To see the other types of publications on this topic, follow the link: SWCNT.
Journal articles on the topic 'SWCNT'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'SWCNT.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Peng, Xiao-Xi, Xuan Qiao, Shuai Luo, Jun-An Yao, Yun-Fei Zhang, and Fei-Peng Du. "Modulating Carrier Type for Enhanced Thermoelectric Performance of Single-Walled Carbon Nanotubes/Polyethyleneimine Composites." Polymers 11, no. 8 (August 2, 2019): 1295. http://dx.doi.org/10.3390/polym11081295.
Full textAbstract:
Thermoelectric (TE) generators consisting of flexible and lightweight p- and n-type single-walled carbon nanotube (SWCNT)-based composites have potential applications in powering wearable electronics using the temperature difference between the human body and the environment. Tuning the TE properties of SWCNTs, particularly p- versus n-type control, is currently of significant interest. Herein, the TE properties of SWCNT-based flexible films consisting of SWCNTs doped with polyethyleneimine (PEI) were evaluated. The carrier type of the SWCNT/PEI composites was modulated by regulating the proportion of SWCNTs and PEI using simple mixing techniques. The as-prepared SWCNT/PEI composite films were switched from p- to n-type by the addition of a high amount of PEI (>13.0 wt.%). Moreover, interconnected SWCNTs networks were formed due to the excellent SWNT dispersion and film formation. These parameters were improved by the addition of PEI and Nafion, which facilitated effective carrier transport. A TE generator with three thermocouples of p- and n-type SWCNT/PEI flexible composite films delivered an open circuit voltage of 17 mV and a maximum output power of 224 nW at the temperature gradient of 50 K. These promising results showed that the flexible SWCNT/PEI composites have potential applications in wearable and autonomous devices.
2
Aasi, Aref, Sadegh Aghaei, Matthew Moore, and Balaji Panchapakesan. "Pt-, Rh-, Ru-, and Cu-Single-Wall Carbon Nanotubes Are Exceptional Candidates for Design of Anti-Viral Surfaces: A Theoretical Study." International Journal of Molecular Sciences 21, no. 15 (July 23, 2020): 5211. http://dx.doi.org/10.3390/ijms21155211.
Full textAbstract:
As SARS-CoV-2 is spreading rapidly around the globe, adopting proper actions for confronting and protecting against this virus is an essential and unmet task. Reactive oxygen species (ROS) promoting molecules such as peroxides are detrimental to many viruses, including coronaviruses. In this paper, metal decorated single-wall carbon nanotubes (SWCNTs) were evaluated for hydrogen peroxide (H2O2) adsorption for potential use for designing viral inactivation surfaces. We employed first-principles methods based on the density functional theory (DFT) to investigate the capture of an individual H2O2 molecule on pristine and metal (Pt, Pd, Ni, Cu, Rh, or Ru) decorated SWCNTs. Although the single H2O2 molecule is weakly physisorbed on pristine SWCNT, a significant improvement on its adsorption energy was found by utilizing metal functionalized SWCNT as the adsorbent. It was revealed that Rh-SWCNT and Ru-SWCNT systems demonstrate outstanding performance for H2O2 adsorption. Furthermore, we discovered through calculations that Pt- and Cu-decorated SWNCT-H2O2 systems show high potential for filters for virus removal and inactivation with a very long shelf-life (2.2 × 1012 and 1.9 × 108 years, respectively). The strong adsorption of metal decorated SWCNTs and the long shelf-life of these nanomaterials suggest they are exceptional candidates for designing personal protection equipment against viruses.
3
Krause, Beate, Viktor Bezugly, Vyacheslav Khavrus, Liu Ye, Gianaurelio Cuniberti, and Petra Pötschke. "Boron Doping of SWCNTs as a Way to Enhance the Thermoelectric Properties of Melt-Mixed Polypropylene/SWCNT Composites." Energies 13, no. 2 (January 13, 2020): 394. http://dx.doi.org/10.3390/en13020394.
Full textAbstract:
Composites based on the matrix polymer polypropylene (PP) filled with single-walled carbon nanotubes (SWCNTs) and boron-doped SWCNTs (B-SWCNTs) were prepared by melt-mixing to analyze the influence of boron doping of SWCNTs on the thermoelectric properties of these nanocomposites. It was found that besides a significantly higher Seebeck coefficient of B-SWCNT films and powder packages, the values for B-SWCNT incorporated in PP were higher than those for SWCNTs. Due to the higher electrical conductivity and the higher Seebeck coefficients of B-SWCNTs, the power factor (PF) and the figure of merit (ZT) were also higher for the PP/B-SWCNT composites. The highest value achieved in this study was a Seebeck coefficient of 59.7 µV/K for PP with 0.5 wt% B-SWCNT compared to 47.9 µV/K for SWCNTs at the same filling level. The highest PF was 0.78 µW/(m·K2) for PP with 7.5 wt% B-SWCNT. SWCNT macro- and microdispersions were found to be similar in both composite types, as was the very low electrical percolation threshold between 0.075 and 0.1 wt% SWCNT. At loadings between 0.5 and 2.0 wt%, B-SWCNT-based composites have one order of magnitude higher electrical conductivity than those based on SWCNT. The crystallization behavior of PP is more strongly influenced by B-SWCNTs since their composites have higher crystallization temperatures than composites with SWCNTs at a comparable degree of crystallinity. Boron doping of SWCNTs is therefore a suitable way to improve the electrical and thermoelectric properties of composites.
4
Yamamoto, Go, Yoshinori Sato, Toru Takahashi, Mamoru Omori, Toshiyuki Hashida, Akira Okubo, and Kazuyuki Tohji. "Single-walled carbon nanotube-derived novel structural material." Journal of Materials Research 21, no. 6 (June 1, 2006): 1537–42. http://dx.doi.org/10.1557/jmr.2006.0186.
Full textAbstract:
Binder-free macroscopic single-walled carbon nanotube (SWCNT) solids were prepared by spark plasma sintering (SPS) of purified SWCNTs. The effects of processing temperatures and pressures on the mechanical properties of the SWCNT solids and structural change of SWCNTs in the SWCNT solids were investigated. Transmission electron microscope observation of the SWCNT solids revealed thatthe high-temperature treatment has transformed some part of the SWCNTs into amorphous-like structure and the rest of the SWCNTs remained buried into the above structure. The mechanical properties of the SWCNT solids increased with the increasing processing temperature, probably reflecting the improvement of interfacial strength between SWCNTs and disordered structure of carbon due to the spark plasma generated in the SPS process.
5
Abbasian, Mojtaba, and Saeed Yeganeh Fathi. "A convenient method for preparation of polystyrene-single-walled carbon nanotubes by metal-catalyzed living radical polymerization method." Journal of Polymer Engineering 33, no. 5 (August 1, 2013): 463–69. http://dx.doi.org/10.1515/polyeng-2013-0030.
Full textAbstract:
Abstract In this research, a new direction for functionalizing of single-walled carbon nanotubes (SWCNTs) via the atom transfer radical polymerization (ATRP) method was utilized. SWCNTs were grafted with polystyrene (PSt) by the in situ ATRP method, in the presence of α-phenyl chloro acetylated SWCNT. This functional SWCNT was synthesized by the reaction between α-phenyl chloro acetyl chloride and a hydroxylated SWCNT that was obtained by reduction of a carboxylated SWCNT by lithium aluminum hydride (LiAlH4). Oxidation, reduction and coupling reactions of SWCNTs were confirmed by Fourier transform infrared (FTIR) spectroscopy and polymerization of styrene from SWCNTs surfaces was illustrated by transfer electron microscopy (TEM). Thermal properties of attached polymers onto SWCNTs surfaces were investigated by thermogravimetry analysis (TGA), and differential scanning calorimetry (DSC) analysis.
6
Kim, Kyung-Tae, Keon Woo Lee, Sanghee Moon, Joon Bee Park, Chan-Yong Park, Seung-Ji Nam, Jaehyun Kim, Myoung-Jae Lee, Jae Sang Heo, and Sung Kyu Park. "Conformally Gated Surface Conducting Behaviors of Single-Walled Carbon Nanotube Thin-Film-Transistors." Materials 14, no. 12 (June 17, 2021): 3361. http://dx.doi.org/10.3390/ma14123361.
Full textAbstract:
Semiconducting single-walled carbon nanotubes (s-SWCNTs) have gathered significant interest in various emerging electronics due to their outstanding electrical and mechanical properties. Although large-area and low-cost fabrication of s-SWCNT field effect transistors (FETs) can be easily achieved via solution processing, the electrical performance of the solution-based s-SWCNT FETs is often limited by the charge transport in the s-SWCNT networks and interface between the s-SWCNT and the dielectrics depending on both s-SWCNT solution synthesis and device architecture. Here, we investigate the surface and interfacial electro-chemical behaviors of s-SWCNTs. In addition, we propose a cost-effective and straightforward process capable of minimizing polymers bound to s-SWCNT surfaces acting as an interfering element for the charge carrier transport via a heat-assisted purification (HAP). With the HAP treated s-SWCNTs, we introduced conformal dielectric configuration for s-SWCNT FETs, which are explored by a carefully designed wide array of electrical and chemical characterizations with finite-element analysis (FEA) computer simulation. For more favorable gate-field-induced surface and interfacial behaviors of s-SWCNT, we implemented conformally gated highly capacitive s-SWCNT FETs with ion-gel dielectrics, demonstrating field-effect mobility of ~8.19 cm2/V⋅s and on/off current ratio of ~105 along with negligible hysteresis.
7
Anakha, D. R., and R. Yamuna. "COVALENT LINKING OF Ni (II) COMPLEX OF MESO TETRA(4-AMINOPHENYL) PORPHYRIN WITH SINGLEWALLED CARBON NANOTUBE AND ITS PHOTO-PHYSICAL PROPERTIES." Rasayan Journal of Chemistry, Special (2021): 118–25. http://dx.doi.org/10.31788/rjc.2021.1456425.
Full textAbstract:
5, 10, 15, 20 meso tetra(4-aminophenyl) porphyrinato nickel (II) complex (Ni-TAP) was connected covalently with a single-walled carbon nanotube (SWCNT). The Infrared (IR) spectrum of SWCNT-NiTAP nanohybrid conveys the shifting of C=O stretching frequency from 1714 cm-1 to 1695 cm-1 which substantiates the covalent bond connection of porphyrin with SWCNT. In Raman spectroscopy, there is a decrease in the ID/IG ratio after the covalent linkage of SWCNT with Ni-TAP compared to SWCNT-COOH, which specifies enriched electronic properties of SWCNTNiTAP. This is perhaps due to the method of acylation. The morphology study of SWCNT-NiTAP retains the tubelike structure even after the covalent functionalization. The presence of significant peaks in the C 1s and N 1s XP spectra of SWCNT-NiTAP indicate the covalent bond connection of porphyrin chromophores on SWCNTs. Fluorescence spectra of SWCNT-NiTAP show that effective fluorescent quenching is due to energy or electron transfer from Ni-TAP to SWCNTs. Moreover, SWCNT-NiTAP reveals hypsochromic shift compared to Ni-TAP, which specifies the covalent linkage of SWCNT with Ni-TAP.
8
Alam, Rabeya Binta, Md Hasive Ahmad, S. M. Nazmus Sakib Pias, Eashika Mahmud, and Muhammad Rakibul Islam. "Improved optical, electrical, and thermal properties of bio-inspired gelatin/SWCNT composite." AIP Advances 12, no. 4 (April 1, 2022): 045317. http://dx.doi.org/10.1063/5.0089118.
Full textAbstract:
In this study, we report a facile route to synthesize gelatin-based Single-Walled Carbon Nanotube (gelatin/SWCNT) nanocomposites using a simple solution casting process and investigate the impact of SWCNT filler on the structural, surface morphological, optical, electrical, and thermal features. According to the Fourier transform infrared spectroscopy study, the addition of SWCNTs improves the interaction between gelatin and SWCNTs. The field emission scanning electron microscope images showed the presence of the fillers increased with the increment of SWCNT. The roughness of the samples increased caused by high interfacial interactions between Gel and SWCNTs. The nanocomposite’s optical bandgap was observed to be reduced from 2.1 to 1.9 eV as the SWCNT was varied from 0% to 0.5 vol. %. The addition of SWCNTs significantly boosted the DC electrical conductivity of the prepared samples by four orders of magnitude. The incorporation of SWCNT into the gelatin matrix was also observed to improve the nanocomposite's melting enthalpy and degree of crystallinity up to 94.5%. The gelatin/SWCNT nanocomposites were found to be decomposed completely in 4 days in the soil in an open environment.
9
TACCHINI, IGNACIO, EVA TERRADO, ALEJANDRO ANSÓN-CASAOS, and M. TERESA MARTÍNEZ. "SWCNTs AS ELECTRON WITHDRAWERS IN NANOCRYSTALLINE ANATASE PHOTOCATALYSTS." Nano 07, no. 03 (June 2012): 1250020. http://dx.doi.org/10.1142/s1793292012500208.
Full textAbstract:
Single-walled carbon nanotube (SWCNT)/anatase TiO2 composite materials were prepared by successive sol–gel and hydrothermal processes. The composites contained thin SWCNT bundles embedded in aggregates of ~ 12 nm anatase crystallites. A series of SWCNT/ TiO2 photocatalysts was prepared with various SWCNT contents; a SWCNT content of ~ 8 wt.% was found to be optimal for methylene blue (MB) degradation under combined UV/visible radiation. The optimized SWCNT/ TiO2 composite demonstrated substantially higher photocatalytic activity than pure nanocrystalline anatase (5.2 times) and Degussa P-25 TiO2 powder (2.7 times). The MB degradation and mineralization processes were separately evaluated and complete decomposition of MB was shown to take place. The presence of SWCNTs caused an increase in the visible light absorbance of TiO2 ; however, SWCNT/ TiO2 composites did not show any photocatalytic activity when the UV part of the UV/visible light source was filtered. Therefore SWCNTs worked as acceptors for the TiO2 photoexcited electrons, but did not act as sensitizers for TiO2 .
10
Khazi-Syed, Afeefah, Md Tanvir Hasan, Elizabeth Campbell, Roberto Gonzalez-Rodriguez, and Anton V. Naumov. "Single-Walled Carbon Nanotube-Assisted Antibiotic Delivery and Imaging in S. epidermidis Strains Addressing Antibiotic Resistance." Nanomaterials 9, no. 12 (November 25, 2019): 1685. http://dx.doi.org/10.3390/nano9121685.
Full textAbstract:
Although conventional antibiotics have evolved as a staple of modern medicine, increasing antibiotic resistance and the lack of antibiotic efficacy against new bacterial threats is becoming a major medical threat. In this work, we employ single-walled carbon nanotubes (SWCNTs) known to deliver and track therapeutics in mammalian cells via intrinsic near-infrared fluorescence as carriers enhancing antibacterial delivery of doxycycline and methicillin. SWCNTs dispersed in water by antibiotics without the use of toxic bile salt surfactants facilitate efficacy enhancement for both antibiotics against Staphylococcus epidermidis strain showing minimal sensitivity to methicillin. Doxycycline to which the strain did not show resistance in complex with SWCNTs provides only minor increase in efficacy, whereas the SWCNTs/methicillin complex yields up to 40-fold efficacy enhancement over antibiotics alone, suggesting that SWCNT-assisted delivery may circumvent antibiotic resistance in that bacterial strain. At the same time SWCNT/antibiotic formulations appear to be less toxic to mammalian cells than antibiotics alone suggesting that nanomaterial platforms may not restrict potential biomedical applications. The improvement in antibacterial performance with SWCNT delivery is tested via 3 independent assays—colony count, MIC (Minimal Inhibitory Concentration) turbidity and disk diffusion, with the statistical significance of the latter verified by ANOVA and Dunnett’s method. The potential mechanism of action is attributed to SWCNT interactions with bacterial cell wall and adherence to the membrane, as substantial association of SWCNT with bacteria is observed—the near-infrared fluorescence microscopy of treated bacteria shows localization of SWCNT fluorescence in bacterial clusters, scanning electron microscopy verifies SWCNT association with bacterial surface, whereas transmission electron microscopy shows individual SWCNT penetration into bacterial cell wall. This work characterizes SWCNTs as novel advantageous antibiotic delivery/imaging agents having the potential to address antibiotic resistance.
11
Harvey, Joseph, Lifeng Dong, Kyoungtae Kim, Jacob Hayden, and Jianjie Wang. "Uptake of Single-Walled Carbon Nanotubes Conjugated with DNA by Microvascular Endothelial Cells." Journal of Nanotechnology 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/196189.
Full textAbstract:
Single-walled carbon nanotubes (SWCNTs) have been proposed to have great therapeutic potential. SWCNTs conjugated with drugs or genes travel in the systemic circulation to reach target cells or tissues following extravasation from microvessels although the interaction between SWCNT conjugates and the microvascular endothelial cells (ECs) remains unknown. We hypothesized that SWCNT-DNA conjugates would be taken up by microvascular ECs and that this process would be facilitated by SWCNTs compared to facilitation by DNA alone. ECs were treated with various concentrations of SWCNT-DNA-FITC conjugates, and the uptake and intracellular distribution of these conjugates were determined by a confocal microscope imaging system followed by quantitative analysis of fluorescence intensity. The uptake of SWCNT-DNA-FITC conjugates (2 μg/mL) by microvascular ECs was significantly greater than that of DNA-FITC (2 μg/mL), observed at 6 hrs after treatment. For the intracellular distribution, SWCNT-DNA-FITC conjugates were detected in the nucleus of ECs, while DNA-FITC was restricted to the cytoplasm. The fluorescence intensity and distribution of SWCNTs were concentration and time independent. The findings demonstrate that SWCNTs facilitate DNA delivery into microvascular ECs, thus suggesting that SWCNTs serving as drug and gene vehicles have therapeutic potential.
12
Chiashi, Shohei. "(Invited) One-Dimensional Features of Electron Transport in Single-Walled Carbon Nanotube Thin Films." ECS Meeting Abstracts MA2022-01, no. 10 (July 7, 2022): 773. http://dx.doi.org/10.1149/ma2022-0110773mtgabs.
Full textAbstract:
Single-walled carbon nanotubes (SWCNTs) are excellent conductors with high flexibility, high thermal conductivity, and high transparency. Flexible and transparent SWCNT thin films and SWCNT yarns with high mechanical strength have been produced, and in particular, the improvement of electrical conduction characteristics of these SWCNT aggregates has been studied intensively. The electrical conductivity of SWCNT aggregates have improved year by year, but it is worse than those of a single SWCNT, so far. SWCNT aggregates contain complex structures such as SWCNTs with different chirality structures, many junctions, and bundle structures, which could be the cause of deterioration of transport characteristics, however, it has not been clarified. In this study, we focused on low-density SWCNT thin films and investigated their electron transport characteristics. The low-density SWCNT thin film has a simple network structure since the network consists of the bundles of a small number of long SWCNTs. Here, the magnetic field dependence, temperature dependence, and gate voltage dependence of the electrical conductivity were measured and analyzed. The SWCNT thin films were synthesized by a floating catalyst CVD method, and they were transparent (90%T), and electrically conductive [1]. The thin film consisted of a network structure of bundles, which consisted of about 10 SWCNTs. The films were mixtures with metallic and semiconducting SWCNTs. The electrical resistivity of the SWCNT thin film was measured by the four-point probes method, and the gate voltage (Vg) was applied using an ionic liquid. The direction of the magnetic field was perpendicular to the thin film surface. The areal density of SWCNT length was estimated from the light absorption cross-section of the SWCNT thin films, and then the electrical resistivity was calculated from the actual volume of SWCNTs excluding the void space. SWCNTs generally show p-type characteristics in the atmosphere in the back-gate configuration due to the dope effects of oxygen and/or water molecules. However, the Vg dependence of the electrical resistivity of the thin film showed a bipolar behavior under the ionic liquid gate. The change ratio of the resistivity in the Vg range (-3 to +3 V) was more than 10, which suggested that not only did the non-conductive semiconducting SWCNT become conductive, but the number of percolation paths increased accordingly. Raman scattering spectroscopy also exhibited that semi-conducting SWCNTs were heavily doped by the ionic liquid gating. The electrical resistivity decreased down to approximately 20 μΩcm at room temperature with Vg=-3 V. The temperature dependence in the temperature range (30-110 K) with Vg=-3 V was explained by the variable range hopping (VRH) model with the dimensionality of one, although the SWCNT thin films are two-dimensional structures. Hall resistivity of the thin film slightly changed at different Vg, however, it was almost negligible. It is probably because most of the SWCNT thin films were linear bundle parts, and the bundle diameter was a few nm, which is much smaller than the cyclotron radius [2]. Additionally, the thermoelectric measurement was performed. The Vg dependence of thermoelectrical conductivity showed one-dimensional characteristics [3]. These measurements showed one-dimensional features of electron transport properties of SWCNT thin films. A single SWCNT can be regarded as a one-dimensional system, but in general, one-dimensional features do not appear in the electron transport of SWCNTs in the form of thin films or yarns. In this study, probably because the thin film has a very low density (light transmittance 90% T) and forms a network consisting of a thin bundle structure, the one-dimensional features clearly appeared. The one-dimensionality is one of the origins of the excellent properties of SWCNTs and it is could be a useful index for improving electrical conductivity. Acknowledgments I would like to thank H. Date (Univ. of Tokyo) for the experiments and measurements, Prof. T. Fujii (Univ. of Tokyo) for the measurements, and Prof. E. I. Kauppinen for the sample supply. [1] A.G. Nasibulin, et al., ACS Nano, 5 (2011) 3214. [2] M. L. Roukes, et al., Phys. Rev. Lett., 59 (1987) 3011. [3] Y. Ichinose, et al., Phys. Rev. Mater., 5 (2021) 025404.
13
Krause, Beate, Alice Liguoro, and Petra Pötschke. "Blend Structure and n-Type Thermoelectric Performance of PA6/SAN and PA6/PMMA Blends Filled with Singlewalled Carbon Nanotubes." Nanomaterials 11, no. 5 (April 28, 2021): 1146. http://dx.doi.org/10.3390/nano11051146.
Full textAbstract:
The present study investigates how the formation of melt-mixed immiscible blends based on PA6/SAN and PA6/PMMA filled with single walled nanotubes (SWCNTs) affects the thermoelectric (TE) properties. In addition to the detailed investigation of the blend morphology with compositions between 100/0 wt.% and 50/50 wt.%, the thermoelectric properties are investigated on blends with different SWCNT concentrations (0.25–3.0 wt.%). Both PA6 and the blend composites with the used type of SWCNTs showed negative Seebeck coefficients. It was shown that the PA6 matrix polymer, in which the SWCNTs are localized, mainly influenced the thermoelectric properties of blends with high SWCNT contents. By varying the blend composition, an increase in the absolute Seebeck coefficient, power factor (PF), and figure of merit (ZT) was achieved compared to the PA6 composite which is mainly related to the selective localization and enrichment of SWCNTs in the PA6 matrix at constant SWCNT loading. The maximum PFs achieved were 0.22 µW/m·K2 for PA6/SAN/SWCNT 70/30/3 wt.% and 0.13 µW/m·K2 for PA6/PMMA/SWCNT 60/40/3 wt.% compared to 0.09 µW/m·K2 for PA6/3 wt.% SWCNT which represent increases to 244% and 144%, respectively. At higher PMMA or SAN concentration, the change from matrix-droplet to a co-continuous morphology started, which, despite higher SWCNT enrichment in the PA6 matrix, disturbed the electrical conductivity, resulting in reduced PFs with still increasing Seebeck coefficients. At SWCNT contents between 0.5 and 3 wt.% the increase in the absolute Seebeck coefficient was compensated by lower electrical conductivity resulting in lower PF and ZT as compared to the PA6 composites.
14
Al-Shaeri, Majed, Lynn Paterson, Margret Stobie, Paul Cyphus, and Mark G. J. Hartl. "Trophic Transfer of Single-Walled Carbon Nanotubes at the Base of the Food Chain and Toxicological Response." Nanomaterials 12, no. 24 (December 7, 2022): 4363. http://dx.doi.org/10.3390/nano12244363.
Full textAbstract:
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.
15
Kofoed Andersen, Camilla, Sangita Khatri, Jonas Hansen, Sofie Slott, Rohith Pavan Parvathaneni, Ana C. Mendes, Ioannis S. Chronakis, et al. "Carbon Nanotubes—Potent Carriers for Targeted Drug Delivery in Rheumatoid Arthritis." Pharmaceutics 13, no. 4 (March 27, 2021): 453. http://dx.doi.org/10.3390/pharmaceutics13040453.
Full textAbstract:
Two types of single-walled carbon nanotubes (SWCNTs), HiPco- and carboxyl-SWCNT, are evaluated as drug carriers for the traditional anti-inflammatory drug methotrexate (MTX) and a small interfering RNA (siRNA) targeting NOTCH1 gene. The nanotubes are solubilized by PEGylation and covalently loaded with MTX. The coupling efficiency (CE%) of MTX is 77–79% for HiPco-SWCNT and 71–83% for carboxyl-SWCNT. siRNA is noncovalently attached to the nanotubes with efficiency of 90–97% for HiPco-SWCNT and 87–98% for carboxyl-SWCNT. Through whole body imaging in the second near-infrared window (NIR-II window, 1000–1700 nm), SWCNTs were found to be selectively accumulated in inflamed joints in a serum transfer mouse model. We further investigated the interactions of the siRNA/MTX loaded nanotubes with human blood and mice bone marrow cells. In human blood, both types of unloaded SWCNTs were associated with B cells, monocytes and neutrophils. Interestingly, loading with MTX suppressed SWCNTs targeting specificity to immune cells, especially B cells; in contrast, loading siRNA alone enhanced the targeting specificity. Loading both MTX and siRNA to carboxyl-SWCNT enhanced targeting specificity to neutrophils and monocytes but not B cells. The targeting specificity of SWCNTs can potentially be adjusted by altering the ratio of MTX and siRNA loaded. The combined results show that carbon nanotubes have the potential for delivery of cargo drugs specifically to immune cells involved in rheumatoid arthritis.
16
Irita, Masaru, Takahiro Yamamoto, and Yoshikazu Homma. "Chirality Distributions for Semiconducting Single-Walled Carbon Nanotubes Determined by Photoluminescence Spectroscopy." Nanomaterials 11, no. 9 (September 6, 2021): 2309. http://dx.doi.org/10.3390/nano11092309.
Full textAbstract:
To realize single-walled carbon nanotube (SWCNT) chiral selective growth, elucidating the mechanism of SWCNT chirality (n,m) selectivity is important. For this purpose, an accurate evaluation method for evaluating the chirality distribution of grown SWCNTs without post-growth processing or liquid-dispersion of SWCNTs is indispensable. Here, we used photoluminescence spectroscopy to directly measure the chirality distributions of individual semiconducting SWCNTs suspended on a pillar-patterned substrate. The number of chirality-assigned SWCNTs was up to 332 and 17 chirality types with the chiral angles ranging from 0° to 28.05° were detected. The growth yield of SWCNTs was confirmed to primarily depends on the chiral angle in accordance with the screw dislocation model. Furthermore, when higher-yield chiralities are selected, the chiral angle distribution with a peak corresponding to near-armchair SWCNTs is well fitted with a model that incorporates the thermodynamic effect at the SWCNT-catalyst interface into the kink growth-based kinetic model. Our quantitative and statistical data provide new insights into SWCNT growth mechanism as well as experimental confirmation of theoretical predictions.
17
Sharma, Deepa, and Neena Jaggi. "Effect of co-doping on dielectric function spectra and static refractive indices of single-walled carbon nanotubes: A first principles study." Canadian Journal of Physics 95, no. 12 (December 2017): 1194–99. http://dx.doi.org/10.1139/cjp-2016-0823.
Full textAbstract:
This paper details a density functional theory (DFT) based ab initio study on the effect of co-doping on the dielectric function spectra and refractive indices of single-walled carbon nanotubes (SWCNTs). Dielectric function spectra of a pristine (8,0) SWCNT; (8,0) SWCNT co-doped with aluminum (Al) and phosphorus (P); (8,0) SWCNT co-doped with Al, P, and nitrogen (N); (9,0) SWCNT doped with Al; and (9,0) SWCNT co-doped with Al and boron (B) have been calculated using DFT-based Cambridge sequential total energy package (CASTEP) code. Polarized and unpolarized light as well as light through polycrystalline media have been considered. Analysis involves calculation and comparison of static refractive indices of the pristine and co-doped SWCNTs. Co-doping with Al and P results in a substantial increase in the value of the static refractive index while co-doping of Al, N, and P results in a reduction in the value of static refractive index though it does not fall lower than that of the pristine SWCNT. Thus, it can be concluded that co-doping with atoms of different combinations of elements can be evolved as a novel and effective tool for tuning the dielectric function and static refractive index values of SWCNTs. It will prove to be highly significant for effective designing of various sensitive optical devices using SWCNTs.
18
Hasan, Md Tanvir, Elizabeth Campbell, Olga Sizova, Veronica Lyle, Giridhar Akkaraju, D. Lynn Kirkpatrick, and Anton V. Naumov. "Multi-Drug/Gene NASH Therapy Delivery and Selective Hyperspectral NIR Imaging Using Chirality-Sorted Single-Walled Carbon Nanotubes." Cancers 11, no. 8 (August 14, 2019): 1175. http://dx.doi.org/10.3390/cancers11081175.
Full textAbstract:
Single-walled carbon nanotubes (SWCNTs) can serve as drug delivery/biological imaging agents, as they exhibit intrinsic fluorescence in the near-infrared, allowing for deeper tissue imaging while providing therapeutic transport. In this work, CoMoCAT (Cobalt Molybdenum Catalyst) SWCNTs, chirality-sorted by aqueous two-phase extraction, are utilized for the first time to deliver a drug/gene combination therapy and image each therapeutic component separately via chirality-specific SWCNT fluorescence. Each of (7,5) and (7,6) sorted SWCNTs were non-covalently loaded with their specific payload: the PI3 kinase inhibitor targeting liver fibrosis or CCR5 siRNA targeting inflammatory pathways with the goal of addressing these processes in nonalcoholic steatohepatitis (NASH), ultimately to prevent its progression to hepatocellular carcinoma. PX-866-(7,5) SWCNTs and siRNA-(7,6) SWCNTs were each imaged via characteristic SWCNT emission at 1024/1120 nm in HepG2 and HeLa cells by hyperspectral fluorescence microscopy. Wavelength-resolved imaging verified the intracellular transport of each SWCNT chirality and drug release. The therapeutic efficacy of each formulation was further demonstrated by the dose-dependent cytotoxicity of SWCNT-bound PX-866 and >90% knockdown of CCR5 expression with SWCNT/siRNA transfection. This study verifies the feasibility of utilizing chirality-sorted SWCNTs for the delivery and component-specific imaging of combination therapies, also suggesting a novel nanotherapeutic approach for addressing the progressions of NASH to hepatocellular carcinoma.
19
ZHANG, QIANG, YI LIU, JIAQI HUANG, WEIZHONG QIAN, YAO WANG, and FEI WEI. "SYNTHESIS OF SINGLE-WALLED CARBON NANOTUBES FROM LIQUEFIED PETROLEUM GAS." Nano 03, no. 02 (April 2008): 95–100. http://dx.doi.org/10.1142/s179329200800085x.
Full textAbstract:
Hydrocarbons such as methane, ethylene, and CO with high purity (> 99.9%) have been widely used to synthesize single-walled carbon nanotubes (SWCNTs). Here, liquefied petroleum gas (LPG) was used to synthesize SWCNTs by catalytic chemical vapor deposition. The LPG converted into CNTs and other stable hydrocarbons. The BET specific surface area of SWCNT was about 583 m2/g. The as-grown SWCNT showed good graphitization. The graphitization can be further modulated by the growth temperature. Certain amount of sulfur in LPG was a promoter for SWCNT growth. Compared SWCNTs obtained from methane, more semiconductive SWCNTs were synthesized from LPG as carbon source. The LPG is in low price, thus, a methodology to lower the production cost of SWCNTs with hydrocarbon mixtures is realized.
20
Fujii, Takayuki, Takuya Okada, Takahiro Saida, Shigeya Naritsuka, and Takahiro Maruyama. "RETRACTED - Growth of single-walled carbon nanotube at a low temperature by alcohol catalytic chemical vapor deposition using Ru catalysts." MRS Advances 3, no. 1-2 (2018): e1-e7. http://dx.doi.org/10.1557/adv.2018.26.
Full textAbstract:
ABSTRACTGrowth of single-walled carbon nanotube (SWCNT) was achieved by an alcohol catalytic chemical vapor deposition (CVD) mechanism that was conducted in a high vacuum using Ru catalysts. By optimizing the ethanol pressure, SWCNTs can grow in a wide range of temperature between 500 °C and 900 °C. Both the yield and crystalline quality of SWCNTs reached their maxima at 700 °C. Significantly, the SWCNT growth was achieved even at 450 °C, which was much lower than the growth temperatures that were required for SWCNT growth using Ru catalysts previously. Raman measurements exhibited that the diameter distribution of the SWCNTs that were grown at 450 °C was quite narrow and (11, 4) nanotubes were dominant. The observations of transmission electron microscope (TEM) suggested that the size of the Ru particles were larger than the diameter of SWCNT. Such a relation was similar to the relation observed in the growth of SWCNTs using Pt catalysts.
21
Fujii, Takayuki, Takuya Okada, Takahiro Saida, Shigeya Naritsuka, and Takahiro Maruyama. "Growth of single-walled carbon nanotube at a low temperature by alcohol catalytic chemical vapor deposition using Ru catalysts." MRS Advances 3, no. 1-2 (2018): 53–59. http://dx.doi.org/10.1557/adv.2018.4.
Full textAbstract:
ABSTRACTGrowth of single-walled carbon nanotube (SWCNT) was achieved by an alcohol catalytic chemical vapor deposition (CVD) mechanism that was conducted in a high vacuum using Ru catalysts. By optimizing the ethanol pressure, SWCNTs can grow in a wide range of temperature between 500 °C and 900 °C. Both the yield and crystalline quality of SWCNTs reached their maxima at 700 °C. Significantly, the SWCNT growth was achieved even at 450 °C, which was much lower than the growth temperatures that were required for SWCNT growth using Ru catalysts previously. Raman measurements exhibited that the diameter distribution of the SWCNTs that were grown at 450 °C was quite narrow and (11, 4) nanotubes were dominant. The observations of transmission electron microscope (TEM) suggested that the size of the Ru particles were larger than the diameter of SWCNT. Such a relation was similar to the relation observed in the growth of SWCNTs using Pt catalysts.
22
Dong, Chensong. "Effective Elastic Modulus of Wavy Single-Wall Carbon Nanotubes." C 9, no. 2 (May 26, 2023): 54. http://dx.doi.org/10.3390/c9020054.
Full textAbstract:
A simple method for determining the effective elastic modulus of wavy single-wall carbon nanotubes (SWCNTs) is presented in this paper. The effective modulus of curved SWCNTs is derived using Castigliano’s theorem. The effect of curvature on the effective modulus is studied. This method is verified by finite element analysis (FEA). The distributions of effective moduli are studied by Monte Carlo simulation. The effective modulus of a general wavy SWCNT is derived by considering the SWCNT as a number of curved SWCNT sections.
23
Sedelnikova, Olga, Olga Gurova, Anna Makarova, Anastasiya Fedorenko, Anton Nikolenko, Pavel Plyusnin, Raul Arenal, Lyubov Bulusheva, and Alexander Okotrub. "Light-Induced Sulfur Transport inside Single-Walled Carbon Nanotubes." Nanomaterials 10, no. 5 (April 25, 2020): 818. http://dx.doi.org/10.3390/nano10050818.
Full textAbstract:
Filling of single-walled carbon nanotubes (SWCNTs) and extraction of the encapsulated species from their cavities are perspective treatments for tuning the functional properties of SWCNT-based materials. Here, we have investigated sulfur-modified SWCNTs synthesized by the ampoule method. The morphology and chemical states of carbon and sulfur were analyzed by transmission electron microscopy, Raman scattering, thermogravimetric analysis, X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopies. Successful encapsulation of sulfur inside SWCNTs cavities was demonstrated. The peculiarities of interactions of SWCNTs with encapsulated and external sulfur species were analyzed in details. In particular, the donor–acceptor interaction between encapsulated sulfur and host SWCNT is experimentally demonstrated. The sulfur-filled SWCNTs were continuously irradiated in situ with polychromatic photon beam of high intensity. Comparison of X-ray spectra of the samples before and after the treatment revealed sulfur transport from the interior to the surface of SWCNTs bundles, in particular extraction of sulfur from the SWCNT cavity. These results show that the moderate heating of filled nanotubes could be used to de-encapsulate the guest species tuning the local composition, and hence, the functional properties of SWCNT-based materials.
24
Hopkins, Seantel, Manoj Gottipati, Vedrana Montana, Elena Bekyarova, Robert Haddon, and Vladimir Parpura. "Effects of Chemically-Functionalized Single-Walled Carbon Nanotubes on the Morphology and Vitality of D54MG Human Glioblastoma Cells." Neuroglia 1, no. 2 (October 16, 2018): 327–38. http://dx.doi.org/10.3390/neuroglia1020022.
Full textAbstract:
The unique properties of single-walled carbon nanotubes (SWCNTs) have made them interesting candidates for applications in biomedicine. There are diverse chemical groups that can be attached to SWCNTs in order for these tiny tubes to gain various functionalities, for example, water solubility. Due to the availability of these “functionalization” approaches, SWCNTs are seen as agents for a potential anti-cancer therapy. In this context, we tested different chemically-functionalized forms of SWCNTs to determine which modifications make them better combatants against glioblastoma (astrocytoma grade IV), the deadliest brain cancer. We investigated the effects that two types of water soluble SWCNTs, functionalized with polyethylene glycol (SWCNT-PEG) or tetrahydrofurfuryl-terminated polyethylene glycol (SWCNT-PEG-THFF), have on the morphology and vitality, that is, cell adhesion, proliferation and death rate, of the D54MG human glioblastoma cells in culture. We found that SWCNT-PEG-THFF solute, when added to culture media, makes D54MG cells less round (measured as a significant decrease, by ~23%, in the form factor). This morphological change was induced by the PEG-THFF functional group, but not the SWCNT backbone itself. We also found that SWCNT-PEG-THFF solute reduces the proliferation rate of D54MG cells while increasing the rate of cell death. The functional groups PEG and PEG-THFF, on the other hand, reduce the cell death rate of D54MG human glioma cells. These data indicate that the process of functionalization of SWCNTs for potential use as glioma therapeutics may affect their biological effects.
25
Stanojev, Jovana, Stevan Armaković, Sara Joksović, Branimir Bajac, Jovan Matović, and Vladimir V. Srdić. "Comprehensive Study of the Chemistry behind the Stability of Carboxylic SWCNT Dispersions in the Development of a Transparent Electrode." Nanomaterials 12, no. 11 (June 1, 2022): 1901. http://dx.doi.org/10.3390/nano12111901.
Full textAbstract:
Single-walled carbon nanotubes (SWCNTs) are well-known for their excellent electrical conductivity. One promising application for SWCNT-based thin films is as transparent electrodes for uncooled mid-IR detectors (MIR). In this paper, a combination of computational and experimental studies were performed to understand the chemistry behind the stability of carboxylic SWCNTs (SWCNTs-COOH) dispersions in different solvents. A computational study based on the density functional tight-binding (DFTB) method was applied to understand the interactions of COOH-functionalized carbon nanotubes with selected solvents. Attention was focused on understanding how the protonation of COOH groups influences the binding energies between SWCNTs and different solvents. Thin film electrodes were prepared by alternately depositing PEI and SWCNT-COOH on soda lime glass substrates. To prepare a stable SWCNT dispersion, different solvents were tested, such as deionized (DI) water, ethanol and acetone. The SWCNT-COOH dispersion stability was tested in different solvents. Samples were prepared to study the relationship between the number of depositions, transparency in the MIR range (2.5–5 µm) and conductivity, looking for the optimal thickness that would satisfy the application. The MIR transparency of the electrode was reduced by 20% for the thickest SWCNT layers, whereas sheet resistance values were reduced to 150–200 kΩ/sq.
26
Yan, Lu, Shu Zhang, Chao Zeng, Yu Hua Xue, Zhong Lou Zhou, Fan Lu, Hao Chen, Jia Qu, Li Ming Dai, and Yong Liu. "Cytotoxicity of Single-Walled Carbon Nanotubes with Human Ocular Cells." Advanced Materials Research 287-290 (July 2011): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.32.
Full textAbstract:
In this paper, we report the first study on cytotoxicity of single-walled carbon nanotubes (SWCNTs) and theirs derivatives with human ocular cells, such as ARPE-19 cells. In particular, we have systematically investigated the cytotoxicity of SWCNTs, hydroxyl-functionalized SWCNTs (SWCNT-OH), and carboxylic functionalized SWCNTs (SWCNT-COOH) with ARPE-19 cells by examining their influence on the cell morphology, viability, oxidative stress, membrane integrity and apoptosis. To this end, various methods, including optical micrography, CCK-8 assay, LDH assay, SOD assay, TEM and Apoptosis assay, have been used in this study. Our results suggest that SWCNTs could cause an decrease in the cell survival rate, changes in the SOD level, membrane integrity and cell apoptosis, indicating a high toxicity to ARPE-19 cells. However, chemical functionalization of SWCNTs with –OH and –COOH groups was found to significantly improve the biocompatibility of SWCNTs. Among the SWCNTs and their derivatives studied in this work, the SWCNT-COOH exhibits the best biocompatibility to ARPE-19 cells.
27
SONG, HAI-YANG, MING-LIANG HU, and XIN-WEI ZHA. "CONNECTION OF SINGLE-WALLED CARBON NANOTUBES BY BANDAGING WITH A BIGGER RADIUS SINGLE-WALLED CARBON NANOTUBE." Modern Physics Letters B 23, no. 07 (March 20, 2009): 1005–12. http://dx.doi.org/10.1142/s0217984909019193.
Full textAbstract:
We report molecular dynamics studies of single-walled carbon nanotubes (SWCNT) as a bandage to connect separated SWCNTs for getting structures of random length. The mechanical properties of the connected SWCNT strands with different joint length under axial loads are investigated using the classical molecular dynamics simulations method. The interaction between atoms is modeled using the second-generation of reactive empirical bond-order (REBO) potential coupled with the Lennard–Jones (L–J) potential. The mechanical properties, such as Young's modulus, tensile strength, critical buckling strains and critical buckling loads are determined and presented for SWCNT and connected SWCNT strands. The results indicates that the joints made in this way have relatively high mechanical properties corresponding to that of the ideal SWCNTs.
28
Sajjadi, Sayyed Hashem, Shang-Jung Wu, Melania Reggente, Elaheh K. Goharshadi, Niloufar Sharif, Hossein Ahmadzadeh, and Ardemis Anoush Boghossian. "Photoluminescence Brightening of Single-Walled Carbon Nanotubes Using Graphene Quantum Dots." ECS Meeting Abstracts MA2022-01, no. 9 (July 7, 2022): 720. http://dx.doi.org/10.1149/ma2022-019720mtgabs.
Full textAbstract:
Single-walled carbon nanotubes (SWCNTs) emit near-infrared (NIR) photoluminescence (PL) that spans the tissue transparency window, allowing them to optically penetrate biological tissue for deep-tissue optical sensing. Such optical SWCNT sensors are often functionalized with single stranded DNA (ssDNA) to promote biocompatibility, responsivity, and selectivity. However, the low brightness of these ssDNA-wrapped sensors restricts the depth at which such sensors can be implanted in biological tissue. In this work, we overcome this limitation by demonstrating the PL enhancement of ssDNA-wrapped SWCNTs through the incorporation of biocompatible graphene quantum dots (GQDs). We compare the enhancement effects of two preparations of GQDs, pristine (PGQDs) and nitrogen-doped (NGQDs) graphene quantum dots. Both preparations of GQDs were shown to significantly increase the fluorescence emissions of ssDNA-SWCNTs to a comparable extent after 3 h of incubation. We further observed a diameter dependence of this enhancement, with the larger (8,6) SWCNT chirality demonstrating a 30-fold enhancement as compared to the 2-fold enhancement observed for the (6,5) SWCNT chirality. This PL enhancement was shown to vary with the exposed surface area of the SWCNTs, whereby SWCNT chiralities with wrappings that yield larger exposed SWCNT surfaces resulted in increased PL enhancement on conjugation with the GQDs. Despite the similarities in the final fluorescence enhancements, the NGQDs and PGQDs showed kinetic differences in their brightening effects. The NGQDs were able to achieve stabilized SWCNT fluorescence brightening 2 min after their addition, whereas the SWCNTs showed continued PL increases even 1 h after the addition of the PGQDs. Electrochemical analysis of the NGQDs confirms their behavior as reducing agents, which have been previously shown to enhance the rate of SWCNT brightening through the passivation of oxygen defect sites. The brightening effects of the NGQDs were further demonstrated in confocal single-molecule measurements, where we observed a 3-fold increase in the detection of individual SWCNTs on conjugation to the NGQDs compared to the unconjugated ssDNA-SWCNTs. The photoluminescence enhancements enabled by the GQDs thus provides a promising tool for engineering the brightness of NIR sensors for biomedical applications and enabling improved detection in deep-tissue sensing and imaging applications.
29
Lee, Ji Young, Changhoon Lee, Eiji Osawa, Jong Woan Choi, Jung Chul Sur, and Kee Hag Lee. "Snapshots of the Fragmentation for C70@Single-Walled Carbon Nanotube: Tight-Binding Molecular Dynamics Simulations." International Journal of Molecular Sciences 22, no. 8 (April 10, 2021): 3929. http://dx.doi.org/10.3390/ijms22083929.
Full textAbstract:
In previously reported experimental studies, a yield of double-walled carbon nanotubes (DWCNTs) at C70@Single-walled carbon nanotubes (SWCNTs) is higher than C60@SWCNTs due to the higher sensitivity to photolysis of the former. From the perspective of pyrolysis dynamics, we would like to understand whether C70@SWCNT is more sensitive to thermal decomposition than C60@SWCNT, and the starting point of DWCNT formation, which can be obtained through the decomposition fragmentation of the nanopeapods, which appears in the early stages. We have studied the fragmentation of C70@SWCNT nanopeapods, using molecular dynamics simulations together with the empirical tight-binding total energy calculation method. We got the snapshots of the fragmentation structure of carbon nano-peapods (CNPs) composed of SWCNT and C70 fullerene molecules and the geometric spatial positioning structure of C70 within the SWCNT as a function of dynamics time (for 2 picoseconds) at the temperatures of 4000 K, 5000 K, and 6000 K. In conclusion, the scenario in which C70@SWCNT transforms to a DWCNT would be followed by the fragmentation of C70, after C70, and the SWCNT have been chemically bonding in the early stages. The relative stability of fullerenes in CNPs could be reversed, compared to the ranking of the relative stability of the encapsulated molecules themselves.
30
Müller, Christian, Ammar Al-Hamry, Olfa Kanoun, Mahfujur Rahaman, Dietrich R. T. Zahn, Elaine Yoshiko Matsubara, and José Mauricio Rosolen. "Humidity Sensing Behavior of Endohedral Li-Doped and Undoped SWCNT/SDBS Composite Films." Sensors 19, no. 1 (January 5, 2019): 171. http://dx.doi.org/10.3390/s19010171.
Full textAbstract:
We have investigated single-walled carbon nanotube (SWCNT) networks wrapped with the cationic surfactant sodium dodecyl-benzenesulfonate (SBDS) as promising candidates for water detection. This is the first time that the humidity behavior of endohedral Li-doped (Li@) and undoped SWCNTs/SDBS has been shown. We identified a strong and almost monotonic decrease in resistance as humidity increased from 11 to 97%. Sensitivities varied between −3 and 65% in the entire humidity range. Electrical characterization, Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) analysis revealed that a combination of the electron donor behavior of the water molecules with Poole-Frenkel conduction accounted for the resistive humidity response in the Li@SWCNT/SDBS and undoped SWCNT/SDBS networks. We found that Li@SWCNTs boosted the semiconducting character in mixtures of metallic/semiconducting SWCNT beams. Moreover, electrical characterization of the sensor suggested that endohedral Li doping produced SWCNT beams with high concentration of semiconducting tubes. We also investigated how frequency influenced film humidity sensing behavior and how this behavior of SWCNT/SDBS films depended on temperature from 20 to 80 ° C. The present results will certainly aid design and optimization of SWCNT films with different dopants for humidity or gas sensing in general.
31
Ahmed Jamal, G. R., M. Asraf Siddique, Sawon, Khalid Hasan, and M. Jane Alam. "An Improved Technique for Chirality Assignment of SWCNTs Exploiting their (2n+m) Family Behavior." Materials Science Forum 889 (March 2017): 253–57. http://dx.doi.org/10.4028/www.scientific.net/msf.889.253.
Full textAbstract:
In this work, an improved technique for chirality assignment of single wall carbon nanotubes (SWCNT) is proposed which work for both isolated and bundles SWCNTs. The technique exploits the (2n+m) family pattern both in optical transitions vs diameter plot and Raman G-mode frequency vs diameter plot of SWCNTs. Using two different plots can give accurate value of the family of unknown SWCNTs that can be used to find chiral index (n, m) of unknown SWCNT unambiguously in most of the cases. Unlike existing methods, graphical comparison or pattern recognition with an existing Kataura plot is not required here. Chirality of 13 SWCNTs are assigned here using this technique. Validity of assigned chirality is cross checked from previous experimental reports. The technique is especially useful for determining chirality of isolated SWCNT.
32
Raja, Pavan M. V., Gibran L. Esquenazi, Cathren E. Gowenlock, Daniel R. Jones, Jianhua Li, Bruce Brinson, and Andrew R. Barron. "Electrodeposition of Cu–SWCNT Composites." C 5, no. 3 (July 13, 2019): 38. http://dx.doi.org/10.3390/c5030038.
Full textAbstract:
Single walled carbon nanotubes (SWCNTs) are used as a component of a plating solution of CuSO4 for direct current electrodeposition of Cu–SWCNT composites with varying nanotube proportions without the use of either a surfactant, a dispersing agent, or functionalization of the SWCNTs. The Cu–SWCNT composites are characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The composites are comprised of metallic Cu and SWCNTs with minor oxide impurities, as well as the residual (Fe) catalyst from the unpurified SWCNTs, in addition to displaying nanotube-mediated morphological differences. EDX analysis of carbon (wt%) is close to quantitative with respect to the wt% of SWCNTs added to the electrolysis solution. The presence of SWCNTs decreases the oxidation of the copper, as well as changing the identity of the oxide from CuO, for electrolysis of Cu, to Cu2O. Hard adherent Cu–SWCNT coatings are prepared by the addition of Cu powder to the electrolysis solution. The approach described in this paper will enable controlled synthesis of metal-nanomaterial composites that can potentially be processed further into high ampacity electrical conductors.
33
Abdulla, Estabraq T. "Synthesis and electrical properties of conductive polyaniline/ SWCNT nanocomposites." Iraqi Journal of Physics (IJP) 15, no. 34 (January 8, 2019): 106–13. http://dx.doi.org/10.30723/ijp.v15i34.126.
Full textAbstract:
The synthesis of conducting polyaniline (PANI) nanocomposites containing various concentrations of functionalized single-walled carbon nanotubes (f-SWCNT) were synthesized by in situ polymerization of aniline monomer. The morphological and electrical properties of pure PANI and PANI/SWCNT nanocomposites were examined by using Fourier transform- infrared spectroscopy (FTIR), and Atomic Force Microscopy (AFM) respectively. The FTIR shows the aniline monomers were polymerized on the surface of SWCNTs, depending on the -* electron interaction between aniline monomers and SWCNTs. AFM analysis showed increasing in the roughness with increasing SWCNT content. The AC, DC electrical conductivities of pure PANI and PANI/SWCNT nanocomposite have been measured in frequency range (50Hz - 600KHz) and in the temperature range from (30 to 160K). The results show the electrical conductivity of the nanocomposite is higher than pure PANI.
34
Maruyama, Takahiro, Hiroki Kondo, Akinari Kozawa, Takahiro Saida, Shigeya Naritsuka, and Sumio Iijima. "Growth Mechanism of Single-Walled Carbon Nanotubes from Pt Catalysts by Alcohol Catalytic CVD." MRS Proceedings 1752 (2015): 27–30. http://dx.doi.org/10.1557/opl.2015.43.
Full textAbstract:
ABSTRACTSingle-walled carbon nanotube (SWCNT) growth from Pt catalysts by an alcohol gas source method, a type of cold-wall chemical vapor deposition (CVD), was investigated. Raman results showed that the diameters of SWCNTs grown from Pt were below 1.2 nm, while transmission electron microscopy (TEM) showed that the diameters of most Pt catalyst particles were above 1.2 nm. This suggests that SWCNT diameters were smaller than Pt catalysts particles. X-ray photoelectron spectroscopy measurements showed that reduction of Pt particles occurred during the SWCNT growth. Based on these experimental data, growth mechanism of SWCNTs was discussed.
35
Li, Huaping. "Electronically Pure Single Chirality Semiconducting Single-Walled Carbon Nanotube for Large Scale Electronic Devices." MRS Advances 2, no. 02 (2017): 83–88. http://dx.doi.org/10.1557/adv.2017.15.
Full textAbstract:
Abstract Carbon nanotube thin film transistors (TFTs) with characteristics resembling those of TFTs constructed on amorphous silicon, low-temperature polycrystalline silicon and metal oxides were fabricated on (6,5) single chirality single-walled carbon nanotube (SWCNT) thin film deposited from electronically pure semiconducting (6,5) single chirality single-walled carbon nanotube (SWCNT) ink. This ink was extracted in industrial scale from raw SWCNTs produced using high pressure carbon monoxide conversion, and deposited on pretreated substrates to form uniform and consistent (6,5) HiPCO SWCNT thin film using solution process. The (6,5) HiPCO SWCNT thin films were characterized as pure semiconductor without metallic impurities showing classic nonlinear current-bias curves in Schottky-type diodes. Both N-type and P-type (6,5) HiPCO SWCNT TFTs were fabricated with femto Ampere off-current and ION/IOFF ratio of 108 by depositing SiNx and HfO2 dielectrics on the top of (6,5) HiPCO SWCNT thin films, respectively. The (6,5) HiPCO SWCNT inverter with voltage gain of 52 was also demonstrated by wire-bonding one P-type HiPCO SWCNT TFT to one N-type HiPCO SWCNT TFT.
36
CHEN, CHANGXIN, and YAFEI ZHANG. "FABRICATION OF DISPERSED ALIGNED CARBON NANOTUBE ARRAY BETWEEN METAL ELECTRODES." International Journal of Nanoscience 05, no. 04n05 (August 2006): 389–94. http://dx.doi.org/10.1142/s0219581x06004528.
Full textAbstract:
Dispersed aligned single-wall carbon nanotube (SWCNT) array has been formed between electrodes by electric field assisted alignment of surface decorated SWCNTs. The surface decoration of SWCNTs with functional molecules allows them to dispersedly bridge metal electrodes and effectively obviates the entanglement between SWCNTs. The influences of solution volatility and electric-field type on the alignment are investigated. It is indicated that the well-oriented SWCNT array can be achieved by using the high-volatility solvent and the high-frequency AC electric field to align SWCNTs.
37
Ding, Er-Xiong, Aqeel Hussain, Saeed Ahmad, Qiang Zhang, Yongping Liao, Hua Jiang, and Esko I. Kauppinen. "High-performance transparent conducting films of long single-walled carbon nanotubes synthesized from toluene alone." Nano Research 13, no. 1 (December 10, 2019): 112–20. http://dx.doi.org/10.1007/s12274-019-2581-7.
Full textAbstract:
AbstractSingle-walled carbon nanotube (SWCNT) transparent conducting films (TCFs) are attracting increasing attention due to their exceptional optoelectronic properties. Toluene is a proposed carbon source for SWCNT synthesis, but the growth parameters of SWCNTs and their TCF optoelectronic performance (i.e., sheet resistance versus transmittance) have been insufficiently evaluated. Here, we have for the first time reported a systematic study of the fabrication of high-performance SWCNT TCFs using toluene alone as the carbon source. The mechanisms behind each observed phenomenon were elucidated using optical and microscopy techniques. By optimizing the growth parameters, high yields of SWCNT TCFs exhibiting a considerably low sheet resistance of 57 Ω/sq at 90% transmittance were obtained. This competitive optoelectronic performance is mainly attributable to long SWCNT bundles (mean length is 41.4 μm) in the film. Additionally, a chirality map determined by electron diffraction displays a bimodal distribution of chiral angles divided at 15°, which is close to both armchair and zigzag edges. Our study paved the way towards scaled-up production of SWCNTs for the fabrication of high-performance TCFs for industrial applications.
38
Lafta, Holya A., Shaymaa Abed Hussein, Aiman Mohammed Baqir Al-Dhalimy, and Ayad F. Alkaim. "Synthesis and Application UV100/SWCNTs/Pt in Binary and Ternary Composites for Hydrogen Production: Sonochemical / Photodeposition." NeuroQuantology 20, no. 3 (March 26, 2022): 56–62. http://dx.doi.org/10.14704/nq.2022.20.3.nq22041.
Full textAbstract:
Titanium dioxide Hombickat UV100 was used as semiconductor for hydrogen production reaction without and with modification by 0.5% single walled carbon nanotubes SWCNTs and platinum Pt. the modification includes synthesize binary composites with SWCNTs by sonochemical addition while with Pt was accrued by photo deposition method. Structural properties and morphology of the synthesized materials SWCNT/UV100, UV100: Pt and ternary composites SWCNT/UV100: Pt with pristine UV100 were characterized by x-ray diffraction, UV-visible diffraction and Fourier transform infrared spectroscopy FTIR. The results showed that SWCNTs reduce the activities of UV100 in producing H2 from solution 10% MeOH/H2O while in the ternary composites SWCNT/UV100: Pt the SWCNTs play very important roles in increase the activity of UV100 with Pt to more than 20%. The role of SWCNTs was related to dispersion Pt with less agglomerates as compare with UV100: Pt and that create more active cites on the surface of UV100-TiO2.
39
Guo, Shu-Yu, Peng-Xiang Hou, Feng Zhang, Chang Liu, and Hui-Ming Cheng. "Gas Sensors Based on Single-Wall Carbon Nanotubes." Molecules 27, no. 17 (August 24, 2022): 5381. http://dx.doi.org/10.3390/molecules27175381.
Full textAbstract:
Single-wall carbon nanotubes (SWCNTs) have a high aspect ratio, large surface area, good stability and unique metallic or semiconducting electrical conductivity, they are therefore considered a promising candidate for the fabrication of flexible gas sensors that are expected to be used in the Internet of Things and various portable and wearable electronics. In this review, we first introduce the sensing mechanism of SWCNTs and the typical structure and key parameters of SWCNT-based gas sensors. We then summarize research progress on the design, fabrication, and performance of SWCNT-based gas sensors. Finally, the principles and possible approaches to further improving the performance of SWCNT-based gas sensors are discussed.
40
Yahya, Iskandar, Arulampalam Kunaraj, Seri Mastura Mustaza, Steven Clowes, and S. Ravi P. Silva. "Methods for Estimating Composition of Single Walled Carbon Nanotubes Based on Electronic Type." Materials Science Forum 1055 (March 4, 2022): 77–86. http://dx.doi.org/10.4028/p-073fwj.
Full textAbstract:
— Synthesized single-walled carbon nanotubes (SWCNTs) consist of a mixture of chiralities and therefore a post-synthesis separation is essential to separate them based on electronic type i.e., metallic (m-SWCNT) or semiconducting (s-SWCNT) for device applications. A key parameter to measure the effectiveness of separation process is the enrichment composition percentage between m-SWCNT and s-SWCNT, which can be estimated via several methods based on optical characterizations. In this paper, we compare the composition percentage estimations from 3 different methods based on Raman spectroscopy and UV-Vis optical absorption spectroscopy. The estimation methods are radial breathing mode (RBM) peak analysis, optical absorption area under curve (OUA) and first derivative amplitude of the optical absorption curve (FDA). Four different SWCNT sources were used in this study, which were subjected to post-synthesis separation process via agarose gel chromatography. Raman and UV-Vis spectroscopy measurements were carried out on all samples, before and after separation. From the estimations, we observed firstly that there are some variations on the estimated enrichment compositions between different methods, although the values are comparable. Secondly, for some SWCNTs samples, only a certain estimation method showed reliable composition percentage. The results presented in this work may provide viable options for characterizations of SWCNTs as there is no direct method to quantify the absolute composition percentage of SWCNTs based on electronic type. Keywords—single-walledcarbon nanotube, separation, electronic type, optical characterization, purity percentage.
41
Yengejeh, Sadegh Imani, Andreas Öchsner, Seyedeh Alieh Kazemi, and Maksym Rybachuk. "Numerical Analysis of the Structural Stability of Ideal (Defect-Free) and Structurally and Morphologically Degenerated Homogeneous, Linearly- and Angle-Adjoined Nanotubes and Cylindrical Fullerenes Under Axial Loading Using Finite Element Method." International Journal of Applied Mechanics 10, no. 09 (November 2018): 1850100. http://dx.doi.org/10.1142/s1758825118501004.
Full textAbstract:
We report on the structural stability of ideal (defect-free) and structurally and morphologically degenerate carbon nanotubes and nanotube junction systems under axial loading based on the finite element method. We estimated the values for critical buckling load for uncapped and capped single-walled carbon nanotubes (SWCNTs) and linear and angle-adjoined SWCNT heterojunctions in ideal and structurally degenerate systems containing single-, double-, triple-, pinhole- and pentagon–heptagon (i.e., 5–7) structural defects and also containing a substitutional nitrogen (N) atom inclusion under compressive loading. Absolute atomic vacancy (defect) concentration in studied SWCNTs models was assumed to be nil for ideal systems, and was up to 3.0 at.% for structurally and morphologically degenerate systems. It was found that all types of structural defects and the morphological N-defect had reduced the load carrying capacity and mechanical strength in all SWCNT systems studied. The SWCNT models containing physically large vacant sites, such as triple- and pinhole-defects, displayed significantly lower critical load values compared to the systems that contained only a single-, double- or triple-vacancies. In addition, we found that capped SWCNTs performed marginally better in critical load carrying capacity compared to uncapped SWCNT systems. Furthermore, majority of the investigated structures displayed reduced load in SWCNTs with narrower tube widths, proportional to the size and the type of the defect investigated. The effects of chirality, such as zigzag- versus armchair-type, on the structural stability of the investigated SWCNT models were also investigated.
42
JEONG, MUN SEOK, CLARE C. BYEON, OK HWAN CHA, HYUN JEONG, JONG HUN HAN, YOUNG CHUL CHOI, KAY HYEOK AN, KYUNG HUI OH, KI KANG KIM, and YOUNG HEE LEE. "PURITY MEASUREMENT OF SINGLE-WALLED CARBON NANOTUBES BY UV-VIS-NIR ABSORPTION SPECTROSCOPY AND THERMOGRAVIMETRIC ANALYSIS." Nano 03, no. 02 (April 2008): 101–8. http://dx.doi.org/10.1142/s1793292008000885.
Full textAbstract:
We measured the content of single-walled carbon nanotubes (SWCNTs) in SWCNT soot within 3.7% error using UV-VIS-NIR absorption spectroscopy. We also propose a better overall evaluation method by combining thermogravimetic analysis with UV-VIS-NIR absorption spectroscopy to analyze the purity of SWCNT providing the accurate assessment of the amounts of noncarbonaceous impurity, carbonaceous impurity, and SWCNT each with respect to a highly purified reference.
43
Park, Boik, Jongsu Jang, Hyeonggyu Kim, Jiseok Seo, Hyunjun Yoo, Taehoon Kim, and Yongtaek Hong. "Enhanced current path by circularly and periodically-aligned semiconducting single-walled carbon nanotubes for logic circuit device." Flexible and Printed Electronics 7, no. 1 (February 4, 2022): 015005. http://dx.doi.org/10.1088/2058-8585/ac4ea0.
Full textAbstract:
Abstract Improving the performance of solution-processed single-walled carbon nanotube thin film transistors (SWCNT TFTs) is essential to their wide usage in next generation large-area electronic devices. However, uncontrollable tube-tube junction and random network formation from conventional solution processes of SWCNTs has limited mobility and on-current level of SWCNT TFTs. Herein, we demonstrate a facile method by switching idea of reducing coffee-ring of the conventionally solution-processed or inkjet-printed thin films. Spontaneous coffee-ring formation of the inkjet-printed droplets is found to enhance directional alignment of SWCNTs in the outer rim of the coffee-rings. The evaporation-driven capillary flow toward the rim inside induces migration of SWCNT and thus forms densely aligned SWCNT rings. Periodic connection of such rings can provide high-current path at a given voltage. Therefore, by additionally forming the periodically connected rings on a pre-established random network of SWCNT in channel area of TFTs, we significantly improved the mobility and I on/I off ratio of SWCNT TFTs without degradations in other electrical parameters such as threshold voltage and subthreshold swing. We also demonstrated all-solution-processed inverters with higher voltage-gain in comparison with conventional ones.
44
El-Hami, Khalil, and Abdelkhalak El Hami. "Predicting the Reliability of Aligned Carbon Nanotube Bundles in Mechanical Structures." Applied Mechanics and Materials 146 (December 2011): 124–29. http://dx.doi.org/10.4028/www.scientific.net/amm.146.124.
Full textAbstract:
We report new experimental and theoretical study of mechanical property of aligned and nonaligned (entangled) single walled carbon nanotubes (SWCNTs), and their effect on nanostructures. Experimentally, the contact mode atomic force microscopy cantilever tip is used to measure the Young’s modulus of aligned and nonaligned SWCNTs. The measured Young's modulus of aligned SWCNT bundles ranged between 1100 GPa (1.1 TPa) and 1300 GPa (1.3 TPa) with a relative uncertainty of 5 % whereas that of the entangled SWCNT bundles ranged between 500 GPa and 700 GPa. Young’s modulus increase with aligned SWCNT bundles and then increase their performance in nanostructure comparing with entangled SWCNT bundles. We put emphasis on the combination of physical modeling and reliability based design optimization of nanomaterials. After investigation, we could make suggestions such as how to improve the reliability of nanodevices and nanosystems, and how to reduce cost and economic rates.
45
Uçar, Ezgi, Mustafa Dogu, Elcin Demirhan, and Beate Krause. "PMMA/SWCNT Composites with Very Low Electrical Percolation Threshold by Direct Incorporation and Masterbatch Dilution and Characterization of Electrical and Thermoelectrical Properties." Nanomaterials 13, no. 8 (April 21, 2023): 1431. http://dx.doi.org/10.3390/nano13081431.
Full textAbstract:
In the present study, Poly(methyl methacrylate) (PMMA)/single-walled carbon nanotubes (SWCNT) composites were prepared by melt mixing to achieve suitable SWCNT dispersion and distribution and low electrical resistivity, whereby the SWCNT direct incorporation method was compared with masterbatch dilution. An electrical percolation threshold of 0.05–0.075 wt% was found, the lowest threshold value for melt-mixed PMMA/SWCNT composites reported so far. The influence of rotation speed and method of SWCNT incorporation into the PMMA matrix on the electrical properties and the SWCNT macro dispersion was investigated. It was found that increasing rotation speed improved macro dispersion and electrical conductivity. The results showed that electrically conductive composites with a low percolation threshold could be prepared by direct incorporation using high rotation speed. The masterbatch approach leads to higher resistivity values compared to the direct incorporation of SWCNTs. In addition, the thermal behavior and thermoelectric properties of PMMA/SWCNT composites were studied. The Seebeck coefficients vary from 35.8 µV/K to 53.4 µV/K for composites up to 5 wt% SWCNT.
46
Liu, Wei Wen, Azizan Aziz, Siang Piao Chai, Abdul Rahman Mohamed, U. Hashim, and Chin Wei Lai. "Synthesis of Fe3O4 Nanoparticles to Synthesize Bundles of Single-Walled Carbon Nanotubes." Advanced Materials Research 1109 (June 2015): 108–12. http://dx.doi.org/10.4028/www.scientific.net/amr.1109.108.
Full textAbstract:
Magnetite (Fe3O4) nanoparticles were synthesized in aqueous solutions without any surfactants. The Fe3O4 nanoparticles are nearly spherical and have an average diameter of 10.33nm and a narrow size distribution. Bundles of single-walled carbon nanotube (SWCNT) were synthesized using these Fe3O4 nanoparticles supported by MgO. Transmission electron microscopy (TEM) images show that tremendous amount of bundles SWCNT with uniform diameters were produced. The average diameter of bundles SWCNT is 1.22nm. Raman spectrum shows that well graphitized SWCNTs were formed based on the low ratio of ID/IG. Fe3O4 nanoparticles could be an effective active metal to synthesize large quantity bundles of SWCNT.
47
Frayère, Charlotte, Christophe Galindo, Laurent Divay, Michel Paté, and Pierre Le Barny. "Covalent Chemical Modification of Single-walled Carbon Nanotubes Using Azide Functionalised Anthraquinone Derivatives for Pseudocapacitor Application." MRS Proceedings 1549 (2013): 111–16. http://dx.doi.org/10.1557/opl.2013.965.
Full textAbstract:
ABSTRACTElectrodes made of single-walled carbon nanotubes (SWCNTs) chemically modified by a series of anthraquinone derivatives (AQ) have been prepared and characterized by cyclic voltammetry in 0.1M H2SO4, using the standard 3 electrode set-up and by Raman spectroscopy. It has been demonstrated that a AQ modified SWCNT electrode provided between 114 to 220% higher specific capacitance, compared to pristine SWCNT electrode, depending on the length of the spacer between SWCNT and AQ.
48
Raja, Esquenazi, Jones, Li, Brinson, Wright, Gowenlock, and Barron. "Electroless Deposition of Cu-SWCNT Composites." C — Journal of Carbon Research 5, no. 4 (October 7, 2019): 61. http://dx.doi.org/10.3390/c5040061.
Full textAbstract:
In this work, as-received HiPCO single walled carbon nanotubes (SWCNTs) are incorporated in a controllable manner at various concentrations into Cu-SWCNT composites via electroless plating, by varying the related reaction times, with polyethylene glycol (PEG) used as a dispersing agent. The resultant samples were analyzed using scanning electron microscopy (SEM) for morphology assessment, energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) for elemental analysis, X-ray diffraction (XRD) for the assessment of crystal phase identification, and Raman spectroscopy for the confirmation of the presence of the incorporated SWCNTs. The Cu-SWCNT composites were found to contain carbon, catalytic iron (associated with the raw, as-received SWCNTs), oxygen, and copper; the latter was found to be inversely proportional to carbon and iron contents. The oxygen (associated with both the SWCNT defect sites and oxidized copper surfaces) remained more or less constant regardless of the proportion of SWCNTs in the composites. The Raman IG:ID ratio remains within the experimental error constant, indicating that the electroless deposition does not have a deleterious effect on the SWCNTs. At short deposition times, SEM revealed a relatively dense structure comprising a distinctive fibrous morphology, suggestive of an underlying SWCNT substrate coated with copper; however, with increasing deposition, a more porous morphology is observed. The size of the granular particles increases up until 10 min of reaction, after which time it remains unchanged.
49
Sapkota, Kamal Prasad, Md Akherul Islam, Md Abu Hanif, Jeasmin Akter, and Jae Ryang Hahn. "Chemical Assembly of Copper Oxide and Single Walled Carbon Nanotubes for Enhanced Photocatalytic Dye Degradation under Solar Light Irradiation." Materials Proceedings 4, no. 1 (November 10, 2020): 18. http://dx.doi.org/10.3390/iocn2020-07790.
Full textAbstract:
We elaborate the synthesis and remarkable photocatalytic efficiency of a series of heterojunction nanocomposites with a cauliflower-like architecture composed of copper oxide (CuO) and single-walled carbon nanotubes (SWCNTs). The photocatalysts with such a peculiar design were constructed via facile recrystallization followed by calcination and were symbolized as CuO-SWCNT-1, CuO-SWCNT-2, and CuO-SWCNT-3, representing the components and calcination time in hours. The photocatalytic efficiency of the synthesized nanocomposite samples were investigated by evaluating the decomposition of methylene blue (MB) solution under natural sunlight exposure. All of the as-synthesized photocatalysts were substantially effectual for the photo-deterioration of MB solution. Moreover, CuO-SWCNT-3 revealed the top photocatalytic capability with 96% decomposition of MB solution in 2 h while being exposed to visible light. Pristine CuO nanocrystals and the SWCNTs were employed as controls, whereas the photocatalytic performance of the hetero-composites was significantly better than that of pure CuO as well as SWCNTs. The recyclability of the photocatalysts was also explored, and the results asserted that the samples could be reused for five cycles without being altered notably in photocatalytic performance or morphology.
50
Romashkin, Alexey V., Andrey V. Lashkov, Victor V. Sysoev, Nikolay S. Struchkov, Evgeny V. Alexandrov, and Denis D. Levin. "Energy-Efficient Chemiresistive Sensor Array Based on SWCNT Networks, WO3 Nanochannels and SWCNT-Pt Heterojunctions for NH3 Detection against the Background Humidity." Chemosensors 10, no. 11 (November 12, 2022): 476. http://dx.doi.org/10.3390/chemosensors10110476.
Full textAbstract:
Recently, promising results have been achieved in improving the sensitivity to ammonia in gas sensors through the use of structures composed of heterojunctions or nanochannels. However, their sensitivity is highly dependent on the background humidity under air conditions. The sensor structures which could ensure selective ammonia detection with a low detection limit, despite interference from changing background humidity, remain highly demanded. In this work, we consider sensing units containing (i) nanochannels formed by a continuous tungsten oxide nanolayer to appear in contact between single-walled carbon nanotubes (SWCNTs) and a Pt sublayer and (ii) SWCNT-Pt junctions in frames of mass-scale microelectronic technologies. SWCNTs were deposited by spray-coating on a thin WO3/Pt/W sublayer formed by a photolithographic pattern to be accompanied by satellite samples with just SWCNTs for reference purposes. We elucidate the specific differences that appeared in the response of sensors based on SWCNT-Pt junctions and WO3 nanochannels relative to satellite SWCNT samples with a similar SWCNT network density. Particularly, while a similar response to NH3 vapors mixed with dry air is observed for each sensor type, the response to NH3 is reduced significantly in the presence of background humidity, of 45 rel.%, especially in the case of WO3 nanochannel structures even at room temperature. A multisensor array based on the four various sensing structures involving SWCNT-Pt junctions, WO3 nanochannels, and their satellite-only-SWCNT ones allowed us to determine a correct ammonia concentration via utilizing the linear discriminant analysis despite the presence of background air humidity. Thus, such an energy-efficient multisensor system can be used for environmental monitoring of ammonia content, health monitoring, and other applications.