Carbon-based Nanostructures Research Articles

Adsorption of Tetranitrocarbazole on the Surface of Six Carbon-Based Nanostructures: A Density Functional Theory Investigation

In this study, the interaction of Tetranitrocarbazole (TNC) with six various carbon-based nanostructures including carbon nanotubes, graphene, carbon nanocones and three fullerenes (C20, C24 and C60) was investigated by Density functional theory (DFT). The calculated adsorption energies, Gibbs free energy changes, enthalpy variations and thermodynamic equilibrium constants revealed that the adsorption of TNC is exothermic process, spontaneous, one-sided, non-equilibrium and experimentally feasible on the surface of all of the studied nano-adsorbents except carbon nanotube. The increasing of N–O and C–NO2 bond lengths after reacting with nano-substituents proved that the energetic and explosive properties of TNC has defused significantly. The computed density values substantiated the detonation pressure and explosive velocity of TNC have improved after adsorbing on the surface of C20.Some frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied and the results showed that C20 is an ideal candidate for being used as a sensing material in the construction of TNC conductometric sensor. Graphenecould also be utilized as an electroactive sensing material in the development of TNC selective potentiometric electrodes.

Introductory lecture: origins and applications of efficient visible photoluminescence from silicon-based nanostructures.

A variety of silicon-based nanostructures with dimensions in the 1-5 nm range now emit tunable photoluminescence (PL) spanning the visible range. Achievement of high photoluminescence quantum efficiency (PLQY) relies critically on their surface chemistry passivation and an impressive "tool box" of options have been developed. Two distinct PL bands are dominant. The "S-Band" (red-green emission with Slow microsecond decay) has PLQY that has steadily improved from ∼3% in 1990 to 65 ± 5% by 2017. The "F-Band" (blue-yellow with Fast nanosecond decay) has reported PLQY values that have improved from ∼0.1% in 1994 to as high as ∼90% by 2016. The vast literature on both bands is surveyed and for the S-band, size-structure-PL correlations and selective photo-excitation studies are highlighted. Resonant photoexcitation and single quantum dot studies have revealed the key role of quantum confinement and the excitonic phonon-assisted nature of the radiative transitions. For the F-band, in contrast, specific phenomenological studies are highlighted that demonstrate similar emission without the presence of silicon nanostructures. Low PLQY F-band emission from pure silicon-silica core shell systems is probably associated with oxide-related defects, but ultrahigh PLQY from many lower temperature synthesis routes is likely to be from carbon-based nanostructures or chromophores, not silicon nanostructures. Potential applications for both PL bands include sensing, medical imaging, theranostics, photovoltaics, LED colour converters and nano-thermometry. Emerging "green" synthesis routes are mentioned. If scalability and cost are significantly improved then a number of other proposed uses of ultra-efficient PL from "nano-Si" could become viable in cosmetics, catalysis, security and forensics.

Influence of thermostatting on nonequilibrium molecular dynamics simulations of heat conduction in solids.

Nonequilibrium molecular dynamics (NEMD) has been extensively used to study thermal transport at various length scales in many materials. In this method, two local thermostats at different temperatures are used to generate a nonequilibrium steady state with a constant heat flux. Conventionally, the thermal conductivity of a finite system is calculated as the ratio between the heat flux and the temperature gradient extracted from the linear part of the temperature profile away from the local thermostats. Here, we show that, with a proper choice of the thermostat, the nonlinear part of the temperature profile should actually not be excluded in thermal transport calculations. We compare NEMD results against those from the atomistic Green's function method in the ballistic regime and those from the homogeneous nonequilibrium molecular dynamics method in the ballistic-to-diffusive regime. These comparisons suggest that in all the transport regimes, one should directly calculate the thermal conductance from the temperature difference between the heat source and sink and, if needed, convert it into the thermal conductivity by multiplying it with the system length. Furthermore, we find that the Langevin thermostat outperforms the Nosé-Hoover (chain) thermostat in NEMD simulations because of its stochastic and local nature. We show that this is particularly important for studying asymmetric carbon-based nanostructures, for which the Nosé-Hoover thermostat can produce artifacts leading to unphysical thermal rectification.

Carbon nanotube accelerator — Path toward TeV/m acceleration: Theory, experiment, and challenges

Aspirations of modern high energy particle physics call for compact and cost efficient lepton and hadron colliders with energy reach and luminosity significantly beyond the modern HEP facilities. Strong interplanar fields in crystals of the order of 10–100 V/Å can effectively guide and collimate high energy particles. Besides continuous focusing crystals plasma, if properly excited, can be used for particle acceleration with exceptionally high gradients [Formula: see text](TeV/m). However, the angstrom-scale size of channels in crystals might be too small to accept and accelerate significant number of particles. Carbon-based nano-structures such as carbon-nanotubes (CNTs) and graphenes have a large degree of dimensional flexibility and thermo-mechanical strength and thus could be more suitable for channeling acceleration of high intensity beams. Nano-channels of the synthetic crystals can accept a few orders of magnitude larger phase-space volume of channeled particles with much higher thermal tolerance than natural crystals. This paper presents conceptual foundations of the CNT acceleration, including underlying theory, practical outline and technical challenges of the proof-of-principle experiment. Also, an analytic description of the plasmon-assisted laser acceleration is detailed with practical acceleration parameters, in particular with specifications of a typical tabletop femtosecond laser system. The maximally achievable acceleration gradients and energy gains within dephasing lengths and CNT lengths are discussed with respect to laser-incident angles and the CNT-filling ratios.

On‐Surface Synthesis and Characterization of Triply Fused Porphyrin–Graphene Nanoribbon Hybrids

On-surface synthesis offers a versatile approach to prepare novel carbon-based nanostructures that cannot be obtained by conventional solution chemistry. Graphene nanoribbons (GNRs) have potential for a variety of applications. A key issue for their application in molecular electronics is in the fine-tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non-benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) is a highly appealing strategy. Herein we present the selective on-surface synthesis of a Por-GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the Por-GNR hybrid has been characterized by bond-resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM). The electronic properties have been investigated by scanning tunneling spectroscopy (STS), in combination with DFT calculations, which reveals a low electronic gap of 0.4 eV.

HICOLM: High-Performance Platform of Physical Simulations by Using Low Computational Cost Methods

For decades, computational simulation models have been used by scientists in search for new materials with technological applications in several areas of knowledge. For this, software based on several theoretical-computational models were developed in order to obtain an analysis of the physical properties at atomic levels. The objective of this work is proposing a widely functional software to analyze the physical properties of nanostructures based on carbon and condensed systems using theories of low computational cost. Therefore, a Fortran language computational program called HICOLM was developed, whose theoretical bases are based on two commonly known models (Tight-binding and Molecular Dynamics). The physical properties of condensed systems can be obtained in the thermodynamic equilibrium in several statistical ensembles, and possible to obtain an analysis of the properties of the material and its evolution in the time-dependent on its thermodynamic conditions like temperature and pressure. Moreover, from the tight-binding model, the HICOLM program is also capable of performing a physical analysis of carbon-based nanostructures from the calculation of the material band structure.

Electrical conductivity and mechanical property improvement by low-temperature carbon nanotube growth on carbon fiber fabric with nanofiller incorporation

Carbon fiber reinforced polymer composites offer many advantages due to their great combination of high strength and modulus combined with low density and light-weight; however, they typically feature low electrical conductivity. These advanced composites are often unsatisfactory compared to conventional conductive metals that are vulnerable to lightning strike damage. To develop a new generation of highly conductive carbon fiber composites that address these shortcomings, carbon nanotubes (CNTs) were grown on nickel-coated carbon fiber using low-temperature growth to create a fuzzy fiber surface. An additional conductive filler, graphene nanoplatelets (GNPs), was then dispersed on the fuzzy fiber surface to form synergistic physical interactions between two different low-dimensional carbon-based nanostructures. The results reveal a synergistic enhancement in both functional conductivity and mechanical properties. The electrical conductivity of composites with the inclusion of GNPs resulted in approximately 40%, 300%, and 190% enhancement in the fiber, surface, and through-thickness direction compared to the fuzzy fiber composites. Mechanical properties, including flexural, work of fracture, impact, and interlaminar shear stress properties were further enhanced. These results reveal that the presence of GNPs creates more electron transfer pathways, and also promotes a synergistic effect in physical interactions. Altogether, these enhancements provide avenues for future high-performance conductive carbon fiber composites in aircraft structures.

Chemically Synthesized Carbon Nanorods with Dual Polarized Emission.

We realized the synthesis of carbon nanorods-monodisperse colloidal particles with a length of 50 nm and a width of 20 nm-which can be considered an addition to the family of light-emitting carbon-based nanostructures. Their anisotropic shape is determined by the use of the surfactant aminopropylisobutyl polyhedral oligomeric silsesquioxane, and their optical properties originate from domains of polycyclic aromatic hydrocarbons incorporated within an inorganic framework. The nanorods show dual polarized emission with a quantum yield of 15-20% and emission anisotropy of ∼0.3, which changes from blue (460 nm) to yellow (565 nm) depending on the excitation wavelength. These carbon nanorods expand the range of light-emitting carbon nanomaterials available for optoelectronic and biolabeling applications.

RuO2 nanorods decorated CNTs grown carbon cloth as a free standing electrode for supercapacitor and lithium ion batteries

Engineering carbon-based nanostructures, including synthesis, structural designing, and characterization between carbon and active nanomaterials, possesses enormous potential for enabling exceptional electrochemical characteristics and fundamental breakthroughs. Here, we reported RuO2 nanorods (RuO2-NRs) decorated CNTS grown carbon cloth (CNTS-CC) via simple single step CVD and annealing process, as an excellent combination having advantages of the supercapacitors (SCs) and Li-ion batteries (LIBs). A number of characterizations, including scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction measurements affirm that RuO2-NRs are consistently covering the surface of CNTS-CC. The Brunauere Emmette Teller analysis displays that the fabricated architecture holds a well organized 3D interconnected hierarchically micro-mesoporous network that simultaneously facilitates rapid electron transfer and ion diffusion. Furthermore, the electrochemical performance revealing that the RuO2-CNTS-CC has outstanding Li-ion storage potential, including impressive rate capability, large specific capacity and excellent cyclic stability. For supercapacitor application, it is found that RuO2-CNT-CC holds an admirable specific capacitance that can maintain up to 97% after 10,000 cycles. The compatible and inexpensive preparation strategy presented here can contribute as a dynamic methodology towards the advancement of efficient hybrid devices.

Carbonized metal\u2013organic frameworks with trapped cobalt nanoparticles as biocompatible and efficient azo-dye adsorbent

BackgroundMetal–organic frameworks (MOFs) derived carbonaceous materials functionalized with metal/metal-oxide nanoparticles are obtained by its carbonization. The carbonization of MOFs occurs simultaneously with the metal and metal-oxide particle formation. The carbon-based flake-like nanostructures with trapped metal/metal-oxide nanoparticles have been formed. Due to its non-toxicity and environmental friendliness, the capacity for pollution adsorption using model anionic dye has been revealed.ResultsThe structure of the hybrid is formed as the effect of carbonization of metal–organic frameworks with cobalt as a metal counterpart (CoOF). The cobalt nanoparticles are placed between the carbon layers what limits the dissolution of cobalt nanoparticles and protects the environment from its toxicity. It is preliminary validated by means of two reference micro-organisms (Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus) and in in vitro analysis with human cell line (A375). The efficiency of the adsorption properties of the material was tested with Acid Red 18 as a model anionic dye. The mechanism of dye adsorption was analyzed in details. In addition, various thermodynamic parameters, such as standard enthalpy, standard entropy, and standard Gibbs free energy, were tested. In addition, it was proved that the main substrate of CoOF (terephthalic acid) can be used from PET bottles, while the organic solvent used in its synthesis (N,N-dimethylformamide) was distilled and reused. The obtained carbonized CoOF revealed the same morphology and properties as pristine material.ConclusionsThe kinetic data of dye adsorption fit well with the pseudo-second-order model and Langmuir type. Acid Red 18 adsorption is more favourable at lower temperatures and lower pH. The location of the cobalt nanoparticles between the carbon flakes effectively limits their toxicity compared to the free metal nanoparticles. The CoOF can be obtained from recycled substrates, which revealed the same morphology as pristine material. Therefore, it is believed that this work highlights the practical application of carbonized CoOF as an adsorbate and provides the evidence that such nanocomposite can be applied without environmental risks.

A mechanistic approach for the modulation of band gap of nanopolyaniline using various heterogeneous carbon nanostructures

The present work introduces a mechanistic approach for the synthesis of nanopolyaniline (nPANI) and modulation of its band gap using various carbon nanostructured materials. Carbon-based different nanostructures, viz. graphene oxide, reduced graphene oxide and multiwall carbon nanotubes, have been incorporated in situ for the preparation of nanocomposites. Polyethylene glycol (PEG)-based non-ionic surfactant-assisted oxidative polymerization of aniline was implemented. The major concern of this study is to present a possible mechanism and chemistry for the development of the nanomaterials (nPANI and its nanocomposites) and further the effect of heterogeneous carbon nanomaterials on both types of band gaps (optical and electrochemical) of nPANI in the presence of PEG. First time a comparative study between optical and electrochemical band gap has also been done to analyze the effect of carbon nanomaterials on nPANI. The prepared samples were characterized by Field-emission scanning electron microscopy, Fourier transform-infrared spectroscopy and X-ray diffraction. Electrochemical and optical properties were assessed by cyclic voltammetry (CV) and ultraviolet–visible spectroscopy (UV–Vis), respectively. The electrochemical ( $$E_{\text{g}}^{\text{CV}}$$ ) and optical ( $$E_{\text{g}}^{\text{opt}}$$ ) energy gap of nPANI was evaluated as 2.74 and 2.34 eV by CV and UV–Vis quantification, respectively. It was observed that incorporation of carbon nanomaterials at lower percentage improves $$E_{\text{g}}^{\text{CV}}$$ of nPANI to as minimum as 2.34 eV as per the CV data. Schematic energy diagram showing the band gap reduction and electron transport mechanism using CV has also been presented.

Regulating the properties of carbon dots via a solvent-involved molecule fusion strategy for improved sensing selectivity

Carbon dots (CDs) were prepared by a solvent-involved molecular fusion strategy using o-phenylenediamine (OPD) as the carbon source and formamide as the reaction solvent. The CDs possessed not only the functional groups inherited from the carbon source and the reaction solvent, but also numerous C=N groups in the structure, resulting from the Schiff base reaction between –NH2 of OPD and C=O of formamide. These functional groups endowed the final CDs with a favorable soft-base property, leading to the high tolerance level toward hard-acid type metal ions and prominent detection selectivity toward Ag+. Moreover, the obtained CDs displayed outstanding biocompatibility and low cytotoxicity, and demonstrated potential as an effective photoluminescence probe for intercellular Ag+ and Cys imaging, preventing the interference of autofluorescence from living tissues. This study focused on the solvent-involved molecular fusion strategy could provide new insights into the design of novel carbon-based nanostructures and optimization of the structure-property relationship of CDs.

1D Carbon-Based Nanocomposites for Electrochemical Energy Storage.

Electrochemical energy storage (EES) devices have attracted immense research interests as an effective technology for utilizing renewable energy. 1D carbon-based nanostructures are recognized as highly promising materials for EES application, combining the advantages of functional 1D nanostructures and carbon nanomaterials. Here, the recent advances of 1D carbon-based nanomaterials for electrochemical storage devices are considered. First, the different categories of 1D carbon-based nanocomposites, namely, 1D carbon-embedded, carbon-coated, carbon-encapsulated, and carbon-supported nanostructures, and the different synthesis methods are described. Next, the practical applications and optimization effects in electrochemical energy storage devices including Li-ion batteries, Na-ion batteries, Li-S batteries, and supercapacitors are presented. After that, the advanced in situ detection techniques that can be used to investigate the fundamental mechanisms and predict optimization of 1D carbon-based nanocomposites are discussed. Finally, an outlook for the development trend of 1D carbon-based nanocomposites for EES is provided.

Evaluation of carbon-based nanostructures suitable for the development of black pigments and glazes

Five different carbon-based samples were chosen for the fabrication of black pigments and glazes: historical ‘unknown’ wood charcoal, graphite, tailored graphitized soot, as-prepared multi-walled carbon nanotubes (MWCNTs) and purified MWCNTs. Ceramic glazes with carbon pigments were prepared with Pb3O4 and SiO2 in molar ratio of 2.85:1.9 and using 5 wt. % of pigment at 900 °C. The black pigments and glazes were characterized by scanning electron microscopy (SEM), optical microscopy, diffuse reflectance spectroscopy and contact angle measurements. International Commission on Illumination (CIE) parameters L*, a* and b* (CIELab-parameters) of the samples were also determined. It was demonstrated that nanostructured carbon pigments showed better black colour and higher quality of black ceramic glaze. Our investigation let us to conclude that these results possibly were affected by initial microstructure of applied carbon derivatives. The obtained nanostructured carbon black pigments could be successfully used for artefact restoration.

Role of Chemical Doping in Large Deformation Behavior of Spiral Carbon-Based Nanostructures: Unraveling Geometry-Dependent Chemical Doping Effects

The ever-increasing need for miniaturization of electromechanical devices has led us to exploit the properties of nanomaterials as well as controlling them. Chemical doping is one of the most commonly used techniques for controlling the properties of nanomaterials. Spiral carbon-based nanostructures possess excellent electrical properties, which are highly improved with chemical doping; however, the effect of chemical doping on their mechanical properties is still unknown. In this study, molecular dynamics simulation is conducted to study the effect of random/patterned boron and nitrogen doping in different percentages on the mechanical properties of spiral carbon-based nanostructures. The results show a significant impact of the geometry on the mechanical response of doped spiral nanostructures. Furthermore, increasing the percentage of the chemical doping influences the mechanical behavior of these nanoparticles, which can reduce their extensive stretchability even up to 50%. Chemical doping at the posi...

Hot-Tailoring of Carbon Nitride Dots with Redshifted Photoluminescence for Visual Double Text Encryption and Bioimaging.

The fabrication of carbon dots and their doped forms by top-down chemical cleavage has attracted considerable attention in the efforts to meet the increasing demands for optoelectronic applications ranging from biosensing to electro- and photocatalysis. However, due to strong quantum confinement effects, the size decrease often leads to an increase in the band gap, even in the emission of deep-ultraviolet (DUV) light, which greatly limits their applications. Here, we report a facile hot-tailoring strategy for fabricating carbon nitride nanodots (CNDs) with redshifted intrinsic photoluminescent (PL) emission, compared with the pristine bulk precursor. It has been found that the different leaving abilities of the C,N-containing groups during the pyrolysis stage and the chemical passivation during the liquid-collection stage played vital roles. Due to the redshifted photoluminescence and other attractive features, the as-obtained CNDs were successfully applied in visual double text encryption with higher security and also in bioimaging with photostability superior to traditional dyes. This work highlights the great potential of the hot-tailoring method in modulating carbon-based nanostructures and offsetting band-gap widening as the size decreases.

On-Surface Synthesis of One-Dimensional Carbon-Based Nanostructures via C-X and C-H Activation Reactions.

The past decades have witnessed the emergence of low-dimensional carbon-based nanostructures owing to their unique properties and various subsequent applications. It is of fundamental importance to explore ways to achieve atomically precise fabrication of these interesting structures. The newly developed on-surface synthesis approach provides an efficient strategy for this challenging issue, demonstrating the potential of atomically precise preparation of low-dimensional nanostructures. Up to now, the formation of various surface nanostructures, especially carbon-based ones, such as graphene nanoribbons (GNRs), kinds of organic (organometallic) chains and films, have been achieved via on-surface synthesis strategy, in which in-depth understanding of the reaction mechanism has also been explored. This review article will provide a general overview on the formation of one-dimensional carbon-based nanostructures via on-surface synthesis method. In this review, only a part of the on-surface chemical reactions (specifically, C-X (X=Cl, Br, I) and C-H activation reactions) under ultra-high vacuum conditions will be covered.

Tailoring Diindenochrysene through Intramolecular Multi-Assemblies by C-F Bond Activation on Aluminum Oxide.

The unique nature of the alumina-mediated cyclodehydrofluorination gives the opportunity to execute the preprogrammed algorithm of the C-C couplings rationally built into a precursor. Such multi-assemblies facilitate the construction of the carbon-skeleton, superseding the conventional step-by-step by the one-pot intramolecular assembly. In this work, the feasibility of the alumina-mediated C-F bond activation approach for multi-assembly is demonstrated on the example of a fundamental bowl-shaped polycyclic aromatic hydrocarbon (diindenochrysene) through the formation of all "missing" C-C bonds at the last step. Beside valuable insights into the reaction mechanism and the design of the precursors, a facile pathway enabling the two-step synthesis of diindenochrysene was elaborated, in which five C-C bonds form in a single synthetic step. It is shown that the relative positions of fluorine atoms play a crucial role in the outcome of the assembly and that governing the substituent positions enables the design of effective precursor molecules "programmed" for the consecutive C-C bond formations. In general, these findings push the state of the field towards the facile synthesis of sophisticated bowl-shaped carbon-based nanostructures through multi-assembly of fluoroarenes.

Finger-Like Carbon-Based Nanostructures Produced by Combustion of Flour-Based Sticks (Spaghetti)

Biomass is becoming particularly important as a starting material for advanced carbon structures. In this study, we found interesting nanostructures on the surface of burnt spaghetti using scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) for analysis. The structures were elongated and finger-like, with evidence that the tubes have shell and core components. The shell was carbon that included amorphous and layered graphene structures. EDX showed enriched potassium and phosphorous in the core and at the tip of the tubes. The results indicate that tube formation depends on phase separation of polar/ionic and nonpolar moieties when water is produced in the biomass from the pyrolysis/combustion. The tube growth is most probably due to the raising pressure of vapor that cannot escape through the carbon film that is formed at the surface of the stick from flame heat. This process resembles glass blowing or volcanic activity, where the carbon acts as the glass or earth’s crust, respectively. These observations suggest that new interesting tubular nanostructures with different properties on the inside and outside can be produced in a relatively simple way, utilizing processes of combustion of starch-rich biomass materials.

Recent Advances and Perspectives of Carbon-Based Nanostructures as Anode Materials for Li-ion Batteries.

Rechargeable batteries are attractive power storage equipment for a broad diversity of applications. Lithium-ion (Li-ion) batteries are widely used the superior rechargeable battery in portable electronics. The increasing needs in portable electronic devices require improved Li-ion batteries with excellent results over many discharge-recharge cycles. One important approach to ensure the electrodes’ integrity is by increasing the storage capacity of cathode and anode materials. This could be achieved using nanoscale-sized electrode materials. In the article, we review the recent advances and perspectives of carbon nanomaterials as anode material for Lithium-ion battery applications. The first section of the review presents the general introduction, industrial use, and working principles of Li-ion batteries. It also demonstrates the advantages and disadvantages of nanomaterials and challenges to utilize nanomaterials for Li-ion battery applications. The second section of the review describes the utilization of various carbon-based nanomaterials as anode materials for Li-ion battery applications. The last section presents the conclusion and future directions.