed Single Wall Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Popescu, Adrian; Woods, Lilia; Bondarev, Igor

    2008-03-01

    The van der Waals potential energy is calculated between two parallel infinitely long radially deformed single walled carbon nanotubes within the pairwise Lennard-Jones approximation for extended systems. The nanotubes will undergo different geometrical radial shape transitions if an external hydrostatic pressure with an increasing strength is applied. We describe these shapes with analytically in order to facilitate the calculations. The most preferred mutual orientations are determined in all considered cases in terms of their potential well depths, equilibrium distances, and geometrical parameters. We find that the interaction evolves in such a way as to keep the distance between the interacting surfaces comparable to the graphene-graphene distance in graphite. In addition, the universal graphitic potential concept is extended to radially deformed carbon nanotubes. These results can be used as a guide for future experiments to investigate interactions between deformed carbon nanotubes.

  13. Sound wave propagation in armchair single walled carbon nanotubes under thermal environment

    NASA Astrophysics Data System (ADS)

    Naceri, Mokhtar; Zidour, Mohamed; Semmah, Abdelwahed; Houari, Mohammed Sid Ahmed; Benzair, Abdelnour; Tounsi, Abdelouahed

    2011-12-01

    This paper develops a model that analyzes the wave propagation in armchair single-walled carbon nanotubes (SWCNTs) under thermal environment. The effect of a small length scale is incorporated in the formulations using nonlocal Levinson beam model. Unlike Timoshenko beam theory, Levinson beam theory satisfies zero traction boundary conditions on the upper and lower surface of the structures, so there is no need to use a shear correction factor. The equivalent Young's modulus and shear modulus for armchair SWCNT are derived using an energy-equivalent model. Results indicate significant dependence of natural frequencies on the temperature change as well as the chirality of armchair carbon nanotube. These findings are important in mechanical design considerations of devices that use carbon nanotubes.

  14. 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.

  15. Investigation of the effect of single wall carbon nanotubes on interlaminar fracture toughness of woven carbon fiber—epoxy composites

    Microsoft Academic Search

    Piyush R. Thakre; Dimitris C. Lagoudas; Jaret C. Riddick; Thomas S. Gates; Sarah-Jane V. Frankland; James G. Ratcliffe; Jiang Zhu; Enrique V. Barrera

    2011-01-01

    Single wall carbon nanotubes (SWCNTs) were introduced in the interlaminar region of woven carbon fiber—epoxy composites and the mode-I delamination behavior was investigated. Pristine (P-SWCNT) and functionalized (F-SWCNT) nanotubes were sprayed in the mid-plane of these laminates and delamination was initiated using a teflon pre-crack insert. The composite laminates were produced using vacuum-assisted resin transfer molding process. The interlaminar fracture

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  17. 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.

  18. 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.

  19. 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...

  20. Theoretical comparison between field emission from single-wall and multi-wall carbon nanotubes A. Mayer,1,

    E-print Network

    Mayer, Alexandre

    Theoretical comparison between field emission from single-wall and multi-wall carbon nanotubes A s : 73.63.Fg, 79.70. q, 85.35.Kt, 03.65.Nk I. INTRODUCTION Carbon nanotubes show interesting field-emission of field emission from carbon nanotubes,13­16 we now consider the depen- dence of the emission from single