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1

Direct observation of confined states in metallic single-walled carbon nanotubes  

E-print Network

Direct observation of confined states in metallic single-walled carbon nanotubes Theophilos metallic single-walled carbon nanotubes using low-temperature scanning tunneling spectroscopy. We observed Institute of Physics. DOI: 10.1063/1.1598282 Single-walled carbon nanotubes SWCNTs are consid- ered

Dekker, Cees

2

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

E-print Network

Hydrogen Storage in Metal-Modified Single-Walled Carbon Nanotubes (start 9/15/01) Channing Ahn, PI Intercalation of carbons Characterization of intercalated single walled nanotubes Gravimetric and volumetric-metal) additions to single-walled nanotubes on H2 adsorption. Potassium intercalated graphite long known to absorb

3

Process for separating metallic from semiconducting single-walled carbon nanotubes  

NASA Technical Reports Server (NTRS)

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.

Sun, Ya-Ping (Inventor)

2008-01-01

4

Random telegraph noise in metallic single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

5

Random telegraph noise in metallic single-walled carbon nanotubes  

SciTech Connect

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

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

2014-05-12

6

Single-Walle 4. Single-Walled Carbon Nanotubes  

E-print Network

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 classified into single-walled and multi- walled nanotubes. Single-walled carbon nano- tubes, the subject

Kono, Junichiro

7

Terahertz detection mechanism and contact capacitance of individual metallic single-walled carbon nanotubes  

E-print Network

Terahertz detection mechanism and contact capacitance of individual metallic single-walled carbon a filament for single-scan coherent terahertz wave detection Appl. Phys. Lett. 100, 121105 (2012) Development, 034703 (2012) Electromagnetic characteristics of surface modified iron nanowires at x-band frequencies J

Kim, Philip

8

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

NASA Technical Reports Server (NTRS)

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 .

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

9

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

E-print Network

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.

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

2006-01-23

10

Disentanglement of the electronic properties of metallicity-selected single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

The inherent structure of single-walled carbon nanotubes (SWCNTs) provides them tremendous value as archetypical one-dimensional (1D) solids, which exhibit van Hove singularities in their local density of states, Tomonaga-Luttinger liquid behavior, ballistic transport properties, and in many other aspects, features of 1D quantum systems, which allow the study of fundamental problems. Therefore, unraveling the signature of their peculiar electronic structure as pristine material is a prerequisite for tracing any modification. Here, we show the disentanglement of the unique 1D features and bonding environments in clean metallicity sorted nanotube films. The photoemission and x-ray absorption responses unambiguously reveal how the fine structure in the C1s edge and photoemission valence band separately discerns the SWCNT metallic and semiconducting nature. This has crucial implications for applications allowing for instance finding the limit of maximum conductivity in transparent electrodes or the uniformity of power transistors, among others.

Ayala, P.; Miyata, Y.; de Blauwe, K.; Shiozawa, H.; Feng, Y.; Yanagi, K.; Kramberger, C.; Silva, S. R. P.; Follath, R.; Kataura, H.; Pichler, T.

2009-11-01

11

States of Excitons and Linear Optical Spectra in Metallic Single-Walled Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

Considering the exciton effect, the excitation energy and its binding energy of the metallic single-walled carbon nanotubes (SWNTs) are theoretically studied by using the simple tight-binding model, based on which the linear absorption spectra are also calculated. It is found that due to the trigonal warping effect, the excitation energies of the linear optical spectra all are split into two corresponding ones. Additionally, the splitting depends on both the chirality and the transition energy: (1) the splitting is maximal for the zigzag tubes, the splitting decreases with the increasing chiral angle; (2) the higher the transition energy is, the larger the splitting is. It is very interesting to find that the obtained results are in good agreement with the experimental results.

Yu, Gui-Li; Li, Gui-Chen; Jia, Yong-Lei; Tang, Gang

2014-09-01

12

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

E-print Network

Effects of hydrogen adsorption on single-wall carbon nanotubes: Metallic hydrogen decoration O. Gu¨lseren,1,2 T. Yildirim,1 and S. Ciraci3 1 NIST Center for Neutron Research, National Institute of Standards of carbon nanotubes undergo dramatic changes with hydrogen chemisorption from first principle calculations

Yildirim, Taner

13

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

PubMed

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

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

2013-12-01

14

Enhancement of semiconducting single-wall carbon nanotubes photoluminescence  

E-print Network

Enhancement of semiconducting single-wall carbon nanotubes photoluminescence Etienne Gaufr`es1.vivien@u-psud.fr Photoluminescence properties of semiconducting single wall carbon nanotubes (s-SWNT) thin films with different metallic single wall carbon nanotubes (m-SWNT) concentrations are reported. s-SWNT purified samples are ob

Boyer, Edmond

15

Investigation of superconductivity in the single-walled carbon nanotubes  

Microsoft Academic Search

Superconductivity in the single-walled carbon nanotubes is investigated. First, effect of diameter increasing on the clean systems critical temperature, Tc, is calculated. Then effect of impurity doping on the reduction of critical temperature Tc, of single-walled carbon nanotubes, is discussed. Our calculations illustrate that metallic zigzag single-walled carbon nanotubes have higher Tc than armchair single-walled carbon nanotubes with approximately same

Rostam Moradian; Ali Fathalian

2008-01-01

16

Doping effects on metallic and semiconductor single-wall carbon nanotubes  

Microsoft Academic Search

In this paper we investigate nitrogen- and boron-doped zigzag and armchair single-wall carbon nanotubes (SWNTs) with theoretical models based on the density functional theory. We take into account nitrogen and boron doping for two isomers in which substitutive atoms are on opposite sides of the tube, but only in one isomer the impurity sites are symmetrical with respect to the

F. Buonocore

2007-01-01

17

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

Microsoft Academic Search

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

Tarek Ragab; Cemal Basaran

2010-01-01

18

Exciton states in metallic zigzag single-walled carbon nanotubes under uniaxial strain  

NASA Astrophysics Data System (ADS)

The exciton energy spectrum and its binding energy under the uniaxial strain have been theoretically studied by using the tight-binding model in the metallic zigzag single-walled carbon nanotubes (SWNTs). It is found that the energy of M 11 - and M 22 - excitons and their binding energies increase with the increase of uniaxial strain, but the energy of M 11 + and M 22 + excitons and their binding energies decrease as the uniaxial strain increase. So, we can deduce that the splitting of M11 and M22 exciton will disappear as the uniaxial strain increases up to some degree, which is expected to be detected by the future experiment. On the other hand, it is interesting to calculate the exciton energy spectrum and binding energies of the bands that nearest to the Fermi level, with a narrow gap under the uniaxial strain. The obtained results show that they increase with increasing the uniaxial strain, based on which a supplemented tool is offered to detect the deformation degree of a metallic SWNT under uniaxial strain. In addition, we expect the results obtained here can offer some useful information for the future THz applications.

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

2014-11-01

19

Excitonic Rayleigh scattering spectra of metallic single-walled carbon nanotubes  

E-print Network

We have performed microscopic calculations of the Rayleigh scattering cross section for arbitrary metallic single-walled carbon nanotubes. The focus of our investigations lies on excitonic effects and their influence on the characteristic features in a Rayleigh scattering spectrum. Our approach is based on density matrix theory including tight-binding energies, the carrier-light coupling as well as the carrier-carrier interaction. Due to the refractive index contribution to the scattering cross section, we observe characteristic features in Rayleigh spectra, such as a strong deviation from the Lorentz peak shape and the larger oscillator strength of the lower-lying transition $M_{ii}^-$ in the double-peaked structure, independently of the chiral angle and the diameter of the investigated nanotubes. We observe excitonic binding energies in the range of $\\unit[60-80]{meV}$ for metallic nanotubes with diameters of $\\unit[1.5-2.5]{nm}$. The overlap of the excitonic transition with the close-by continuum has a sig...

Malic, Ermin; Reich, Stephanie; Knorr, Andreas

2010-01-01

20

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

21

Single-walled carbon nanotube electronics  

Microsoft Academic Search

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

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

2002-01-01

22

Single-Walled Carbon Nanotubes for Nanoelectronics  

E-print Network

CHAPTER 6 Single-Walled Carbon Nanotubes for Nanoelectronics M. S. Fuhrer UNIVERSITY OF MARYLAND . . . . . . . . . . . . 299 1. Synthesis of Single-Walled Carbon Nanotubes . . . . . . . . . . . . . 299 2. Fabrication 1991) (``multi-walled carbon nanotubes'' or MWNTs). Soon thereafter, single-walled carbon nanotubes

Rubloff, Gary W.

23

Alloy hydride catalyst route for the synthesis of single-walled carbon nanotubes, multi-walled carbon nanotubes and magnetic metal-filled multi-walled carbon nanotubes  

Microsoft Academic Search

This paper presents a novel, cost-effective and single-step technique for the synthesis of single-walled carbon nanotubes (SWNTs), multi-walled carbon nanotubes (MWNTs) and magnetic metal-filled MWNTs using a fixed bed reaction thermal chemical vapour deposition (CVD) using alloy hydride catalyst. The single-step method involves the pyrolysis of methane at suitable temperatures over fine powders of certain Mischmetal-based AB3 alloy hydride catalysts,

A. Leela Mohana Reddy; M. M. Shaijumon; S. Ramaprabhu

2006-01-01

24

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

NASA Astrophysics Data System (ADS)

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.

Hamadanian, Masood; Tavangar, Zahra; Noori, Banafsheh

2014-11-01

25

Catalytic Routes Towards Single Wall Carbon Nanotubes  

Microsoft Academic Search

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

Emmanuel Lamouroux; Philippe Serp; Philippe Kalck

2007-01-01

26

Carbon nanotubes Growth of Single-Walled Carbon Nanotubes from Sharp  

E-print Network

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

Nordlund, Kai

27

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

NASA Technical Reports Server (NTRS)

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.

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

28

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

NASA Astrophysics Data System (ADS)

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.

Xu, Xiaoyou

29

Electrical behavior of Langmuir-Blodgett networks of sorted metallic and semiconducting single-walled carbon nanotubes.  

PubMed

Langmuir-Blodgett deposition has been used to form thin film networks of both metallic and semiconducting single-walled carbon nanotubes. These have been investigated to understand their physical, optical, and morphological properties. The electrical conductivities over the temperature range 80-350 K and across electrode gaps of 220 nm and 2 mm have been explored. In the case of semiconducting tubes, the results suggest that Poole-Frenkel conduction is the dominant electrical process at temperatures below 150 K and electric fields of greater than 1 MV m(-1). Metallic nanotube networks exhibit a decrease in resistance with a reduction in temperature. This can be approximated by a linear relationship, giving a temperature coefficient of resistance of 10(-3) K(-1). PMID:23036116

Massey, Mark K; Rosamond, Mark C; Pearson, Christopher; Zeze, Dagou A; Petty, Michael C

2012-10-30

30

Preferential growth of short aligned, metallic-rich single-walled carbon nanotubes from perpendicular layered double hydroxide film.  

PubMed

Direct bulk growth of single-walled carbon nanotubes (SWCNTs) with required properties, such as diameter, length, and chirality, is the first step to realize their advanced applications in electrical and optical devices, transparent conductive films, and high-performance field-effect transistors. Preferential growth of short aligned, metallic-rich SWCNTs is a great challenge to the carbon nanotube community. We report the bulk preferential growth of short aligned SWCNTs from perpendicular Mo-containing FeMgAl layered double hydroxide (LDH) film by a facile thermal chemical vapor deposition with CH(4) as carbon source. The growth of the short aligned SWCNTs showed a decreased growth velocity with an initial value of 1.9 nm s(-1). Such a low growth velocity made it possible to get aligned SWCNTs shorter than 1 ?m with a growth duration less than 15 min. Raman spectra with different excitation wavelengths indicated that the as-grown short aligned SWCNTs showed high selectivity of metallic SWCNTs. Various kinds of materials, such as mica, quartz, Cu foil, and carbon fiber, can serve as the substrates for the growth of perpendicular FeMoMgAl LDH films and also the growth of the short aligned SWCNTs subsequently. These findings highlight the easy route for bulk preferential growth of aligned metallic-rich SWCNTs with well defined length for further bulk characterization and applications. PMID:22373876

Zhao, Meng-Qiang; Tian, Gui-Li; Zhang, Qiang; Huang, Jia-Qi; Nie, Jing-Qi; Wei, Fei

2012-04-01

31

Lithographically Cut Single-Walled Carbon Nanotubes: Controlling Length  

E-print Network

Lithographically Cut Single-Walled Carbon Nanotubes: Controlling Length Distribution ambient conditions. Although single-walled carbon nanotubes (SWNTs) exhibit many favorable electronic 19880 Received April 11, 2003; Revised Manuscript Received June 9, 2003 ABSTRACT Single-walled carbon

Rollins, Andrew M.

32

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

NASA Astrophysics Data System (ADS)

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.

Kharlamova, M. V.

2014-11-01

33

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

NASA Astrophysics Data System (ADS)

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.

Kharlamova, M. V.

2015-01-01

34

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

35

1. CVD SWNT single-walled carbon  

E-print Network

1. CVD SWNT single-walled carbon nanotube, SWNT SWNT 1993 Iijima SWNT 1) 2) SWNT SWNT 6 SWNT SWNT SWNT 1000 C carbon fiber multi-walled carbon nanotube, MWNT chemical vapor. Sugime, et al : Carbon, 47, 234 (2009). 15) Y. Murakami, et al : Chem. Phys. Lett., 377, 49 (2003). 16) Y

Maruyama, Shigeo

36

Single-walled carbon nanohorns and their applications  

Microsoft Academic Search

Single-walled carbon nanohorns (SWCNHs) are horn-shaped single-walled tubules with a conical tip. They are generally synthesized by laser ablation of pure graphite without using metal catalyst with high production rate and high yield, and typically form radial aggregates. SWCNHs are essentially metal-free and very pure, which avoids cumbersome purification and makes them user-friendly and environmentally benign. Currently, SWCNHs have been

Shuyun Zhu; Guobao Xu

2010-01-01

37

Hydrogenation of single-walled carbon nanotubes  

E-print Network

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.

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

2005-10-14

38

2004 11 -2-(Single-Walled Carbon  

E-print Network

~~ 2004 11 -2- 1. (Single-Walled Carbon Nanotubes, SWNTs) 13 nm [1] SWNT van Hove [1., Physical Properties of Carbon Nanotubes, Imperial College Press, London, 1998. (2004). [2] S. Maruyama et. Murakami et al., Carbon, to be submitted. [12]Y. Shibuta et al., Chem. Phys. Lett., 382 (2003) 381. [13]Y

Maruyama, Shigeo

39

Preferential growth of short aligned, metallic-rich single-walled carbon nanotubes from perpendicular layered double hydroxide film  

NASA Astrophysics Data System (ADS)

Direct bulk growth of single-walled carbon nanotubes (SWCNTs) with required properties, such as diameter, length, and chirality, is the first step to realize their advanced applications in electrical and optical devices, transparent conductive films, and high-performance field-effect transistors. Preferential growth of short aligned, metallic-rich SWCNTs is a great challenge to the carbon nanotube community. We report the bulk preferential growth of short aligned SWCNTs from perpendicular Mo-containing FeMgAl layered double hydroxide (LDH) film by a facile thermal chemical vapor deposition with CH4 as carbon source. The growth of the short aligned SWCNTs showed a decreased growth velocity with an initial value of 1.9 nm s-1. Such a low growth velocity made it possible to get aligned SWCNTs shorter than 1 ?m with a growth duration less than 15 min. Raman spectra with different excitation wavelengths indicated that the as-grown short aligned SWCNTs showed high selectivity of metallic SWCNTs. Various kinds of materials, such as mica, quartz, Cu foil, and carbon fiber, can serve as the substrates for the growth of perpendicular FeMoMgAl LDH films and also the growth of the short aligned SWCNTs subsequently. These findings highlight the easy route for bulk preferential growth of aligned metallic-rich SWCNTs with well defined length for further bulk characterization and applications.Direct bulk growth of single-walled carbon nanotubes (SWCNTs) with required properties, such as diameter, length, and chirality, is the first step to realize their advanced applications in electrical and optical devices, transparent conductive films, and high-performance field-effect transistors. Preferential growth of short aligned, metallic-rich SWCNTs is a great challenge to the carbon nanotube community. We report the bulk preferential growth of short aligned SWCNTs from perpendicular Mo-containing FeMgAl layered double hydroxide (LDH) film by a facile thermal chemical vapor deposition with CH4 as carbon source. The growth of the short aligned SWCNTs showed a decreased growth velocity with an initial value of 1.9 nm s-1. Such a low growth velocity made it possible to get aligned SWCNTs shorter than 1 ?m with a growth duration less than 15 min. Raman spectra with different excitation wavelengths indicated that the as-grown short aligned SWCNTs showed high selectivity of metallic SWCNTs. Various kinds of materials, such as mica, quartz, Cu foil, and carbon fiber, can serve as the substrates for the growth of perpendicular FeMoMgAl LDH films and also the growth of the short aligned SWCNTs subsequently. These findings highlight the easy route for bulk preferential growth of aligned metallic-rich SWCNTs with well defined length for further bulk characterization and applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr00043a

Zhao, Meng-Qiang; Tian, Gui-Li; Zhang, Qiang; Huang, Jia-Qi; Nie, Jing-Qi; Wei, Fei

2012-03-01

40

Identification of the structures of superlong oriented single-walled carbon nanotube arrays by electrodeposition of metal and Raman spectroscopy.  

PubMed

In this Communication, we have demonstrated a facile and effective approach to identify the structure of the superlong well-aligned single-walled carbon nanotubes (SWNTs) by the combination of electrodeposition of metal (Ag) with Raman spectroscopy. The suitable density and the visibility of the Ag-deposited long oriented nanotubes make it possible to acquire Raman spectra from isolated individual nanotubes very easily. The results reveal that the well-oriented SWNT arrays on SiO2/Si wafer fabricated by EtOH chemical vapor deposition using Fe/Mo nanoparticles as catalyst exhibit a low percentage of metallic SWNTs (5%). Among other SWNTs about 62.3% are semiconducting SWNTs, and a small amount of nanotubes are quasimetallic. About 32% are a so-called quasi-insulator, which is caused inevitably by the defects during growth. Furthermore, the structural uniformity of the long SWNTs can be also evaluated by the deposition of Ag along the length and Raman spectroscopy. This method also provides an approach to deposit other metals on long SWNTs, which could have various potential applications such as for use as sensors, etc. More importantly, this facile method can be applied to long SWNT arrays fabricated from other different catalytic systems so that the relationship between the growth conditions and the structures of SWNTs are expected to be ruled out. PMID:18702491

Huang, Shaoming; Qian, Yong; Chen, Jiangying; Cai, Qiran; Wan, Li; Wang, Shun; Hu, Wenbing

2008-09-10

41

3-D perpendicular assembly of single walled carbon nanotubes for complimentary metal oxide semiconductor interconnects.  

PubMed

Due to their superior electrical properties such as high current density and ballistic transport, carbon nanotubes (CNT) are considered as a potential candidate for future Very Large Scale Integration (VLSI) interconnects. However, direct incorporation of CNTs into Complimentary Metal Oxide Semiconductor (CMOS) architecture by conventional chemical vapor deposition (CVD) growth method is problematic since it requires high temperatures that might damage insulators and doped semiconductors in the underlying CMOS circuits. In this paper, we present a directed assembly method to assemble aligned CNTs into pre-patterned vias and perpendicular to the substrate. A dynamic electric field with a static offset is applied to provide the force needed for directing the SWNT assembly. It is also shown that by adjusting assembly parameters the density of the assembled CNTs can be significantly enhanced. This highly scalable directed assembly method is conducted at room temperature and pressure and is accomplished in a few minutes. I-V characterization of the assembled CNTs was conducted using a Zyvex nanomanipulator in a scanning electron microscope (SEM) and the measured value of the resistance is found to be 270 komega s. PMID:24734611

Kim, Tae-Hoon; Yilmaz, Cihan; Somu, Sivasubramanian; Busnaina, Ahmed

2014-05-01

42

Fluidic patch antenna based on liquid metal alloy/single-wall carbon-nanotubes operating at the S-band frequency  

E-print Network

., 151 Hymus Boulevard, Montreal H9R 1E9, Canada 2 Center for Applied Research on Polymers (CREPEC-band frequency (4GHz). The antenna prototype is composed of a nanocomposite material made by a liquid metal alloy (eutectic gallium indium) blended with single-wall carbon-nanotube (SWNTs). The nanocomposite

43

Molecular Dynamics Simulation of Nucleation Process of Single-Walled Carbon Nanotubes  

E-print Network

Molecular Dynamics Simulation of Nucleation Process of Single-Walled Carbon Nanotubes YASUSHI SHIBUTA, SHIGEO MARUYAMA Nucleation process of single-walled carbon nanotubes by the catalytic chemical on these potentials, interactions between catalytic metals and carbon atoms on formation process of single-walled

Maruyama, Shigeo

44

NMR Study of Single Wall Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

^13C NMR experiments have been carried out for single-wall carbon nanotubes (SWNTs), which were produced by using non-ferromagnetic Rh-Pt mixed catalysts. Hydrogen peroxide was used to remove amorphous carbon particles in the raw soot almost perfectly. From the line shape analysis of the ^13C spectrum measured at 100.1MHz(9.4 T), the shift tensor was evaluated to be (?_11,?_22,?_33)=(192,186,132) ppm. Small anisotropic value(??= -57 ppm) compared with that reported for MWNTs suggests that this SWNTs sample contains metallic tubes with larger electronic density of states at the Fermi level than that of multi-wall carbon nanotubes(MWNTs) sample. We also performed ^13C spin lattice relaxation time(T_1) . It is found that SWNTs follows a Korringa-like behavior(T_1^o T=940^o60(sec.K)) in the temperature region between 4.2 K and 100 K. Alkali metal-doping effects and hydrogen uptake effects will be discussed.

Ogata, Hironori; Bandow, Syunji; Kuno, Shogo; Saito, Yahachi

2000-03-01

45

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

NASA Astrophysics Data System (ADS)

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.

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

46

Electrically robust metal nanowire network formation by in-situ interconnection with single-walled carbon nanotubes.  

PubMed

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

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

47

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

PubMed Central

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

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

48

Separation of the semiconducting and the metallic types of single-wall carbon nanotube by electrophoresis method  

NASA Astrophysics Data System (ADS)

This study was to separate the semiconducting and the metallic types of single-wall carbon nanotubes (SWNTs) by electrophoresis with the different dispersants that are deoxyribonucleic acid (DNA), Triton X-100 and sodium dodecyl sulfate (SDS), respectively. The dispersants modify the surface of SWNTs and disperse in the de-ionized water. and used electric power supply 100V to electrophoresis. However, the different dispersants such as DNA, Triton X-100 and SDS coated on SWNTs have different property of electronic field. Hence, in the same power of electrophoresis was applied to separate out s-SWNT and m-SWNT from the raw-SWNT. In addition, the DNA base pair and quantitative can be determine by electrophoresis with standard mark. The electrophoresis has features that low sample need, low energy required and efficiently for this fabrication. The results of Raman spectrum could verify the separation efficiency and determine the electrical of the samples with the radial breathing mode (RBM, 100-400cm-1) of SWNT. After the dispersion process with DNA, a new peak (~1450 cm-1) has been observed between D-band (~1350cm-1) and G-band (~1550cm-1) that also can identify s-SWNT and m-SWNT.

Chen, Hsi-Chao; Yen, Chih-Feng; Chen, Guan-Jhen; Hsiao, Tzu-Ti; Zhou, Yang; Huang, Kuo-Ting; Lee, Hsin-Ta; Yang, Wan-Ting

2014-09-01

49

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

50

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

NASA Astrophysics Data System (ADS)

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.

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

51

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

E-print Network

Coulomb blockade in suspended Si3N4-coated single-walled carbon nanotubes H. B. Peng and J. A of suspended single-walled carbon nanotubes with high-quality dielectric silicon nitride has been obtained nanotubes as templates.3,4 The coating behavior of a variety of metals on suspended single-walled nanotubes

Golovchenko, Jene A.

52

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

SciTech Connect

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.

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

53

Molecular discriminators using single wall carbon nanotubes  

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

54

Single-walled carbon nanotubes as excitonic optical wires  

Microsoft Academic Search

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

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

2011-01-01

55

Progress towards monodisperse single-walled carbon nanotubes  

Microsoft Academic Search

The defining characteristic of a nanomaterial is that its properties vary as a function of its size. This size dependence can be clearly observed in single-walled carbon nanotubes, where changes in structure at the atomic scale can modify the electronic and optical properties of these materials in a discontinuous manner (for example, changing metallic nanotubes to semiconducting nanotubes and vice

Mark C. Hersam

2008-01-01

56

Characterization of single wall carbon nanotubes by nonane preadsorption  

E-print Network

Characterization of single wall carbon nanotubes by nonane preadsorption Oleg Byl a , Jie Liu b The preferential blocking of the interior adsorption sites of single walled carbon nanotubes (SWNTs) by n the result of our study of nitro- gen adsorption on single walled carbon nanotubes where the interior sites

Liu, Jie

57

PREPARATION OF SINGLE-WALLED CARBON NANOTUBE SAMPLES FOR MICROPHOTOLUMINESCENCE  

E-print Network

PREPARATION OF SINGLE-WALLED CARBON NANOTUBE SAMPLES FOR MICROPHOTOLUMINESCENCE C. Martinez1, 2 , T the photoluminescence (PL) signal emitted from individual single-walled carbon nanotubes (SWCNTs). PL from SWCNTs & Education Program (OISE-0968405). Preparation of Single-Walled Carbon Nanotube Samples

Mellor-Crummey, John

58

Symmetry of electron diffraction from single-walled carbon nanotubes  

E-print Network

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

Qin, Lu-Chang

59

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 of individual single-walled carbon nanotubes and nanotube junctions by AFM. We present ma- nipulation experiments on individual single-walled carbon nanotubes, where the tip of an AFM is used to change

60

Individual Single-Walled Carbon Nanotubes as Nanoelectrodes for  

E-print Network

Individual Single-Walled Carbon Nanotubes as Nanoelectrodes for Electrochemistry Iddo Heller, Jing single-walled carbon nanotubes (SWNTs) as nanoelectrodes for electrochemistry. SWNTs were contacted data.6 Here we explore the use of individual single-walled carbon nanotubes (SWNTs) as electrodes

Dekker, Cees

61

Photoconductivity of single-walled carbon nanotubes under CW illumination.  

E-print Network

Photoconductivity of single-walled carbon nanotubes under CW illumination. I. A. Levitsky Emitech placed on the electronic and optical properties of single-walled carbon nanotubes (SWNTs) is associated of single-walled carbon nanotubes in the NIR and far-IR spectral range. II. EXPERIMENT SWNTs were

Euler, William B.

62

Simulations of nanosensors based on single walled carbon nanotubes  

E-print Network

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 Chowdhury et al [17] examined the potential of single-walled carbon nanotubes (SWCNTs) as mass sensors

Adler, Joan

63

Optical microcavity with semiconducting single-wall carbon nanotubes  

E-print Network

Optical microcavity with semiconducting single- wall carbon nanotubes Etienne Gaufrès,1 Nicolas-Perot microcavities based on semiconducting single-wall carbon nanotubes with a quality factor of 160. We. Meunier, P. Desjardins, D. Ménard and R. Martel, "Electroluminescence from single-wall carbon nanotube

Paris-Sud XI, Université de

64

Enhanced Cellular Activation with Single Walled Carbon Nanotube Bundles  

E-print Network

Enhanced Cellular Activation with Single Walled Carbon Nanotube Bundles Presenting Antibody Stimuli the body using single walled carbon nanotube (SWNT) bundles presenting antibody stimuli. Owing to the large of lymphocytes, useful for basic science applications and clinical immunotherapy. Single walled carbon nanotubes

Fahmy, Tarek

65

Raman Measurements on Electrochemically Doped Single-Walled Carbon Nanotubes  

E-print Network

Raman Measurements on Electrochemically Doped Single-Walled Carbon Nanotubes P. M. Rafailov, M and studied the Raman response of electro- chemically doped single-walled carbon nanotubes (SWNT) using is proposed. Introduction. Single-wall carbon nanotubes (SWNT) are novel one-dimensional nanostructures

Nabben, Reinhard

66

Absorption spectroscopy of individual single-walled carbon nanotubes  

E-print Network

Absorption spectroscopy of individual single-walled carbon nanotubes Stéphane Berciaud,a Laurent, published in "Nano Letters 7, 5 (2007) 1203-1207" DOI : 10.1021/nl062933k #12;Single-walled carbon nanotubes and Environmental Nanotechnology, Rice University, Houston, TX 77005, USA Current methods for producing single-walled

Boyer, Edmond

67

Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes  

E-print Network

Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes B. J. LeRoy,a) S. G measurements on single-wall carbon nano- tubes SWCNTs show Coulomb blockade1,2 and Luttinger liquid behavior.3 online 7 May 2004 We have performed low-temperature scanning tunneling microscopy measurements on single-wall

Dekker, Cees

68

Useful vacancies in Single Wall Carbon Nanotubes  

E-print Network

The electronic and structural properties of zigzag and armchair single-wall carbon nanotubes (SWCNT) with a single vacancy or two vacancies located at various distances have been obtained within the frame of the Density Function Theory (DFT) and a Molecular Dynamics method. It is found that the vacancy defects interact at long ranges in armchair SWCNTs unlike the short-range interaction in zigzag SWCNTs. The density of states for different vacancy densities shows that the local energy gap shrinks with the vacancy density increase. This and other results of the investigation provide insight into understanding the relation between the local deformation of a defective nanotube and its measurable electronic properties.

Proykova, A; Li, Feng Yin

2008-01-01

69

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

SciTech Connect

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.

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

2013-03-26

70

Synthesis and Characterization of Single-Walled Carbon Nanotubes  

Microsoft Academic Search

Single-walled carbon nanotubes (SWNTs) were synthesized by ablating a graphite target mixed with metal catalysts by either the primary (1064nm) or the second harmonic (532nm) beam of a pulsed Nd:YAG laser at high temperature. Materials synthesized under different conditions were characterized by x-ray diffraction, AFM, TEM, ESR, and micro-Raman techniques. The morphology of the materials produced is similar to those

C. Bower; O. Zhou; L. Jin; S. Paulson; R. Superfine; L. McNeil; S. Suzuki; K. Tanigaki

1998-01-01

71

Photon enhanced aggregation of single walled carbon nanotube dispersions  

SciTech Connect

The authors describe a photon enhanced aggregation of dispersed single walled carbon nanotubes in the presence of electron transfer reagents. A recently synthesized metallodendrimer strongly and specifically binds to the ends of the nanotubes. Upon optical excitation, of the metal to ligand charge transfer absorption, of various ruthenium complexes, the nanotubes rapidly coagulate. The electron transfer mechanism is consistent with observed photon enhancement process. These results support a directed self-assembly paradigm for nanostructured materials.

Chaturvedi, H.; Poler, J. C. [Department of Chemistry, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, North Carolina 28223-0001 and Center for Optoelectronics and Optical Communications, University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, North Carolina 28223-0001 (United States)

2007-05-28

72

Direct imaging of single-walled carbon nanotubes in cells  

Microsoft Academic Search

The development of single-walled carbon nanotubes for various biomedical applications is an area of great promise. However, the contradictory data on the toxic effects of single-walled carbon nanotubes highlight the need for alternative ways to study their uptake and cytotoxic effects in cells. Single-walled carbon nanotubes have been shown to be acutely toxic in a number of types of cells,

Alexandra E. Porter; Mhairi Gass; Karin Muller; Jeremy N. Skepper; Paul A. Midgley; Mark Welland

2007-01-01

73

Single-walled carbon nanohorns and their applications  

NASA Astrophysics Data System (ADS)

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

Zhu, Shuyun; Xu, Guobao

2010-12-01

74

Effective wall thickness of a single-walled carbon nanotube  

Microsoft Academic Search

This paper investigates the effective wall thickness of a single-walled carbon nanotube, a critical quantity for any research in mechanics and property characterization of carbon nanotubes. To this end, the response of a bundle of single-walled carbon nanotubes to external hydrostatic pressure was modeled using the ring theory of continuum mechanics. The model predicted that the equivalent thickness should be

T. Vodenitcharova; L. C. Zhang

2003-01-01

75

Electrochemical and Raman measurements on single-walled carbon nanotubes  

E-print Network

Electrochemical and Raman measurements on single-walled carbon nanotubes M. Stoll a,*, P. Introduction Single-wall carbon nanotubes (SWNTs) are novel one-dimensional nanostructures with prom- ising performed on a carbon nanotube mat as a working electrode using different salt solutions. The gravimetric

Nabben, Reinhard

76

Oblique incidence scattering from single-walled carbon nanotubes  

SciTech Connect

A theory of electromagnetic wave scattering by metallic single-walled carbon nanotubes at oblique incidence is provided using modal techniques. Electronic excitations on the nanotube's surface are modeled by an infinitesimally thin layer of free-electron gas described previously by means of the linearized fluid theory. The current induced on the surface of the nanotube and the echo width of both transverse magnetic and transverse electric uniform plane wave by system at oblique incidences is obtained. Numerical results show that the optical wave scattering by carbon nanotubes strongly depends on the nanotube's radius and angle of incidence wave with system.

Moradi, Afshin [Department of Nano Science, Kermanshah University of Technology, 67178-63766 Kermanshah, Iran and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), 19395-5531 Tehran (Iran, Islamic Republic of)

2010-03-15

77

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

78

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

PubMed

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

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

2015-01-01

79

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

SciTech Connect

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

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

2009-06-22

80

Exohydrogenated single-wall carbon nanotubes T. Yildirim,1  

E-print Network

Exohydrogenated single-wall carbon nanotubes T. Yildirim,1 O. Gu¨lseren,1,2 and S. Ciraci3 1 NIST exohydrogenated zigzag (n,0) and armchair (n,n) single-wall carbon nanotubes (CnHn), polyhedral molecules to the radius of a 8,8 nanotube, with binding energies proportional to 1/R. Attaching a single hydrogen to any

Yildirim, Taner

81

Metal impurities provide useful tracers for identifying exposures to airborne single-wall carbon nanotubes released from work-related processes  

NASA Astrophysics Data System (ADS)

This study investigated the use of metal impurities in single-wall carbon nanotubes (SWCNT) as potential tracers to distinguish engineered nanomaterials from background aerosols. TEM and SEM were used to characterize parent material and aerosolized agglomerates collected on PTFE filters using a cascade impactor. SEM image analysis indicated that the SWCNT agglomerates contained about 45% amorphous carbon and backscatter electron analysis indicated that metal impurities were concentrated within the amorphous carbon component. Two elements present as impurities (Y and Ni) were selected as appropriate tracers in this case as their concentrations were found to be highly elevated in the SWCNT parent material (% range) compared to ambient air particles (?g/g range), and background air concentrations were below detection limits for both elements. Bioaccessibility was also determined using physiologically-based extractions at pH conditions relevant to both ingestion and inhalation pathways. A portable wet electrostatic precipitation system effectively captured airborne Y and Ni released during sieving processes, in proportions similar to the bulk sample. These observations support the potential for catalysts and other metal impurities in carbon nanotubes to serve as tracers that uniquely identify emissions at source, after an initial analysis to select appropriate tracers.

Rasmussen, Pat E.; Jayawardene, Innocent; Gardner, H. David; Chénier, Marc; Levesque, Christine; Niu, Jianjun

2013-04-01

82

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)

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.

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

2014-09-01

83

Controlled synthesis of single-walled carbon nanotubes.  

E-print Network

??The chemistry and applications of carbon nanotubes are critically dependent on nanotube chirality. To date, no one has demonstrated chirality-selective synthesis of single-walled carbon nanotubes… (more)

McJilton, Laura Anne

2009-01-01

84

Electrochemically Functionalized Single-Walled Carbon Nanotube Ting Zhang,a  

E-print Network

Full Paper Electrochemically Functionalized Single-Walled Carbon Nanotube Gas Sensor Ting Zhang using single-walled carbon nanotubes (SWNT) electrochemically functionalized with polyaniline (PANI sensitivity, detection limit, and reproducibility. Keywords: Single-walled carbon nanotubes, Conducting

85

Single wall carbon nanotubes: Separation and applications to biosensors  

NASA Astrophysics Data System (ADS)

Single wall carbon nanotubes uniquely exhibit one-dimensional quantum confined properties by being either semiconducting (sem-) or metallic (met-) depending on their atomic arrangements. The stochastic nature of SWNT growth renders met-:sem- ratio being 1:2 and diameter range being distributed in 0.4-2nm with a close-packed bundle configuration. For many high-performance devices using SWNTs, acquiring well-separated and/or isolated single-diameter, metallicity and/or chirality nanotubes is greatly in demand. Recently, the bulk separation and/or enrichment of single wall carbon nanotubes (SWNTs) according to type (or otherwise termed "metallicity") and diameter (dt) has become possible. This thesis presents a route to probe mechanisms in diameter and metallicity dependent separation of SWNTs. A systematic analysis tool, that enables the quantitative examination of resonance Raman spectra, is established from nanotube samples that have been separated according to metallicity and d t via an octadecylamine mediated protocol. This protocol uses the relative changes in the integrated intensities of the radial-breathing mode region for the quantitative evaluation. By further establishing the physicochemical properties of charge-stabilized SWNT dispersions in polar aprotic media (i.e. N,N-dimethylformide) a more detailed description of the underlying separation mechanism is given. Here, I use resonance Raman spectroscopy (RRS) as a tool to probe SWNT redox chemistry. The Gibbs free energy, modeled by calculating the charge-loss from the (n,m)-dependent integrated density of states across the corresponding jump in the redox potential, is utilized to support the separation mechanism. Additionally, the evaluation of SWNT forest platforms for amperometric protein immunoassays is presented. Horseradish peroxidase is used as the label and the sensing signals are acquired from electrochemical reduction of hydrogen peroxide. Specific studies on human serum albumin and prostate specific antigen detection are explained. Signal amplification strategies are introduced by using redox mediator, enzyme, and enzyme-decorated carbon nanotubes.

Kim, Sang Nyon

86

Liquid crystal behavior of single wall carbon nanotubes  

Microsoft Academic Search

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

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

2010-01-01

87

Superhard phase composed of single-wall carbon nanotubes  

Microsoft Academic Search

Single-wall carbon nanotubes (SWNT's) have been studied under pressure up to 55 GPa. We report experimental data on irreversible changes of mechanical and structure properties of SWNT under pressure. The new superhard phase (SP-SWNT) composed of single-wall carbon nanotubes has been studied which exhibits a bulk modulus exceeding or comparable with diamond and hardness belongs to the range between cubic

M. Popov; M. Kyotani; R. J. Nemanich; Y. Koga

2002-01-01

88

Center for Applications of Single-Walled Carbon Nanotubes  

SciTech Connect

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

Resasco, Daniel E

2008-02-21

89

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

Microsoft Academic Search

Molecular nanowires inside single-walled carbon nanotubes are produced by capillary filling. Bismuth was drawn into single-walled carbon nanotubes, where it formed single-crystal nanowires of nanometer dimensions. Metal was introduced in its gas, solution, and solid phases, with the solution phase process the most efficient and versatile method of filling. The majority of fillings are one-dimensional nanowires with high length to

Ching-Hwa Kiang; Jong-Suk Choi; Todd T. Tran; Alfred Dirk Bacher

1999-01-01

90

Absorption spectroscopy of individual single-walled carbon nanotubes  

E-print Network

Current methods for producing single-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 offer the possibility to examine these heterogeneities provided that both SWNT species are equally well detected. Here, we used photothermal heterodyne detection to record absorption images and spectra of individual SWNTs. Because this photothermal method relies only on light absorption, it readily detects metallic nanotubes as well as the emissive semiconducting species. The first and second optical transitions in individual semicontucting nanotubes have been probed. Comparison between the emission and absorption spectra of the lowest-lying optical transition reveal mainly small Stokes shifts. Side bands in the near-infrared absorption spectra are observed and assigned to exciton-phonon bound states. No such sidebands are detected around the lowest transiti...

Berciaud, Stéphane; Poulin, Philippe; Weisman, R Bruce; Lounis, Brahim

2007-01-01

91

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

E-print Network

of the catalytic metal atoms in the formation process is critical for future control of the diameter and chiralityBond-order potential for transition metal carbide cluster for the growth simulation of a single, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan 2 Department of Mechanical Engineering

Maruyama, Shigeo

92

Thermoelectric power of a single-walled carbon nanotubes rope.  

PubMed

In this work, a rope of single-walled carbon nanotubes is prepared by using a diamond wire drawing die. At atmospheric condition, the electrical conductance and the thermoelectric voltage of single-walled carbon nanotubes rope have been investigated with the hot-side temperature ranging from 292 to 380 K, and cold-side temperature at 292 K. For different temperatures in the range of 292 to 380 K at hot-side, the current-voltage curves are almost parallel to each other, indicating that the electrical conductance does not change. The dynamic characteristics of voltage at positive, zero and negative current bias demonstrate that a thermoelectric voltage is induced with a direction from hot- to cold-side. The induced thermoelectric voltage shows linear dependence on the temperature difference between hot- and cold-side. The thermoelectric power of single-walled carbon nanotubes rope is found to be positive and has a value about 17.8 +/- 1.0 microV/K. This result suggests the hole-like carriers in single-walled carbon nanotubes rope. This study will pave the way for single-walled carbon nanotubes based thermoelectric devices. PMID:23646631

Yu, Fang; Hu, Lijun; Zhou, Haiqing; Qiu, Caiyu; Yang, Huaichao; Chen, Minjiang; Lu, Jianglei; Sun, Lianfeng

2013-02-01

93

Single-walled carbon nanotubes as excitonic optical wires.  

PubMed

Although metallic nanostructures are useful for nanoscale optics, all of their key optical properties are determined by their geometry. This makes it difficult to adjust these properties independently, and can restrict applications. Here we use the absolute intensity of Rayleigh scattering to show that single-walled carbon nanotubes can form ideal optical wires. The spatial distribution of the radiation scattered by the nanotubes is determined by their shape, but the intensity and spectrum of the scattered radiation are determined by exciton dynamics, quantum-dot-like optical resonances and other intrinsic properties. Moreover, the nanotubes display a uniform peak optical conductivity of approximately 8 e(2)/h, which we derive using an exciton model, suggesting universal behaviour similar to that observed in nanotube conductance. We further demonstrate a radiative coupling between two distant nanotubes, with potential applications in metamaterials and optical antennas. PMID:21170038

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

2011-01-01

94

Single-walled carbon nanotubes as excitonic optical wires  

NASA Astrophysics Data System (ADS)

Although metallic nanostructures are useful for nanoscale optics, all of their key optical properties are determined by their geometry. This makes it difficult to adjust these properties independently, and can restrict applications. Here we use the absolute intensity of Rayleigh scattering to show that single-walled carbon nanotubes can form ideal optical wires. The spatial distribution of the radiation scattered by the nanotubes is determined by their shape, but the intensity and spectrum of the scattered radiation are determined by exciton dynamics, quantum-dot-like optical resonances and other intrinsic properties. Moreover, the nanotubes display a uniform peak optical conductivity of ~8 e2/h, which we derive using an exciton model, suggesting universal behaviour similar to that observed in nanotube conductance. We further demonstrate a radiative coupling between two distant nanotubes, with potential applications in metamaterials and optical antennas.

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

2011-01-01

95

Single Wall Carbon Nanotube-Based Structural Health Sensing Materials  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

96

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

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

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

2010-01-01

97

PEM fuel cell electrodes using Single Wall Carbon Nanotubes  

Microsoft Academic Search

Single wall carbon nanotubes (SWCNT) have previously been considered potential catalyst supports in proton exchange membrane fuel cells (PEMFC) (1). Earlier research and development of SWCNT for PEMFC catalyst supports has been advanced by utilizing differing SWCNT purities and carbon blacks in differing ratios. This study validates the performance of SWCNT and introduces new concepts for SWCNT membrane fabrication.

Padraig Moloney; Chad Huffman; Micah Springer; Olga Gorelik; Pasha Nikolaev; Edward Sosa; Sivaram Arepalli; Leonard Yowell

98

Adsorption of Small Gas Molecules onto Pt-Doped Single-Walled Carbon Nanotubes Charles See Yeung, Lei Vincent Liu, and Yan Alexander Wang*  

E-print Network

Adsorption of Small Gas Molecules onto Pt-Doped Single-Walled Carbon Nanotubes Charles See Yeung The adsorption of small gaseous molecules to the metal center in Pt-doped (5,5) single-walled carbon nanotubes an application of Pt- doped single-walled carbon nanotubes as gas sensors and hope to motivate experimental work

Wang, Yan Alexander

99

Purification Procedures for Single-Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

100

Uniform Directional Alignment of Single-Walled Carbon Nanotubes in Viscous Polymer Flow  

E-print Network

Uniform Directional Alignment of Single-Walled Carbon Nanotubes in Viscous Polymer Flow Erin flow on the alignment of dispersed single-walled carbon nanotubes in polymer solutions. Two different systems were compared: Single-walled carbon nanotubes dispersed using an anionic surfactant and single-walled

Garmestani, Hamid

101

Growth of single wall carbon nanotubes from 13C isotope labelled organic solvents inside single wall carbon nanotube hosts  

Microsoft Academic Search

We present the growth of single wall carbon nanotubes (SWCNTs) from organic solvents such as benzene and toluene inside a host SWCNT. The solvents encapsulated in SWCNTs are transformed to an inner tube when subject to a heat treatment under dynamic vacuum at 1270°C. We used isotope labeling of the different carbon sources to prove that the source of the

Ferenc Simon; Hans Kuzmany

2006-01-01

102

Enhanced Raman Microprobe Imaging of Single-Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

103

Elastic properties of single-walled carbon nanotubes  

Microsoft Academic Search

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

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

2000-01-01

104

Electromagnetic Interference (EMI) Shielding of Single-Walled Carbon  

E-print Network

Electromagnetic Interference (EMI) Shielding of Single-Walled Carbon Nanotube Epoxy Composites Ning (SWNT)-polymer composites have been fabricated to evaluate the electromagnetic interference (EMI EMI shielding materials. Composites with greater than 20 dB shielding efficiency were obtained easily

Gao, Hongjun

105

A Computational Experiment on Single-Walled Carbon Nanotubes  

ERIC Educational Resources Information Center

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…

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

2013-01-01

106

Intertube Coupling in Ropes of Single-Wall Carbon Nanotubes  

Microsoft Academic Search

We investigate the coupling between individual tubes in a rope of single-wall carbon nanotubes using four probe resistance measurements. By introducing defects through the controlled sputtering of the rope we generate a strong nonmonotonic temperature dependence of the four terminal resistance. This behavior reflects the interplay between localization in the intentionally damaged tubes and coupling to undamaged tubes in the

H. Stahl; J. Appenzeller; R. Martel; Ph. Avouris; B. Lengeler

2000-01-01

107

Quantum rotation of hydrogen in single-wall carbon nanotubes  

E-print Network

, hydrogen storage sys- tems have been the focus of much recent research and development activity. A safeQuantum rotation of hydrogen in single-wall carbon nanotubes C.M. Brown a,b , T. Yildirim b , D of Standards and Technology, NIST Center for Neutron Research, Gaithersburg, MD 208991, USA c Center for Basic

Yildirim, Taner

108

Electronic Raman Scattering On Individual Semiconducting Single Walled Carbon Nanotubes  

PubMed Central

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

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

2014-01-01

109

Macroscopic, Neat, Single-Walled Carbon Nanotube Fibers  

Microsoft Academic Search

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical

Lars M. Ericson; Hua Fan; Haiqing Peng; Virginia A. Davis; Wei Zhou; Joseph Sulpizio; Yuhuang Wang; Richard Booker; Juraj Vavro; Csaba Guthy; A. Nicholas G. Parra-Vasquez; Myung Jong Kim; Sivarajan Ramesh; Rajesh K. Saini; Carter Kittrell; Gerry Lavin; Howard Schmidt; W. Wade Adams; W. E. Billups; Matteo Pasquali; Wen-Fang Hwang; Robert H. Hauge; John E. Fischer; Richard E. Smalley

2004-01-01

110

Chemical Sensing with Polyaniline Coated Single-Walled Carbon Nanotubes  

SciTech Connect

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

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

2011-01-25

111

Flexural wave propagation in single-walled carbon nanotubes  

Microsoft Academic Search

The paper presents the study on the flexural wave propagation in a single-walled carbon nanotube through the use of the continuum mechanics and the molecular dynamics simulation based on the Terroff-Brenner potential. The study focuses on the wave dispersion caused not only by the rotary inertia and the shear deformation in the model of a traditional Timoshenko beam, but also

Lifeng Wang; Haiyan Hu

2005-01-01

112

Optical properties of single-wall carbon nanotubes  

Microsoft Academic Search

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

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

1999-01-01

113

Raman spectroscopy on isolated single wall carbon nanotubes  

Microsoft Academic Search

A review is presented on the resonance Raman spectra from one isolated single wall carbon nanotube. The reasons why it is possible to observe the spectrum from only one nanotube are given and the important structural information that is provided by single nanotube spectroscopy is discussed. Emphasis is given to the new physics revealed by the various phonon features found

M. S. Dresselhaus; G. Dresselhaus; A. Jorio; A. G. Souza Filho; R. Saito

2002-01-01

114

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

E-print Network

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

Maruyama, Shigeo

115

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

NASA Astrophysics Data System (ADS)

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.

Wang, Guo; Huang, Yuanhe

2012-10-01

116

Thermionic Emission of Single-Wall Carbon Nanotubes Measured  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

117

Chirality Characterization of Dispersed Single Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

118

Production of single-walled carbon nanotube grids  

DOEpatents

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.

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

2013-12-03

119

Doping single-walled carbon nanotubes with surfactant peptides containing electron-donor substituents  

E-print Network

Doping single-walled carbon nanotubes with surfactant peptides containing electron of single-walled carbon nanotubes (SWCNTs) in nanoelectronics has created much interest as these materials possess remarkable intrinsic electronic properties. For exam- ple, carbon nanotubes permit ballistic

Nielsen, Steven O.

120

Spectroscopy-Based Characterization of Single Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

121

Solid–liquid–solid growth mechanism of single-wall carbon nanotubes  

Microsoft Academic Search

Reasons are presented which suggest that the liquefaction of the catalytic particles is a decisive condition for formation of single wall carbon nanotubes (SWNTs) by physical synthesis techniques. It is argued that the SWNT growth mechanism is a kind of solid–liquid–solid graphitization of amorphous carbon or other imperfect carbon forms catalyzed by molten supersaturated carbon–metal nanoparticles. The assumption of low

A Gorbunov; O Jost; W Pompe; A Graff

2002-01-01

122

Structure changes of single-wall carbon nanotubes and single-wall carbon nanohorns caused by heat treatment  

Microsoft Academic Search

Raman spectra and transmission electron microscope images showed that diameter enlargement of HiPco, a kind of single-wall carbon nanotube, accompanied by tube–wall corrugation was caused by heat treatment (HT) at 1000 to 1700°C. Further enlargement accompanied by straightening of the tube walls and incorporation of carbon fragments within the tubes became obvious after HT at 1800 to 1900°C. The transformation

M. Yudasaka; T. Ichihashi; D. Kasuya; H. Kataura; S. Iijima

2003-01-01

123

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

NASA Astrophysics Data System (ADS)

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

Ryu, Koungmin

124

Fabrication of stretchable single-walled carbon nanotube logic devices.  

PubMed

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

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

2014-07-01

125

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

E-print Network

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

Maruyama, Shigeo

126

Efficient CVD Growth of Single-Walled Carbon Nanotubes on Surfaces Using  

E-print Network

Efficient CVD Growth of Single-Walled Carbon Nanotubes on Surfaces Using Carbon Monoxide Precursor; Revised Manuscript Received June 26, 2002 ABSTRACT Single Walled carbon nanotubes (SWNTs) were grown. Since their discovery, single-walled carbon nanotubes (SWNTs) have been heavily studied owing

Finkelstein, Gleb

127

Supporting Information to: Single-Molecule Electrocatalysis by Single-Walled Carbon Nanotubes  

E-print Network

S1 Supporting Information to: Single-Molecule Electrocatalysis by Single-Walled Carbon Nanotubes. Experimental Methods I.1. Purification of SWNTs. The single-walled carbon nanotubes were purchased from Carbon Nanotechnologies Incorporated (Purified HiPCO single-walled carbon nanotubes). These SWNTs have an average diameter

Chen, Peng

128

Modified Single-Wall Carbon Nanotubes for Reinforce Thermoplastic Polyimide  

NASA Technical Reports Server (NTRS)

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.

Lebron-COlon, Marisabel; Meador, Michael A.

2006-01-01

129

Ambipolar Electrical Transport in Semiconducting Single-Wall Carbon Nanotubes  

Microsoft Academic Search

Ambipolar electrical transport is reported in single-wall carbon nanotube (SWNT) field-effect transistors. In particular, the properties of SWNT junctions to TiC are discussed in detail. The carbide-nanotube junctions are abrupt and robust. In contrast to planar junctions, these contacts present low resistance for the injection of both p- and n-type carriers-the apparent barrier height of the junction is modified by

R. Martel; V. Derycke; C. Lavoie; J. Appenzeller; K. K. Chan; J. Tersoff; Ph. Avouris

2001-01-01

130

Ultrafast optical spectroscopy of single-walled carbon nanotubes  

Microsoft Academic Search

Wavelength-dependent, near-infrared pump-probe study of micelle-suspended Single-Walled Carbon Nanotubes (SWCNTs) whose linear absorption spectra show chirality-assigned peaks is presented. Two distinct relaxation regimes were observed: fast (0.3--1.2 ps) and slow (5--20 ps). The slow component, which has previously been unobserved in pump-probe measurements of bundled tubes, was resonantly enhanced whenever the pump photon energy matched with an interband absorption peak,

Gordana Ostojic

2004-01-01

131

Functionalized single-walled carbon nanohorns for electrochemical biosensing  

Microsoft Academic Search

Single-walled carbon nanohorns (SWNHs), distinguished by their high purity and distinct structure, were noncovalently functionalized with poly(sodium 4-styrenesulfonate). The functionalized SWNHs were characterized by scanning electron microscopy, atomic force microscopy, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetry. Heme protein myoglobin was adsorbed onto surface of functionalized SWNHs to prepare electrochemical biosensor. Surface assembly process and direct electrochemistry

Xiaoqing Liu; Haijuan Li; Fuan Wang; Shuyun Zhu; Yuling Wang; Guobao Xu

2010-01-01

132

Reversible separation of single-walled carbon nanotubes in bundles  

SciTech Connect

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

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

2008-08-25

133

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

E-print Network

1 Growth mechanism of single-walled carbon nanotube from catalytic reaction inside carbon nanotube shiomi@photon.t.u-tokyo.ac.jp, maruyama@photon.t.u-tokyo.ac.jp RECEIVED DATE (to be automatically of a single- walled carbon nanotube (SWNT) inside a template SWNT, i.e. formation of a double-walled carbon

Maruyama, Shigeo

134

Removal of amorphous carbon for the efficient sidewall functionalisation of single-walled carbon nanotubes{  

E-print Network

of a sample of as-made single-walled carbon nanotubes (SWNTs) with nitric acid produces a uniformRemoval of amorphous carbon for the efficient sidewall functionalisation of single-walled carbon DOI: 10.1039/b712614j The sidewall functionalisation of carbon nanotubes using the standard nitric

Davis, Ben G.

135

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

E-print Network

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

Park, J. S.

136

Nose–Hoover thermostat length effect on thermal conductivity of single wall carbon nanotubes  

Microsoft Academic Search

Non-equilibrium molecular dynamics simulations are used to determine the thermal conductivities of single wall carbon nanotubes. By fixing opposing ends of an armchair single wall carbon nanotube with a Nose–Hoover thermostat, the length dependence of thermal conductivities of single wall carbon nanotubes were studied in a vacuum. Specifically, single wall carbon nanotubes of 12.3nm, 24.6nm, and 36.9nm lengths with varying

Robert A. Shelly; Kasim Toprak; Yildiz Bayazitoglu

2010-01-01

137

Near-edge X-ray absorption fine structure spectroscopy-assisted purification of single-walled carbon nanotubes  

Microsoft Academic Search

Single-walled carbon nanotubes were produced by the conventional arc discharge method, and purified with a two-step treatment. First, the raw soot containing single-walled carbon nanotubes was burned up at ca. 350 °C in air to remove amorphous carbon, and then it was treated by strong acidic solvents to remove metal catalysts. Near-edge X-ray absorption fine structure spectroscopy was applied to analyze

Dong-Wei Yan; Jun Zhong; Chun-Ru Wang; Zi-Yu Wu

2007-01-01

138

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

E-print Network

. This represents the highest lateral resolution reported to date for a SWNT probe. Single-wall carbon nanotubesCorrelating AFM Probe Morphology to Image Resolution for Single-Wall Carbon Nanotube Tips Lawrence and transmission electron microscopy were used to image hundreds of single-wall carbon nanotube probes

Quake, Stephen R.

139

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

E-print Network

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

Maruyama, Shigeo

140

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

E-print Network

Single-walled carbon nanotubes as a multimodal- thermoacoustic and photoacoustic-contrast agent thermoacoustic and photoacoustic tomography. In comparison to deionized water, single-walled carbon nanotubes ex wavelength. The large contrast enhancement of single- walled carbon nanotubes was further corroborated

Wang, Lihong

141

Electrochemical gating of individual single-wall carbon nanotubes observed by electron transport measurements and resonant  

E-print Network

Electrochemical gating of individual single-wall carbon nanotubes observed by electron transport patterned lithographically on top of individual single-wall carbon nanotubes are used to gate the nanotubes and device applications.1,2 The ability to change the resistivity of a semi- conducting single-wall carbon

142

The Effect of Electrochemical Pretreatment on the Performance of Single Walled Carbon Nanotubes  

Microsoft Academic Search

In this paper, we report the effect of subsequent electrochemical anodization and cathodization subjected to single walled carbon nanotubes. The performance of the single walled carbon nano- tubes before and after activation was evaluated electrochemically using different charged redox probes and a biologically important neurotransmitter-dopamine. Further, for the first time, the sur- face of single walled carbon nanotubes before and

Subbiah Alwarappan; Shradha Prabhulkar; Andriy Durygin; Chen-Zhong Li

143

Optical circular dichroism of single-wall carbon nanotubes Ariadna Snchez-Castillo  

E-print Network

Optical circular dichroism of single-wall carbon nanotubes Ariadna Sánchez-Castillo Instituto de 2006 The circular dichroism CD spectra of single-wall carbon nanotubes are calculated using a dipole. Among nanostructures, carbon nanotubes are known to be chiral. The atomic structure of single-wall

Noguez, Cecilia

144

Enhanced Thermal Conductivity of Water with Surfactant Encapsulated and Individualized Single-Walled Carbon Nanotube Dispersions  

E-print Network

, the effective thermal conductivity of single walled carbon nanotube dispersions in water was investigated experimentally using a transient hot wire technique at room temperature. Single-walled carbon nanotubes (SWNTs with previous findings in the literature and classical theoretical models. Keywords: Single-walled carbon

Maruyama, Shigeo

145

Synthesis and Electronic Transport in Known Chirality Single Wall Carbon Nanotubes  

E-print Network

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 and unbundled single wall carbon nanotubes. Two technological applications which directly utilize nanotubes

Hone, James

146

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

E-print Network

Electrochemistry at Single-Walled Carbon Nanotubes: The Role of Band Structure and Quantum description of the kinetics of electrochemical charge transfer at single- walled carbon nanotube (SWNT material.1 Recently, there has been a large interest in using single-walled carbon nanotubes (SWNTs

Dekker, Cees

147

Modifying the Electronic Character of Single-Walled Carbon Nanotubes Through Anisotropic Polymer Interaction  

E-print Network

Modifying the Electronic Character of Single-Walled Carbon Nanotubes Through Anisotropic Polymer, single-walled carbon nanotube (SWNT)±polymer composites have received much attention due to their im that the anisotropic interaction between single-walled carbon nanotubes (SWNTs) and poly(methyl methacrylate) (PMMA

Harmon, Julie P.

148

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

E-print Network

Plasmonic Nature of the Terahertz Conductivity Peak in Single-Wall Carbon Nanotubes Qi Zhang, Erik and plasmonic properties of charge carriers in single-wall carbon nanotubes (SWCNTs) is crucial for emerging alternative explanations such as absorption due to curvature-induced gaps. KEYWORDS: Single-wall carbon

Kono, Junichiro

149

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

E-print Network

about the biotransformation potential of single-walled carbon nanotubes (SWNTs). In this study, we, and mechanical properties.1 Single-walled carbon nanotubes (SWNTs) are particularly attractive for potentialManganese Peroxidase Degrades Pristine but Not Surface-Oxidized (Carboxylated) Single-Walled Carbon

Alvarez, Pedro J.

150

Size dependent thermal conductivity of single-walled carbon nanotubes Ajing Cao and Jianmin Qu  

E-print Network

Size dependent thermal conductivity of single-walled carbon nanotubes Ajing Cao and Jianmin Qu-dependent thermal conductivity in single-walled carbon nanotubes with lengths up to micrometers at room temperature. It is found that the size-dependent thermal conductivity of single-walled carbon nanotubes can be described

Chen, Wei

151

Dissolution of Pristine Single Walled Carbon Nanotubes in Superacids by Direct Protonation  

E-print Network

ARTICLES Dissolution of Pristine Single Walled Carbon Nanotubes in Superacids by Direct Protonation Strong tube-tube van der Waal attractions that hinder the dissolution of single walled carbon nanotubes single walled carbon nanotubes (SWNTs) as individual molecular entities remains the single largest

Natelson, Douglas

152

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

E-print Network

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 a breathinglike deformation of the entire tube. This mode is unique to single-walled carbon nanotubes and is taken

Nabben, Reinhard

153

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

E-print Network

Extinction and orientational dependence of electron diffraction from single-walled carbon nanotubes dependence of electron diffraction from single-walled carbon nanotubes have been observed experimentally- dimensional graphene along a chosen tubule axis [1,2]. The atomic structure of a single-walled carbon nanotube

Qin, Lu-Chang

154

Multimodal optical sensing and analyte specificity using single-walled carbon nanotubes  

E-print Network

Multimodal optical sensing and analyte specificity using single-walled carbon nanotubes Daniel A constrained environments. Single-walled carbon nanotubes have several advantages when used as optical sensors1 photoluminescent single- walled carbon nanotube (SWNT) species suggests untapped poten- tial for multimodality

Silverman, Scott K.

155

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

E-print Network

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

Resasco, Daniel

156

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

E-print Network

Localized modes in capped single-walled carbon nanotubes Alexander V. Savin1,2,a and Yuri S single- walled carbon nanotubes and predict the existence of highly localized modes at the tips consider four types of single-walled carbon nano- tubes SWCNs , which are known to have the smallest

157

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

E-print Network

Photoconductivity of single-wall carbon nanotubes under continuous-wave near-infrared illumination 2003; accepted 15 July 2003 The photoconductivity of films of single-wall carbon nanotubes has been of single-wall carbon nanotubes SWNTs is asso- ciated with both the nanotube's well-defined one- dimensional

Euler, William B.

158

Fluorescence spectroscopy of single-walled carbon nanotubes synthesized from alcohol  

E-print Network

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, and Characterization of Single-Walled Carbon Nanotubes (SWNT's) (sponsored by Advanced Materials & Nanotechnology

Maruyama, Shigeo

159

Optical microcavity with semiconducting single-wall carbon nanotubes  

E-print Network

We report studies of optical Fabry-Perot microcavities based on semiconducting single-wall carbon nanotubes with a quality factor of 160. We experimentally demonstrate a huge photoluminescence signal enhancement by a factor of 30 in comparison with the identical film and by a factor of 180 if compared with a thin film containing non-purified (8,7) nanotubes. Futhermore, the spectral full-width at half-maximum of the photo-induced emission is reduced down to 8 nm with very good directivity at a wavelength of about 1.3 $\\mu$m. Such results prove the great potential of carbon nanotubes for photonic applications.

Gaufrès, Etienne; Roux, Xavier Le; Kazaoui, Saïd; Marris-Morini, Delphine; Cassan, Eric; Vivien, Laurent; 10.1364/OE.18.005740

2010-01-01

160

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

Microsoft Academic Search

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

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

1999-01-01

161

Experimental structure determination of individual single-wall and double-wall carbon nanotubes  

Microsoft Academic Search

A critical issue in current carbon nanotube applications and science study is the structure determination of a given individual tube, e.g, tubes of different chiral vectors can be metal or semiconductor and multi-wall tubes consists of tubes of different helicities. Here we report a first quantitative structure determination of CVD grown individual single-wall and double-wall carbon nanotubes by electron nanodiffraction.

Min Gao; Jianmin Zuo; Larry Nagahara; Ruth Zhang; Ray Twesten; Ivan Petrov

2003-01-01

162

Hexahapto-lanthanide interconnects between the conjugated surfaces of single-walled carbon nanotubes.  

PubMed

We report the response of the electrical conductivity of semiconducting single-walled carbon nanotube (SWNT) thin films on exposure to metal vapors of the early lanthanides under high vacuum conditions. We attribute the strongly enhanced conductivities observed on deposition of samarium and europium to charge transfer from the metals to the SWNT backbone, thereby leading to the first examples of mixed covalent-ionic bis-hexahapto bonds [(?(6)-SWNT)M(?(6)-SWNT), where M = Sm, Eu]. PMID:24553843

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

2014-05-28

163

Stabilization and carbonization of gel spun polyacrylonitrile\\/single wall carbon nanotube composite fibers  

Microsoft Academic Search

Gel spun polyacrylonitrile (PAN) and PAN\\/single wall carbon nanotube (SWNT) composite fibers have been stabilized in air and subsequently carbonized in argon at 1100°C. Differential scanning calorimetry (DSC) and infrared spectroscopy suggests that the presence of single wall carbon nanotube affects PAN stabilization. Carbonized PAN\\/SWNT fibers exhibited 10–30nm diameter fibrils embedded in brittle carbon matrix, while the control PAN carbonized

Han Gi Chae; Marilyn L. Minus; Asif Rasheed; Satish Kumar

2007-01-01

164

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

E-print Network

Patterned growth of single-walled carbon nanotube arrays from a vapor-deposited Fe catalyst H. B September 2003 Single-walled carbon nanotubes have been grown on a variety of substrates by chemical vapor suspended single-walled nanotubes SWNTs oriented parallel to the substrate surfaces on spe- cific sites

Golovchenko, Jene A.

165

Raman Characterization and Polarity Tuning of Aligned Single-Walled Carbon Nanotubes on Quartz  

E-print Network

Raman Characterization and Polarity Tuning of Aligned Single-Walled Carbon Nanotubes on Quartz Bo been employed to study key features of highly aligned single-walled carbon nanotubes grown on quartz-talking between nanotubes.12) However, previous studies uncovered some important aspects of highly aligned single-walled

166

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

E-print Network

Growth 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. We must therefore produce either a very high den- sity of single-walled nanotubes SWNTs of up to 1014

Nabben, Reinhard

167

Electronically modified single wall carbon nanohorns with iodine adsorption  

NASA Astrophysics Data System (ADS)

Tailoring electronic properties of single wall carbon nanohorn (SWCNH) is expected to develop the application potential in various fields. SWCNH is efficiently modified with iodine molecules by liquid phase adsorption. The adsorption isotherm of iodine on SWCNH was Langmuirian with the saturated adsorption amount of 185 ± 10 mg g-1 (coverage 0.18), indicating a specific interaction between SWCNH and iodine. The DC electrical conductivity of SWCNH film prepared by dip-coating method increased with the iodine adsorption amount almost by a factor 10.

Khoerunnisa, Fitri; Fujimori, Toshihiko; Itoh, Tsutomu; Kanoh, Hirofumi; Ohba, Tomonori; Yudasaka, Masako; Iijima, Sumio; Kaneko, Katsumi

2011-01-01

168

Characterization of single-walled carbon nanotubes for environmental implications  

USGS Publications Warehouse

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).

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

2004-01-01

169

Binding of Nucleobases with Single-Walled Carbon Nanotubes  

E-print Network

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.

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

2007-09-19

170

Translocation events in a single walled carbon nanotube  

PubMed Central

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

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

2010-01-01

171

Heat transport and thermal management in single walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Results from our investigation of thermal transport in CVD grown Single-Walled Carbon nanotubes (SWNT) on different substrates will be reported. Chiu et al. recently showed that multi-walled carbon nanotube devices cool by ballistic phonon heat transport. To harness the remarkable thermal properties of nanotubes for thermal management, it is of interest to understand how heat energy is transported into or out of nanotubes. In this work, we investigate the breakdown power for SWNT nanotube devices using different substrate materials to determine the effect of substrate thermal conductivity on nanotube breakdown. We compare our results with those obtained with the Si/ SiO2 substrate. Our results indicate higher power dissipation on a sapphire substrate for few micron SWNTs but lower than expected dissipation for the longer length scales. We will discuss the mechanism of power dissipation and thermal transport in our devices in light of our results.

Maune, Hareem; Bockrath, Marc

2006-03-01

172

Processing of single walled carbon nanotubes for nanocomposites  

NASA Astrophysics Data System (ADS)

An existing electric arc discharge (EAD) apparatus was found to produce only small quantities of single-walled carbon nanotubes (SWNT), therefore an in depth evaluation of the various parameters was performed in order to optimize the SWNT yield. A systematic study on the current applied (48-116 A) and morphology of the arc during EAD experiments was performed, a study of this type has not been previously reported in literature. Our findings include that the current being applied to the electrodes, as controlled by a commercial software program, was ˜ 20 A lower than expected. Currents in the range of 70-90 A appear to be optimal for this EAD system as the yield of SWNT is consistent with commercially produced SWNT also fabricated with an EAD system. During the experiments, the current was not constant, but fluctuated over a range of values, 7-20 A ranges were not uncommon. Concurrently, the gap between the electrodes was also non-constant, a gap of less than 1 mm or contact as the anode "stabs" the cathode was witnessed. Subsequent analysis of the yield of SVVNT, as a function of the current as well as the physical location in the EAD chamber where the yield was greatest, was performed with simultaneous thermogravimetric analysis and differential thermal analysis. Significant differences in the concentration of metal catalysts used to fabricate the SWNT were observed between sample areas in the chamber. Moreover, an anomalous peak was observed in the differential thermal analysis trace between the 350-400°C. Subsequent analysis of relevant constituent materials was investigated to identify the cause of this anomaly. Static and dynamic mechanical analysis was performed on highly drawn fibers of neat polystyrene and its composites containing 0.3 wt.% of a commercial SWNT containing soot. Though the dynamic and static measurements of fibers in the 130-150 mum did not show improvement with the addition of the filler, composite fibers of 20-50 mum were statistically higher in strain to break over the neat fibers. Moreover, these composite fibers had a ten-fold higher strain to break than those in the 130-150 mum.

Knapp, Angela M.

173

Fast electron beam-plasma interaction in single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

A theoretical study on the plasmon-polariton modes coupled with a fast electron beam inside a metallic single-walled carbon nanotube is presented. The Maxwell's equations coupled with a linearized hydrodynamic model for the nanotube's charge oscillations are used. By considering the electron beam effects, general expression of dispersion relation of electromagnetic modes on nanotube's surface is obtained. It is shown numerically that by considering the electron beam effects, the polariton frequency shifts to lower values.

Moradi, Afshin

2013-04-01

174

Mechanism of single-walled carbon nanotube growth on natural magnesite  

NASA Astrophysics Data System (ADS)

Fe K-edge X-ray absorption fine structure (XAFS) measurements were performed in order to elucidate the formation mechanism of single-walled carbon nanotubes (SWCNTs) grown on natural magnesite by pyrolyzing methane gas. It was clearly shown by XAFS analyses that iron metal fine particles, which were reduced from iron oxides by methane gas, worked as a catalyst for SWCNT growth. Structural characteristics of the initial iron state in the natural magnesite were also discussed.

Kawasaki, S.; Shinoda, M.; Iwai, Y.; Ogawa, M.; Hara, T.; Hattori, Y.; Kubota, T.

2006-05-01

175

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

SciTech Connect

We grow high-density, aligned single wall carbon nanotube mats for use as interconnects in integrated circuits by remote plasma chemical vapor deposition from a Fe-Al{sub 2}O{sub 3} thin film catalyst. We carry out extensive Raman characterization of the resulting mats, and find that this catalyst system gives rise to a broad range of nanotube diameters, with no preferential selectivity of semiconducting tubes, but with at least 1/3 of metallic tubes.

Robertson, J.; Zhong, G. [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Telg, H.; Thomsen, C. [Institut fuer Festkoerperphysik, Technische Universitaet Berlin, 10623 Berlin (Germany); Warner, J. H.; Briggs, G. A. D. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Dettlaff-Weglikowska, U.; Roth, S. [Max Planck Institut fuer Festkoerperphysik, D-70569 Stuttgart (Germany)

2008-10-20

176

High-Field Electrical Transport in Single-Wall Carbon Nanotubes  

Microsoft Academic Search

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

Zhen Yao; Charles L. Kane; Cees Dekker

2000-01-01

177

Theoretical studies on the charge-induced failure of single-walled carbon nanotubes  

Microsoft Academic Search

Electromechanical coupling in single-walled carbon nanotubes has been studied theoretically. The charge distribution on single-walled carbon nanotubes in an electric field is obtained by an atomistic moment method based on classical electrostatics theory. The electrostatic interactions between charged carbon atoms are calculated using the Coulomb law. The charge-induced deformations of single-walled carbon nanotubes in axial and radial directions are obtained

Chunyu Li; Tsu-Wei Chou

2007-01-01

178

Growth Energetics of Single-Wall Carbon Nanotubes with Carbon Monoxide Kwanyong Seo, Changwook Kim, and Bongsoo Kim*  

E-print Network

Growth Energetics of Single-Wall Carbon Nanotubes with Carbon Monoxide Kwanyong Seo, Changwook Kim energetics of single-wall carbon nanotubes (SWNTs) with gas-phase CO molecules is investigated. Our density-6 Though single-wall carbon nanotubes (SWNTs) have different electronic properties depending

Kim, Bongsoo

179

Surface fractal dimension of single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Isolated single-walled carbon nanotubes (SWNTs), SWNT bundles, and ropes (or strands) show a structural self-similar characteristic. By calculating the Hausdorff dimension, it was found that their self-similar organization leads to surface fractality and the value of the surface dimension (Ds) depends on self-similar patterns. Experimentally, Ds obtained by nitrogen adsorption measurements at 77.3 K and by the small-angle x-ray scattering technique in our study proved our calculation that the surface dimension of SWNTs is nonintegral, 2

Sun, Cheng-Hua; Li, Feng; Ying, Zhe; Liu, Chang; Cheng, Hui-Ming

2004-01-01

180

Thermal oscillations of structurally distinct single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

181

Vertical semiconducting single-walled carbon nanotube Schottky diode  

NASA Astrophysics Data System (ADS)

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.

Jung, Sunghwan

2014-07-01

182

Single-walled carbon nanotubes for high-performance electronics.  

PubMed

Single-walled carbon nanotubes (SWNT) could replace silicon in high-performance electronics with their exceptional electrical properties and intrinsic ultra-thin body. During the past five years, the major focus of this field is gradually shifting from proof-of-concept prototyping in academia to technology development in industry with emphasis on manufacturability and integration issues. This article reviews recent advances, starting with experimental and modeling works that evaluate the potential of adopting SWNTs in ultimately scaled transistors. Techniques to separate nanotubes according to their electronic types and assemble them into aligned arrays are then discussed, followed by a description of the engineering aspects in their implementation in integrated circuits and systems. A concluding discussion provides some perspectives on future challenges and research opportunities. PMID:23921893

Cao, Qing; Han, Shu-jen

2013-10-01

183

Amperometric glucose biosensor based on single-walled carbon nanohorns.  

PubMed

The biosensing application of single-walled carbon nanohorns (SWCNHs) was demonstrated through fabrication of an amperometric glucose biosensor. The biosensor was constructed by encapsulating glucose oxidase in the Nafion-SWCNHs composite film. The cyclic voltammograms for glucose oxidase immobilized on the composite film displayed a pair of well-defined and nearly symmetric redox peaks with a formal potential of -0.453 V. The biosensor had good electrocatalytic activity toward oxidation of glucose. To decrease detection potential, ferrocene monocarboxylic acid was used as a redox mediator. The mediated glucose biosensor shows a linear range from 0 to 6.0 mM. The biosensor shows high sensitivity (1.06 microA/mM) and stability, and can avoid the commonly coexisted interference. Because of impressive properties of SWCNHs, such as high purity and high surface area, SWCNHs and their composites are expected to be promising material for biomolecular immobilization and biosensing applications. PMID:18387291

Liu, Xiaoqing; Shi, Lihong; Niu, Wenxin; Li, Haijuan; Xu, Guobao

2008-07-15

184

Functionalized single-walled carbon nanohorns for electrochemical biosensing.  

PubMed

Single-walled carbon nanohorns (SWNHs), distinguished by their high purity and distinct structure, were noncovalently functionalized with poly(sodium 4-styrenesulfonate). The functionalized SWNHs were characterized by scanning electron microscopy, atomic force microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetry. Heme protein myoglobin was adsorbed onto surface of functionalized SWNHs to prepare electrochemical biosensor. Surface assembly process and direct electrochemistry of immobilized myoglobin were investigated by electrochemical impedance spectroscopy and cyclic voltammetry, respectively. The proposed biosensor exhibited good electrocatalysis to the reduction of hydrogen peroxide. The response was linear over the range 3-350 microM with a detection limit of 0.5 microM. Good reproducibility and stability of the biosensor were obtained toward hydrogen peroxide detection. PMID:20299202

Liu, Xiaoqing; Li, Haijuan; Wang, Fuan; Zhu, Shuyun; Wang, Yuling; Xu, Guobao

2010-06-15

185

Generalizing thermodynamic properties of bulk single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

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

Rodriguez, Kenneth R.; Malone, Marvin A.; Nanney, Warren A.; A. Maddux, Cassandra J.; Coe, James V.; Martínez, Hernán L.

2014-12-01

186

ccsd-00008772,version1-15Sep2005 Nucleation and growth of single wall carbon nanotubes  

E-print Network

ccsd-00008772,version1-15Sep2005 Nucleation and growth of single wall carbon nanotubes F. Beuneu and growth of single wall carbon nanotubes from a carbon-saturated catalytic particle surrounded by a single. INTRODUCTION Since their discovery nearly fifteen years ago, sin- gle wall carbon nanotubes (SWNT) have

Boyer, Edmond

187

Extracellular entrapment and degradation of single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Neutrophils extrude neutrophil extracellular traps (NETs) consisting of a network of chromatin decorated with antimicrobial proteins to enable non-phagocytic killing of microorganisms. Here, utilizing a model of ex vivo activated human neutrophils, we present evidence of entrapment and degradation of carboxylated single-walled carbon nanotubes (SWCNTs) in NETs. The degradation of SWCNTs was catalyzed by myeloperoxidase (MPO) present in purified NETs and the reaction was facilitated by the addition of H2O2 and NaBr. These results show that SWCNTs can undergo acellular, MPO-mediated biodegradation and imply that the immune system may deploy similar strategies to rid the body of offending microorganisms and engineered nanomaterials.Neutrophils extrude neutrophil extracellular traps (NETs) consisting of a network of chromatin decorated with antimicrobial proteins to enable non-phagocytic killing of microorganisms. Here, utilizing a model of ex vivo activated human neutrophils, we present evidence of entrapment and degradation of carboxylated single-walled carbon nanotubes (SWCNTs) in NETs. The degradation of SWCNTs was catalyzed by myeloperoxidase (MPO) present in purified NETs and the reaction was facilitated by the addition of H2O2 and NaBr. These results show that SWCNTs can undergo acellular, MPO-mediated biodegradation and imply that the immune system may deploy similar strategies to rid the body of offending microorganisms and engineered nanomaterials. Electronic supplementary information (ESI) available: Suppl. Fig. 1 - length distribution of SWCNTs; suppl. Fig. 2 - characterization of pristine vs. oxidized SWCNTs; suppl. Fig. 3 - endotoxin evaluation; suppl. Fig. 4 - NET characterization; suppl. Fig. 5 - UV-Vis/NIR analysis of biodegradation of oxidized SWCNTs; suppl. Fig. 6 - cytotoxicity of partially degraded SWCNTs. See DOI: 10.1039/c3nr06047k

Farrera, Consol; Bhattacharya, Kunal; Lazzaretto, Beatrice; Andón, Fernando T.; Hultenby, Kjell; Kotchey, Gregg P.; Star, Alexander; Fadeel, Bengt

2014-05-01

188

Effect of Single-walled Carbon Nanotubes on Cellulose Phenylcarbamate Chiral Stationary Phases  

Microsoft Academic Search

Single-walled carbon nanotubes (SWNTs) have a high adsorption ability and nanoscale interactions. Cellulose trisphenylcarbamates possess high enantioseparation ability in high-performance liquid chromatography (HPLC). Single-walled carbon nanotubes mixed with cellulose trisphenylcarbamate are coated on the silica gel as chiral stationary phases and higher enantioseparation factors are obtained. After a single-walled carbon nanotube is linked to the 6-position of cellulose 2,3-bisphenylcarbamate, its

Yin-xia CHANG; Chao-xing REN; Qiong RUAN; Li-ming YUAN

2007-01-01

189

Preparation and characterization of soluble methyl- ?-cyclodextrin functionalized single-walled carbon nanotubes  

Microsoft Academic Search

Methyl-?-cyclodextrin and octadecylamine-modified single-walled carbon nanotube composites were prepared using standard techniques. Oxidized single-walled carbon nanotube was acyl halogenated with thionyl chloride and dimethylformamide, then reacted with methyl-?-cyclodextrin and octadecylamine simultaneously to obtain soluble products. The formation of surface functional groups and changes of nanotubes structures of functionalized single-walled carbon nanotubes were monitored by Fourier transform infrared spectroscopy and transmission

Jin-Gang Yu; Ke-Long Huang; Su-Qin Liu; Jin-Chun Tang

2008-01-01

190

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

E-print Network

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 intensities for single-walled carbon nanotubes. #12;0 10 20 30 Chiral angle (°) 1 1.5 2 2.5 |(E c -E v )/u

Nabben, Reinhard

191

A pilot toxicology study of single-walled carbon nanotubes in a small sample of mice  

Microsoft Academic Search

Single-walled carbon nanotubes are currently under evaluation in biomedical applications, including in vivo delivery of drugs, proteins, peptides and nucleic acids (for gene transfer or gene silencing), in vivo tumour imaging and tumour targeting of single-walled carbon nanotubes as an anti-neoplastic treatment. However, concerns about the potential toxicity of single-walled carbon nanotubes have been raised. Here we examine the acute

Meike L. Schipper; Nozomi Nakayama-Ratchford; Corrine R. Davis; Nadine Wong Shi Kam; Pauline Chu; Zhuang Liu; Xiaoming Sun; Hongjie Dai; Sanjiv S. Gambhir

2008-01-01

192

Single-Wall Carbon Nanotube Anodes for Lithium Cells  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

193

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

E-print Network

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

van der Zwaag, Daan

194

Patching and Tearing Single-Wall Carbon-Nanotube Ropes into Multiwall Carbon Nanotubes  

Microsoft Academic Search

Bundles of single-wall carbon nanotubes (SWCNTs) coalesce forming multiwall carbon nanotubes (MWCNTs), containing from two to six nested tubes, under thermal treatment at high temperatures [(2200-2400) °C]. This structural transformation is confirmed by extensive molecular dynamics (MD) simulations. The simulations suggest a ``patching-and-tearing'' mechanism for the single-wall-to-multiwall transformation underlying the ``concerted'' coalescence of the tubes that begins with their polymerization.

María J. López; Angel Rubio; Julio A. Alonso; Serge Lefrant; Karine Méténier; Sylvie Bonnamy

2002-01-01

195

CVD growth mechanism of single-walled carbon nanotubes from alcohol  

E-print Network

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

Maruyama, Shigeo

196

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

E-print Network

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

Maruyama, Shigeo

197

Ultrafast Carrier Dynamics in Single Wall Carbon Nanotubes J-S. Lauret1,3  

E-print Network

-sur-Yvette Cedex, France (Dated: February 2, 2006) Time-resolved carrier dynamics in single wall carbon nanotubesUltrafast Carrier Dynamics in Single Wall Carbon Nanotubes J-S. Lauret1,3 , C. Voisin1 , G that the opening of the band gap in semi-conducting carbon nanotubes determines the non-linear response dynamics

Paris-Sud XI, Université de

198

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

E-print Network

, France (Dated: June 22, 2012) Optimized growth of Single Wall Carbon Nanotubes requires a full knowledgeImportance of carbon solubility and wetting properties of nickel nanoparticles for single wall atomistic computer simulations, we calculate carbon adsorption isotherms on nanoparticles of nickel

Paris-Sud XI, Université de

199

Short Communication Single-Walled Carbon Nanotube Based Real-Time  

E-print Network

Short Communication Single-Walled Carbon Nanotube Based Real-Time Organophosphate Detector Ningyi Abstract A novel single-walled carbon nanotube (SWNT) based biosensor for real-time detection- gle-walled carbon nanotubes (SWNTs), exhibit high sensi- tivity to variations of surrounding

Chen, Wilfred

200

Characterization of Single-Walled Carbon Nanotubes by Scanning Transmission X-ray Spectromicroscopy  

E-print Network

Characterization of Single-Walled Carbon Nanotubes by Scanning Transmission X-ray Spectromicroscopy: The C 1s X-ray absorption spectra of several isolated bundles of single-walled carbon nanotubes (SWCNT mapping of an individual SWCNT bundle is demonstrated. 1. Introduction Carbon nanotubes (CNT) are often

Hitchcock, Adam P.

201

Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes  

E-print Network

Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes Jared J. Crochet-hole Coulomb interaction. Single-wall carbon nanotubes are ideal models of infinite orbital conjugation where@lanl.gov KEYWORDS: carbon nanotube, exciton, dephasing, transport, exchange interaction Abstract We present

Boyer, Edmond

202

Modifying the electronic properties of single-walled carbon nanotubes using designed surfactant peptides  

E-print Network

Modifying the electronic properties of single-walled carbon nanotubes using designed surfactant can be altered significantly by modifying the nanotube surface. In this study, single-walled carbon February 2012, Accepted 25th May 2012 DOI: 10.1039/c2nr30423f The electronic properties of carbon nanotubes

Nielsen, Steven O.

203

SCANNING PHOTOCURRENT SPECTROSCOPY OF ALIGNED SINGLE-WALLED CARBON NANOTUBE FILMS  

E-print Network

SCANNING PHOTOCURRENT SPECTROSCOPY OF ALIGNED SINGLE-WALLED CARBON NANOTUBE FILMS S. Mineshige1 photocurrent measurements of aligned single-walled carbon nanotube films (SWCNTs) provide local information: Why we use Carbon Nanotube (CNT) Films Individual CNTs Transistors[1] Efficient Photovoltaic

Mellor-Crummey, John

204

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

E-print Network

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

Ludwig-Maximilians-Universität, München

205

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

E-print Network

Structure Controlled Synthesis of Single-Walled Carbon Nanotubes Using Solution Based Catalyst and physical properties, single-walled carbon nanotube (SWCNT) has been considered for many applications. We, mechanical application, etc. #12;Structure Controlled Synthesis of Carbon Nanotubes Theerapol Thurakitseree1

Mellor-Crummey, John

206

Selective Coating of Single Wall Carbon Nanotubes with Thin SiO2 Layer  

E-print Network

Selective Coating of Single Wall Carbon Nanotubes with Thin SiO2 Layer Qiang Fu, Chenguang Lu January 27, 2002; Revised Manuscript Received February 19, 2002 ABSTRACT Single walled carbon nanotubes-aminopropyltriethoxyysilane was also discussed. Carbon nanotubes have been the most actively studied materials in the past few

207

Strain Determination in Electrochemically Doped Single-Walled Carbon Nanotubes via Raman Spectroscopy  

E-print Network

Strain Determination in Electrochemically Doped Single-Walled Carbon Nanotubes via Raman-point of the Brillouin zone. I. Introduction Single-wall carbon nanotubes (SWNT) are novel one-di- mensional: October 1, 2004 We studied the Raman response upon electrochemical p-doping of carbon nanotubes

Nabben, Reinhard

208

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

E-print Network

Origin of the high-energy Raman modes in single-wall carbon nanotubes J. Maultzsch, C. Thomsen, S. We present a new interpretation of the origin of the first-order Raman modes in single- wall carbon of the first-order high-energy Raman modes in carbon nanotubes has been a puzzling question since the first

Nabben, Reinhard

209

Single-walled B-doped carbon, B\\/N-doped carbon and BN nanotubes synthesized from single-walled carbon nanotubes through a substitution reaction  

Microsoft Academic Search

Bundles of single-walled boron-doped carbon (BxC1?x), boron- and nitrogen-doped carbon (BxC1?x?yNy) and boron nitride (BN) nanotubes were prepared by thermal treatment of a mixture of boron trioxide and bundles of single-walled carbon nanotubes at 1523–1623 K in a nitrogen flow. The (BxC1?x+BxC1?x?yNy)\\/BN nanotube yield ratio increased with decreasing temperature in the reaction zone. The nanotubes were characterised by using high-resolution

D. Golberg; Y Bando; W Han; K Kurashima; T Sato

1999-01-01

210

Selectable functionalization of single-walled carbon nanotubes resulting from CHn (n=1 3) adsorption  

Microsoft Academic Search

Chemical functionalization of single-walled carbon nanotubes with different hydrocarbon radicals through collisional reaction between energetic methane molecule and single-walled carbon nanotubes in the energy range from 5 to 100 eV has been studied by using classical molecular dynamics simulations combined with ab initio calculations. We find that through controlling the incident energy of the methane molecule, chemical decoration of single-walled

Feng Li; Yueyuan Xia; Mingwen Zhao; Xiangdong Liu; Boda Huang; Zhenyu Tan; Yanju Ji

2004-01-01

211

Single-Walled Carbon Nanotube Transporter for Gene Delivery  

NASA Astrophysics Data System (ADS)

Recent studies have shown great promises in integrating nanomaterials in biomedicine. To explore the feasibility of using single-walled carbon nanotubes (SWNTs) as transporters for gene delivery, we have investigated the binding of SWNTs and RNA polymer poly(rU), and the diffusion and the translocation of the SWNT-poly(rU) complexes. Through single-molecule fluorescence imaging, we have found that the pi- stacking dominates the hydrophobic interactions between the carbon rings on tubes and the nitrogenous bases of RNA. Our diffusion study has further demonstrated the feasibility of tracking the motion of water soluble SWNT-poly(rU) complexes. The uptake of SWNT-poly(rU) by breast cancer cells MCF7 was observed using confocal scanning fluorescence microscopy. It was evident that the complexes could penetrate through cell membrane into cytoplasm and cell nucleus. Our cell culture, MTS assay, and radioisotope labeling showed the negligible cytotoxicity of surface modified SWNTs with RNA polymer and amino acids in cell growth medium. These studies have paved the way for gene transfection using SWNTs as transporters.

Ke, Pu-Chun

2005-03-01

212

Measuring the Uniaxial Strain of Individual Single-Wall Carbon Nanotubes: Resonance Raman Spectra of Atomic-Force-Microscope Modified Single-Wall Nanotubes  

E-print Network

Measuring the Uniaxial Strain of Individual Single-Wall Carbon Nanotubes: Resonance Raman Spectra is used to measure the strain in individual single-wall carbon nanotubes, strained by manipulation in the elec- tronic band structure upon application of strain [5­8]. Recent conductance measurements on atomic

Cronin, Steve

213

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

SciTech Connect

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.

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

214

High yield of single-wall carbon nanotubes by arc discharge using Rh Pt mixed catalysts  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes (SWNT) were produced using binary mixtures of the platinum-group metals as catalysts by arc evaporation in helium gas. Transmission electron microscopy and Raman scattering spectroscopy revealed that the production yield of SWNTs was remarkably enhanced when a Rh-Pt mixture was used as a catalyst. The density of SWNTs in raw soot was as high as that obtained from Fe-Ni and Y-Ni. The distribution of diameters of SWNTs was narrow (1.28±0.07 nm). The merit of this catalyst is that it is free from magnetic metals.

Saito, Yahachi; Tani, Yoshihiko; Miyagawa, Norihisa; Mitsushima, Koichi; Kasuya, Atsuo; Nishina, Yuichiro

1998-09-01

215

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

216

Growth Thursday, March 6 Cross-polarized optical excitation of single-walled carbon nanotubes  

E-print Network

of the depolarization effect, or so-called antenna effect, cross-polarized op- tical absorption of single-walled carbonGrowth Thursday, March 6 19:00 Cross-polarized optical excitation of single-walled carbon nanotubes of micelle wrapped SWNTs, clearly identified PL peaks due to cross-polarized excitation gives an im- portant

Maruyama, Shigeo

217

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

E-print Network

From isotope labeled CH3CN to N2 inside single-walled carbon nanotubes Christian Kramberger to this peculiar place? We have used N15 and C13 isotope labeled acetonitrile during the synthesis of single-walled carbon nanotubes to investigate this process. The isotope shifts of phonons and vibrons are observed

Maruyama, Shigeo

218

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

E-print Network

Isotope-induced elastic scattering of optical phonons in individual suspended single-walled carbon 10, 2011) Isotope-induced scattering of optical phonons in individual single-walled carbon nanotubes (SWNTs) was investigated by resonance Raman scattering measurements of more than 600 sus- pended, isotope

Maruyama, Shigeo

219

Digital and FM demodulation of a doubly-clamped single wall carbon nanotube oscillator: towards a  

E-print Network

1 Digital and FM demodulation of a doubly-clamped single wall carbon nanotube oscillator: towards experimental realization of AM, FM and digital demodulation with suspended single wall carbon nanotube in demodulation is clearly demonstrated. The FM technique is shown to lead to the suppression of unwanted

Boyer, Edmond

220

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

E-print Network

1 Optical Characterization of Single-Walled Carbon Nanotubes Synthesized by Catalytic Decomposition The single-walled carbon nanotubes (SWNTs) synthesized by a catalytic decomposition of alcohol (Alcohol CVD synthesis of SWNTs. At present, CVD approaches including the high-pressure CO (HiPco) technique [8, 12] have

Maruyama, Shigeo

221

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

E-print Network

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

Maruyama, Shigeo

222

Diameter-Controlled and Nitrogen-Doped Vertically Aligned Single-Walled Carbon Theerapol Thurakitsereea  

E-print Network

1 Diameter-Controlled and Nitrogen-Doped Vertically Aligned Single-Walled Carbon Nanotubes controlled and vertically aligned single-walled carbon nanotubes were synthesized from pure and mixed ethanol/acetonitrile feedstock. With increasing acetonitrile concentration in the feedstock, nitrogen incorporation into the sp2

Maruyama, Shigeo

223

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

E-print Network

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

Maruyama, Shigeo

224

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

E-print Network

Microwave Absorption of Single-Walled Carbon Nanotubes/Soluble Cross-Linked Polyurethane Composites composites of single-walled carbon nanotubes (SWNTs) with soluble cross-linked polyurethane (SCPU) were because of their easy fabrication into various shapes.20-24 Polyurethanes (PUs), with possessing

Gao, Hongjun

225

ccsd00004222, Low frequency excitations of C 60 chains inserted inside single-walled carbon nanotubes  

E-print Network

single-walled carbon nanotubes J. Cambedouzou, S. Rols, R. Almairac, J.-L. Sauvajol Groupe de Dynamique-38042 Grenoble, France (Dated: February 10, 2005) The low frequency excitations of C60 chains inserted inside single-walled carbon nanotubes (SWNTs) have been studied by inelastic neutron scattering (INS

226

Covalent Attachment and Hybridization of DNA Oligonucleotides on Patterned Single-Walled Carbon  

E-print Network

Covalent Attachment and Hybridization of DNA Oligonucleotides on Patterned Single-Walled Carbon in nanomaterials.1-6 Single- walled carbon nanotubes (SWNTs) are promising materi- als for highly sensitive DNA biosensors or chemical sensors.9,10 Most studies reported to date have concentrated on the ap- plications

227

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

E-print Network

Interaction of Acetone with Single Wall Carbon Nanotubes at Cryogenic Temperatures: A Combined The interaction of acetone with single wall carbon nanotubes (SWCNTs) at low temperatures was studied simulations, the desorption peaks of acetone can be assigned to the following adsorption sites: (i) sites

Borguet, Eric

228

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

E-print Network

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

Maruyama, Shigeo

229

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

E-print Network

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

Maruyama, Shigeo

230

Computational modeling of thermal conductivity of single walled carbon nanotube polymer composites  

E-print Network

1 Computational modeling of thermal conductivity of single walled carbon nanotube polymer was developed to study the thermal conductivity of single walled carbon nanotube (SWNT)-polymer composites for the prediction of the thermal conductivity within a wide range of volume fractions of the SWNTs, so long

Maruyama, Shigeo

231

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

E-print Network

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

Maruyama, Shigeo

232

Molecular Beam-Controlled Nucleation and Growth of Vertically Aligned Single-Wall Carbon Nanotube Arrays  

Microsoft Academic Search

The main obstacle to widespread application of single-wall carbon nanotubes is the lack of reproducible synthesis methods of pure material. We describe a new growth method for single-wall carbon nanotubes that uses molecular beams of precursor gases that impinge on a heated substrate coated with a catalyst thin film. In this growth environment the gas and the substrate temperature are

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

2005-01-01

233

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

E-print Network

1 Structure-Dependent Fluorescence Efficiencies of Individual Single-Walled Carbon Nanotubes Dmitri-section #12;3 All current methods for producing single-walled carbon nanotubes (SWNTs) give mixtures of (n, F-33405 France AUTHOR EMAIL ADDRESS: weisman@rice.edu RECEIVED DATE #12;2 ABSTRACT: Single-nanotube

Boyer, Edmond

234

Single-Walled Carbon Nanotube-Based Chemiresistive Affinity Biosensors for Small Molecules: Ultrasensitive Glucose Detection  

E-print Network

Single-Walled Carbon Nanotube-Based Chemiresistive Affinity Biosensors for Small Molecules of various analytes. Single-walled carbon nanotubes (SWNTs) are one such class of nanomaterials that have such as nanowires, nanobelts and nanotubes as transducer elements in affinity (bio)sensors. Use of nanomaterials

Chen, Wilfred

235

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

E-print Network

Fracture resistance of single-walled carbon nanotubes through atomistic simulation Qiang Lu of the important failure modes, or even the dominant mode of Single-Walled Nanotube (SWNT) failure due 19716, USA Keywords: Atomistic simulation, carbon nanotube, fracture resistance, strain-energy, brittle

Bhattacharya, Baidurya

236

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

E-print Network

Elastic properties and pressure-induced phase transitions of single-walled carbon nanotubes S 2002 Published online 4 February 2003 PACS 61.46.+w, 61.50.Ks We studied the structure of single-walled carbon nanotubes under hydrostatic pressure by first-princi- ples calculations. The circular tubes

Nabben, Reinhard

237

Single walled carbon nanotubes induce indirect cytotoxicity by medium depletion in A549 lung cells  

Microsoft Academic Search

The ability of two types of single walled carbon nanotubes (SWCNT), namely Arc Discharge (AD) and HiPco® single walled carbon nanotubes, to induce an indirect cytotoxicity in A549 lung cells by means of medium depletion was investigated. The nanotubes were dispersed in a commercial cell culture medium and subsequently removed by centrifugation and filtration. Spectroscopic analysis confirmed the removal of

A. Casey; E. Herzog; F. M. Lyng; H. J. Byrne; G. Chambers; M. Davoren

2008-01-01

238

Exponential Decay Lifetimes of Excitons in Individual Single-Walled Carbon Nanotubes Axel Hagen,3  

E-print Network

Exponential Decay Lifetimes of Excitons in Individual Single-Walled Carbon Nanotubes Axel Hagen,3 April 2005; published 31 October 2005) The dynamics of excitons in individual semiconducting single-walled carbon nanotubes was studied using time-resolved photoluminescence (PL) spectroscopy. The PL decay from

Peinke, Joachim

239

Strong effect of chirality on doped single walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Carbon nanotubes (CNTs) are one of the important 'tailor made' materials, in the sense that their properties can be tuned in desired ways. A lot of research work is in progress to investigate the various properties of CNTs to exploit them for possible technological applications. It has been observed that impurity doping largely affects the band structure of CNTs, giving rise to novel phenomena. In this work, we have investigated the effect of curvature on the donor binding energies of both chiral and achiral CNTs with n-m=1, 2 such as (5, 4), (6, 5), (5, 3) and (6, 4) with diameter ranging from 0.5 to 1.3 nm. Band curvature has been included through the corresponding effective mass derived from a suitable energy dispersion relation, and binding energies are calculated as a function of impurity concentration. The results show that binding energy decreases as the curvature and impurity concentration increase for all types of tubes, but the rate of decrease is very high for chiral tubes, indicating the strong effect of chirality on doped single walled CNTs.

Geetha, R.; Gayathri, V.

2009-08-01

240

Nonlinear resonances of a single-wall carbon nanotube cantilever  

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

241

Fluorescence Correlation Spectroscopy of Single-wall Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

We demonstrate the application of fluorescence correlation spectroscopy (FCS) for the characterization of semiconductor type single-wall carbon nanotubes (SWCNT) in aqueous solution at low concentrations. The technique relies on the intrinsic nanotube bandgap luminescence in the near infrared (NIR) range and does not require nanotube functionalization. The nanotubes used in this study have been dispersed in solution of sodium deoxycholate and length fractionated via centrifugation in an iodixanol density gradient. The (6,5) type nanotubes were resonantly excited by focusing a circularly-polarized 568 nm laser beam into a diffraction limited spot in solution and the luminescence intensity fluctuations were detected at wavelengths above 950 nm using a custom FCS setup with enhanced NIR transmission optics. Correlation functions were analyzed using a model of segmental dynamics of weakly bending rods, modified to account for an additional fast relaxation mode associated with nanotube rotational dynamics and its polarization dependent luminescence. The accessible sample concentration range and the optimum excitation power range were identified. Sample luminescent signal stability significantly exceeding a typical measurement time of few minutes was demonstrated.

Pristinski, Denis; Prabhu, Vivek M.; Fagan, Jeffrey A.

2010-03-01

242

Observation and Modeling of Single Wall Carbon Nanotube Bend Junctions  

NASA Technical Reports Server (NTRS)

Single wall carbon nanotube (SWNT) bends, with diameters from approx. 1.0 to 2.5 nm and bend angles from 18 deg. to 34 deg., are observed in catalytic decomposition of hydrocarbons at 600 - 1200 C. An algorithm using molecular dynamics simulation (MD) techniques is developed to model these structures that are considered to be SWNT junctions formed by topological defects (i.e. pentagon-heptagon pairs). The algorithm is used to predict the tube helicities and defect configurations for bend junctions using the observed tube diameters and bend angles. The number and arrangement of the defects at the junction interfaces are found to depend on the tube helicities and bend angle. The structural and energetic calculations using the Brenner potential show a number of stable junction configurations for each bend angle with the 34 deg. bends being more stable than the others. Tight binding calculations for local density of state (LDOS) and transmission coefficients are carried out to investigate electrical properties of the bend junctions.

Han, Jie; Anantram, M. P.; Jaffe, R. L.; Kong, J.; Dai, H.; Saini, Subhash (Technical Monitor)

1998-01-01

243

Reinforced thermoplastic polyimide with dispersed functionalized single wall carbon nanotubes.  

PubMed

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 T(g) of the polyimide increased from 169 to 197 degrees 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(-4) Scm(-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. PMID:20356267

Lebrón-Colón, Marisabel; Meador, Michael A; Gaier, James R; Solá, Francisco; Scheiman, Daniel A; McCorkle, Linda S

2010-03-01

244

Hypergolic fuel detection using individual single walled carbon nanotube networks  

SciTech Connect

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

Desai, S. C.; Willitsford, A. H. [Department of Electrical and Computer Engineering, University of Louisville, Louisville, Kentucky 40292 (United States); Sumanasekera, G. U. [Department of Electrical and Computer Engineering, University of Louisville, Louisville, Kentucky 40292 (United States); Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292 (United States); Yu, M.; Jayanthi, C. S.; Wu, S. Y. [Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292 (United States); Tian, W. Q. [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

2010-06-15

245

Hypergolic fuel detection using individual single walled carbon nanotube networks  

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

246

Effects of single-walled carbon nanotubes on soil microorganisms  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes (SWCNTs) are novel materials that have the potential to be used in various commercial fields due to their unique physicochemical properties. As a result of commercial development of nanotechnology, SWCNTs may be discharged to the soil environment with unknown consequences. However, there are as yet no data in the scientific literature that demonstrate the effects of SWCNTs on microbial function in soils. Therefore, we aimed to determine the effects of SWCNTs on soil microbial activity through a 2-week incubation study on urban soils supplemented with different concentrations of SWCNTs ranging from 0 to 1000 ?g CNT/g soil. Fluorometric test using fluorogenic substrates were employed for the measurement of several enzyme activities in soil samples. More specifically, we determined the changes in the activities of cellobiohydrolase, ?-1,4-glucosidase, ?-1,4-xylosidase, ?-1,4-N-acetylglucosaminidase, L-leucine aminopeptidase and acid phosphatase which play important roles in the carbon, nitrogen, and phosphorus cycles in response to the addition of SWCNTs. We found that microbial enzyme activities decreased as the concentrations of SWCNT added increased. The lowest enzyme activities were observed under 1000 ?g CNT/g soil. The overall pattern shows that enzyme activities decreased slightly in the first 2-3 days and increased in the later stage of the incubation. Our results suggest that relatively high concentrations of SWCNTs can inhibit microbial activities, and this may be due to microbial cell membrane damage caused by SWCNTs. However, further study needs to be conducted to determine the mechanism responsible for inhibitory effect of SWCNTs on soil microbial activity. It can be concluded that changes in the activities of extracellular enzymes can indicate the effect of SWCNTs on soil microorganisms and nutrient cycling.

Jin, L.; Chung, H.; Son, Y.

2011-12-01

247

Radiation effects in single-walled carbon nanotube papers  

SciTech Connect

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.

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

248

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

NASA Technical Reports Server (NTRS)

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.

Lebron, Marisabel; Meador, Michael A.

2003-01-01

249

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

E-print Network

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

Maruyama, Shigeo

250

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

SciTech Connect

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

Imazato, N.; Imano, M.; Hayashi, Y. [Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan)

2008-09-07

251

Optical Heating and Temperature Determination of Core-Shell Gold Nanoparticles and Single-Walled Carbon Nanotube Microparticles.  

PubMed

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

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

2014-11-01

252

Single-walled carbon nanotube-silicon nitride composites  

NASA Astrophysics Data System (ADS)

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 suspensions in order to optimize the pH and amount of adsorbed CTAB. The composite suspension viscosity was pH sensitive and adjusted accordingly before consolidation into three-dimensional solid parts using a rapid prototyping fabrication method called robocasting. High-density composites were produced using spark plasma sintering and structurally intact SWNTs were directly observed in the final sintered microstructure using scanning electron microscopy and Raman spectroscopy. When processed with SWNTs the highly insulative ceramic became electrically conductive and resulted in increased grindability for the otherwise hard to machine ceramic. The high hardness, fracture toughness and density of Si 3N4 was maintained for the composite due to the detailed development of colloidal processing and sintering methods used during fabrication. In addition, the thermal conductivity of the ceramic was reduced with the incorporation of well-dispersed SWNTs. Indentation load studies on the composites revealed sub-surface chipping and deformation around the indent before radial crack development indicating a degree of damage tolerance over the monolith. Along the wake of the crack SWNTs were also observed bridging the crack therefore showing their potential to act as toughening agents in brittle ceramics.

Corral, Erica Lorrane

253

Single-walled carbon nanotube networks in conductive composite materials.  

PubMed

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

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

2014-01-01

254

Fast Characterization of Magnetic Impurities in Single-Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

255

Noncovalent functionalization of single-walled carbon nanotubes by aromatic diisocyanate molecules: A computational study  

NASA Astrophysics Data System (ADS)

We investigate the noncovalent functionalization of metallic single-walled carbon nanotubes (SWCNT) (6,0) by 4,4?-methylene diphenyl diisocyanate (MDI) and toluene-2,4-diisocyanate (TDI) molecules using the density functional theory (DFT) method with van der Waals dispersion correction. The obtained local minima show the dependence between the molecular arrangement of the adsorbates on SWCNT surface and their binding energies. We analyze the interplay between the ?-? stacking interactions and isocyanate functional groups. For the analysis of the changes in the electronic structure we calculate the density of states (DOS) and charge density plots.

Goclon, Jakub; Kozlowska, Mariana; Rodziewicz, Pawel

2014-04-01

256

Breakdown of diameter selectivity in a reductive hydrogenation reaction of single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Reductive hydrogenation was applied to two types of single-walled carbon nanotubes with different diameter range. Alkali metal intercalation, followed by reaction with methanol, led to hydrogenated products. Both yield and selectivity of this reaction showed strong dependence on diameter, contrary to expectation based on simple curvature effects. The observed yield, as detected by thermogravimetry-mass spectrometry and 1H NMR, is drastically reduced in small-diameter tubes where the alkali dopant does not reach the inside of the bundles. Wide range optical transmission measurements were employed to determine the selectivity and indicate that besides higher yield, lower diameter selectivity occurs above a critical diameter.

Nemeth, Katalin; Jakab, Emma; Borondics, Ferenc; Tóháti, Hajnalka M.; Pekker, Áron; Bokor, Mónika; Verebélyi, Tamás; Tompa, Kálmán; Pekker, Sándor; Kamarás, Katalin

2015-01-01

257

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

258

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

SciTech Connect

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

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

2012-09-03

259

Effect of Environmental Temperatures on Elastic Properties of Single-Walled Carbon Nanotube  

Microsoft Academic Search

Based on a method of molecular structural mechanics (MSM), the effect of environmental temperature on elastic properties of armchair and zigzag single-walled carbon nanotubes is investigated. Single-walled carbon nanotubes with different chiral vectors are considered as a molecular structural mechanics model, which is composed of the discrete molecular structures through the carbon-to-carbon bonds. By considering the effect of environmental temperature

S. Q. Zhu; X. Wang

2007-01-01

260

Spectroscopic analysis of single-wall carbon nanotubes and carbon nanotube peapods  

Microsoft Academic Search

Raman spectra have been demonstrated repeatedly to be a very valuable tool for the analysis of new carbon phases such as fullerenes and single wall carbon nanotubes (SWCNTs). Recently it was demonstrated from TEM analysis that C60 can be encapsulated into SWCNTs. The structures have been given the name ‘peapods’. The concentration of the encapsulated ‘peas’ and the bonding structure

R. Pfeiffer; H. Kuzmany; W. Plank; T. Pichler; H. Kataura; Y. Achiba

2002-01-01

261

Adhesion and friction of a multiwalled carbon nanotube sliding against single-walled carbon nanotube  

Microsoft Academic Search

The adhesion and friction at crossed nanotube junctions were investigated in ambient by using an atomic force microscope (AFM) in tapping mode. A multiwalled carbon nanotube (MWNT) tip attached to a conventional AFM probe was scanned across a single-walled carbon nanotube (SWNT) suspended over a 2-mum -wide trench. The interaction between nanotubes was found to critically depend on the morphology

Bharat Bhushan; Xing Ling; Alain Jungen; Christofer Hierold

2008-01-01

262

Self-assembled three-dimensional conducting network of single-wall carbon nanotubes  

E-print Network

Self-assembled three-dimensional conducting network of single-wall carbon nanotubes Graciela B (Received 11 March 2004; accepted 8 June 2004) We described here the self-assembling of a three-dimensional array of single-wall nanotubes (SWNTs). The distinctive choice of materials allowed for the self

Hone, James

263

Adsorption of Bacillus subtilis on single-walled carbon nanotube aggregates, activated carbon and NanoCeram™  

Microsoft Academic Search

Adsorption equilibrium and kinetics of Bacillus subtilis spores on single-walled carbon nanotube aggregates were investigated to explore the possibility of using single-walled carbon nanotubes for concentration, detection and removal of pathogens from contaminated water sources. Batch adsorption experiments were conducted to determine adsorption kinetics and adsorption equilibrium of B. subtilis spores on single-walled carbon nanotube aggregates, activated carbon and NanoCeram™.

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

2009-01-01

264

Single-walled carbon nanotube buckypaper and mesophase pitch carbon/carbon composites  

NASA Astrophysics Data System (ADS)

Carbon/carbon composites consisting of single-walled carbon nanotube (SWCNT) buckypaper (BP) and mesophase pitch resin have been produced through impregnation of BP with pitch using toluene as a solvent. Drying, stabilization and carbonization processes were performed sequentially, and repeated to increase the pitch content. Voids in the carbon/carbon composite samples decreased with increasing impregnation process cycles. Electrical conductivity and density of the composites increased with carbonization by two to three times that of pristine BP. These results indicate that discontinuity and intertube contact barriers of SWCNTs in the BP are partially overcome by the carbonization process of pitch. The temperature dependence of the Raman shift shows that mechanical strain is increased since carbonized pitch matrix surrounds the nanotubes.

Park, Jin Gyu; Yun, Nam Gyun; Park, Young Bin; Liang, Richard; Lumata, Lloyd; Brooks, James; Zhang, Chuck; Wang, Ben

2011-03-01

265

Thermal conductivity of single-walled carbon nanotubes  

Microsoft Academic Search

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

J. Hone; M. Whitney; A. Zettl

1999-01-01

266

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

PubMed Central

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

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

2009-01-01

267

Thermal vibration and apparent thermal contraction of single-walled carbon nanotubes  

Microsoft Academic Search

It is of fundamental value to understand the thermo-mechanical properties of carbon nanotubes. In this paper, by using molecular dynamics simulation, a systematic numerical investigation is carried out to explore the natural thermal vibration behaviors of single-walled carbon nanotubes and their quantitative contributions to the apparent thermal contraction behaviors. It is found that the thermo-mechanical behavior of single-walled carbon nanotubes

Guoxin Cao; Xi Chen; Jeffrey W. Kysar

2006-01-01

268

Structural characterization of macroscopic single-walled carbon nanotube materials  

NASA Astrophysics Data System (ADS)

In this thesis, we studied the structural properties of macroscopic materials of single-walled carbon nanotubes (SWNTs) in the form of fibers, films and suspensions. We characterized the preferred orientations in partially aligned SWNT fibers and films, combining x-ray fiber diagram and polarized Raman scattering. Our texture model consists of an aligned fraction, characterized by the angular distribution width of tube axes, plus a completely unaligned fraction. For neat fibers extruded from SWNT/superacid suspensions through a small orifice, the distribution width and the aligned fraction both improve with decreasing orifice diameter. For magnetic field-aligned SWNT films deposited from surfactant suspensions, the aligning effects of deposition and external magnetic field force in the film plane are additive, the out-of-plane mosaic being narrower than the in-plane one. SWNTs dispersed in superacid or aqueous surfactant solutions are precursors for many applications. In oleum, SWNTs can be charged and protonated by H 2SO4 molecules. X-ray scattering indicates that H2SO 4 molecules align along nanotube axes to form cylindrical shells wrapped around nanotubes. This finding establishes the validity of a long-standing important but still debated physical chemistry concept, "structured solvent shells surrounding dissolved ions". Differential scanning calorimetry confirms that the partly ordered H2SO4 molecules are a new phase, with distinct freezing/melting behavior. X-ray scattering at low temperature further shows that crystallization of the bulk-like acid surrounding the structured shells is templated by the SWNTs. The specific orientation of the acid crystallites provides solid evidence for direct protonation of SWNT. We studied the morphologies of SWNT suspensions using small-angle neutron scattering. We observed rigid rod behavior from SWNTs dispersed in water using sodium dodecylbenzene sulfonate surfactant, suggesting that SWNTs exist mainly as individual tube and small ropes in the suspension. In many other surfactants and organic solvents, SWNTs form aggregates. In superacid, SWNTs dissolve as isolated individual tubes and small ropes at low concentration (˜00.01 wt%) while at high concentration, the tubes and ropes self-assemble into liquid crystalline strands of mobile solvated nanotube spaghettis, which exhibit a self-similar fractal-like structure.

Zhou, Wei

269

Single Walled Carbon Nanohorns as Photothermal Cancer Agents  

SciTech Connect

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

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

2011-01-01

270

Antimicrobial Biomaterials based on Single-Walled Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

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.

Aslan, Seyma

271

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

PubMed Central

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. PMID:24352224

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

2013-01-01

272

Theoretical Elastic Properties of Single Walled Carbon Nanotubes J. T. Alford, B. A. Landis, J. W. Mintmire  

E-print Network

Theoretical Elastic Properties of Single Walled Carbon Nanotubes J. T. Alford, B. A. Landis, J. W graphite. #12;- 2 - Introduction Single-walled carbon nanotubes (SWNTs) have attracted considerable carried many studies of single-walled carbon nanotubes using first-principles methods that take advantage

Mintmire, John W.

273

Role of PeptidePeptide Interactions in Stabilizing Peptide-Wrapped Single-Walled Carbon Nanotubes: A Molecular Dynamics Study  

E-print Network

Role of Peptide­Peptide Interactions in Stabilizing Peptide-Wrapped Single-Walled Carbon Nanotubes-Wrapped Single-Walled Carbon Nanotubes: A Molecular Dynamics Study Correspondence to: Steven O. Nielsen; e-mail: steven.nielsen@utdallas.edu ABSTRACT: Single-walled carbon nanotubes (SWNTs) have unique properties

Nielsen, Steven O.

274

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

E-print Network

Tip-enhanced Raman scattering on single-wall carbon nanotubes Niculina Peica, Christian Thomsen of the key spectroscopic signatures for both identification of single-wall carbon nanotubes (SWCNTs on single-wall carbon nanotubes - identification of Raman features that are not well visible with confocal

Nabben, Reinhard

275

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

E-print Network

Determination and mapping of diameter and helicity for single-walled carbon nanotubes using June 2005 The atomic structures of 124 single-walled carbon nanotubes, described by their diameter, the unique structure u,v can be assigned. We have examined 124 individual single-walled carbon nanotubes

Qin, Lu-Chang

276

Modifications of single-wall carbon nanotubes upon oxidative purification treatments  

NASA Astrophysics Data System (ADS)

A systematic characterization of single-wall carbon nanotube (SWCNT) material after successive purification steps, including reflux treatment with nitric acid, air oxidation, and annealing, has been performed. Inductively coupled plasma-optical emission spectroscopy shows that a considerable reduction of the metal impurities by up to 95% can be obtained by the nitric acid reflux treatment. During this process, Raman spectroscopy clearly proves that HNO3 molecules are intercalated into the bundles of SWCNTs. At the same time, SWCNTs have suffered a high degree of degradation and defects are being introduced. The subsequent thermal processes lead to the removal of further defect carbon materials and to the almost complete de-intercalation of the HNO3 molecules. Transmission electron microscopy reveals that the remaining SWCNT bundles tend to form thick bundles. Thus the applied purification process results in a high-purity SWCNT material with a drastically reduced content of metal nanoparticles and composed of large bundles of SWCNTs.

Martínez, M. T.; Callejas, M. A.; Benito, A. M.; Cochet, M.; Seeger, T.; Ansón, A.; Schreiber, J.; Gordon, C.; Marhic, C.; Chauvet, O.; Maser, W. K.

2003-07-01

277

Gas sensors based on single-wall carbon nanotubes and polypyrrole-coated carbon nanotubes  

Microsoft Academic Search

We have fabricated gas sensors based on single-wall carbon nanotubes and detected NH3 and NO2 gas. At the room temperature, the absorbed gas molecules are not easily detached from the CNT surface. So, we have testes the gas sensor at high temperatures and investigated the temperature dependences of electrical properties of CNTs above the room temperatures. Depending on the gas

Young Wook Chang; Je Seung Oh; Seung Hwan Yoo; Ji Hun Kim; Hyang Hee Choi; Kyung-Hwa Yoo

2007-01-01

278

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

E-print Network

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. ...

Heller, Daniel Alan

279

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

E-print Network

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

Deshmukh, Sujay

2007-04-25

280

Robust Cyclohexanone Selective Chemiresistors Based on Single-Walled Carbon Nanotubes  

E-print Network

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 ...

Frazier, Kelvin Mitchell

281

Catalytic CVD Synthesis of Single-Walled Carbon Nanotubes from Alcohol  

E-print Network

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

Maruyama, Shigeo

282

Figure 1: Optical absorbance spectra indicating average diameter of vertically aligned single-walled carbon  

E-print Network

spectroscopy. We found that there is some critical concentration or catalyst density below which SWNTsFigure 1: Optical absorbance spectra indicating average diameter of vertically aligned single-walled carbon nanotubes synthesized using different concentrations of molybdenum catalyst. Diameter

Maruyama, Shigeo

283

Excitonic effects on coherent phonon dynamics in single-wall carbon nanotubes  

E-print Network

We discuss how excitons can affect the generation of coherent radial breathing modes in the ultrafast spectroscopy of single-wall carbon nanotubes. Photoexcited excitons can be localized spatially and give rise to a spatially ...

Nugraha, A. R. T.

284

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

E-print Network

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 ...

Dresselhaus, Mildred

285

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

PubMed

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

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

2014-12-01

286

Purification and chiral selective enrichment of single-walled carbon nanotubes for macroelectronic applications.  

E-print Network

??This thesis focuses on the purification and chiral selective enrichment of single-walled carbon nanotubes (SWCNTs) obtained from cobalt incorporated MCM-41 catalyst (Co-MCM-41) and their potential… (more)

Wei, Li.

2011-01-01

287

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

E-print Network

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 ...

Nair, Nitish

2009-01-01

288

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

E-print Network

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

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

2012-11-09

289

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

E-print Network

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 ...

Vieira, Bruno G.?M.

290

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

E-print Network

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

Iverson, Nicole M.

291

Evidence for substitutional boron in doped single-walled carbon nanotubes  

SciTech Connect

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

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

2010-05-03

292

Diameter Tuning of Single Walled Carbon Nanotubes with Reaction Temperature Using a Co Monometallic Catalyst  

SciTech Connect

Metal incorporated MCM-41 has proven to be a valuable template for the growth of narrow distributions of single-walled carbon nanotubes (SWNT), producing samples with a wide range of different mean diameters. The ability to obtain narrow diameter distributions at different mean diameters is important for applications that require particular (n,m) nanotubes. Another advantage of this system is the ease of cleaning and low metal content as compared to bimetallic systems. In this Article, we show that Co-MCM-41 allows diameter tuning of SWNT produced over a broad diameter range (from 0.6-0.8 to 1.8-2.0 nm) by changing reaction temperature. The lower temperature reaction provides a robust means to obtain very small diameter SWNT. X-ray absorption experiments show that the change in SWNT diameter correlates with the change in metal particle size.

Li, N.; Wang, X; Ren, F; Haller, G; Pfefferle, L

2009-01-01

293

Increasing the efficiency of charge extraction limited poly-(3-hexylthiophene):[6,6] phenyl C61 butyric acid methyl ester solar cells using single walled carbon nanotubes with metallic characteristics  

NASA Astrophysics Data System (ADS)

The charge transport properties of bulk heterojunction solar cells formed by blending poly-(3-hexylthiophene) (P3HT) and [6,6] phenyl C61 butyric acid methyl ester (PCBM) were improved by doping with single walled carbon nanotubes (SWNTs). The SWNTs used were not functionalized, and contained both metallic and semiconducting tubes. Their work function was found to be 4.89 eV. Unlike P3HT:PCBM interface, the P3HT:SWNT interface has been inefficient for charge generation. Using SWNTs at concentrations below 1 wt. %, the solar cell efficiency increased from 2.86% to 3.52% for 80 nm devices and from 2% to 3% in 125 nm devices at low light intensities. In both cases, the increment is because of higher fill factor with no change in short circuit current density and open circuit voltage. At higher light intensities, a 43% increase in fill factor and a 37% increase in short circuit current density were obtained, which doubled the efficiency. These improvements were primarily because of reduced recombination through improved charge extraction by SWNTs.

Mallajosyula, Arun Tej; Sundar Kumar Iyer, S.; Mazhari, Baquer

2011-06-01

294

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

Microsoft Academic Search

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

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

2003-01-01

295

Single-wall carbon nanotube-based voltammetric sensor and biosensor  

Microsoft Academic Search

The pH-sensitive property of the single-wall carbon nanotube modified electrode based on the electroactive group on the single-wall carbon nanotube was explored by differential pulse voltammetry technique. In pH range 1–13 investigated in Britton–Robinson (B–R) buffer, the anodic peak shifted negatively along with the increase of pH exhibiting a reversible Nernstian response. Experiments were carried out to investigate the response

Zhiai Xu; Xu Chen; Xiaohu Qu; Jianbo Jia; Shaojun Dong

2004-01-01

296

Formation and Raman spectroscopy of single wall carbon nanotubes synthesized by CO 2 continuous laser vaporization  

Microsoft Academic Search

Single wall carbon nanotubes of tubule diameter 1.0–1.7nm were synthesized by the irradiation of continuous CO2 laser (500–900W) onto a graphite–Co\\/Ni composite target at room temperature. We suggest that the high temperature plays a unique key role in the growth of single-wall carbon nanotubes in the laser ablation method, while laser wavelength is less important. The transmission electron microscope observations

H. Zhang; K. Chen; Y. He; Y. Zhu; Y. Chen; C. Wu; J. Wang; J. H. Liao; S. H. Liu

2001-01-01

297

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

NASA Astrophysics Data System (ADS)

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.

Caldwell, Robert Victor

298

van der Waals interaction between a microparticle and a single-walled carbon nanotube  

SciTech Connect

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

Blagov, E. V.; Mostepanenko, V. M. [Noncommercial Partnership 'Scientific Instruments', Tverskaya Street 11, Moscow 103905 (Russian Federation); Klimchitskaya, G. L. [North-West Technical University, Millionnaya Street 5, St. Petersburg 191065 (Russian Federation)

2007-06-15

299

Effects of nanotube alignment and measurement direction on percolation resistivity in single-walled carbon nanotube films  

E-print Network

alignment and measurement direction on the resistivity in single-walled carbon nanotube films. These films Single-walled carbon nanotube CNT two-dimensional 2D networks and three-dimensional 3D films are promisEffects of nanotube alignment and measurement direction on percolation resistivity in single-walled

Ural, Ant

300

Novel Actuating System Based on a Composite of Single-Walled Carbon Nanotubes and an Ionomeric Polymer  

E-print Network

Novel Actuating System Based on a Composite of Single-Walled Carbon Nanotubes and an Ionomeric, 5]. The discovery of single-walled carbon nanotube (SWNT) electro-mechanical actuation [6 We report the fabrication and characterization of a novel composite material based on single walled

Euler, William B.

301

PHYSICAL REVIEW B 83, 113404 (2011) Intrinsic radial breathing oscillation in suspended single-walled carbon nanotubes  

E-print Network

of RBM oscillations of structurally defined single-walled carbon nanotubes (SWNTs) by combining Raman.67.Ch, 61.46.Np, 73.22.-f, 78.30.Na I. INTRODUCTION Single-walled carbon nanotubes (SWNTs) are onePHYSICAL REVIEW B 83, 113404 (2011) Intrinsic radial breathing oscillation in suspended single-walled

Wang, Feng

302

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

E-print Network

Electronic transitions in single-walled carbon nanotubes: A resonance Raman study P. M. Rafailov Resonance excitation profiles of the high-frequency peaks in the Raman spectra of single-walled carbon experimentally through comparative Raman measurements on graphite, mul- tiwalled and single-walled nanotubes.5

Nabben, Reinhard

303

Coupled thermo-mechanics of single-wall carbon nanotubes  

E-print Network

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

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

2010-01-01

304

Atomic Force Microscopy of Single-Walled Carbon Nanotubes Using Carbon Nanotube Tip  

Microsoft Academic Search

We succeeded in observing individual single-walled carbon nanotubes (SWNTs) using an atomic force microscope (AFM) in the tapping mode by paying attention to the preparation of both samples and AFM tips. To disentangle the bundles of SWNTs, we added a small amount of amine into N,N-dimethylformamide. To achieve a high resolution in tapping-mode AFM imaging, we used carbon nanotube (CNT)

Nami Choi; Takayuki Uchihashi; Hidehiro Nishijima; Takao Ishida; Wataru Mizutani; Seiji Akita; Yoshikazu Nakayama; Mitsuru Ishikawa; Hiroshi Tokumoto

2000-01-01

305

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

Microsoft Academic Search

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

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

1999-01-01

306

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

PubMed

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

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

2010-03-19

307

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

E-print Network

Cancer photothermal therapy in the near-infrared region by using single-walled carbon nanotubes-walled carbon nanotubes SWNTs have a high op- tical absorbance in the near-infrared NIR region. In this special, such as gold nanoshells6­8 and carbon nanotubes,9,10 with unique optical properties such as a strong near-infrared

Resasco, Daniel

308

Synthesis of single-walled carbon nanotubes by chemical vapor deposition and their electronic devices  

Microsoft Academic Search

This dissertation describes a series of studies on chemical vapor deposition (CVD) synthesis of single-walled carbon nanotubes (SWNTs) and their electronic applications. A novel finding on the relationship between the carbon feeding rate and the SWNT diameters and growth efficiency is summarized. Electronic devices, including polymer electrolyte gated carbon nanotube field effect transistors and Schottky barrier diodes, are fabricated and

Chenguang Lu

2006-01-01

309

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

E-print Network

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

Nabben, Reinhard

310

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

DOEpatents

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.

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

2008-10-07

311

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

DOEpatents

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.

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

2014-09-23

312

Conductivity enhancement in single-walled carbon nanotube bundles doped with K and Br  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes (SWNTs), prepared by metal-catalysed laser ablation of graphite, form close-packed bundles or `ropes. These rope crystallites exhibit metallic behaviour above 50K (ref. 2), and individual tubes behave as molecular wires, exhibiting quantum effects at low temperatures,. They offer an all-carbon host lattice that, by analogy with graphite and solid C60 (ref. 6), might form intercalation compounds with interesting electronic properties, such as enhanced electrical conductivity and superconductivity. Multi-walled nanotube materials have been doped with alkali metals and FeCl3 (ref. 8). Here we report the doping of bulk samples of SWNTs by vapour-phase reactions with bromine and potassium-a prototypical electron acceptor and donor respectively. Doping decreases the resistivity at 300K by up to a factor of 30, and enlarges the region where the temperature coefficient of resistance is positive (the signature of metallic behaviour). These results suggest that doped SWNTs represent a new family of synthetic metals.

Lee, R. S.; Kim, H. J.; Fischer, J. E.; Thess, A.; Smalley, R. E.

1997-07-01

313

Effect of carbon network defects on the electronic structure of semiconductor single-wall carbon nanotubes  

Microsoft Academic Search

For a single-wall (14, 0) carbon nanotube, the total density of electronic states of the ideal structure and of some possible\\u000a defect structures is calculated in the framework of the band theory approach using Gaussian-type orbitals and the approximation\\u000a of the generalized density gradient. It is shown that allowance for defects of the atomic structure of a nanotube makes it

P. V. Avramov; B. I. Yakobson; G. E. Scuseria

2004-01-01

314

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

Microsoft Academic Search

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

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

2010-01-01

315

High Purity and Low-Temperature Generation of Single-Walled Carbon Nanotubes by a Catalytic CVD Method  

E-print Network

High Purity and Low-Temperature Generation of Single-Walled Carbon Nanotubes by a Catalytic CVD chemical vapor deposition technique to generate high-purity single walled carbon nanotubes (SWNTs) is demonstrated. Pure SWNTs without amorphous carbon coating, multi-walled carbon nanotubes, carbon nanoparticles

Maruyama, Shigeo

316

Three-dimensional polymeric structures of single-wall carbon nanotubes  

SciTech Connect

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.

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

317

Single-walled carbon nanotubes/hydroxyapatite coatings on titanium obtained by electrochemical deposition  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes/hydroxyapatite (SWNTs/HA) composite coatings were successfully fabricated by electrochemical deposition technique. Different concentrations of SWNTs were incorporated into the apatite coating by adding functionalized SWNTs into the electrolyte. Homogeneous and crack-free SWNTs/HA composite coatings were achieved and the coatings had higher crystallinity compared to pure HA coating. In addition, the highest bonding strength of the SWNTs/HA coating reached 25.7 MPa, which was nearly 70% higher than that of pure HA coating. The in-vitro cellular biocompatibility tests revealed that SWNTs/HA composite coatings exhibited higher in-vitro bioactivity than that of pure HA coating and pure titanium (Ti). It suggests that SWNTs/HA composite coating may have enormous potential applications in the field of biomaterials, especially for the metal implants.

Pei, Xibo; Zeng, Yongxiang; He, Rui; Li, Zhongjie; Tian, Lingyang; Wang, Jian; Wan, Qianbing; Li, Xiaoyu; Bao, Hong

2014-03-01

318

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

PubMed

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

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

2014-10-28

319

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

NASA Astrophysics Data System (ADS)

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

Chao, Wan-Jung

2011-12-01

320

Heteroepitaxial Growth of Single-Walled Carbon Nanotubes from Boron Nitride  

NASA Astrophysics Data System (ADS)

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.

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

321

Heteroepitaxial growth of single-walled carbon nanotubes from boron nitride.  

PubMed

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

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

322

Heteroepitaxial Growth of Single-Walled Carbon Nanotubes from Boron Nitride  

PubMed Central

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

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

323

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

324

All-printed and transparent single walled carbon nanotube thin film transistor devices  

NASA Astrophysics Data System (ADS)

We present fully transparent single-walled all-carbon nanotube thin film transistors (SWCNT TFT) fabricated using low-cost inkjet printing methods. Such a demonstration provides a platform towards low cost fully printed transparent electronics. The SWCNT TFTs were printed with metallic and semiconducting SWCNT using a room temperature printing process, without the requirement of expensive cleanroom facilities. The unoptimized SWCNT TFTs fabricated exhibited an Ion/off ratio of 92 and mobility of 2.27 cm2V-1s-1 and transmissivity of 82%. The combination of both high electrical performance and high transparency make all-SWCNT TFTs desirable for next generation transparent display backplanes and products such as Google Glass.

Sajed, Farzam; Rutherglen, Christopher

2013-09-01

325

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

PubMed

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

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

2007-07-01

326

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

Microsoft Academic Search

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

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

2003-01-01

327

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

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

Li, Mo

328

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

Microsoft Academic Search

We report a study of second-order combination and overtone modes in highly ordered pyrolytic graphite (HOPG), in single-wall carbon nanotube (SWNT) bundles and in isolated SWNTs. We found both dispersive and nondispersive Raman bands in the range 1650-2100 cm-1, and we show that the appearance and frequency versus laser energy Elaser behavior of these features are in agreement with predictions

V. W. Brar; Ge. G. Samsonidze; M. S. Dresselhaus; G. Dresselhaus; R. Saito; A. K. Swan; M. S. Ünlü; B. B. Goldberg; A. G. Souza Filho; A. Jorio

2002-01-01

329

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

Microsoft Academic Search

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

Ali Kara; Nalan Tekin; Saadet Beyaz; Hakan Köçkar

330

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

E-print Network

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

Maruyama, Shigeo

331

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

E-print Network

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

Maruyama, Shigeo

332

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

SciTech Connect

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.

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

333

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

334

Radial breathing mode of single-walled carbon nanotubes: Optical transition energies and chiral-index assignment  

E-print Network

Radial breathing mode of single-walled carbon nanotubes: Optical transition energies and chiral. INTRODUCTION Single-walled carbon nanotubes are tiny cylinders made out of carbon.1­3 They have many unique of carbon nanotubes in aqueous suspen- sions by resonant Raman scattering of the radial breathing mode. We

Nabben, Reinhard

335

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

Microsoft Academic Search

Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Y-junction carbon nanotubes with smaller\\u000a diameters than those obtained by the pyrolysis of organometallic-thiophene mixtures. In the presence of water vapour, the\\u000a pyrolysis of organometallic-hydrocarbon mixtures yields single-walled nanotubes, as well as relatively narrow-diameter carbon\\u000a nanotubes with Y-junctions. Pyrolysis of organometallic-hydrocarbon mixtures, in the absence of water

F. L. Deepak; A. Govindaraj; C. N. R. Rao

2006-01-01

336

Iron filled single-wall carbon nanotubes - A novel ferromagnetic medium  

Microsoft Academic Search

In our study we use a highly efficient and simple methodology based on\\u000a wet chemistry to fill single-wall carbon nanotubes (SWCNTs) with iron,\\u000a and thus create quantum wires in a bulk. The research shown is unique in\\u000a that it is the first experimental single-wall carbon nanotubes that have\\u000a iron continuously within their core for extended length scale. The\\u000a resulting Fe-filled

E Borowiak-Palen; E. Mendoza; A. Bachmatiuk; M. H. Rummeli; T. Gemming; J. Nogues; V. Skumryev; R. J. Kalenczuk; T. Pichler; S. R. P. Silva

2006-01-01

337

Photoexcitation of the triplet exciton in single wall carbon nanotubes  

E-print Network

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), ...

Santos, Tiffany S.

338

Spatially resolved scanning tunneling spectroscopy on single-walled carbon nanotubes L. C. Venema, J. W. Janssen, M. R. Buitelaar,* J. W. G. Wildoer, S. G. Lemay, L. P. Kouwenhoven, and C. Dekker  

E-print Network

Spatially resolved scanning tunneling spectroscopy on single-walled carbon nanotubes L. C. Venema of a metallic single-walled nanotube. They attributed this result to a specific arrangement of pentagons the electronic band structure of carbon nanotubes as well as to locally investigate electronic features

339

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

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

340

Work functions of functionalized singled-walled carbon nanotubes  

E-print Network

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 ...

Ryu, Janet. (Janet Sun)

2006-01-01

341

Ruthenium porphyrin functionalized single-walled carbon nanotube arrays--a step toward light harvesting antenna and multibit information storage.  

PubMed

Ruthenium porphyrin functionalized single-walled carbon nanotube arrays have been prepared using coordination of the axial position of the metal ion onto 4-aminopyridine preassembled single-walled carbon nanotubes directly anchored to a silicon(100) surface (SWCNTs-Si). The formation of these ruthenium porphyrin functionalized single-walled carbon nanotube array electrodes (RuTPP-SWCNTs-Si) has been monitored using infrared spectroscopy (IR), differential pulse voltammetry (DPV), atomic force microscopy (AFM), laser desorption time-of-flight mass spectroscopy (LDI-TOF-MS), UV-vis spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. Electrochemical results show two successive one-electron reversible redox waves. The surface concentration of the ruthenium porphyrin molecules is 3.44 x 10 (-8) mol cm (-2). Optical results indicate that the immobilization of ruthenium porphyrin enhances the light absorption of SWCNTs-Si surfaces in the visible light region. Moreover mixed assembly of ferrocene/porphyrin onto carbon nanotube arrays has been achieved by altering the ratio of two redox-active species in the deposition solution. These results suggest the ruthenium porphyrin modified electrodes are excellent candidates for molecular memory devices and light harvesting antennae. PMID:18597433

Yu, Jingxian; Mathew, Simon; Flavel, Benjamin S; Johnston, Martin R; Shapter, Joe G

2008-07-01

342

Dispersion of Single-Walled Carbon Nanotubes in Aqueous Solutions of the Anionic Surfactant NaDDBS  

E-print Network

Dispersion of Single-Walled Carbon Nanotubes in Aqueous Solutions of the Anionic Surfactant Na Form: October 2, 2003 The insolubility of single-walled carbon nanotubes (SWNT) in either water to different extents, the exact mechanism by which carbon nanotubes and the different surfactants interact

Resasco, Daniel

343

Catalytic CVD Synthesis of Single-Walled Carbon Nanotubes from Shigeo Maruyama, Yuhei Miyauchi and Shohei Chiashi  

E-print Network

Catalytic CVD Synthesis of Single-Walled Carbon Nanotubes from Fullerene Shigeo Maruyama, Yuhei, Bunkyo-ku, Tokyo 113-8656, Japan Single-walled carbon nanotubes (SWNTs) were synthesized by a catalytic CVD technique using fullerene as the carbon source. Powder of C$_{60}$ in a quartz test tube and Fe

Maruyama, Shigeo

344

Adhesion energy of single wall carbon nanotube loops on various substrates Department of Physics, Shaoxing University -508,  

E-print Network

Adhesion energy of single wall carbon nanotube loops on various substrates Tianjun LI Department. In this paper, we present force spectroscopy experiments of a single wall carbon nanotube loop using our home is a potentially powerful technique to character- ize the adhesion properties of carbon nanotubes or nano wires

Boyer, Edmond

345

The effect of boundary conditions on the vibrations of armchair, zigzag, and chiral single-walled carbon nanotubes  

E-print Network

of armchair, zigzag, and chiral single-walled carbon nanotubes Polina Pine,1,a) Yuval E. Yaish,2 and Joan of the vibrational modes of single-walled carbon nanotubes (SWCNTs), on achieving extremely high Q values. Appl. Phys. 110, 094308 (2011) Thermal transport in double-wall carbon nanotubes using heat pulse J

Adler, Joan

346

Polyglycerol-derived amphiphiles for single walled carbon nanotube suspension  

NASA Astrophysics Data System (ADS)

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.

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

2010-06-01

347

Iijima Ichihashi (1) (single-walled carbon nanotubes, SWNTs)  

E-print Network

CVD (chemical vapor deposition) SWNTs SWNTs CVD Fe(CO)5 HiPco (high pressure carbon monoxide) (3) CVD (alcohol catalytic chemical vapor deposition, ACCVD) (4) CoMoCAT (cobalt Monoxide Catalytic CVD (COCCVD) Method Toshiaki NISHII *3 and Shigeo MARUYAMA *3 Electric Power Development

Maruyama, Shigeo

348

THERMAL PROPERTIES OF SINGLE-WALLED CARBON NANOTUBES Shigeo MARUYAMA  

E-print Network

SWNT ACCVD SWNT CVD (Catalytic chemical vapor deposition, CCVD Smalley HiPco (High Pressure for nanotube-junction, bundle, and water-nanotubes cases. Recent developments of catalytic CVD generation-purity SWNTs can be generated at relatively low CVD temperatures from metal catalytic particles supported

Maruyama, Shigeo

349

Modifying the electronic structure of semiconducting single-walled carbon nanotubes by Ar+ ion irradiation  

Microsoft Academic Search

Local controllable modification of the electronic structure of carbon nanomaterials is important for the development of carbon-based nanoelectronics. By combining density-functional theory simulations with Ar-ion-irradiation experiments and low-temperature scanning tunneling microscopy and spectroscopy (STM\\/STS) characterization of the irradiated samples, we study the changes in the electronic structure of single-walled carbon nanotubes due to the impacts of energetic ions. As nearly

Antti Tolvanen; Gilles Buchs; Pascal Ruffieux; Pierangelo Gröning; Oliver Gröning; Arkady V. Krasheninnikov

2009-01-01

350

Growth of horizontally aligned single-walled carbon nanotubes on anisotropically etched silicon substrate  

Microsoft Academic Search

Directional controllability of single-walled carbon nanotubes (SWNTs) is an important issue for future nanoelectronics applications. For direct integration of carbon nanotubes with modern electronics, aligned growth of carbon nanotubes on SiO2\\/Si is desirable. We developed a new method to horizontally align SWNTs directly on SiO2\\/Si substrate by creating trenches on Si(100) through anisotropic etching followed by thermal oxidation. The V-shaped

Carlo M. Orofeo; Hiroki Ago; Tatsuya Ikuta; Koji Takahasi; Masaharu Tsuji

2010-01-01

351

Water Solubilization of Single-Walled Carbon Nanotubes by Functionalization with Glucosamine  

Microsoft Academic Search

Water solubilization of single-walled carbon nanotubes (SWNTs) has been achieved by functionalizing the SWNT with glucosamine. The grafting of glucosamine to the nanotubes was attained by producing acyl chloride on the carboxylic groups associated with the nanotubes. Subsequently, amide bonds were formed between the glucosamine and the SWNT. This grafting results in solubility of SWNT in water, which ranges from

Francisco Pompeo; Daniel E. Resasco

2002-01-01

352

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

E-print Network

. The thermal conductivity contrast between liquid and solid state was found to increase with increasing SWCNT-8 Recently, Zheng et al.9 reported a thermal conductivity contrast between liquid and solid state by a factorAnomalous thermal conduction characteristics of phase change composites with single walled carbon

Maruyama, Shigeo

353

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

E-print Network

/emission of light polarized parallel to the tube axis, known as the antenna effect. On the other hand, GPolarized Raman and Photoluminescence Characterization of Vertically Aligned Single-Walled Carbon of Mechanical Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, JAPAN Polarized Raman

Maruyama, Shigeo

354

Peptides that non-covalently functionalize single-walled carbon nanotubes to give controlled solubility characteristics  

Microsoft Academic Search

Methods which solubilize single-walled carbon nanotubes (SWNTs) in water as individuals, not bundles, while retaining their unique electronic, photonic and mechanical properties are highly desirable. Furthermore, functionalization with a diverse array of selectable chemical moieties would allow the range of useful applications to be significantly extended and may permit the designed assembly of SWNT networks. This paper presents a series

Leah S. Witus; John-David R. Rocha; Virany M. Yuwono; Sergey E. Paramonov; R. Bruce Weisman; Jeffrey D. Hartgerink

2007-01-01

355

Fluorescence from a gelatin-based film containing isolated and orientated single-walled carbon nanotubes  

E-print Network

Fluorescence from a gelatin-based film containing isolated and orientated single-walled carbon a technique to fabricate a gelatin thin film that contains orientated and individually dispersed single with gelatin, and the gelatin-SWNTs solution was spread over a SiO2 substrate by sliding a wire-bar uniformly

Maruyama, Shigeo

356

Reversible water-solubilization of single-walled carbon nanotubes by polymer wrapping  

Microsoft Academic Search

Single-walled carbon nanotubes (SWNTs) have been solubilized in water by non-covalently associating them with linear polymers, most successfully with polyvinyl pyrrolidone (PVP) and polystyrene sulfonate (PSS). This association is characterized by tight, uniform association of the polymers with the sides of the nanotubes. A general thermodynamic drive for this wrapping is discussed, wherein the polymer disrupts both the hydrophobic interface

Michael J. O'Connell; Peter Boul; Lars M. Ericson; Chad Huffman; Yuhuang Wang; Erik Haroz; Cynthia Kuper; Jim Tour; Kevin D. Ausman; Richard E. Smalley

2001-01-01

357

Ionic self-assembly provides dense arrays of individualized, aligned single-walled carbon nanotubes.  

PubMed

Wrap and stack: Polyanionic [arylene]ethynylene polymers that helically wrap single-walled carbon nanotubes (SWNTs) enable the production of functionalized SWNTs that are soluble in organic solvents. These SWNTs can assemble into structures featuring aligned nanotubes that maintain the optoelectronic properties of individual SWNTs. PMID:24130000

Olivier, Jean-Hubert; Deria, Pravas; Park, Jaehong; Kumbhar, Amar; Andrian-Albescu, Maria; Therien, Michael J

2013-12-01

358

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

E-print Network

High-Purity Catalytic CVD Generation of Single-Walled Carbon Nanotubes from Alcohol Shigeo Maruyama developed a new simple catalytic chemical vapor deposition (CCVD) technique to generate high-purity single]. The low-pressure vapor of ethanol or methanol was introduced to catalysts on a quartz boat inside

Maruyama, Shigeo

359

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

E-print Network

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

Maruyama, Shigeo

360

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

E-print Network

1 Air-Stable High-Efficiency Solar Cells Using Improved Single-Walled Carbon Nanotube Films Kehang 11% power conversion efficiency (PCE) with the stability of more than six months in air by exploiting intensities. The high efficiency and stability demonstrated in this study make SWNT/Si solar cell very

Maruyama, Shigeo

361

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

E-print Network

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

Maruyama, Shigeo

362

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

E-print Network

Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Non-stationary heat conduction in a single of the simulations exhibit non-Fourier heat conduction where the distinct amount of heat is transported in a wavelike

Maruyama, Shigeo

363

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

E-print Network

Diffusive-Ballistic Heat Conduction along a Single-Walled Carbon Nanotube Shigeo Maruyama *E-mail address: maruyama@photon.t.u-tokyo.ac.jp The diffusive-ballistic heat conduction of finite unique stationary and non-stationary heat conduction characteristics [3,4]. Furthermore, several issues

Maruyama, Shigeo

364

TEMPERATURE MEASUREMENTS OF SINGLE-WALLED CARBON NANOTUBES BY RAMAN SCATTERINGS  

E-print Network

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

Maruyama, Shigeo

365

Alcohol Vapor Sensors Based on Single-Walled Carbon Nanotube Field  

E-print Network

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

Kim, Philip

366

The influence of single-walled carbon nanotube structure on the electromagnetic interference shielding  

E-print Network

The influence of single-walled carbon nanotube structure on the electromagnetic interference.01­15%) have been evaluated for electromagnetic interference (EMI) shielding effectiveness (SE) in the X and aerospace sectors with uses such as electrostatic dissipation, electromagnetic interference (EMI) shielding

Gao, Hongjun

367

Polarization State Control of Light by Single-Walled Carbon Nanotubes  

E-print Network

absorption. Fig. 2. Experimental setup for measuring polarization change induced by SWCNT film on quartz subsPolarization State Control of Light by Single-Walled Carbon Nanotubes S. Yoo, Y. Jung, D. Lee, W. T by catalytic CVD on quartz plate. We report the control of both the polarization state and transmission

Maruyama, Shigeo

368

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

E-print Network

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

Natelson, Douglas

369

Large-scale synthesis of single-walled carbon nanohorns by submerged arc  

Microsoft Academic Search

We report on the synthesis of single-walled carbon nanohorns (SWNHs) by arc discharge between two graphite electrodes submerged in liquid nitrogen. The product in its powder form was found to consist of spherical aggregates with sizes in the range of 50-100 nm. The nanohorns are characterized by transmission electron microscopy (TEM), Raman and electron energy loss spectroscopies and surface area

H. Wang; M. Chhowalla; N. Sano; S. Jia; G. A. J. Amaratunga

2004-01-01

370

Highly stretchable, integrated supercapacitors based on single-walled carbon nanotube films with continuous reticulate architecture.  

PubMed

Highly stretchable, integrated, single-walled carbon nanotube (SWCNT) film supercapacitors are prepared by combining directly grown SWCNT films with continuous reticulate architecture with polydimethylsiloxane with enhanced prestrain. The performance of the prepared stretchable supercapacitors remains nearly unchanged even during the stretching process under 120% strain. PMID:23255187

Niu, Zhiqiang; Dong, Haibo; Zhu, Bowen; Li, Jinzhu; Hng, Huey Hoon; Zhou, Weiya; Chen, Xiaodong; Xie, Sishen

2013-02-20

371

Aqueous-phase synthesis of monodisperse plasmonic gold nanocrystals using shortened single-walled carbon nanotubes  

PubMed Central

Monodisperse gold nanocrystals with unique near-infrared optical properties were synthesized by simple mixing of highly shortened and well disperse single-walled carbon nanotubes and chloroauric acid in water at ambient conditions with a step-wise increase of gold ion concentration. PMID:20737105

Kim, Jin-Woo; Moon, Hyung-Mo; Benamara, Mourad; Sakon, Joshua; Salamo, Gregory J.; Zharov, Vladimir P.

2015-01-01

372

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

E-print Network

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

Maruyama, Shigeo

373

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

Microsoft Academic Search

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

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

2003-01-01

374

Magnetoresistance devices based on single-walled carbon nanotubes Oded Hod and Eran Rabania  

E-print Network

Magnetoresistance devices based on single-walled carbon nanotubes Oded Hod and Eran Rabania School demonstrate the physical principles for the construction of a nanometer-sized magnetoresistance device based large magnetoresistance have been demonstrated based on the Zeeman spin splitting of individual

Rabani, Eran

375

Atomic Layer Deposition on Suspended Single-Walled Carbon Nanotubes via  

E-print Network

). Approximately 0.5 nm of ALD aluminum oxide (Al2O3)9,10 was deposited on the electrode surfaces to prevent, and mechanical properties of the nanotubes. Atomic layer deposition (ALD) on single-walled carbon nanotubes to produce a benign dielectric/SWNT interface that does not adversely affect the electrical properties

376

Crosslinked polymer sheaths for dispersing individual single-walled carbon nanotubes in nonaqueous solvents  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes have been suspended individually in water by encasing them in a thin, uniform layer of the crosslinkable polymer poly (N-vinylpyrrolidone-co-allylamine). When this polymer is crosslinked under dilute conditions, the polymer sheath, formerly stabilized by the hydrophobic effect, becomes stable to changes in the solvent system.

Ojha, L. R.; Tchoul, M. N.; Bastola, K. P.; Ausman, K. D.

2013-11-01

377

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

E-print Network

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

Maruyama, Shigeo

378

Ultrafast Optical Spectroscopy of Chirality-Resolved Single-Walled Carbon Nanotubes  

Microsoft Academic Search

Single-walled carbon nanotubes (SWCNTs) represent one-dimensional (1D) systems that can be used to explore a variety of interesting physical phenomena. However, their linear and nonlinear optical properties have been poorly explored up to now due to the complex interactions between different tubes in macroscopic samples leading to \\

G. N. Ostojic; S. Zaric; M. Pontier-Johnson; B. E. Brinson; J. Kono; Y. D. Jho; M. S. Strano; V. C. Moore; R. H. Hauge; R. E. Smalley

2003-01-01

379

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

E-print Network

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

Adler, Joan

380

A framework for stress computation in single-walled carbon nanotubes under uniaxial tension  

Microsoft Academic Search

A procedure is proposed for computing the stresses in an armchair single-walled carbon nanotube (SWCNT) under uniaxial tension. Computation is based on molecular dynamics simulations and the virial stress theorem. The proposed approach is compared with other methods used in the literature for calculating the stresses in CNTs. The loading is applied under two different boundary conditions and different strain

Tarek Ragab; Cemal Basaran

2009-01-01

381

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...

382

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 ...

383

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

Microsoft Academic Search

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

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

384

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

SciTech Connect

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.

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

2009-01-01

385

Where the K are in Doped Single Walled Carbon Nanotube Crystals  

E-print Network

9/3/97 Nature Where the K are in Doped Single Walled Carbon Nanotube Crystals G. Gao, T. Cagin the tubes, we find the optimum stoichiometry to be KC 16 , leading to a trigonal crystal with a tube­tube trigonal (closest packed) and square packing of the tubes. The Young's modulus per tube along the tube axis

Ã?agin, Tahir

386

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

NASA Technical Reports Server (NTRS)

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.

Nikolaev, Pavel

2009-01-01

387

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

E-print Network

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

Maruyama, Shigeo

388

Electro-oxidized Epitaxial Graphene Channel Field-Effect Transistors with Single-Walled Carbon Nanotube Thin Film  

E-print Network

Electro-oxidized Epitaxial Graphene Channel Field-Effect Transistors with Single-Walled Carbon the introduction of the reaction medium into the graphene galleries during electro-oxidation. The device-effect transistors were fabricated on the electro-oxidized and pristine graphene channels using single-walled carbon

389

Investigations of single-wall carbon nanotube growth by time-restricted laser vaporization Alex A. Puretzky,1,2  

E-print Network

limits of the growth rates of SWNT's were estimated as 0.6 and 5.1 m/s for the typical nanosecond NdInvestigations of single-wall carbon nanotube growth by time-restricted laser vaporization Alex A-22100 Received 1 February 2002; published 24 June 2002 The growth times of single-wall carbon nanotubes SWNT

Geohegan, David B.

390

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

E-print Network

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

Zhou, Chongwu

391

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

E-print Network

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

Natelson, Douglas

392

Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect of Alignment and Selective Breakdown  

E-print Network

Full Paper Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect DOI: 10.1002/elan.200900314 1. Introduction Carbon nanotubes have many potential applications, batteries, polymer matrix composites, and nanoscale reactors [1 ­ 4]. Among these applications, the single-walled

393

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

E-print Network

Side-Wall Functionalization of Single-Walled Carbon Nanotubes with 4-Hydroxymethylaniline Followed attempted. 1. Introduction Because of their exceptional electronic and mechan- ical properties, single-walled carbon nanotubes (SWNTs) have stirred the interest of academic and industrial researchers worldwide.1

Resasco, Daniel

394

Thermal transpiration through single walled carbon nanotubes and graphene channels.  

PubMed

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 (?(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. PMID:24206327

Thekkethala, Joe Francis; Sathian, Sarith P

2013-11-01

395

Thermal transpiration through single walled carbon nanotubes and graphene channels  

SciTech Connect

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.

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

396

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

NASA Astrophysics Data System (ADS)

This Letter involved the preparation of a conjugate between single-walled carbon nanotubes and folic acid that was obtained without covalent chemical functionalization using a simple 'one pot' synthesis method. Subsequently, the conjugate was investigated by a computational hybrid method: our own N-layered Integrated Molecular Orbital and Molecular Mechanics (B3LYP(6-31G(d):UFF)). The results confirmed that the interaction occurred via hydrogen bonding between protons of the glutamic moiety from folic acid and ? electrons from the carbon nanotubes. The single-walled carbon nanotube-folic acid conjugate presented herein is believed to lead the way to new potential applications as carbon nanotube-based drug delivery systems.

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

2013-03-01

397

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

NASA Astrophysics Data System (ADS)

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.

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

398

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

PubMed

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

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

399

All-Organic Actuator Fabricated with Single Wall Carbon Nanotube Electrodes  

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

400

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

NASA Astrophysics Data System (ADS)

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).

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

2015-01-01

401

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

Microsoft Academic Search

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

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

402

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

Microsoft Academic Search

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

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

2008-01-01

403

Hydrogen Storage in Single-Walled Carbon Nanotubes at Room Temperature  

Microsoft Academic Search

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

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

1999-01-01

404

Biotesting the biological effects of single-wall carbon nanotubes using bioluminescent bacteria test-system  

Microsoft Academic Search

The effect of single-wall carbon nanotubes (carbon SWNTs) on bacterial cells Escherichia coli K12 TG1 with cloned lux-operon of natural marine bacteria Photobacterium leiognathi was studied. Using atomic force microscopy (AFM), bacterial cell morphological changes were revealed and a cell viability\\u000a decrease controlled by the number of colony-forming units was registered. It was shown that prior to this we can

A. P. Zarubina; E. P. Lukashev; L. I. Deev; I. M. Parkhomenko; A. B. Rubin

2009-01-01

405

Characterization of diffusion flames for synthesis of single-walled carbon nanotubes  

Microsoft Academic Search

Recent studies have shown that Fe\\/Si\\/O catalysts on the fuel side of an oxygen-enriched inverse diffusion flame produce micron-length single-walled carbon nanotubes at rapid rates (>100m\\/s). Despite the favorable catalyst\\/flame interaction for nanotube nucleation and growth, the catalyst lifetimes are only a few milliseconds. To increase catalyst lifetime and hence, carbon nanotube length, it is necessary to know how the

C. J. Unrau; R. L. Axelbaum; V. R. Katta

2010-01-01

406

Characterization of diffusion flames for synthesis of single-walled carbon nanotubes  

Microsoft Academic Search

Recent studies have shown that Fe\\/Si\\/O catalysts on the fuel side of an oxygen-enriched inverse diffusion flame produce micron-length single-walled carbon nanotubes at rapid rates (>100?m\\/s). Despite the favorable catalyst\\/flame interaction for nanotube nucleation and growth, the catalyst lifetimes are only a few milliseconds. To increase catalyst lifetime and hence, carbon nanotube length, it is necessary to know how the

C. J. Unrau; V. R. Katta; R. L. Axelbaum

2010-01-01

407

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

Microsoft Academic Search

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

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

2010-01-01

408

Shape Engineerable Single Walled Carbon Nanotube Solid as a Flexible Conducting Mesoporous Material  

Microsoft Academic Search

We present a new form of carbon nanotubes (CNT) material where CNTs are aligned and packed densely in a bulk solid. This single-walled carbon nanotube (SWNT) solid is fabricated from liquid-induced collapse of the sparse as-grown SWNT forest synthesized by super-growth CVD [1], which results in a 20x increase in mass density and a 70x increase in the Vickers hardness

Don N. Futaba; Kenji Hata; Tatsuki Hiraoka; Takeo Yamada; Kohei Mizuno; Yuhei Hayamizu; Tatsunori Namai; Yozo Kakudate; Osamu Tanaike; Hiroaki Hatori; Koji Miyake; Shinya Sasaki; Motoo Yumura; Sumio Iijima

2006-01-01

409

Fabrication of discrete nanoscaled force sensors based on single-walled carbon nanotubes  

Microsoft Academic Search

We present a fabrication technique for discrete, released carbon-nanotube-based nanomechanical force sensors. The fabrication technique uses prepatterned coordinate markers to align the device design to predeposited single-walled carbon nanotubes (SWNTs): Atomic force microscope (AFM) images are recorded to determine spatial orientation and location of each discrete nanotube to be integrated in a nanoscaled force sensor. Electron beam lithography is subsequently

Christoph Stampfer; Alain Jungen; Christofer Hierold

2006-01-01

410

Determination of concentrated hydrogen peroxide at single-walled carbon nanohorn paste electrode  

Microsoft Academic Search

Single-walled carbon nanohorn (SWCNH) paste electrode was used for amperometric determination of concentrated hydrogen peroxide, and was compared with other carbon electrodes. The calibration plots are linear from 0.5 to 100mM at activated SWCNH paste electrode and edge plane graphite (EPG) electrode. In contrast, the calibration plots are linear only at concentrations lower than 45mM at graphite paste electrode, multi-walled

Shuyun Zhu; Lishuang Fan; Xiaoqing Liu; Lihong Shi; Haijuan Li; Shuang Han; Guobao Xu

2008-01-01

411

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

Microsoft Academic Search

ESR investigations on single-wall carbon nanotubes irradiated with accelerated protons, helium ions, and neon ions are reported. All spectra were accurately simulated assuming that the resonance line is a convolution of up to 4 lines originating from catalyst residues, amorphous carbon, and electrons delocalized over the conducting domains of nanotubes. The faint line observed in irradiated nanotubes at g>2.25 was

A. R. Adhikari; H. Bakhru; P. M. Ajayan; R. Benson; M. Chipara

2007-01-01

412

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

Microsoft Academic Search

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

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

2004-01-01

413

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

414

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

PubMed

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. PMID:25503929

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

2015-01-01

415

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

PubMed Central

A class of peptides from the bombolitin family, not previously identified for nitroaromatic recognition, allows near-infrared fluorescent single-walled carbon nanotubes to transduce specific changes in their conformation. In response to the binding of specific nitroaromatic species, such peptide–nanotube complexes form a virtual “chaperone sensor,” which reports modulation of the peptide secondary structure via changes in single-walled carbon nanotubes, near-infrared photoluminescence. A split-channel microscope constructed to image quantized spectral wavelength shifts in real time, in response to nitroaromatic adsorption, results in the first single-nanotube imaging of solvatochromic events. The described indirect detection mechanism, as well as an additional exciton quenching-based optical nitroaromatic detection method, illustrate that functionalization of the carbon nanotube surface can result in completely unique sites for recognition, resolvable at the single-molecule level. PMID:21555544

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

2011-01-01

416

Anomalous small charge transfer in doped single wall carbon nanohorn aggregates with Li, K and Br  

NASA Astrophysics Data System (ADS)

Single wall carbon nanohorns (SWNHs) produced by CW CO2 laser vaporization of a carbon target are examined for their ability to undergo charge transfer reactions. A typical SWNH has been shown by HRTEM to be a short ( ~ 40 nm) ~ 2 nm diameter nanotube with a conical tip ( ~ 20 ^circ full cone angle). Charge transfer chemical doping of SWNHs with K and Br was examined by vapor phase reaction and studied by Raman scattering. Electrochemical Li ion doping was also carried out. All these experiments indicate that an anomalously small charge transfer occurs for SWNHs in sharp contrast to the behavior observed for single wall carbon nanotube bundles and graphite. This rather remarkable result is not understood at present. The Raman spectrum (488 nm excitation) exhibits a pair of surprisingly narrow bands at 1350 and 1580 cm -1 with nearly equal intensity. These bands shift due to charge transfer.

Bandow, S.; Iijima, S.; Rao, A. M.; Sumanasekera, G. U.; Eklund, P. C.; Kokai, F.; Takahashi, K.; Yudasaka, M.

2000-03-01

417

Horizontally aligned single-walled carbon nanotube field emitters fabricated on vertically aligned multi-walled carbon nanotube electrode arrays  

Microsoft Academic Search

Vertically aligned multi-walled carbon nanotube (MWCNT) arrays were fabricated on an anodic aluminum oxide membrane bonded to a Si wafer. After obtaining a protruding tip for the MWCNTs by etching away some oxide, they were used as electrodes in the fabrication of carbon nanotube field emitters. Long single-walled carbon nanotubes (SWCNTs) were spin coated on the MWCNT arrays of uniform

Hyun Young Jung; Sung Mi Jung; Jung Sang Suh

2008-01-01

418

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

Microsoft Academic Search

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

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

2004-01-01

419

Directed assembly techniques for nano-manufacturing of scalable single walled carbon nanotube based devices  

NASA Astrophysics Data System (ADS)

Single Walled Carbon Nanotubes (SWNTs) are being considered building blocks for next generation electronics due to their unique electrical, mechanical and thermal properties. A number of SWNT based devices including scanning probes, field emitters, field effect transistors, biological and chemical sensors, and memory devices have been demonstrated. Despite successful demonstration of these single devices, the success of SWNT based nanoelectronics is hampered due to the lack of a successful nano-manufacturing method. Precise alignment and placement of SWNTs is necessary for successful integration of SWNTs into nanoelectronics. The work described in this thesis is focused on developing electric field assisted assembly techniques for precise placement and controlled orientation of SWNTs. In a first set of experiments we evaluate the use of micro/nano finger shaped metal electrodes to assemble SWNTs. Eventhough this assembly technique help in understanding the electrophoretic behavior of SWNTs, problems related with orientation, assembly at nanoscale and electrode degradation demanded evaluating alternative techniques. Nanotemplates that use trenches made in PMMA on a conductive substrate are utilized for the directed, controlled assembly of SWNTs This technique uses a combination of electrophoretic forces and fluidic forces to assemble and align the SWNTs. We were able to assemble SWNTs in trenches that are as small as 80 nm wide and 100,000 nm long over a 2.25 cm2 area in 30-90 seconds. Based on the experimental results and analysis a model is proposed to explain the assembly and alignment mechanism of SWNT s. The technique has been utilized to fabricated interconnects and field effect transistors to demonstrate the feasibility to make devices. Finally we introduce a novel room temperature assembly technique for fabricating a three dimensional single walled carbon nanotube platform. A top down lithographic approach is used to fabricate the platform while a bottom-up dielectrophoresis method is used to assemble the SWNTs in a 3D architecture. This is a scalable, high throughput and room temperature technique making it compatible with current CMOS technology. We demonstrate the ability to precisely control the density of SWNTs. A finite element model is used to simulate and study the behavior the SWNTs during assembly. We also demonstrate that these structures can be utilized directly as 3D interconnects. Finally, we show that the packaging of these devices, using a conformal pin-free parylene layer, provides a complete process flow for making SWNT based 3D nano-devices.

Makaram, Prashanth

420

Review of Laser Ablation Process for Single Wall Carbon Nanotube Production  

NASA Technical Reports Server (NTRS)

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.

Arepalli, Sivaram

2003-01-01

421

Two photon polymerization lithography for 3D microfabrication of single wall carbon nanotube/polymer composites  

NASA Astrophysics Data System (ADS)

Two photon polymerization (TPP) lithography has been established as a powerful tool to develop 3D fine structures of polymer materials, opening up a wide range applications such as micro-electromechanical systems (MEMS). TPP lithography is also promising for 3D micro fabrication of nanocomposites embedded with nanomaterials such as metal nanoparticles. Here, we make use of TPP lithography to fabricate 3D micro structural single wall carbon nanotube (SWCNT)/polymer composites. SWCNTs exhibit remarkable mechanical, electrical, thermal and optical properties, which leads to enhance performances of polymers by loading SWCNTs. SWCNTs were uniformly dispersed in an acrylate UV-curable monomer including a few amounts of photo-initiator and photo-sensitizer. A femtosecond pulsed laser emitting at 780 nm was focused onto the resin, resulting in the photo-polymerization of a nanometric volume of the resin through TPP. By scanning the focus spot three dimensionally, arbitrary 3D structures were created. The spatial resolution of the fabrication was sub-micrometer, and SWCNTs were embedded in the sub-micro sized structures. The fabrication technique enables one to fabricate 3D micro structural SWCNT/polymer composites into desired shapes, and thus the technique should open up the further applications of SWCNT/polymer composites such as micro sized photomechanical actuators.

Ushiba, Shota; Shoji, Satoru; Kuray, Preeya; Masui, Kyoko; Kono, Junichiro; Kawata, Satoshi

2013-03-01

422

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

NASA Astrophysics Data System (ADS)

Flexible and highly conductive single-walled carbon nanotube/polycellulose papers (SWCNT/PPs) were developed as current collectors for lithium-ion batteries by a simple and scalable process. The flexible electrodes based on SWCNT/PP conductors consisted of a unique three-dimensional interwoven structure of electrode materials and cellulose fibers with CNTs and exhibited flexibility, good electrochemical performance and excellent cyclic stability. Full cells using Li4Ti5O12 and LiFePO4 electrodes based on SWCNT/PPs showed a first discharge capacity of 153.5 mA h g-1 with Coulombic efficiencies of 90.6% at 0.1 C and discharge capacity of 102.6 mA h g-1 at high rate (10 C). Full cells based SWCNT/PP conductors showed higher capacities and lower electrochemical interfacial resistance compared to metallic current collectors. Half cells using anatase TiO2 hierarchical spheres based on SWCNT/PP conductors also exhibited outstanding electrochemical performance, verifying the stability of SWCNT/PP conductors to various electrode materials. Our results demonstrated the potential versatility of composite electrodes and conductive SWCNT/PPs for flexible and portable micropower devices.

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

2012-12-01

423

Selective Synthesis of Subnanometer Diameter Semiconducting Single-Walled Carbon Nanotubes  

SciTech Connect

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.

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

2010-01-01

424

Surface modification of single-wall carbon nanotube thin films irradiated by microwaves: a Raman spectroscopy study  

NASA Astrophysics Data System (ADS)

In this work, we present the results of a Raman spectroscopy study of single-wall carbon nanotube (SWCNT) thin films treated with microwave irradiation. SWCNT thin films were deposited by the vacuum filtration method and transferred onto alumina substrate. These thin films were exposed to microwave irradiation of 25 and 250 W at 2.45 GHz. All samples were characterized by Raman spectroscopy and atomic force microscopy. Raman spectroscopy analysis showed that there was neither selective destruction of metallic nor semiconducting nanotubes. It was noticed that samples were heated only during microwave irradiation at 250 W. The major effect of microwave irradiation on SWCNTs was their debundling.

Kepi?, D.; Markovi?, Z.; Toši?, D.; Holclajtner Antunovi?, I.; Adnadjevi?, B.; Prekodravac, J.; Kleut, D.; Drami?anin, M.; Todorovi? Markovi?, B.

2013-11-01

425

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

NASA Astrophysics Data System (ADS)

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.

Goclon, Jakub; Kozlowska, Mariana; Rodziewicz, Pawel

2015-01-01

426

Jointly modified single-walled carbon nanotubes on low resistance monolayer modified electrode for arsenic(III) detection  

Microsoft Academic Search

Taking advantages of the larger specific surface area of single-walled carbon nanotubes and the lower contact resistance of –NH–C than that of multiple-walled carbon nanotubes and that of –S–Au, respectively, a ethylenediamine monolayer modified glassy carbon electrode (GCE) grafted by non-covalent and covalent sulphydryl groups jointly modified single-walled carbon nanotubes for arsenic(III) detection was developed. The resistance of ethylenediamine monolayer

Yaxiong Liu; Wanzhi Wei

2008-01-01

427

Acceptor doping of single-walled carbon nanotubes by encapsulation of zinc halogenides  

NASA Astrophysics Data System (ADS)

To modify the electronic properties of single-walled carbon nanotubes (SWCNTs), ZnX2@SWCNT (X = Cl, Br, I) nanostructures were prepared by capillary filling of 1.4-1.6 nm single-walled carbon nanotubes (SWCNT) with zinc halogenide melts. The loading factor is estimated as 30% for ZnCl2 and approximately 60% for ZnBr2 and ZnI2. Well-ordered 1D crystals were observed by TEM only for ZnI2@SWCNT. We propose two possible atomic structures of the 1D crystals, (Zn4I7) n and less stable (Zn4I9) n . According to the optical absorption and photoemission data, there is a charge transfer from the nanotube to the filler for all ZnX2@SWCNT nanostructures. The results of the DFT PW-GGA modeling indicate that the acceptor properties correspond to (Zn4I9) n only.

Kharlamova, M. V.; Yashina, L. V.; Volykhov, A. A.; Niu, J. J.; Neudachina, V. S.; Brzhezinskaya, M. M.; Zyubina, T. S.; Belogorokhov, A. I.; Eliseev, A. A.

2012-01-01

428

Field electron emission form single-walled carbon nanotubes with deposited cesium atoms  

NASA Astrophysics Data System (ADS)

It has been found that deposition g of cesium atoms on single-walled carbon nanotubes covered with potassium atoms not only drastically increases emission current but also considerably changes the shape of current-voltage characteristics of field electron emission, namely, the characteristics become nonlinear in Fowler-Nordheim coordinates. It has been assumed that this effect is associated with the fact that field electron emission in these layers comes from single-walled carbon nanotubes, which have p-type conductivity after potassium treatment, while deposition of cesium leads to the formation of p-n junctions near nanotube tips. Part of the applied voltage drops in p-n junction, thus causing a nonlinearity of current-voltage characteristics.

Musatov, A. L.; Izrael'yants, K. R.; Chirkova, E. G.; Krestinin, A. V.

2011-07-01

429

Photoluminescence imaging of electronic-impurity-induced exciton quenching in single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

The electronic properties of single-walled carbon nanotubes can be altered by surface adsorption of electronic impurities or dopants. However, fully understanding the influence of these impurities is difficult because of the inherent complexity of the solution-based colloidal chemistry of nanotubes, and because of a lack of techniques for directly imaging dynamic processes involving these impurities. Here, we show that photoluminescence microscopy can be used to image exciton quenching in semiconducting single-walled carbon nanotubes during the early stages of chemical doping with two different species. The addition of AuCl3 leads to localized exciton-quenching sites, which are attributed to a mid-gap electronic impurity level, and the adsorbed species are also found sometimes to be mobile on the surface of the nanotubes. The addition of H2O2 leads to delocalized exciton-quenching hole states, which are responsible for long-range photoluminescence blinking, and are also mobile.

Crochet, Jared J.; Duque, Juan G.; Werner, James H.; Doorn, Stephen K.

2012-02-01

430

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

431

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

E-print Network

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

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

2013-01-01

432

Palladium Nanoparticles Decorated Single-Walled Carbon Nanotube Hydrogen Sensor Syed Mubeen, Ting Zhang, Bongyoung Yoo, Marc A. Deshusses,* and Nosang V. Myung*  

E-print Network

Palladium Nanoparticles Decorated Single-Walled Carbon Nanotube Hydrogen Sensor Syed Mubeen, Ting-effective fabrication technique to construct a hydrogen nanosensor by decorating single-walled carbon nanotubes with Pd or semiconductive, depending on their helicity.12 Further, since all carbon atoms in a single-walled carbon nanotube

433

Theoretical investigation on carbon nucleation on nickel carbides at initial stages of single-walled carbon nanotube formation.  

PubMed

It is a long-standing controversy whether metal carbide clusters do exist during the nucleation and growth process of single-walled carbon nanotubes (SWCNTs). In the current work, we are trying to elucidate the carbon nucleation on nickel carbides during the initial stages based on density functional theory calculated formation energy and chemical potential for a series of Ni55Cn carbides (n is the number of carbon atoms dissolved in the Ni55 cluster). It is found that the formation energies of the Ni55Cn carbides decrease gradually with an increase of dissolved carbon atomic numbers, meaning the Ni55Cn carbides are thermodynamically stable. Meanwhile, the calculated chemical potentials indicate that not only nickel carbides are preferentially formed during the initial stage of the SWCNT nucleation, but also saturated nickel carbides may be able to exist during the nucleation and growth process of SWCNTs. In addition, the nickel carbides have a high selectivity for the formation of the carbon pentagon and carbon structures with pentagon-incorporated end-edge according to the adsorption energies. All of these findings provide opportunities in controlling the growth of the SWCNTs. PMID:25111778

Yang, Zhimin; Wang, Qiang; Shan, Xiaoye; Yang, Shuo-Wang; Zhu, Hongjun

2014-09-28

434

Immobilizing Shortened Single-Walled Carbon Nanotubes (SWNTs) on Gold Using a Surface Condensation Method  

Microsoft Academic Search

We propose a surface condensation method for assembling single-walled carbon nanotubes (SWNTs) on gold. The as-prepared long and randomly tangled SWNTs were cut into short pipes by chemical oxidation, allowing the nanotubes to be terminated by carboxyl functionalities. A surface condensation reaction was then performed by immersing an amino self-assembled monolayer (SAM)-modified gold substrate into the dimethylformamide suspension of carboxylic

Xiaolin Nan; Zhennan Gu; Zhongfan Liu

2002-01-01

435

Molecular Ordering of Organic Molten Salts Triggered by Single-Walled Carbon Nanotubes  

Microsoft Academic Search

When mixed with imidazolium ion-based room-temperature ionic liquid, pristine single-walled carbon nanotubes formed gels after being ground. The heavily entangled nanotube bundles were found to untangle within the gel to form much finer bundles. Phase transition and rheological properties suggest that the gels are formed by physical cross-linking of the nanotube bundles, mediated by local molecular ordering of the ionic

Takanori Fukushima; Atsuko Kosaka; Yoji Ishimura; Takashi Yamamoto; Toshikazu Takigawa; Noriyuki Ishii; Takuzo Aida

2003-01-01

436

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

Microsoft Academic Search

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

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

2003-01-01

437

Electrocatalytic detection of dopamine at single-walled carbon nanotubes–iron (III) oxide nanoparticles platform  

Microsoft Academic Search

Electrochemical sensors using edge-plane pyrolytic graphite electrode (EPPGEs) modified with single-wall carbon nanotubes–iron (III) oxide (SWCNT\\/Fe2O3) nanoparticles for the sensitive detection of dopamine (DA) are described for the first time. The surface of the EPPGE-SWCNT–Fe2O3 was characterized using field emission scanning electron microscopy, atomic force microscopy and energy dispersive X-ray spectroscopy while the electrochemical properties were investigated using the cyclic

Abolanle S. Adekunle; Bolade O. Agboola; Jeseelan Pillay; Kenneth I. Ozoemena

2010-01-01

438

Photocurrent spectroscopy of (n, m) sorted solution-processed single-walled carbon nanotubes.  

PubMed

Variable-wavelength photocurrent microscopy and photocurrent spectroscopy are used to study the photoresponse of (n, m) sorted single-walled carbon nanotube (SWNT) devices. The measurements of (n, m) pure SWCNT devices demonstrate the ability to study the wavelength-dependent photoresponse in situ in a device configuration and deliver photocurrent spectra that reflect the population of the source material. Furthermore, we show that it is possible to map and determine the chirality population within a working optoelectronic SWCNT device. PMID:25117458

Engel, Michael; Moore, Katherine E; Alam, Asiful; Dehm, Simone; Krupke, Ralph; Flavel, Benjamin S

2014-09-23

439

Random networks and aligned arrays of single-walled carbon nanotubes for electronic device applications  

Microsoft Academic Search

Singled-walled carbon nanotubes (SWNTs), in the form of ultrathin films of random networks, aligned arrays, or anything in\\u000a between, provide an unusual type of electronic material that can be integrated into circuits in a conventional, scalable fashion.\\u000a The electrical, mechanical, and optical properties of such films can, in certain cases, approach the remarkable characteristics\\u000a of the individual SWNTs, thereby making

Qing Cao; John A. Rogers

2008-01-01

440

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

SciTech Connect

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.

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

441

Synthesis and Purification of Single-Walled Carbon Nanotubes by AC Arc Discharge  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes (SWNTs) were synthesized in a mixed gas of H2 and Ar by AC arc discharge. The catalyst used in the synthesis was a single Fe catalyst. SWNTs containing a negligible number of nanoparticles were obtained. A novel purification method, in which synthesized soot is heated and oxidized in situ, was adopted. As a result, high-quality SWNTs with excellent crystallinity containing very few coexisting nanoparticles and fine particles from the catalyst were obtained.

Ohkohchi, Masato; Zhao, Xinluo; Inoue, Sakae; Ando, Yoshinori

2004-12-01

442

A DSC Study on the Nonisothermal Crystallization Kinetics of Polypropylene\\/Single-Walled Carbon Nanotube Nanocomposite  

Microsoft Academic Search

The nonisothermal melt crystallization kinetics of polypropylene (PP) and polypropylene\\/single-walled carbon nanotube (PP\\/SWNT) nanocomposite were analyzed according to Avrami and Mo models. The values of half-life, corrected composite rate constant and F(T) indicated that the crystallization rate increased with the increasing of cooling rates for PP and PP\\/SWNT. However, the crystallization rate of nanocomposite was found to be higher than

Abdolhosein Fereidoon; Morteza Ghorbanzadeh Ahangari; Seyfola Saedodin

2009-01-01

443

Elastic and Shear Moduli of Single-Walled Carbon Nanotube Ropes  

Microsoft Academic Search

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

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

444

Nucleation of polyvinyl alcohol crystallization by single-walled carbon nanotubes  

Microsoft Academic Search

Non-isothermal crystallization experiments were performed on poly(vinyl alcohol) mixed with single-walled carbon nanotubes. Non-isothermal crystallization experiments showed that nanotubes nucleate crystallinity at weight fractions as low as 0.1%. An Ozawa model was applied to the non-isothermal crystallization data, and this approach confirmed the results deduced from the qualitative examination of the data: there was a clear difference in crystallization kinetics

Olga Probst; Eric M. Moore; Daniel E. Resasco; Brian P. Grady

2004-01-01

445

Fabrication of Discrete Nanosized Cobalt Particles Encapsulated Inside Single-Walled Carbon Nanotubes  

SciTech Connect

Single-walled carbon nanotubes (SWNT) with encapsulated nanosized cobalt particles have been synthesized by a facile and scalable method. In this approach, SWNT were filled with a cobalt acetylacetonate solution in dichloromethane by ultrasonication. In a second step, exposure to hydrogen at different temperatures released discrete cobalt particles of controllable size inside the SWNT cavity. The SWNT-Co particles systems were characterized by transmission electron microscopy, X-ray absorption spectroscopy, Raman spectroscopy, and thermal gravimetric analysis.

Zoican Loebick, C.; Majewska, M; Ren, F; Haller, G; Pfefferle, L

2010-01-01

446

A continuum mechanics nonlinear postbuckling analysis for single-walled carbon nanotubes under torque  

Microsoft Academic Search

Nonlinear buckling and postbuckling analysis of single-walled carbon nanotubes subjected to torsional load are examined by continuum mechanics elastic shell model. The boundary layer theory of shell buckling and the singular perturbation technique is applied to solve the governing equations based on the Karman–Donnell-type nonlinear differential equations. The buckling loads and postbuckling equilibrium paths are obtained theoretically. For more detailed

Xiaohu Yao; Qiang Han

2008-01-01

447

Dispersion of Single-Walled Carbon Nanotubes in Poly(E-caprolactone)  

SciTech Connect

The dispersion of single-walled carbon nanotubes (SWNT) in poly({var_epsilon}-caprolactone) with the aid of a zwitterionic surfactant is reported. Melt rheology and electrical conductivity measurements indicate geometrical percolation and electrical percolation for nanocomposites with {approx}0.08 wt % SWNT, implying an effective anisotropy for the nanotubes of at least 600. Spectroscopic measurements and comparison of dispersion using other surfactants established that the excellent dispersion is a result of the compatibilizing effect of the zwitterionic surfactant.

Mitchell,C.; Krishnamoorti, R.

2007-01-01

448

Flavin-derived self-organization and chirality separation of single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Formed by rolling up a two-dimensional sheet of one or more layer of graphite, graphene, carbon nanotubes (SWNTs) are the marvel materials of modern materials science. They are phenomenally strong and stiff, and have the unusual property of being excellent conductors of heat along the tube's axis, but good thermal insulators across it. But it is their electrical characteristics that excite the most interest. Especially, single-walled carbon nanotube (SWNTs), formed by one layer of cylindrical graphene, has better physical properties over multi-walled carbon nanotubes (MWNTs) having over two layer of graphene. Depending on the precise way they are rolled up, which is defined by ( n,m) vector, SWNTs can be made into either metals or semiconductors. So far, SWNTs can generally only be fabricated in batches that vary widely, both in the diameter of the individual tubes and in the orientation of their graphene lattice relative to the tube axis, the property known as chirality. Separating out these various conformations is a challenging, but one that must be solved if nanotubes are ever to fulfill their electrifying potential in devices. This thesis presents that flavin-based helical self-assembly can impart multi degrees of SWNTs separation (i.e., metallicity, diameter, chirality, and handedness). As opening chapters for carbon nanotube and flavin derivative, Chapter 1 provide the introduction of carbon nanotubes, especially single-walled tubes, and the current state-of-the-art nanotube separation. Also, Chapter 1 presents a variety of naturally-occurring flavin derivatives, their redox behavior, and their biological utilization as cofactors for various proteins. Motivated by chemoluminescence of flavin mononucleotide (FMN, phosphorylated form of Vitamin B2) with bacterial luciferase, Chapter 2 discuss about the synthesis and covalent attachment of flavin mononucleotide (FMN, phosphorylated form of Vitamin B2) analogue to oxidized SWNTs. Along with nine step synthesis of synthetic FMN, this study provided two findings: (i) isoalloxazine ring of FMN has strong interaction with the sidewalls of nanotubes and (ii) covalently-attached isoalloxazine ring onto nanotube can be either extended or collapsed by surfactant (long-term) and redox agents or sonication (short-term) from the nanotube surface. The aforementioned two findings lead to utilize strong pi-pi interaction of biologically-relevant FMN for nanotube dispersing agents. Chapter 3 discuss that FMN imparts effective dispersion of SWNTs via helical self-assembly of flavin moiety. This isoalloxazine self-assembly onto nanotube in aqueous media is held by (i) quadruple hydrogen-bonding along the adjacent uracil moiety of isoalloxazine rings, and (ii) concentric pi-pi interaction between isoalloxazine ring toward the underlying nanotube sidewall, and (iii) phosphate group of FMN imparting anionic dispersion and individualization of nanotube in water. In addition, precipitation-less replacement of FMN with sodium dodecyl benzene sulfate (SDBS) enable us to probe the relative binding constant of helical FMN self-organization on SWNTs. The significantly higher affinity of the FMN assembly for (8,6) nanotube results in an 85% chirality enrichment from a nanotube sample with broad diameter distribution. Chapter 4 revisits the surfactant amine-assisted semiconducting ( sem-) SWNTs separation in THF media. For this, we synthesized an asymmetric diacetylenic surfactant amine(57ECA), in which adequate chemical anisotropy was generated along its tail to probe the molecular dynamics in the presence and absence of nanotubes via NMR. This surfactant can simulate the similar sem-SWNTs separation, like ODA. This study suggests that the surfactant amine head is firmly immobilized onto the nanotube surface together with acidic water, while the aliphatic tail progressively gains larger mobility as it gets farther from the SWNT. The spectroscopic results indicate that the sem-enriched sample is populated mainly from small nanotube bundles containing three SWNTs. Molecular simulations in conjunct

Ju, Sang-Yong

2008-07-01

449

Method for separating single-wall carbon nanotubes and compositions thereof  

NASA Technical Reports Server (NTRS)

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.

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

450

Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma  

PubMed Central

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

Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

2012-01-01

451

Computational study on structural modification of single-walled carbon nanotubes by electron irradiation  

SciTech Connect

Molecular dynamics simulation is carried out to investigate structural modifications of single-walled carbon nanotubes by electron irradiation. Electron irradiation effects are introduced by the Monte Carlo method using an elastic collision cross section. We demonstrate the applicability of the method to the analysis of structural modifications with electron beam such as cutting, shrinking, and bending. The behavior of the carbon atoms in the nanotube during the structural modification is revealed. The simulation results also show the variation of the mechanical properties of carbon nanotubes by electron irradiation.

Yasuda, Masaaki; Mimura, Ryosuke; Kawata, Hiroaki; Hirai, Yoshihiko [Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan)

2011-03-01

452

Reduced Carbon Solubility in Fe Nanoclusters and Implications for the Growth of Single-Walled Carbon Nanotubes  

E-print Network

Reduced Carbon Solubility in Fe Nanoclusters and Implications for the Growth of Single of the minimum temperature necessary for the growth. We address this phenomenon in terms of solubility of C in Fe of single-walled carbon nanotubes, corresponding to unaffected, reduced, and no solubility of C

Curtarolo, Stefano

453

Strain sensing of carbon nanotubes: Numerical analysis of the vibrational frequency of deformed single-wall carbon nanotubes  

Microsoft Academic Search

The potential applications as nanostrain sensors and tunable frequency oscillators make it important to analyze the natural vibrational frequency of deformed carbon nanotubes. We perform extensive molecular-dynamics and continuum analyses to explore the effects of several basic deformation modes (axial tension and compression, bending, torsion) on the vibrational characteristics of single-walled carbon nanotubes. The effects of nanotube length and chirality

Guoxin Cao; Xi Chen; Jeffrey W. Kysar

2005-01-01

454

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

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

455

Thermal conductivity of single-walled carbon nanotubes Alexander V. Savin,1,2 Bambi Hu,3,4 and Yuri S. Kivshar1  

E-print Network

Thermal conductivity of single-walled carbon nanotubes Alexander V. Savin,1,2 Bambi Hu,3,4 and Yuri,5 Single-walled carbon nanotubes SWCNTs have sparked great scientific and engineering interest because 2009; published 30 November 2009 We study numerically the thermal conductivity of single-walled carbon

456

Optically anisotropic infinite cylinder above an optically anisotropic half space: Dispersion interaction of a single-walled carbon nanotube with a substrate  

E-print Network

interaction of a single-walled carbon nanotube with a substrate A. Siber, R. F. Rajter, R. H. French, W. Y interaction of a single-walled carbon nanotube with a substrate A. Siber Institute of Physics, Bijenicka cesta initio dielectric response functions of various semiconducting/insulating single wall carbon nanotubes

Rollins, Andrew M.

457

Shape transition of unstrained flattest single-walled carbon nanotubes under pressure Weihua Mu, Jianshu Cao, and Zhong-can Ou-Yang  

E-print Network

Shape transition of unstrained flattest single-walled carbon nanotubes under pressure Weihua Mu single-walled carbon nanotubes under pressure Weihua Mu,1,2,3,a) Jianshu Cao,1,4,b) and Zhong-can Ou section of a single walled carbon nanotube successively deforms from the original round shape to oval

Cao, Jianshu

458

Magnetic heterogeneity and alignment of single wall carbon nanotubes M. F. Islam, D. E. Milkie, O. N. Torrens, A. G. Yodh, and J. M. Kikkawa  

E-print Network

Magnetic heterogeneity and alignment of single wall carbon nanotubes M. F. Islam, D. E. Milkie, O that a fraction of acid purified single wall carbon nanotubes SWNTs exhibit both linear-orbital diamagnetic and s : 78.30.Na, 78.66.Tr, 78.67.Ch The magnetic responses of single wall carbon nanotubes SWNTs provide

Islam, Mohammad F.

459

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

E-print Network

Excited-state carrier lifetime in single-walled carbon nanotubes S. Reich* Department-infrared photoluminescence decay time in several different-chirality single-walled carbon nanotubes by time single-walled carbon nanotubes are again special in that they are expected to have particularly intense

Nabben, Reinhard

460

Effect of substrate on thermal conductivity of single-walled carbon nanotubes This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

Effect of substrate on thermal conductivity of single-walled carbon nanotubes This article has been conductivity of single-walled carbon nanotubes A. V. Savin1,2(a) , Y. S. Kivshar2 and B. Hu3,4 1 Semenov analyze numerically the thermal conductivity of single-walled carbon nanotubes placed on a flat rigid

461

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

PubMed Central

We report the fabrication of devices in which one single-walled carbon nanotube (SWCNT) spans a barrier between two fluid reservoirs, enabling direct electrical measurement of ion transport through the tube. A fraction of the tubes pass anomalously high ionic currents. Electrophoretic transport of small single stranded DNA oligomers through these tubes is marked by large transient increases in ion current and was confirmed by PCR analysis. Each current pulse contains about 107 charges, an 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. PMID:20044570

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

2009-01-01

462

Boron and Nitrogen Doped Single walled Carbon Nanotubes as Possible Dilute Magnetic Semiconductors  

PubMed Central

The structure of single walled armchair and zig-zag carbon nanotubes having 70 atoms and two carbons replaced by boron or nitrogen is obtained at minium energy using HF/6-31G* molecular orbital theory. The calculations show that the ground state of the zig-zag tubes is a triplet state while for the armchair tubes it is a singlet. In the zig-zag tubes the density of states at the Fermi level is greater for the spin down states compared to the spin up state indicating that the doped tubes could be ferromagnetic.

2007-01-01

463

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

SciTech Connect

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.

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

464

Femtosecond laser ablation of single-wall carbon nanotube-based material  

NASA Astrophysics Data System (ADS)

Single- and multi-shot femtosecond laser surface ablation of a single-wall carbon nanotube-based substrate at 515- and 1030?nm wavelengths was studied by scanning electron microscopy and micro-Raman spectroscopy. The laser ablation proceeds in two ways: as the low-fluence mesoscopic shallow disintegration of the surface nanotube packing, preserving the individual integrity and the semiconducting character of the nanotubes or as the high-fluence deep material removal apparently triggered by the strong intrinsic or impurity-mediated ablation of the individual carbon nanotubes on the substrate surface.

Danilov, Pavel A.; Ionin, Andrey A.; Kudryashov, Sergey I.; Makarov, Sergey V.; Mel’nik, Nikolay N.; Rudenko, Andrey A.; Yurovskikh, Vladislav I.; Zayarny, Dmitry V.; Lednev, Vasily N.; Obraztsova, Elena D.; Pershin, Sergey M.; Bunkin, Alexey F.

2014-10-01

465

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

SciTech Connect

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.

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

2012-01-01

466

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

PubMed Central

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.

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

2014-01-01

467

Alcohol CVD Growth of Horizontally Aligned Single-Walled Carbon Nanotubes on R-cut Crystal Quartz Substrates  

E-print Network

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

Maruyama, Shigeo

468

Electronic detection of molecules on the exterior and molecular transport through the interior of single walled carbon nanotubes  

E-print Network

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 ...

Lee, Chang Young

2010-01-01

469

Dithiafulvenyl-grafted phenylene ethynylene polymers as selective and reversible dispersants for single-walled carbon nanotubes.  

PubMed

Phenylene ethynylene-based ?-conjugated polymers grafted with dithiafulvenyl groups on their side chains were found to be efficient in dispersing single-walled carbon nanotubes in a selective and controllable way. PMID:25388522

Mulla, Karimulla; Liang, Shuai; Shaik, Haseena; Younes, Eyad A; Adronov, Alex; Zhao, Yuming

2015-01-01

470

Single-walled carbon nanotubes do not pierce aqueous phospholipid bilayers at low salt concentration.  

PubMed

Because of their unique physical, chemical, and electrical properties, carbon nanotubes are an attractive material for many potential applications. Their interactions with biological entities are, however, not yet completely understood. To fill this knowledge gap, we present experimental results for aqueous systems containing single-walled carbon nanotubes and phospholipid membranes, prepared in the form of liposomes. Our results suggest that dispersed single-walled carbon nanotubes, instead of piercing the liposome membranes, adsorb on them at low ionic strength. Transmission electron microscopy and dye-leakage experiments show that the liposomes remain for the most part intact in the presence of the nanotubes. Further, the liposomes are found to stabilize carbon nanotube dispersions when the surfactant sodium dodecylbenezenesulfonate is present at low concentrations. Quantifying the interactions between carbon nanotubes and phospholipid membranes could not only shed light on potential nanotubes cytotoxicity but also open up new research venues for their use in controlled drug delivery and/or gene and cancer therapy. PMID:23659213

Shi, Liu; Shi, Dachuan; Nollert, Matthias U; Resasco, Daniel E; Striolo, Alberto

2013-06-01

471

Capacitive tunnels in single-walled carbon nanotube networks on flexible substrate  

NASA Astrophysics Data System (ADS)

We report the analysis of single-walled carbon nanotube networks, which are expected to be suitable as miniaturized flexible radio frequency RC filters and also have important implications for high frequency devices. The surface morphology obtained by atomic force microscopy shows that most of the growth on polypropylene carbonate substrate is homogeneous. The large value of peak intensity ratio of G and D band in Raman spectra indicates the high purity network. Nyquist plots of carbon nanotube networks on a flexible substrate are close to real circles, indicating that the material is conducting, and suggest a simple equivalent circuit having a resistor in parallel with a capacitor. The Bode plots give the dependence of real and imaginary impedances on frequency. While at high frequency, the impedance decreases, due to generation of capacitance between a single-walled carbon nanotube; at low frequency, it shows the normal behavior, having constant value. The tunnels among different carbon nanotubes are capable of storing electric charge. The accumulative capacitances of tunnels for three varied concentrations are calculated by electrochemical impedance spectroscopy simulations to fit the observed Nyquist plots.

Iqbal, M. Z.; Iqbal, M. W.; Eom, Jonghwa; Ahmad, Muneer; Ferrer-Anglada, Núria

2012-03-01

472

Molecular dynamics simulations of hydrogen adsorption\\/desorption by palladium decorated single-walled carbon nanotube bundle  

Microsoft Academic Search

Utilising molecular dynamics simulations, the hydrogen molecules adsorption isotherms of the (8,?0) palladium decorated single-walled carbon nanotube (SWNT) were obtained. The hydrogen adsorption was studied on the external, interstial and internal surfaces of the SWNT bundle at several temperatures ranging from 77 to 400?K. The results were compared with the bare single-walled carbon nanotube bundle under the same conditions. The

Seifollah Jalili; Arezou Jaberi; Mohammad Ghasem Mahjani; Majid Jafarian

2012-01-01

473

Single-Stranded DNA Insertion into Single-Walled Carbon Nanotubes by Ion Irradiation in an Electrolyte Plasma  

Microsoft Academic Search

The inside modification of single-walled carbon nanotubes using a single-stranded DNA is demonstrated. In this method, we regard DNA solution as a plasma, i.e., an electrolyte plasma. A direct current electric field is applied to the electrolyte plasma containing DNA negative ions in order to irradiate the single-walled carbon nanotubes with DNA ions. In addition, a radio frequency electric field

Takeru Okada; Toshiro Kaneko; Rikizo Hatakeyama

2006-01-01

474

Measuring the uniaxial strain of individual single-wall carbon nanotubes: resonance Raman spectra of atomic-force-microscope modified single-wall nanotubes.  

PubMed

Raman spectroscopy is used to measure the strain in individual single-wall carbon nanotubes, strained by manipulation with an atomic-force-microscope tip. Under strains varying from 0.06%-1.65%, the in-plane vibrational mode frequencies are lowered by as much as 1.5% (40 cm(-1)), while the radial breathing mode (RBM) remains unchanged. The RBM Stokes/anti-Stokes intensity ratio remains unchanged under strain. The elasticity of these strain deformations is demonstrated as the down-shifted Raman modes resume their prestrain frequencies after a nanotube is broken under excessive strain. PMID:15525030

Cronin, S B; Swan, A K; Unlü, M S; Goldberg, B B; Dresselhaus, M S; Tinkham, M

2004-10-15

475

Carbon nanotube supported Pt electrodes for methanol oxidation: A comparison between multi- and single-walled carbon nanotubes  

Microsoft Academic Search

This work presents a detailed comparison between multi-walled (MWNT) and single-walled carbon nanotubes (SWNT) in an effort to understand which can be the better candidate of a future supporting carbon material for electrocatalyst in direct methanol fuel cells (DMFC). Pt particles were deposited via electrodeposition on MWNT\\/Nafion and SWNT\\/Nafion electrodes to investigate effects of the carbon materials on the physical

Gang Wu; Bo-Qing Xu

2007-01-01

476

Synthesis, characterization, and photoinduced electron transfer in functionalized single wall carbon nanohorns.  

PubMed

Single-wall carbon nanohorns (SWNHs) are a new class of material that is closely related to single-wall carbon nanotubes. Here, we describe the synthesis and characterization of a series of SWNHs functionalized with ethylene glycol chains and porphyrins. Functionalization of carbon nanohorns has been achieved using two different synthetic protocols: (1) direct attack of a free amino group on the nanohorn sidewalls (nucleophilic addition) and (2) amidation reaction of the carboxylic functions in oxidized nanohorns. The nanohorn derivatives have been characterized by a combination of several techniques, and the electronic properties of the porphyrin/nanohorn assemblies (SWNH/H2P) have been investigated by electrochemistry, spectroelectrochemistry, and a series of steady-state and time-resolved spectroscopy. The cyclic voltammetry curve of nanohorn/porphyrin conjugate 6 showed a continuum of faradic and pseudocapacitive behavior, which is associated with multiple-electron transfers to and from the SWNHs. Superimposed on such a pseudocapacitive current, the curve also displays three discrete reduction peaks at -2.26, -2.57, and -2.84 V and an oxidation peak at 1.12 V (all attributed to the porphyrin moiety). Steady-state and time-resolved fluorescence demonstrated a quenching of the fluorescence of the porphyrin in SWNH/H2P conjugates 5 and 6 compared to the reference free base porphyrin. Transient absorption spectra permitted the electron-transfer process between the porphyrins and the carbon nanostructures to be highlighted. PMID:17343379

Cioffi, Carla; Campidelli, Stéphane; Sooambar, Chloé; Marcaccio, Massimo; Marcolongo, Gabriele; Meneghetti, Moreno; Paolucci, Demis; Paolucci, Francesco; Ehli, Christian; Rahman, G M Aminur; Sgobba, Vito; Guldi, Dirk M; Prato, Maurizio

2007-04-01

477

Changing chirality during single-walled carbon nanotube growth: a reactive molecular dynamics/Monte Carlo study.  

PubMed

The growth mechanism and chirality formation of a single-walled carbon nanotube (SWNT) on a surface-bound nickel nanocluster are investigated by hybrid reactive molecular dynamics/force-biased Monte Carlo simulations. The validity of the interatomic potential used, the so-called ReaxFF potential, for simulating catalytic SWNT growth is demonstrated. The SWNT growth process was found to be in agreement with previous studies and observed to proceed through a number of distinct steps, viz., the dissolution of carbon in the metallic particle, the surface segregation of carbon with the formation of aggregated carbon clusters on the surface, the formation of graphitic islands that grow into SWNT caps, and finally continued growth of the SWNT. Moreover, it is clearly illustrated in the present study that during the growth process, the carbon network is continuously restructured by a metal-mediated process, thereby healing many topological defects. It is also found that a cap can nucleate and disappear again, which was not observed in previous simulations. Encapsulation of the nanoparticle is observed to be prevented by the carbon network migrating as a whole over the cluster surface. Finally, for the first time, the chirality of the growing SWNT cap is observed to change from (11,0) over (9,3) to (7,7). It is demonstrated that this change in chirality is due to the metal-mediated restructuring process. PMID:21923157

Neyts, Erik C; van Duin, Adri C T; Bogaerts, Annemie

2011-11-01

478

Calculated Dependence of Vibrational Band Frequencies of Single-Walled Carbon Nanotubes on Diameter  

NASA Astrophysics Data System (ADS)

We have used density functional theory (DFT) at the B3LYP/6-31G level to calculate Raman and IR spectra of the fourteen zigzag (n, 0) single-walled carbon nanotubes (SWCNTs) and (n, 0)&(2n, 0) double walled carbon nanotube (DWCNTs) that have n ranging from 6 to 19 for SWCNTS, n = 6 to 8 for DWCNTs. In the low frequency RBM region, calculated Raman spectra of SWCNTs indicated that there are three vibrational modes, of symmetries A{_1g}, E{_1g} and E{_2g}, whose frequencies depend strongly on nanotube diameter. The E{_2g} g mode is not only diameter dependent, but also the even and odd number hexagon formed in the circumference direction of the CNTs. There are also two IR spectral modes (of A2u and E1u symmetries) found in calculated IR spectra with strong diameter dependencies. We have also found three Raman bands with E{_1g}, A{_1g} and E{_2g} symmetries to exist in the G-band region. For this latter case, computed spectra indicated that while Raman bands with A1g symmetry essentially remain constant for the even number hexagon formed in the circumference direction ((0, 2n)-type CNTs; with band position 1526 61617; 0.5 cm^{-1}), but that for (0, 2n+1)-type CNTs are diameter dependent. The frequencies of the E{_1g} and E{_2g} modes (in the G-band region) are not only strongly diameter dependent, but also expected to converge towards one another with increasing tube diameter. This latter type of behavior can lead to erroneous classification of nanotubes as metallic or semiconducting, since partially overlapping bands in the G-band region might result in bands with diffuse shoulder, a characteristic of metallic SWCNTs. The RBMs for DWCNTs are also strongly diameter dependent and are blue shifted reference to their corresponding RBMs in the spectra of SWCNTs. The relative distance between RBMs vibrational modes in the spectrum of a desired DWCNT is larger than that for the corresponding SWCNTs. The electron density for the small sized DWCNT, (6,0)&(12,0), indicated an intertube CC chemical bonding in the excite state.

Aydin, Metin; Akins, Daniel L.

2009-06-01

479

Formation and growth mechanisms of single-walled metal oxide nanotubes  

NASA Astrophysics Data System (ADS)

In this thesis, main objectives are to discover the first molecular-level mechanistic framework governing the formation and growth of single-walled metal-oxide nanotubes, apply this framework to demonstrate the engineering of nanotubular materials of controlled dimensions, and to progress towards a quantitative multiscale understanding of nanotube formation. In Chapter 2, the identification and elucidation of the mechanistic role of molecular precursors and nanoscale (1-3 nm) intermediates with intrinsic curvature, in the formation of single-walled aluminosilicate nanotubes is reported. The structural and compositional evolution of molecular and nanoscale species over a length scale of 0.1-100 nm, are characterized by electrospray ionization (ESI) mass spectrometry, and nuclear magnetic resonance (NMR) spectroscopy. DFT calculations revealed the intrinsic curvature of nanoscale intermediates with bonding environments similar to the structure of the final nanotube product. It is shown that curved nano-intermediates form in aqueous synthesis solutions immediately after initial hydrolysis of reactants at 25 °C, disappear from the solution upon heating to 95 °C due to condensation, and finally rearrange to form ordered single-walled aluminosilicate nanotubes. Integration of all results leads to the construction of the first molecular-level mechanism of single-walled metal oxide nanotube formation, incorporating the role of monomeric and polymeric aluminosilicate species as well as larger nanoparticles. Then, in Chapter 3, new molecular-level concepts for constructing nanoscopic metal oxide objects are demonstrated. The diameters of metal oxide nanotubes are shaped with Angstrom-level precision by controlling the shape of nanometer-scale precursors. The subtle relationships between precursor shape and structure and final nanotube curvature are measured (at the molecular level). Anionic ligands (both organic and inorganic) are used to exert fine control over precursor shapes, allowing assembly into nanotubes whose diameters relate directly to the curvatures of shaped precursors. Having obtained considerable insight into aluminosilicate nanotube formation, in Chapter 4 the complex aqueous chemistry of nanotube-forming aluminogermanate solutions are examined. The aluminogermanate system is particularly interesting since it forms ultra-short nanotubes of lengths as small as ˜20 nm. Insights into the underlying important mechanistic differences between aluminogermanate and aluminosilicate nanotube growth as well as structural differences in the final nanotube dimensions are provided. Furthermore, an experimental example of control over nanotube length is shown, using the understanding of the mechanistic differences, along with further suggestions for possible ways of controlling nanotube lengths. In Chapter 5, a generalized kinetic model is formulated to describe the reactions leading to formation and growth of single-walled metal oxide nanotubes. This model is capable of explaining and predicting the evolution of nanotube populations as a function of kinetic parameters. It also allows considerable insight into meso/microscale nanotube growth processes. For example, it shows that two different mechanisms operate during nanotube growth: (1) growth by precursor addition, and (2) by oriented attachment of nanotubes to each other. In Chapter 6, a study of the structure of the nanotube walls is presented. A detailed investigation of the defect structures in aluminosilicate single-walled nanotubes via multiple advanced solid-state NMR techniques is reported. A combination of 1H-29Si and 1H- 27Al FSLG-HETCOR, 1H CRAMPS, and 1H- 29Si CP/MAS NMR experiments were employed to evaluate the proton environments around Al and Si atoms during nanotube synthesis and in the final structure. The HETCOR experiments allowed to track the evolving Si and Al environments during the formation of the nanotubes from precursor species, and relate them to the Si and Al coordination environments found in the final nanotube structure. (Abstract shortened by

Yucelen, Gulfem Ipek

480

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

SciTech Connect

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.

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

481

Molecular adsorption study of nicotine and caffeine on single-walled carbon nanotubes from first principles  

NASA Astrophysics Data System (ADS)

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.

Lee, Hyung-June; Kim, Gunn; Kwon, Young-Kyun

2013-08-01

482

? and ? + ? plasmon localization in single-walled carbon nanotube meta-materials.  

PubMed

We have investigated the plasmon excitations and interband transitions in nematic nanotube meta-materials with different nanotube mean diameters. While the characteristic optical low-energy transitions give testimony to the differing mean diameters, the full momentum resolved ? as well as ? + ? plasmon response of the meta-materials is found to be entirely invariant with the nanotube diameters 1 nm < d < 2 nm. We hence demonstrate that plasmons on single-walled carbon nanotubes are fully channeled to be one dimensional in the typical range of nanotube diameters. The internal morphology of the meta-material offers a knob to uniformly tune the plasmon resonances. PMID:24029462

Kramberger, C; Thurakitseree, T; Maruyama, S; Knupfer, M

2013-10-11

483

Fine Structure of the Low-Frequency Raman Phonon Bands of Single-Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

Iliev, M. N.; Litvinchuk, A. P.; Arepalli, S.; Nikolaev, P.; Scott, C. D.

1999-01-01

484

Note: Detecting flow velocity with high purity semiconducting single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

We report the measurement of fluid velocity on a semiconducting single-walled carbon nanotubes film in a microfluidic channel. To investigate the mechanism related to electrical signal change, we performed various experiments along with changing the flow velocity, the ion concentration and liquid viscosity, etc. Our result suggests that the sensing of flow velocity is a closely related to a pulsating asymmetrical thermal ratchet model. The electric signal change was strongly dependent on the electrode alignment, and the channel width of the sample. As the result, we achieved highly sensitive detection of the fluid, roughly 4 times greater than previous results.

Lee, Seungho; Jung, Wonsuk; Woo, Ju Yeon; Kim, Soohyun; Han, Chang-Soo

2013-03-01

485

Topologically closed macromolecules made of single walled carbon nanotubes-'super'-fullerenes.  

PubMed

We propose and theoretically investigated a new class of topologically closed macromolecules built using single walled carbon nanotubes. These macromolecules are based on the fullerene architecture. Classical molecular dynamics simulations were used to predict their stability, thermal, vibrational, and mechanical properties. These macromolecules, named 'super'-fullerenes, present high porosity, low density (approximately 1 g/cm3), and high surface area (approximately equal 2500 m2/g). Our results predict gas phase specific heat of about 0.4 Jg(-1)K(-1) at room temperature and high flexibility under compressive strains. These properties make these hypothetical macromolecules good candidates for gas storage material and biomolecular sieves. PMID:21128429

Coluci, V R; dos Santos, R P B; Galvão, D S

2010-07-01

486

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

NASA Astrophysics Data System (ADS)

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

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

2006-06-01

487

Simulation and vibrational analysis of thermal oscillations of single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

The first four flexural thermal vibrational modes of single-walled carbon nanotubes (SWCNTs) of various lengths and radii were studied using atomistic molecular dynamics within the framework of the Brenner interatomic potential and Fourier analysis. These simulations provide clear evidence for the failure of simplistic analytic models to accurately extract resonance frequencies as the ratio R/L between the tube radius and the length increases. They are in excellent agreement with the Timoshenko beam model, which includes the effect of both rotary inertia and of shearing deformation. In addition, our results partially resolve Yakobson’s paradox and provide an upper cutoff estimate for the effective SWCNT thickness.

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

2011-04-01

488

Vibrational analysis of thermal oscillations of single-walled carbon nanotubes under axial strain  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

489

Ball-milling modification of single-walled carbon nanotubes: purification, cutting, and functionalization.  

PubMed

Single-walled carbon nanotubes (SWNTs) can be successfully cut with relatively homogeneous sizes using a planetary mill. The optimized conditions produce highly dispersible SWNTs that can be efficiently functionalized in a variety of synthetic ways. As clearly shown by Raman spectroscopy, the milling/cutting procedure compares very favorably with the most common way of purifying SWNTs, namely, treatment with strong oxidizing acids. Moreover a similar milling process can be used to functionalize and cut pristine SWNTs by one-step nitrene chemistry. PMID:21290599

Rubio, Noelia; Fabbro, Chiara; Herrero, M Antonia; de la Hoz, Antonio; Meneghetti, Moreno; Fierro, Jose L G; Prato, Maurizio; Vázquez, Ester

2011-03-01

490

Grapevine-like growth of single walled carbon nanotubes among vertically aligned multiwalled nanotube arrays  

NASA Astrophysics Data System (ADS)

Large arrays of self-oriented, multiwalled carbon nanotubes (MWNTs) have been obtained by chemical vapor deposition. It has so far been impossible to translate this idea for growing single walled nanotubes (SWNTs) but we show here that oriented growth of SWNTs among vertically aligned MWNT arrays can be realized by the catalytic pyrolysis of ferrocene and xylene. The MWNTs act as the support structures for SWNTs, forcing them to grow upward steadily, like grapevines. The growth of vertically aligned SWNT over large areas brings about the possibility of exploring their properties in select configurations.

Cao, Anyuan; Zhang, Xianfeng; Xu, Cailu; Liang, Ji; Wu, Dehai; Chen, Xihua; Wei, Bingqing; Ajayan, P. M.

2001-08-01

491

Temperature Dependence of the Thermal Conductivity of Single Wall Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

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.

Osman, Mohamed A.; Srivastava, Deepak

2000-01-01

492

Single wall carbon nanohorn as a drug carrier for controlled release  

NASA Astrophysics Data System (ADS)

A single wall carbon nanohorn (SWNH) is a new kind of single-graphene tubules with a diameter of 2-5 nm and a length 40-50 nm. In this work, we used oxidized SWNH (SWNHox) to incorporate vancomycin hydrochloride (VCM) for its controlled release by taking advantage of the interactions between VCM and SWNHox. Phospholipid-poly(ethylene glycol) was used to modify the hydrophobic surface of SWNHox to improve its dispersion in aqueous systems. In the release study using this complex, a stable release of VCM was achieved for an extended period.

Xu, Jianxun; Yudasaka, Masako; Kouraba, Sachio; Sekido, Mitsuru; Yamamoto, Yuhei; Iijima, Sumio

2008-08-01

493

En route toward high performance electronics based on single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

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.

Cao, Qing

2014-06-01

494

Kinetics of reactive ion etching upon single-walled carbon nanotubes  

SciTech Connect

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

Kato, Toshiaki; Hatakeyama, Rikizo [Department of Electronic Engineering, Tohoku University, Sendai 980-8579 (Japan)

2008-01-21

495

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

E-print Network

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.

Bajaj, Chandrajit; Podio-Guidugli, Paolo

2011-01-01

496

Dispersion Interaction of Atoms with Single-Walled Carbon Nanotubes described by the Dirac Model  

E-print Network

We calculate the interaction energy and force between atoms and molecules and single-walled carbon nanotubes described by the Dirac model of graphene. For this purpose the Lifshitz-type formulas adapted for the case of cylindrical geometry with the help of the proximity force approximation are used. The results obtained are compared with those derived from the hydrodymanic model of graphene. Numerical computations are performed for hydrogen atoms and molecules. It is shown that the Dirac model leads to larger values of the van der Waals force than the hydrodynamic model. For a hydrogen molecule the interaction energy and force computed using both models are larger than for a hydrogen atom.

Yu. V. Churkin; G. L. Klimchitskaya; A. B. Fedortsov; V. A. Yurova

2011-08-30

497

Dispersion Interaction of Atoms with Single-Walled Carbon Nanotubes described by the Dirac Model  

E-print Network

We calculate the interaction energy and force between atoms and molecules and single-walled carbon nanotubes described by the Dirac model of graphene. For this purpose the Lifshitz-type formulas adapted for the case of cylindrical geometry with the help of the proximity force approximation are used. The results obtained are compared with those derived from the hydrodymanic model of graphene. Numerical computations are performed for hydrogen atoms and molecules. It is shown that the Dirac model leads to larger values of the van der Waals force than the hydrodynamic model. For a hydrogen molecule the interaction energy and force computed using both models are larger than for a hydrogen atom.

Churkin, Yu V; Fedortsov, A B; Yurova, V A

2011-01-01

498

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

E-print Network

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.

Chandrajit Bajaj; Antonino Favata; Paolo Podio-Guidugli

2011-11-19

499

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

NASA Astrophysics Data System (ADS)

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.

Kim, Duckjong; Li, Cheng Ai; Choi, Kwang-Min

2015-01-01

500

Synthesis and Electronic Properties of Silicon-Nitrogen Hetero-doped Single Walled Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

We investigated the stability and electronic properties of hetero-doped carbon nanotubes using first-principles density functional theory. Silicon, silicon-nitrogen, and silicon-oxygen were incorporated within the lattice of different types of single-walled carbon nanotubes. The structural stability, electronic density of states, doping energy, band structure, HOMO and LUMO were analyzed. When silicon and nitrogen are bonded and inserted in the nanotube lattice, non-dispersive bands appear around the Fermi level. The Nitrogen arranged in a pyridine-like fashion together with a silicon atom placed inside the vacancy was also studied. The latter configuration becomes more stable than the substitutional nitrogen embedded in the (9,0) and (5,5) nanotubes. We have also succeeded in the synthesis of Si and SiN-doped single-walled carbon nanotubes (CSixNy -SWNTs) by chemical vapor deposition. We carried out Raman spectroscopy, high-resolution electron microscopy, electron energy loss spectroscopy, energy-dispersive X-Ray spectroscopy, Auger spectroscopy and X-Ray photoelectron spectroscopy, in order to identify the presence of both dopants within the nanotube lattice.

Audiffred, Martha; Elias, Ana Laura; Gutierrez, Humberto R.; Lopez-Urias, Florentino; Terrones, Humberto; Terrones, Mauricio; Merino, Gabriel

2012-02-01