scholarly journals A Hybrid Nanomaterial Based on Single Walled Carbon Nanotubes Cross-Linked via Axially Substituted Silicon (IV) Phthalocyanine for Chemiresistive Sensors

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2073 ◽  
Author(s):  
Maxim Polyakov ◽  
Victoria Ivanova ◽  
Darya Klyamer ◽  
Baybars Köksoy ◽  
Ahmet Şenocak ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Relative Humidity ◽  
Single Walled Carbon Nanotubes ◽  
Sensor Response ◽  
Hybrid Nanomaterial ◽  
Single Walled Carbon ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Walled Carbon Nanotubes

In this work, the novel hybrid nanomaterial SWCNT/SiPc made of single walled carbon nanotubes (SWCNT) cross-linked via axially substituted silicon (IV) phthalocyanine (SiPc) was studied as the active layer of chemiresistive layers for the detection of ammonia and hydrogen. SWCNT/SiPc is the first example of a carbon-based nanomaterial in which an axially substituted phthalocyanine derivative is used as a linker. The prepared hybrid material was characterized by spectroscopic methods, thermogravimetry, scanning and transmission electron microscopies. The layers of the prepared hybrid were tested as sensors toward ammonia and hydrogen by a chemiresistive method at different temperatures and relative humidity as well as in the presence of interfering gases like carbon dioxide, hydrogen sulfide and volatile organic vapors. The hybrid layers exhibited the completely reversible sensor response to both gases at room temperature; the recovery time was 100–200 s for NH3 and 50–120 s in the case of H2 depending on the gas concentrations. At the relative humidity (RH) of 20%, the sensor response was almost the same as that measured at RH 5%, whereas the further increase of RH led to its 2–3 fold decrease. It was demonstrated that the SWCNT/SiPc layers can be successfully used for the detection of both NH3 and H2 in the presence of CO2. On the contrary, H2S was found to be an interfering gas for the NH3 detection.

Metal Coated Functionalized Single-Walled Carbon Nanotubes for Composites Application

2007 ◽  
Vol 561-565 ◽  
pp. 655-658 ◽  
Author(s):  
Qiang Zeng ◽  
Jennifer Luna ◽  
Y. Bayazitoglu ◽  
Kenneth Wilson ◽  
M. Ashraf Imam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Single Walled Carbon Nanotubes ◽  
Metal Composite ◽  
X Ray ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Metal Composite Materials ◽  
Walled Carbon Nanotubes

This study is considered as a method for producing multifunctional metal composite materials by using Single-walled Carbon Nanotubes (SWNTs). In this research, various metals (Ni, Cu, Ag ) were successfully deposited onto the surface of SWNTs. It has been found that homogenous dispersion and dense nucleation sites are the necessary conditions to form uniform coating on SWNTs. Functionalization has been applied to achieve considerable improvement in the dispersion of purified single-walled carbon nanotubes. A three-step electroless plating approach was used and the coating mechanism is described in the paper. The samples were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDX). The application of coated SWNTs in Titanium will be discussed in this paper.

Image Restoration of One-Dimensional HgTe Crystals Formed within Single Walled Carbon Nanotubes

2006 ◽  
Vol 514-516 ◽  
pp. 1131-1134
Author(s):  
Jeremy Sloan ◽  
Robin Carter ◽  
Angus I. Kirkland ◽  
Rüdiger R. Meyer ◽  
Alexis Vlandas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Three Dimensional ◽  
Single Walled Carbon Nanotubes ◽  
One Dimensional ◽  
Single Walled Carbon ◽  
Semiconductor Crystals ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes ◽  
Separate Crystal

Restored high resolution transmission electron microscopy (HRTEM) images have been recorded from 1D semiconductor crystals formed within narrow diameter (ca. 1.4 nm) single walled carbon nanotubes (SWNTs). Two unique projections were obtained from separate crystal fragments encapsulated within separate nanotubes that has facilitated the reconstruction of the three dimensional arrangement of atoms within the two encapsulated fragments.

Preparation of Single-Walled Carbon Nanotubes from Starch by Arc Discharge

2012 ◽  
Vol 454 ◽  
pp. 63-66
Author(s):  
Xia Yuan ◽  
Yu Liang An ◽  
Chen Zhang ◽  
Hong Chao Sui
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Arc Discharge ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes ◽  
Discharge Method ◽  
Scanning Electron

Single-walled carbon nanotubes (SWNTs) have been successfully prepared from starch by arc discharge technique. The SWNTs products were characterized by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The growth mechanism of the SWNTs was discussed in terms of the starch. The results demonstrate that starch is one of the suitable precursor for making SWNTs by arc discharge method.

The High Thickness Ni Layer on Single-Walled Carbon Nanotubes Prepared by an Electroless Coating Process

2010 ◽  
Vol 148-149 ◽  
pp. 1607-1610
Author(s):  
Wei Xue Li ◽  
Dun Dong Wang ◽  
Hui Jin ◽  
Jian Feng Dai ◽  
Qing Wang
Keyword(s):  
Carbon Nanotubes ◽  
Single Walled Carbon Nanotubes ◽  
Deposition Process ◽  
X Ray Diffraction ◽  
Electroless Coating ◽  
Single Walled Carbon ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
20 Nm ◽  
Walled Carbon Nanotubes

The Single-walled carbon nanotubes were coated with Ni-P layers by an electroless plating technique. A Ni-P layers are thick and smooth and on individual nanotube with thickness of 20 nm can be obtained after the deposition process. The Single-walled carbon nanotubes were obtained in the suspension of purification solution. The samples have been characterized by X-ray diffraction, selected area electron diffraction, transmission electron microscopy and energy dispersive spectrometry.The coating layers after heat-treatment convert the amorphous Ni-P coated layers into the nanocrystalline Ni-P layers.

The Unravelling of Open-Ended Single Walled Carbon Nanotubes Using Molecular Dynamics Simulations

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Tarek Ragab ◽  
Cemal Basaran
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulations ◽  
Single Walled Carbon Nanotubes ◽  
Atomic Chain ◽  
Single Walled Carbon ◽  
Different Temperatures ◽  
Dynamics Simulations ◽  
Walled Carbon Nanotubes

The unravelling of (10, 10) and (18, 0) single-walled carbon nanotubes (SWCNTs) is simulated using molecular dynamics simulations at different temperatures. Two different schemes are proposed to simulate the unravelling; completely restraining the last atom in the chain and only restraining it in the axial direction. The forces on the terminal atom in the unravelled chain in the axial and radial directions are reported till the separation of the atomic chain from the carbon nanotube structure. The force-displacement relation for a chain structure at different temperatures is calculated and is compared to the unravelling forces. The axial stresses in the body of the carbon nanotube are calculated and are compared to the failure stresses of that specific nanotube. Results show that the scheme used to unravel the nanotube and the temperature can only effect the duration needed before the separation of some or all of the atomic chain from the nanotube, but does not affect the unravelling forces. The separation of the atomic chain from the nanotube is mainly due to the impulsive excessive stresses in the chain due to the addition of a new atom and rarely due to the steady stresses in the chain. From the simulations, it is clear that the separation of the chain will eventually happen due to the closing structure occurring at the end of the nanotube that would not be possible in multiwalled nanotubes.

Nanowelding of Single Walled Carbon Nanotubes onto Electrodes Using Molecular Dynamics Method

2014 ◽  
Vol 527 ◽  
pp. 13-16
Author(s):  
Xuan Liu ◽  
Ze Liu ◽  
Pu Sun ◽  
Ya Rong Wang ◽  
Ying Wu
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Welding Process ◽  
Single Walled Carbon Nanotubes ◽  
Molecular Dynamics Method ◽  
Single Walled Carbon ◽  
Different Temperatures ◽  
Set Up ◽  
Walled Carbon Nanotubes ◽  
Dynamics Method

Nanowelding system is set up to investigate the welding process of nickel electrodes to single walled carbon nanotubes (SWCNTs) with molecular dynamics method. This system consists of C-C, C-Ni, Ni-Ni subsystems. The interaction of C-C, C-Ni Ni-Ni are modeled by adaptive intermolecular reactive empirical bonder order (AIREBO) potential, Lennard-Jones (LJ) potential, as well as embedded atomic method (EAM) model respectively. The dynamic process of nanowelding at different temperatures and times is analyzed and described completely at atomistic length scales. The simulation results indicate that the nanowelding could be accomplished at 1450k which is far lower than the melting point of nickel.

METHODS FOR DISPERSION AND ALIGNMENT OF SINGLE-WALLED CARBON NANOTUBES AND EFFECTS ON THEIR STRUCTURAL AND ELECTRONIC PROPERTIES

2006 ◽  
Vol 05 (04n05) ◽  
pp. 407-411
Author(s):  
JUN JIAO ◽  
LIFENG DONG ◽  
VACHARA CHIRAYOS ◽  
JOCELYN BUSH ◽  
JAMES HEDBERG
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Sodium Dodecyl ◽  
Single Walled Carbon Nanotubes ◽  
Dielectric Medium ◽  
High Yield ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
The Individual ◽  
Walled Carbon Nanotubes

Two effective methods for dispersion and alignment of single-walled carbon nanotubes (SWCNTs) were developed. One is the floating-potential dielectrophoresis (FPD) method, which can achieve the alignment of individual SWCNTs between two electrodes with high yield (more than 30%) and high repeatability. The second is the gas blow method. Using the shear forces associated with a rapidly moving fluid, SWCNTs were positioned in a direction corresponding to the flow vector of the fluid. This technique shows great potential for scaling up the displacement of SWCNTs with controlled orientations. Various dispersion agents including ethanol, dichlorobenzene, sodium dodecyl sulfate (SDS) and DNA were investigated with these two methods. It was found that SDS was the most effective dielectric medium used for FPD dispersion and alignment of SWCNTs. The result of electric measurement for the individual SWCNTs aligned between two electrodes suggests that, using the FPD method, both metallic and semiconducting SWCNTs could be aligned between the electrodes. The individual SWCNT resistances measured range from 20 KΩ to 5 MΩ suggesting a high contact resistance between an aligned SWCNT and metal electrodes. High resolution transmission electron microscopy (TEM) and scanning electron microscopy (SEM) characterization reveal DNA molecules wrapped around the SWNCTs after the dispersion process which may affect the intrinsic properties of SWCNTs.

Functionalization of single-walled carbon nanotubes: Chemistry and characterization

2017 ◽  
Author(s):  
R. Graupner ◽  
F. Hauke
Keyword(s):  
Carbon Nanotubes ◽  
Nir Spectroscopy ◽  
Single Walled Carbon Nanotubes ◽  
Covalent Attachment ◽  
Spectroscopic Techniques ◽  
Force Microscopy ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
Tunnelling Microscopy ◽  
Walled Carbon Nanotubes

This article examines the chemical functionalization and structural alteration of single-walled carbon nanotubes (SWCNTs). It describes the covalent functionalization of the SWCNT framework that is the covalent attachment of functional entities onto the CNT scaffold. In particular, it considers the chemical modification and reactivity of SWCNTs in the context of the reactivity of graphite and fullerenes. It also discusses the defect and sidewall functionalization of SWCNTs, along with various techniques used in the characterization ofSWCNTs upon functionalization, namely: thermogravimetric analysis, spectroscopic techniques such as UV-Vis-NIR spectroscopy and Raman spectroscopy, and microscopic techniques like transmission electron microscopy, atomic force microscopy and scanning tunnelling microscopy.

scholarly journals Antimony Selenide Crystals Encapsulated within Single Walled Carbon Nanotubes-A DFT Study

2009 ◽  
Vol 6 (s1) ◽  
pp. S147-S152 ◽  
Author(s):  
Navaratnarajah Kuganathan
Keyword(s):  
Carbon Nanotubes ◽  
Binding Energy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Single Walled Carbon Nanotubes ◽  
Binding Energies ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
Antimony Selenide ◽  
Walled Carbon Nanotubes

The structure and binding energies of antimony selenide crystals encapsulated within single-walled carbon nanotubes are studied using density functional theory. Calculations were performed on the simulated Sb2Se3structure encapsulated within single walled nanotube to investigate the perturbations on the Sb2Se3crystal and tube structure and electronic structure and to estimate the binding energy. The calculated structures are in good agreement with the experimental high resolution transmission electron microscopy images of the Sb2Se3@SWNT. The calculated binding energy shows that larger diameter tube could accommodate the Sb2Se3crystals exothermically. Minimal charge transfer is observed between nanotube and the Sb2Se3crystals.

scholarly journals Negatively-Doped Single-Walled Carbon Nanotubes Decorated with Carbon Dots for Highly Selective NO2 Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2509
Author(s):  
Namsoo Lim ◽  
Jae-Sung Lee ◽  
Young Tae Byun
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
Cost Effective ◽  
Single Walled Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Walled Carbon ◽  
Sensor Applications ◽  
Transmission Electron ◽  
P Type ◽  
Walled Carbon Nanotubes

In this study, we demonstrated a highly selective chemiresistive-type NO2 gas sensor using facilely prepared carbon dot (CD)-decorated single-walled carbon nanotubes (SWCNTs). The CD-decorated SWCNT suspension was characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-visible spectroscopy, and then spread onto an SiO2/Si substrate by a simple and cost-effective spray-printing method. Interestingly, the resistance of our sensor increased upon exposure to NO2 gas, which was contrary to findings previously reported for SWCNT-based NO2 gas sensors. This is because SWCNTs are strongly doped by the electron-rich CDs to change the polarity from p-type to n-type. In addition, the CDs to SWCNTs ratio in the active suspension was critical in determining the response values of gas sensors; here, the 2:1 device showed the highest value of 42.0% in a sensing test using 4.5 ppm NO2 gas. Furthermore, the sensor selectively responded to NO2 gas (response ~15%), and to other gases very faintly (NO, response ~1%) or not at all (CO, C6H6, and C7H8). We propose a reasonable mechanism of the CD-decorated SWCNT-based sensor for NO2 sensing, and expect that our results can be combined with those of other researches to improve various device performances, as well as for NO2 sensor applications.

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