Single Carbon Nanotubes Research Articles

Femtosecond laser treatment of SWNT onto metal electrodes and its effect on carbon nanotube field effect transistor

With unique electrical, mechanical, and thermal properties, carbon nanotubes (CNTs) have possessed the potential to be the ideal next-generation semiconductor in very large scale integration (VLSI). However, the extremely large schottky contact resistance generated by the interface between CNTs and metal electrodes has recently become a stricky constraint, which can greatly affect the transmission of current. In this paper, we used femtosecond laser to join the CNTs and the metal electrodes. The interconnect quality was investigated under different settings of laser power and scanning speed. Then, the carbon nanotubes field effect transistor (CNFET) based on a single CNT was fabricated and its electrical performance after laser induced interconnect was characterized. It is shown that the operating current of CNFET after irradiation is approximately 1.5 times that of before irradiation.

Influence of single and multi-walled CNT on the mechanical performance of glass fiber hybrid polymer composites

The structural materials of the twenty-first century have evolved with the inclusion of nano scale materials which can be utilized to improve the performances of the materials significantly. One of such widely adopted nano material is carbon nano tubes (CNTs) which can further be categorized as single walled and multi walled CNTs (SWCNT and MWCNT). Similarly, glass fiber reinforced polymer composites (GFRP) are a promising material for a wide range of applications, including automotive parts, aircraft components, boat hulls, wind turbine blades, and construction materials. Research by material designers continues to explore new avenues for further improving properties of GFRP composites by using nanomaterials and other advanced materials. In the present work, a new class of polymeric composite material is developed with different filler loading (i.e., 1% to 5% with a step of 1%) of single and multi-walled CNT with glass fiber as reinforcement phase. The tensile and flexural strengths of the hybrid nano composites were determined. The incorporation of CNT with glass fiber epoxy composites strengthened the matrix phase thereby enhancing the tensile and flexural strengths of the developed composites. Further, the obtained experimental findings outlined that the multi walled carbon nano tube filler provided optimum tensile and flexural strength among developed composites due to the better interphase bonding with multi walled structure of MWCNT filler structure. Further, the microscopic analysis of the fractured surfaces was conducted to analyze different mechanisms leading to failure of composite materials during loading.

Design of efficient thermal conductive epoxy resin composites via highspeed transport pathways of heterogeneous compatible carbon framework

Thermal interface materials are crucial for addressing the hot issues of a rapid increase in thermal density in narrow and limited service spaces. Flexible and designable epoxy resin (EP) based composites are competitive choice yet lacks desirable thermal conductivity (∼0.2 W m−1 K−1) and mechanical properties (tensile strength: ∼19.6 MPa). Herein, EP-based composites with a reinforced three-dimensional (3D) interconnected carbon material architecture were prepared by in-situ growing 1D carbon nanotubes (CNTs) on the surface of 2D carbon fiber braid (CFB) and infiltrating matrix EP. CNTs not only promote the wettability between carbon fibers inside CFB and EP but also observably bridge the adjacent carbon fibers. The analysis of numerical models reveals the prominent contribution of 3D CFB/CNTs network to a significant increase in thermal conductivity. Non-equilibrium molecular dynamics (NEMD) indicates the high intrinsic thermal conductivity of CNTs in both systems: single CNT model and CNT/Ni model. The coupling behavior of high-frequency phonons at the interface contributes to the in-plane thermal transport. The in-plane thermal conductivity of 7.86 W m−1 K−1 and the through-plane thermal conductivity of 5.85 W m−1 K−1 are obtained in the composites with 23.2 wt% hybrid fillers, increased by 3830 % compared to neat EP. The tensile (58.93 MPa) and compressive strength (138.83 MPa) are also enhanced, meeting practical demands. These properties even perform no obvious changes after 100 cycles of bending. The stable and reliable EP-based composites with outstanding comprehensive performance designed by this work have enormous application potential in the advanced heat dissipation system.

Electrically driven light emission from single quantum dots using pulsed MOS capacitors

Robust, nanoscale light-emitting devices are attractive for emerging photonic and quantum engineering applications. However, conventional approaches suffer from fabrication challenges or lack the potential to address individual nanostructures, such as quantum dots. In this paper, we present a device that can produce electrically driven light emission from a single quantum dot using a single carbon nanotube as the charge injection contact. The device has a metal-oxide-semiconductor capacitor structure and operates based on an unconventional mechanism of electroluminescence, which relies on the use of bipolar voltage pulses. The proposed device can be fabricated in a simple manner using conventional lithographic processes, offering a scalable approach toward the development of optoelectronic devices at the single dot level.

A Review Paper on Properties and Applications of Nanofluids

A nanofluid is a liquid that contains nanometer-sized particles. Nanofluids are obtained by dispersing nanometer-sized particles in conventional base fluids such as water, oil, ethylene glycol, etc. Nanoparticles of materials such as metallic oxides (Al2O3, CuO), nitride ceramics (AlN, SiN), carbide ceramics (SiC, TiC), metals (Cu, Ag, Au), semiconductors (TiO2, SiC), single, double or multi-walled carbon nanotubes, alloyed nanoparticles (Al70, Cu30), etc., were used to prepare the nanofluids. This paper presents a procedure for preparing Nanofluids, the properties of Nanofluids, and their applications in various fields, including energy, mechanics, and biomedicine. Then it defines the parameter that challenges the use of Nanofluids in different applications and finally suggests directions for future research on Nanofluids. The thermal conductivity of the Nanofluids is improved at a very low (< 0.1%) percentage of suspended particles. Nowadays, Nanofluids are used efficiently in non-traditional energy resources in absorbing solar energy to increase the temperature.

Magnetic carbon nanotubes (CNTs)-water-based nanofluid in the presence of thermal radiation and heat generation/absorption

The aim of this study is to examine the Marangoni boundary film problem of water-based CNTs nano-liquids in Darcian porous media. Two types of CNTs, namely Single Wall Carbon Nanotubes (SWCNTs-water) and Multi-Wall Carbon Nanotubes (MWCNTs-water), are considered in the presence of Bénard-Carlo Marangoni convection. The impact of an inclined magnetic field is considered. The heat transport mechanism is analyzed under the impression of nonlinear thermal radiation, heat generation, and absorption. Through Marangoni convection scattering, the system of partial differential equations is established. By utilizing generalized transformation, the model system is converted to an ordinary differential problem and then solved by using the Homotopy Asymptotic Method. It is demonstrated that the volume fraction of nanoparticles raises the velocity at the surface, whereas magnetic and porosity parameters lower the velocity at the surface. Furthermore, the controlling parameters help in increasing the heat transfer rate.

Application of Nanoparticles in the Diagnosis of Gastrointestinal Diseases: A Complete Future Perspective.

The diagnosis of gastrointestinal (GI) diseases currently relies primarily on invasive procedures like digestive endoscopy. However, these procedures can cause discomfort, respiratory issues, and bacterial infections in patients, both during and after the examination. In recent years, nanomedicine has emerged as a promising field, providing significant advancements in diagnostic techniques. Nanoprobes, in particular, offer distinct advantages, such as high specificity and sensitivity in detecting GI diseases. Integration of nanoprobes with advanced imaging techniques, such as nuclear magnetic resonance, optical fluorescence imaging, tomography, and optical correlation tomography, has significantly enhanced the detection capabilities for GI tumors and inflammatory bowel disease (IBD). This synergy enables early diagnosis and precise staging of GI disorders. Among the nanoparticles investigated for clinical applications, superparamagnetic iron oxide, quantum dots, single carbon nanotubes, and nanocages have emerged as extensively studied and utilized agents. This review aimed to provide insights into the potential applications of nanoparticles in modern imaging techniques, with a specific focus on their role in facilitating early and specific diagnosis of a range of GI disorders, including IBD and colorectal cancer (CRC). Additionally, we discussed the challenges associated with the implementation of nanotechnology-based GI diagnostics and explored future prospects for translation in this promising field.

Convective flow dynamics with suspended carbon nanotubes in the presence of magnetic dipole: Intelligent solution predicted Bayesian regularization networks

This paper narrates an investigation for the convective flow dynamics involving single and multiwall carbon nanotubes as well as methanol hybrid nanofluids in the presence of magnetic dipole that has many applications in pharmacy, medication, electronics, energy, and biomedical engineering. Mathematical modeling has been performed for the conversion of physical model in to set of mathematical equations. The derived PDEs are reduced to system of ODEs by utilizing the suitable similarity variables. Adams numerical solver is utilized to solve the reduced differential systems for the formulation of reference datasets nanofluidic model for sundry scenarios by variation of ferromagnetic interaction parameter, Biot number, thermal radiation parameter and viscous dissipation parameter. Intelligent solution predicted strategy via supervised artificial neural networks (ANNs) with a Bayesian Regularization (BR), i.e., ANN-BR, is employed to get immediate numerically approximated results via simulations on training, testing and validation samples from reference datasets of complex geometry. Numerical outcomes of exhaustive simulations, in term of negligible error, i.e., MSE ≤ 10−12, unit value of regression metric, i.e., R ≈ 1 and histogram with majority of instance, i.e., ≥ 90%, closed to reference line, certainly endorsed/verified the correctness of ANN-BR for solving each variation in magnetite nanofluidic system model. Validation of the presented computational model, analysis of flow instabilities, effects of heat transfer properties and optimization of suspended nanoparticles are the conducted perquisites of the study.

Unsteady Carbon Nanotubes Nanofluid Flow due to a Moving Cylinder with Thermal Radiation and Temperature Oscillation Effects

This paper discusses transient two-dimensional boundary layer laminar viscous incompressible free convective flow of nanofluids containing carbon nanotubes (SWCNTs and MWCNTs) over a moving vertical cylinder in the presence of thermal radiation and temperature oscillation. The governing boundary layer equations are converted to a dimensionless form and then solved using the Crank Nicolson type’s unconditionally stable and convergent implicit finite difference method. With diverse parameters such as Grashof number (Gr), volume fraction (Φ), phase angle (ωt), and thermal radiation parameter (N), numerical results are achieved for velocity and temperature profiles along with Nusselt number and skin friction coefficients. The numerical results are analysed in detail using graphs for both water-based nanofluid and kerosene-based nanofluids with single and multi-wall carbon nanotubes as the nanomaterials. It has been found that CNTs Water-based nanofluid has higher temperatures, velocities, skin friction coefficient values for all Gr, N, Φ, and ωt when compared to kerosene-based nanofluid with CNTs. But, Kerosene-based CNTs nanofluid has a higher Nusselt number coefficient values concerning all Gr, N, Φ, and ωt than water-based CNTs nanofluid.

Phases of He4 and H2 adsorbed on a single carbon nanotube

Using a diffusion Monte Carlo technique, we calculated the phase diagrams of $^{4}\mathrm{He}$ and ${\mathrm{H}}_{2}$ adsorbed on a single (5,5) carbon nanotube, one of the narrowest that can be obtained experimentally. For a single monolayer, when the adsorbate density increases, both species undergo a series of first-order solid-solid phase transitions between incommensurate arrangements. Remarkably, the $^{4}\mathrm{He}$ lowest-density solid phase shows supersolid behavior, in contrast to the normal solid that we found for ${\mathrm{H}}_{2}$. The nature of the second layer is also different for both adsorbates. Contrary to what happens on graphite, the second layer of $^{4}\mathrm{He}$ on the tube is a liquid, at least up to the density corresponding to a third-layer promotion on a flat substrate. However, the second layer of ${\mathrm{H}}_{2}$ is a solid that, at its lowest stable density, has a small, but observable, superfluid fraction.

X-ray diffraction analysis for main peaks and the noises of single and multi-walled carbon nanotubes

The XRD for carbon nanotubes shows the main two peaks at 2Ө ≈ 25∘ and 43∘ with many noises for all the line from 5∘ to 80∘ which depend on nature of structure. The noises produce from instrumental sources and the physical properties of tubular structure and that represent by inter and intra Van Der Waals forces. Most of the noises were removed by using computerized programs while it is referred to nature of tubular structure with one or many sheets of graphene. The most of this noises represent the nature of structure which reduces with increase graphene sheets, thus removing it delete the specific proprieties of CNTs. The graphite behave the same properties of tubular structure which variant with number of sheets.

Artificial-intelligence-assisted mass fabrication of nanocantilevers from randomly positioned single carbon nanotubes

Nanoscale cantilevers (nanocantilevers) made from carbon nanotubes (CNTs) provide tremendous benefits in sensing and electromagnetic applications. This nanoscale structure is generally fabricated using chemical vapor deposition and/or dielectrophoresis, which contain manual, time-consuming processes such as the placing of additional electrodes and careful observation of single-grown CNTs. Here, we demonstrate a simple and Artificial Intelligence (AI)-assisted method for the efficient fabrication of a massive CNT-based nanocantilever. We used randomly positioned single CNTs on the substrate. The trained deep neural network recognizes the CNTs, measures their positions, and determines the edge of the CNT on which an electrode should be clamped to form a nanocantilever. Our experiments demonstrate that the recognition and measurement processes are automatically completed in 2 s, whereas comparable manual processing requires 12 h. Notwithstanding the small measurement error by the trained network (within 200 nm for 90% of the recognized CNTs), more than 34 nanocantilevers were successfully fabricated in one process. Such high accuracy contributes to the development of a massive field emitter using the CNT-based nanocantilever, in which the output current is obtained with a low applied voltage. We further showed the benefit of fabricating massive CNT-nanocantilever-based field emitters for neuromorphic computing. The activation function, which is a key function in a neural network, was physically realized using an individual CNT-based field emitter. The introduced neural network with the CNT-based field emitters recognized handwritten images successfully. We believe that our method can accelerate the research and development of CNT-based nanocantilevers for realizing promising future applications.

Nonsimilar convection analysis of single and multilayer carbon nanotubes based nanofluid flow over a vertical cone in a complex porous media subjected to thermal radiations and chemical reaction

The objective of this article is to present a novel model and the consequences of natural convection in magneto hydrodynamic (MHD) boundary-layer flow of carbon nanotubes (CNT’s) based nanofluid above a vertical cone immersed in a porous medium subjected to the suction/injection effects. Two distinct types of CNT’s are investigated within the base fluid known as single wall carbon nanotubes (SWCNT’s) and multiple wall carbon nanotubes (MWCNT’s). Moreover, heat and mass transport mechanisms are examined in the presence of thermal radiations and chemical reactions, respectively. Nonsimilarity transformations are operated to transmute the partial differential system (PDE’s) into dimensionless PDE’s. Numerical solution is acquired by employing local nonsimilarity (LNS) via bvp4c algorithm. Graphical results are plotted and discussed comprehensively against the variation of appealing parameters namely Biot number B10.5-35, Buoyancy ratio parameter Nr0.1-8, chemical reaction parameter Cr0.1-20, Prandtl number Pr(6.2-30), injection parameter Vo0.1-2, Magnetic field M0.2-60 and radiation parameter R(0.1-2). Moreover, the values of Sherwood number Sh, amount of concentration and temperature are examined for distinct values of dimensionless parameters and the conclusions are reported in tabular formation. It is noticed that the Sherwood number escalates with increasing B1 in both SWCNT’s-water and MWCNT’s-water nanofluids, while velocity and temperature profiles are decreasing function of Prandtl number. An excellent comparison is noticed that influence of SWCNT’s is higher than MWCNT’s for velocity, temperature and concentration portray. Finally, the present work is certified via comparison with already published article in limiting case. The novelty of the considered model lies in the fact that the nonsimilar model of the considered model has not been addressed in literature.

Induced Navier’s Slip with CNTS on a Stretching/Shrinking Sheet under the Combined Effect of Inclined MHD and Radiation

The present article investigates viscous fluid flow’s heat and mass transfers over a stretching/shrinking sheet using the single and multi-wall carbon nanotube models. The analysis considers the effects of thermal radiation, induced slip, mass transpiration, and inclined magnetic force. The effect of the carbon nanotube model on fluid flow has not been considered in previous studies. By exploiting the similarity variable, the governing nonlinear partial differential equations are converted into nonlinear ordinary differential equation. The derived equations are solved analytically, and we obtained an exact solution for the velocity and energy conservation equation. The physical parameters of interest such as induced slip parameter, suction/injection, magnetic field, thermal radiation, and shear stress are analyzed and presented graphically. In particular, we show that the fluid flow in a single wall carbon nanotube transfers more energy than the multivalued nanotubes.

Intracavity-loss controlled wavelength-tunable bidirectional mode-locked erbium-doped fiber laser.

Bidirectional wavelength-tunable mode-locked fiber lasers have demands for many applications. In our experiment, two frequency combs from a single bidirectional carbon nanotube mode-locked erbium-doped fiber laser are obtained. Continuous wavelength tuning is demonstrated in the bidirectional ultrafast erbium-doped fiber laser for the first time. We utilized the microfiber assisted differential loss-control effect on both directions to tune operation wavelength and it presents different wavelength tuning performances in two directions. Correspondingly, the repetition rate difference can be tuned from 98.6 Hz to 32 Hz by applying strain on microfiber within 23 µm stretching length. In addition, a minor repetition rate difference variation of 4.5 Hz is achieved. Such technique may provide possibility to expand wavelength range of dual-comb spectroscopy and broad its application fields.

Analyzing the Bolometric Performance of Vanadium Oxide Thin Films Modified by Carbon Nanotube Dispersions

The influence of carbon nanotube (CNT) dispersions on the electrical properties and noise signal amplitude of VOx films is investigated. For a critical range of the CNT dispersion density on VOx films, the intrinsic properties of the VOx films are modified by the CNTs. The CNT concentrations reported in this work are about 0.3 μg/cm2 and 1.6 μg/cm2, allowing for low density and high density dispersions on the VOx film surface to be investigated. These values are higher than the percolation threshold of about 0.12 μg/cm2 for these films. The composite film exhibits a significant reduction in the temperature coefficient of resistance (TCR) (from ≈3.8% K-1 to ≈0.3% K-1) for high density dispersions. In contrast, while VOx-CNT composites with low density single wall CNT dispersions exhibit no significant change in TCR values, an approximate two orders of magnitude reduction in the low frequency 1/f noise is measured. The noise signal amplitude measured at 0.1 V and at 1.0 Hz reduces from 6 × 10-5V/(Hz) for VOx films to 5 × 10-7V/(Hz) for the low density SWCNT dispersion on VOx film and to 3 × 10-6V/(Hz) for the low density MWCNT dispersion on VOx film. The CNT concentration is the critical factor for yielding the observed changes in conductivity and low frequency noise. The results presented in this work provide a better understanding of VOx-based composites, thereby enabling the development of new, versatile and functional materials for device applications.

Effect of different concentration of Single and Multi -Walled Carbon Nanotubes in liver texture and hepatic enzymes in the New Zealand white rabbit

The aim of the present study was to investigate the effect of variable doses of single and multiwalled carbon nanotubes (SWCNTs and MWCNTs) instilled intratracheally on texture of liver and hepatic enzymes ,alanine amino transferase (ALT) and aspartate amino transferase (AST) in New Zealand white rabbits. In this study was used 70 males New Zealand white rabbits, their ages range between (12-18 months) divided into seven groups, ten for each group which instilled with Nanoparticles, At days 7 and 90 post exposure, The blood and tissue samples were collected for each group.&#x0D; Instillation of SWCNTs ( 1 or 5 mg/ml/kg (b.w) or MWCNTs (1,3or 5 mg/ml/kg b.w) in the trachea of rabbits induced a significant increase in activity of ALT and AST.&#x0D; Translocation of carbon nanotubes was seen from the lungs to the liver. It was concluded that: SWCNTs and MWCNTs induced hepatic injuries through its effect in activity of hepatic enzyme and the nanotubes translocated from the lung to the liver and pleura.&#x0D; &#x0D;

Piezoelectric performance of lead-free PDMS/CNT/BaTiO3 piezocomposites with imperfect interphases and CNT agglomerations

Three-dimensional (3D) printable lead-free piezocomposites offer scalable and environmentally friendly solutions in many engineering applications. Typically, the composite system consists of polymeric matrices reinforced with active polycrystalline particles, and possibly nanoadditives. The presence of interfacial inclusion/matrix damage could not only compromise the structural integrity of the component but also significantly alter its ability to act as functional smart materials. In addition, both the agglomeration of the nanoadditives, such as carbon nanotubes (CNTs), and the degree of polarization could also affect the electromechanical behavior of the composite. In this paper, we develop a computational micromechanical model for the study of the influence of three types of internal defects on the piezoelectric performance of such composites. We investigate the influence of (a) the texture of the active phase, which is linked to the degree of polarization; (b) the effect of agglomerations of the CNTs; and (c) the presence of damage in the inclusion/matrix interphase region. Performance is assessed through the macroscopic response in various figures of merit. This work provides numerical evidence that the effective piezoelectric constants related to normal strain modes are strongly affected by the presence of damage in the interphase. Instead, the piezoelectric constant related to the shear strain remains unchanged by interfacial damage. Near the percolation threshold of the CNTs, piezocomposites exhibit a notable improvement in the piezoelectric response compared to the composite without nanomodification, as noted in previous works. Interestingly, this trend also applies in the presence of interfacial damage, and it is described in this work. The piezoelectric performance also depends on the texture of the active particles. We find, under some simplifications, the optimal orientation for the crystallites, and we find how the texture changes the performance in the presence of damage. Regarding energy harvesting applications, optimal energy conversion efficiency has been observed for polycrystalline inclusions that resembles a highly oriented single crystal and CNT volume fraction of 60 of percolation threshold. This is a quite surprising result since the optimal is usually expected for volume fractions very close to percolation and active inclusions with some orientational dispersion. The optimal CNT volume fraction depends on the presence of interfacial damage. Under perfect interface conditions, the energy conversion efficiency is improved with the presence of CNT agglomerations. Under imperfect interface conditions, there is no enhancement due to the addition of CNT.

Water filling in carbon nanotubes with different wettability and implications on nanotube/water heat transfer via atomistic simulations

The peculiar heat and mass transfer properties of Carbon Nanotubes (CNTs) envision promising applications in nanoengineering and nanofluidic devices, such as heat sinks and desalination membranes. However, a comprehensive understanding of the intertwined effects of mass transfer (entrance and exit of liquid molecules inside CNTs) and heat transfer mechanisms (thermal exchange at the CNT/solvent interface) as a function of the properties of CNT surface is currently incomplete. In this work, we use molecular dynamics simulations to study heat and mass transfer in single wall CNTs with (5,5) and (10,10) chirality immersed in water. We present a sensitivity analysis where, starting from different choices of interaction potentials between CNTs and water molecules, we deduce the corresponding CNT/water wetting parameters, we model fill-in and fill-out water dynamics and arrangement of water molecules at the equilibrium. Spontaneous water entrance into CNTs is examined and a single energy parameter to model water filling is introduced. Secondly, we compute the CNT/water thermal boundary resistance for the different wetting properties. In perspective, this work supports a more rational design of CNT-based devices operating in nanothermal and nanobiological environments.

Numerical thermal analysis of armchair (6,6) and zig-zag (12,0) carbon nano-tubes (CNTs)

In this study, the thermal behaviour of small-sized single-atom CNTs was examined. CNTs are composed of crystals that form a nanostructure with different geometric shapes by arranging them in different ways according to the length-diameter ratio. Due to the mechanical, electrical, and thermal properties of CNTs, the thermal conduction of CNT materials is critical in controlling the performance and stability of CNTs. CNTs, which are low-dimensional materials with a single atomic layer thickness, have excellent thermal conductivity. According to the simulation technique in ANSYS, CNTs containing the same number of atoms and bonds were developed. The heat transfer of different structures of CNTs in armchairs (6,6) and zig-zag (12,0) were compared. A comparison of zig-zag and armchair CNTs thermal behaviour shows that zig-zag CNTs lattice structure has more advantages than armchair CNTs lattice structure by heat transfer. Highlights In this study, finite element-based thermal analysis of single and double-walled armchair and zig-zag carbon nano-tubes (CNTs) using the lattice method was investigated. A simulation technique was developed and applied in the ANSYS program for single and double-walled carbon nanotubes (CNTs). Armchairs (6,6) and zig-zag (12,0) CNTs in different lattice structures with equal atomic numbers and bond numbers are modelled according to different diameters and length ratios. The CNTs, which have the same material properties as the trays placed at both open ends of the pipes, are kept at different temperature values, and conduction heat transfer behaviour is investigated for certain temperature values. According to the investigated heat conduction behaviour of zig-zag and armchair CNTs, the lattice structure of the zig-zag carbon nano-tubes is more advantageous in terms of heat conduction than the cage structure of armchair CNTs, and it transmits heat faster than the armchair CNTs.