Presence Of Single-walled Carbon Nanotubes Research Articles

Single walled carbon nanotubes/ZnO nanowires heterostructure array for NO2 gas sensing at low ppm levels

A layer-by-layer ZnO nanowire (NW)-Single Walled Carbon Nanotube (CNT) hybrid gas sensor has been proposed for effective detection of NO2 gas under a low exposure limit of 5 ppm. The fabricated hybrid sensor displayed good sensor response (S %), good selectivity and fast response time towards the target gas. S % value of 36.4 % under 5 ppm NO2 level at 250 °C and good selectivity response towards different interfering gases like SO2, CO and H2 have been observed. Meanwhile, fast response time values of 44.08 s (response) and 62.11 s (recovery) were observed at 300 °C under 5 ppm NO2 level. The sensor baseline resistance of the hybrid heterostructure (HS) was also found to be lower when compared to that of a bare ZnO NW sensor. In addition, the presence of Single Walled CNT in the HS was also shown to reduce the operational temperature of the sensor. Temperature played a significant role by controlling the adsorption and desorption kinetics of gas molecules on the surface. Moreover, the formation of p-n interface between Single Walled CNT (p-type) and ZnO NW (n-type) might have modulated the potential charge barrier on interacting with the adsorbed gases which inturn might have impacted the response of the hybrid sensor. In addition, the large surface areas offered by both NWs and nanotubes might have improved the gas adsorption capability thereby enhancing the overall hybrid sensor’s response.

(Invited) A CNT Binding Bis(Zinc Porphyrin)Bodipy-C60 Nano Tweezer: Charge Stabilization in Supramolecular C60-Bodipy-(ZnP)2:SWCNT Hybrids

Single-wall carbon nanotubes (SWCNT) coupled with either electron donor or acceptor are promising functional structures for light energy harvesting and molecular optoelectronics applications. For building such hybrids involving SWCNTs, the p-stacking ability of large aromatic compounds is one of the commonly employed approaches.1-2 Often, the desired donor or acceptor entities are functionalized to carry one or more aromatic entities and allowed to interact with CNTs. However, due to close proximity, the role of SWCNTs in stabilizing the electron transfer product has been a challenge.3 Recently, we overcame this hurdle by employing a multi-modular approach to build donor-acceptor hybrids and successfully demonstrated charge stabilization in the presence of SWCNTs.4 In the present study, we have further improved our design by newly synthesizing a nano tweezer comprised of covalently linked BODIPY-C60 carrying two zinc porphyrin arms as shown in the figure. This compound was further allowed to interact with SWCNT(6,5) and SWCNT(7,6) to form the supramolecular C60-BODIPY-(ZnP)2:SWCNThybrids. Upon spectral, electrochemical, and computational characterization, femtosecond pump-probe spectroscopic studies were performed to establish the occurrence of photoinduced charge separation and charge stabilization. Extending the lifetime of the charge-separated states upon SWCNT binding has been successfully demonstrated in the present molecular design strategy. D’Souza, F.; Sandanayaka, A. S. D.; Ito, O. ‘SWNT-Based Supramolecular Nanoarchitectures with Photosensitizing Donor and Acceptor Molecules’ Phys. Chem. Letts. 2010, 1. 2586-2593.B. KC, G. N. Lim, and F. D’Souza, ‘Accelerated Charge Separation in Graphene Decorated Multi-Modular Tripyrene-Subphthalocyanine-Fullerene Donor-Acceptor Hybrids,’ Angew. Chem. Int. Ed. 2015, 54, 5088-5092.Barrejon, L. M. Arellano, F. D’Souza, F. Langa, ‘Bidirectional charge transfer in carbon-based hybrid nanomaterials’ Nanoscale, 2019, 11, 14978-14992.Kazemi, Y. Jang, A. Liyanage, P. A. Karr, and F. D’Souza, A Carbon Nanotube Binding Bis(pyrenylstyryl)BODIPY-C60 Nano Tweezer: Charge Stabilization through Sequential Electron Transfer, Angew. Chem. Int. Ed. 2022, 61, e202212474 (1-7). Figure 1

Promoted photocatalytic performances over Ti3+-B co-doped TiO2/BN with high carrier transfer and absorption capabilities driven by SWCNT addition

Recently, carbon nanotubes have been widely used as supporting materials for semiconductor photocatalysts due to their excellent electron and mass transportation. Herein, we prepared a novel SWCNT-decorated Ti3+-B co-doped TiO2/BN (STBN) photocatalyst with the presence of single-walled carbon nanotubes (SWCNTs) during the hybridization of BN and TiB2. The effects of SWCNTs on the structural and photocatalytic properties were investigated. Adding SWCNTs enables excellent multifunctional photocatalytic performances (N2 fixation, H2 production, and MO degradation) compared with the TBN synthesized in the previous study. Introducing SWCNTs reduces the transfer resistance and makes the photogenerated carriers transfer more efficiently, thereby improving photocatalytic activity. More defect sites provide extra adsorption sites for reactants and photogenerated electrons, significantly improving the system's photocatalytic activity. The enhanced photocatalytic mechanism of SWCNT-decorated hybrid catalysts was proposed at last.

Dielectric and conductivity properties of liquid crystal MBBA doped with single-walled carbon nanotubes

The effect of single-walled carbon nanotubes (SWCNTs) on the dielectric and conductivity properties of nematic liquid crystal 4-methoxybenzylidene-40-butylaniline (MBBA) has been studied. It was shown that the additive of SWCNTs with concentration of 0.3% leads to an increase in the order parameter of MBBA. Observation under the polarization microscope has shown that the presence of SWCNTs in MBBA increases the clearing temperature from 46.3°C to 47.4°C. This change can be explained by the improvement of the liquid crystalline orientation order. As a result, the transition to a complete disordering of the molecules (transition to an isotropic state) requires more heat energy, correspondingly, more temperature. The dielectric and conductivity measurements have showed that the longitudinal component of the dielectric permittivity decreases while the transverse component increases as well as dielectric anisotropy. The percolation effect promotes to the dominance of hopping electron conductivity over ionic conductivity, leading to an increase in electric conductivity.

Impact of nonlinear radiation on an unsteady magneto hybrid nanofluid flow over an upward/downward rotating disk

In this article, we scrutinized the impact of nonlinear thermal radiation and an externally applied magnetic field over a rotating upward or downward disk on an unsteady 3D hybrid nanofluid flow in the presence of SWCNT(single-walled carbon nanotube)+ F e 3 O 4 (ferrosol ferric oxide) and MWCNT(multi-walled carbon nanotube)+ F e 3 O 4 with water as a base fluid. The foremost partial differential equations (PDEs) with boundary conditions of the flow model are converted into ordinary differential equations (ODEs) by considering suitable transformations and then solved numerically by using RKF-45 by implementing a shooting technique. Fluid flow characteristics are explored for various parameters and presented using graphs and charts. The results show that an increase in the radiation parameter causes an upsurge in the thermal field in the fluid flow of MWCNT+ F e 3 O 4 -water/SWCNT+ F e 3 O 4 -water hybrid nanofluid. The thermal profile and axial velocity profile of MWCNT+ F e 3 O 4 and SWCNT+ F e 3 O 4 with water-based hybrid nanofluid increase as magnetic parameter values rise but radial and azimuthal velocity profiles decrease. Also, the Nusselt number for MWCNT + F e 3 O 4 -water hybrid nanofluid is 0.35% less than SWCNT + F e 3 O 4 -water hybrid nanofluid.

Trophic Transfer of Single-Walled Carbon Nanotubes at the Base of the Food Chain and Toxicological Response.

The potential for trophic transfer of single-walled carbon nanotubes (SWCNTs) was assessed using the green algae Tetraselmis suecica and the blue mussel Mytilus edulis in a series of laboratory experiments. Swanee River Natural Organic Matter (SRNOM)-dispersed SWCNTs were introduced into growing algal cultures. Light microscopical observations, confirmed by scanning electronic microscopy (SEM) and Raman spectroscopy, showed that SWCNT agglomerates adhered to the external algal cell walls and transmission electronic microscopy (TEM) results suggested internalization. A direct effect of SWCNT exposure on the algae was a significant decrease in growth, expressed as chlorophyll a concentration and cell viability. Mussels, fed with algae in the presence of SWCNTs, led to significantly increased pseudofaeces production, indicating selective feeding. Nevertheless, histological sections of the mussel digestive gland following exposure showed evidence of SWCNT-containing algae. Furthermore, DNA damage and oxidative stress biomarker responses in the mussel haemocytes and gill tissue were significantly altered from baseline values and were consistent with previously observed responses to SWCNT exposure. In conclusion, the observed SWCNT-algal interaction demonstrated the potential for SWCNT entrance at the base of the food chain, which may facilitate their trophic transfer with potential consequences for human exposure and health.

Mathematical analysis about influence of Lorentz force and interfacial nano layers on nanofluids flow through orthogonal porous surfaces with injection of SWCNTs

The effort is presented to numerical examine the flow behavior of non-Newtonian fluid through orthogonal porous surfaces. A two-phase model of nanofluids simulations is considered which represents speculative features of materials that are obliged in biomechanics,lubricantsformation,polymer solution, suspension, etc. The mechanism of interfacial nano layer at surfaces is deliberated through thermal conductivity. Numerical sculpting of non-Newtonian CNT fluid including the impact of chemical reaction, heat flux and mass transfer source is manifested in the form of partial differential equations. Similarity variables are capitalized to transmute governing modeled conservation laws into ordinary non-dimensional expressions. Assessment of flow attributing profiles is disclosed by implementing the Runge-Kutta procedure in collaboration with the shooting method. The numerical stability with convergence rate is also discussed here. Graphical visualization and numerical data about surface drag coefficients and heat and mass transfer rates are also presented. The effect of expansion and contraction (−2 <α < 2) on boundary layer thickness is discussed in detail. The rate of heat transfer increases with the increase of boundary layer thickness in the presence of single-wall carbon nanotubes (SWCNT) is observed. An increase in heat transfer profile due to the presence of SWCNTs with the variation of thickness and radius of sustainable particles is perceived. The nano layer thickness is a significant effect related to the heat transfer rate.

Synthesis and characterization of single‐walled carbon nanotube: Cyto‐genotoxicity in Allium cepa root tips and molecular docking studies

Herein, single-walled carbon nanotubes (SWCNTs) were synthesized by the thermal chemical vapor deposition (CVD) method, and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Raman spectroscopy, dynamic light scattering (DLS), and thermo-gravimetric analysis (TGA). The results indicated that obtained nanotubes were SWCNTs with high crystallinity and their average diameter was 10.15 ± 3nm. Allium cepa ana-telophase and comet assays on the root meristem were employed to evaluate the cytotoxic and genotoxic effects of SWCNTs by examining mitotic phases, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. A. cepa root tip cells were exposed to SWCNTs at concentrations of 12.5, 25, 50, and 100 μg/ml for 4h. Distilled water and methyl methanesulfonate (MMS, 10μg/ml) were used as the negative and positive control groups, respectively. It was observed that MIs decreased statistically significantly for all applied doses. Besides, CAs such as chromosome laggards, disturbed anaphase-telophase, stickiness and bridges and also DNA damage increased in the presence of SWCNTs in a concentration-dependent manner. In the molecular docking study, the SWCNT were found to be a strong DNA major groove binder showing an energetically very favorable binding free energy of -21.27 kcal/mol. Furthermore, the SWCNT interacted effectively with the nucleotides on both strands of DNA primarily via hydrophobic π and electrostatic interactions. As a result, cytotoxic and genotoxic effects of SWCNTs in A. cepa root meristematic cells which is a reliable system for assessment of nanoparticle toxicology were demonstrated in this study.

In-situ dilatometry and impedance spectroscopy characterization of single walled carbon nanotubes blended LiNi0.6Mn0.2Co0.2O2 electrode with enhanced performance

Enhancing lithium-ion batteries (LiBs) cycle life is essential from both economic and sustainability perspective. In addition, to make their application in electric vehicles (EVs) even more feasible, the energy and power density have to be enhanced as well. Improvement in the electrical conductivity of battery electrodes can lead to an augmentation in power density and this can be achieved by using highly conductive carbon nanomaterials in the electrode fabrication. On the other hand, cycle life of LiBs is affected by dilation of both positive and negative electrodes during lithium ion (de)-insertion, and this can be also tailored by electrode design. In this work, ozonated long single walled carbon nanotubes (SWCNTs) are utilized to improve electrical conductivity of a LiNi0.6Mn0.2Co0.2O2 (NMC622) positive electrode along with enhancement of the mechanical strength. The enhancement effect of the ozone-treated SWCNTs on the NMC622 positive electrodes is demonstrated by means of electrochemical impedance spectroscopy and in-situ dilatometry. Compared to a conventional conductive carbon containing electrode, the presence of SWCNTs in an NMC622 electrode decreases irreversible height change occurring during a formation cycle from 276 nm to 86 nm and decreases overall electrode height change ∼5.5 times. Furthermore, coulombic and energy efficiencies of the Ozonated SWCNT NMC622 electrodes are improved by 1.2% and 6.4%, respectively, compared to the reference NMC622 electrode after 250 cycles in a three-electrode assembly, showing great potential for SWCNTs to be used in LiBs. Hence, addition of optimized amount of modified SWCNTs is capable of enhancing both power density and cycling stability of LiBs simultaneously.

Влияние одностенных углеродных нанотрубок на биопленкообразование актинобактерий рода Rhodococcus и протеобактерий активного ила

The effect of single-walled carbon nanotubes (SWCNTs) on the formation and eradication of biofilms of activated sludge proteobacteria and actinobacteria of the genus Rhodococcus was studied. It has been shown that SWCNTs do not inhibit the formation of biofilms of these bacteria and do not cause their destruction, while in the presence of SWCNTs, much more massive biofilms of Alcaligenes faecalis 2 and Acinetobacter guillouiae 11h are formed. It was shown that the level of dehydrogenase activity, estimated by the reduction of tetrazolium salt to formazan, in biofilm cells formed in the presence of SWCNTs, exceeded that of biofilms in the control.

Effect of Single Walled Carbon Nanotubes on the Series Resistance and Trap Energy of Malachite Green Dye Based Organic Device

In this paper, we have estimated the series resistance (Rs) and the trap energy (Ec) of the sandwiched type Malachite Green (MG) dye-based organic device and have also observed the influence of single-walled carbon nanotubes (SWCNT) on both of these parameters. To form the organic device, we have used Indium Tin Oxide (ITO) coated glass as the front electrode and Aluminium (Al) as a back electrode by using the spin coating technique. The values of series resistance are measured from both I-V characteristics and by utilizing Cheung Function due to the non ideal behavior of organic devices. We have also extracted the values of Rsby using H (I) versus I plot and verified the values with the measured values of Rsfrom the Cheung function. The extracted values of series resistance using these three processes remain consistent with each other in showing that the values of series resistance have been reduced considerably in the presence of SWCNT. The trap energy has been estimated from the steady-state current-voltage characteristics. There is a significant correlation in between series resistance and the trap energy of the organic device. The presence of Single-Walled Carbon Nanotubes reduces the trap energy from 0.086 eV to 0.057 eV. Lowering of the trap energy of the metal-organic layer interface in presence of Single Walled Carbon Nanotubes attributes to the reduction of the value of the series resistance. The extracted value of Rsdecreases from 0.154 MΩ to 0.0389 MΩ in presence of SWCNT. Decrease in the value of both of these parameters in the presence of SWCNT will definitely improve the charge transport mechanism of the organic device and thereby the conductivity.

Delivery of Capecitabine by Single-Walled Carbon Nanotube

Application of the zigzag (24, 0) single-walled carbon nanotube (SWCNT) in delivery of carbamate and imine tautomers of capecitabine is investigated via quantum mechanical geometry optimizations followed by chemical shielding calculations. Torsion angle between ribose and cytosine rings is very close to the experimental value in both tautomers. This suggests that relative orientation of these rings is independent of presence of SWCNT. Their carbon nuclei become closer to the tube’s internal surface by about 1Å, when going from cytosine ring to aliphatic tail. Their cytosine and ribose rings bend so that fluorine atoms and 2[Formula: see text]-OH group form ion-[Formula: see text] interaction with the surface. Calculated binding energies aside from observation of these sorts of interactions in these tautomers can propose SWCNT as their potent delivery tool. Most of the obtained conclusions are manifested in the observed trends for calculated chemical shielding values. They make connections among the reported experimental and computational distributions of chemical shielding values inside SWCNTs.

Tracking the interaction between single-wall carbon nanotube and SARS-Cov-2 spike glycoprotein: A molecular dynamics simulations study

COVID-19, a newly discovered type of coronavirus, is the cause of the pandemic infection that was first reported in Wuhan, China, in December 2019. One of the most critical problems in this regard is to identify innovative drugs that may reduce or manage this global health concern. Nanoparticles have shown a pivotal role in drug delivery systems in recent decades. The surface of nanoparticles could be covered by a layer composed of different biomolecules (e.g., proteins and macromolecules) following the incubation with a biological fluid. This protein-rich layer is called “Protein Corona.” In this study, an all-atom molecular dynamics simulation was used for investigating the monomeric B domain of the spike glycoprotein due to its role in the accessibility of the spike glycoprotein to single-wall carbon nanotubes (SWCNTs). The interaction energy values between the carbon nanotube and B domain of the viral spike glycoprotein were evaluated. The obtained results, based on Lennard-Jones potentials, demonstrated that SWCNTs had an affinity to the B domain of the S1 subunit in the spike glycoprotein. The adsorption of SWCNTs on the B domain surface led to a significant change in solvent-accessible surface, internal hydrogen bonds, and finally in the tertiary structure, which could provide a reasonable method to impede the interaction between the angiotensin-converting enzyme II and SARS-CoV-2 spike glycoprotein. A decrease in the mean square displacement of the B domain was shown after the adsorption of SWCNTs as a result of increasing the hydrophobic-hydrophilic properties of the B domain. The arrangement of SWCNTs on the B domain surface and their interaction using the 2-acetamido-2-deoxy-β-d-glucopyranose group (988, 991, and 992) demonstrated that a change in the affinity of the S1 subunit could be used as a barrier to viral replication. The analysis of the SWCNT-B domain complex indicated that the presence of SWCNTs is able to cause alterations in the S1 subunit of the spike protein, and these nanotubes could be employed for further in-vitro and in-vivo antiviral studies. Also, SWCNTs are able to be utilized in drug delivery systems.

Comparison of the Dielectric Properties of Ecoflex® with L,D-Poly(Lactic Acid) or Polycaprolactone in the Presence of SWCN or 5CB.

The main goal of this paper was to study the dielectric properties of hybrid binary and ternary composites based on biodegradable polymer Ecoflex®, single walled carbon nanotubes (SWCN), and liquid crystalline 4′-pentyl-4-biphenylcarbonitrile (5CB) compound. The obtained results were compared with other created analogically to Ecoflex®, hybrid layers based on biodegradable polymers such as L,D-polylactide (L,D-PLA) and polycaprolactone (PCL). Frequency domain dielectric spectroscopy (FDDS) results were analyzed taking into consideration the amount of SWCN, frequency, and temperature. For pure Ecoflex®, two relaxation processes (α and β) were identified. It was shown that the SWCN admixture (in the weight ratio 10:0.01) did not change the properties of the Ecoflex® layer, while in the case of PCL and L,D-PLA, the layers became conductive. The dielectric constant increased with an increase in the content of SWCN in the Ecoflex® matrix and the conductive behavior was not visible, even for the greatest concentration (10:0.06 weight ratio). In the case of the Ecoflex® polymer matrix, the conduction relaxation process at a frequency ca. several kilohertz appeared and became stronger with an increase in the SWCN admixture in the matrix. Addition of oleic acid to the polymer matrix had a smaller effect on the increase in the dielectric response than the addition of liquid crystal 5CB. Fourier transform infrared (FTIR) results revealed that the molecular structure and chemical character of the Ecoflex® and PCL matrixes remained unchanged upon the addition of SWCN or 5CB in a weight ratio of 10:0.01 and 10:1, respectively, while molecular interactions appeared between L,D-PLA and 5CB. Moreover, adding oleic acid to pure Ecoflex® as well as the binary and ternary hybrid layers with SWCN and/or 5CB in a weight ratio of Ecoflex®:oleic acid equal to 10:0.3 did not have an influence on the chemical bonding of these materials.

Study on the series resistance of crystal violet dye-based organic photovoltaic device in presence of single walled carbon nanotubes

The series resistance (Rs) of any organic photovoltaic device (OPV) plays an important role on the device performance. Generally, the electrode and the presence of traps at the interface contribute the high Rs. In this present work, we have studied the Rs of crystal violet dye-based OPV device and its variation in the presence of single walled carbon nanotubes (SWCNT). From the dark current voltage (I–V) characteristics, we have extracted Rs by using the Cheung–Cheung method. It is observed that the trap energy (Ec) and the value of Rs are decreased in the presence of SWCNT. The values of Rs and Ec are about 0.246 MΩ and 0.085 eV in the absence of SWCNT and these values change to 0.124 MΩ and 0.060 eV, respectively, in the presence of SWCNT. The light I–V characteristics of the devices have also been studied to find out the Rs of the device under illumination. Under illumination, the charge transport process is governed by the incident photon energy (Em) which is absorbed by the OPV device. So we have extracted the Em from the light I–V characteristics and estimated the Rs by using area method under light illumination in the absence and presence of SWCNT. It is observed that the extracted values of Rs under illumination are low compared to the values of Rs measured from dark I-V characteristics.

Microstructural properties of novel nanocomposite material based on hydroxyapatite and carbon nanotubes: fabrication and nonlinear instability simulation

In this work, a novel porous bio-nanocomposite material containing the commercial nanocrystalline hydroxyapatite (n-HA) composed using single-walled carbon nanotubes (SWCNTs) with different weight fractions (0, 2.5, 5, and 7.5 wt%) is fabricated via a space holder technique for bone tissue engineering applications. The hydroxyapatite (HA) presents a weak mechanical performance which the addition of the SWCNT can enhance the mechanical strength of the matrix. The manufactured n-HA-SWCNT bio-nanocomposite samples are then coated by gelatin-ibuprofen (GN-IBO) bio-polymer with a dip-coating method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) are employed for the phase characterization and surface morphology analysis of the fabricated bio-nanocomposite specimens. The mechanical properties, the rate of drug release, and biological characteristics of the specimens with and without SWCNTs are investigated. After that, the nonlinear instability and vibration responses of an axially loaded plate-form bone implant made of the manufactured n-HA-SWCNT bio-nanocomposite samples coated with GN-IBO thin layers are simulated through a sandwich-plate model and based upon the experimentally extracted mechanical properties. The obtained results indicate the presence of SWCNT and n-HA in the composition due to the fuzzy metamorphism or degradation. It is found that by increasing the amount of SWCNTs, the mass density of the fabricated bio-nanocomposite samples reduces, but the porosity and strength of them are higher than those of the pure n-HA. Therefore, it is expected that these newly manufactured bio-nanocomposites have an excellent capability for bone formation with better bonds with surrounding tissues.

Combined effects of carbon nanotubes and cadmium on the photosynthetic capacity and antioxidant response of wheat seedlings.

A detailed study of nanomaterials has revealed their broad application prospects. However, the presence of carbon nanotubes (CNTs) in the environment has been increasing and has aroused concerns regarding their toxicity to crops when combined with heavy metals. In the present study, the effects of Cd on the photosynthetic capacity and antioxidant activity of wheat seedlings in the presence of single-walled CNTs (SW) and multi-walled CNTs (MW) were investigated. Our results indicated that SW (5-40 mg L-1) and MW (10-40 mg L-1) significantly increased the oxidative stress response of wheat seedlings to Cd. Compared with Cd alone, CNTs combined with Cd decreased net photosynthetic rate, stomatal conductance, transpiration rate, primary maximum photochemical efficiency of photosystem II, actual quantum yield, photosynthetic electron transport rate, root canal protein, and ribulose-1,5-bisphosphate carboxylase/oxygenase content. Moreover, combined treatments increased the content of superoxide anion, superoxide dismutase, guaiacol peroxidase, cytochrome, and malondialdehyde in wheat seedlings. Moreover, membrane lipid peroxidation was aggravated, causing serious damage to the wheat membrane system. In addition, the toxicity of the SW treatment and the combined treatment with SW and Cd was higher than that of the MW treatment.

Modification of barrier height and depletion layer width of methyl red (MR) dye-based organic device in the presence of single-walled carbon nanotubes (SWCNT)

In this paper, barrier height ( $$\phi_{{\text{b}}}$$ ) and depletion layer width (Wd) of ITO-coated glass/Methyl Red (MR) dye/Aluminum (Al)-based organic device have been studied, and effect of single-walled carbon nanotubes (SWCNT) on both of these parameters has been observed. ITO-coated glass as front electrode and Aluminum as back electrode are used to form the device by using spin coating technique. $$\phi_{{\text{b}}}$$ is calculated by analyzing both I–V and C–V characteristics. In the presence of SWCNT, $$\phi_{{\text{b }}}$$ is reduced from 0.870 ± 0.05 eV to 0.754 ± 0.05 eV in I–V characteristics and from 0.850 ± 0.12 eV to 0.784 ± 0.12 eV in C–V characteristics. $$\phi_{{\text{b }}}$$ is also estimated by Norde method, which shows the presence of SWCNT lowers the value of $$\phi_{{\text{b }}}$$ from 0.852 eV to 0.738 eV. Wd has been calculated from C–V characteristics. With SWCNT, value of Wd reduces from (8.74 ± 0.02) × 10−6 cm to (7.85 ± 0.02) × 10−6 cm. Threshold voltage also decreases from 2.52 V to 1.99 V in the presence of SWCNT. Addition of SWCNT within device ameliorates charge injection by lessening $$\phi_{{\text{b}}}$$ and Wd of the device.

One-step synthesis, characterization and properties of novel hybrid electromagnetic nanomaterials based on polydiphenylamine and Co-Fe particles in the absence and presence of single-walled carbon nanotubes.

A one-step preparation method for hybrid electromagnetic nanomaterials based on polydiphenylamine (PDPA) and bimetallic Co–Fe particles in the absence and presence of single-walled carbon nanotubes (SWCNT) was proposed. During IR heating of PDPA in the presence of Co(ii) and Fe(iii) salts in an inert atmosphere at T = 450–600 °C, the polycondensation of diphenylamine (DPA) oligomers and dehydrogenation of phenyleneamine units of the polymer with the formation of C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> N bonds and reduction of metals by evolved hydrogen with the formation of bimetallic Co–Fe particles dispersed in a polymer matrix occur simultaneously. When carbon nanotubes are introduced into the reaction system, a nanocomposite material is formed, in which bimetallic Co–Fe particles immobilized on SWCNT are distributed in the matrix of the polymer. According to XRD data, reflection peaks of bimetallic Co–Fe particles at diffraction scattering angles 2θ = 69.04° and 106.5° correspond to a solid solution based on the fcc-Co crystal lattice. According to SEM and TEM data, a mixture of particles with sizes of 8–30 nm and 400–800 nm (Co–Fe/PDPA) and 23–50 nm and 400–1100 nm (Co–Fe/SWCNT/PDPA) is formed in the nanocomposites. The obtained multifunctional Co–Fe/PDPA and Co–Fe/SWCNT/PDPA nanomaterials demonstrate good thermal, electrical and magnetic properties. The saturation magnetization of the nanomaterials is MS = 14.99–31.32 emu g−1 (Co–Fe/PDPA) and MS = 29.48–48.84 emu g−1 (Co–Fe/SWCNT/PDPA). The electrical conductivity of the nanomaterials reaches 3.5 × 10−3 S cm−1 (Co–Fe/PDPA) and 1.3 S cm−1 (Co–Fe/SWCNT/PDPA). In an inert medium, at 1000 °C the residue is 71–77%.

Chirality luminescent properties of single-walled carbon nanotubes during redox reactions

The optical measurement of single-walled carbon nanotubes (SWNTs) is a useful approach for understanding chirality characteristics because the excitation and emission wavelengths that produce the maximum emission intensity are unique to the chirality of SWNTs. The emission properties of SWNT chirality are useful in various biological applications and are envisaged to be applicable in nanobiosensors. Therefore, it is necessary to detect even small environmental changes, such as redox reactions, and it is important to identify optimal chirality according to the applications. In this study, we focused on the presence of SWNTs with different chiralities within the same SWNT powder, and we investigated the correlation between the rate of change of the emission intensity due to redox reactions and SWNT chirality. We measured the redox change rate of chirality, which was difficult to detect because of the low emission intensity, by increasing the exposure time during photoluminescence (PL) measurement. 0.5 mg of SWNT powder and 1 mL of double-stranded DNA (dsDNA) stock solution were mixed and sonicated using a probe-type sonicator on ice. The supernatant of the prepared dsDNA-SWNT dispersion was stored after centrifugation. Hydrogen peroxide (H 2 O 2 ; final concentration: 0.03%) was added to this dispersion for oxidation, and then, a catechin aqueous solution (final concentration 1.5 μg/mL) was added to the solution to measure PL. The exposure time was 90 s to obtain sufficient emission intensity. The measurement results showed that the magnitude of the rate of change of the PL intensity due to redox reaction was different for each chirality. Focusing on the (8,6) and (9,4) chiralities, which showed a large rate of change, the PL intensity decreased by 57.4% and 54.6% from the initial state, respectively, when H 2 O 2 was added. Subsequently, these values increased by 1024% and 558% with the addition of a catechin aqueous solution, respectively. Furthermore, from the comparison of the PL detection results and optical response characteristics of each chirality, it was observed that the rate of change of the PL intensity of SWNTs during redox reactions using H 2 O 2 and catechin had the strongest correlation with the SWNT diameter. • The exposure time was increased to 90 s to facilitate comparison of PL intensities between chiralities. • The responsiveness of chirality with small emission intensity was detected, which was difficult to detect in previous studies. • The PL change rate during redox using H 2 O 2 and catechin showed the strongest correlation with the SWNTs diameter. • The larger the diameter of SWNTs, the higher will be the PL change rate during redox reactions.