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A spark discharge generator for scalable aerosol CVD synthesis of single-walled carbon nanotubes with tailored characteristics
摘要： We have designed and built an exhaust-free spark discharge generator for robust aerosol CVD synthesis of single-walled carbon nanotubes. The systematic study has shown the generator to provide a facile and repeatable route to precisely control the size of the catalyst particle and, therefore, carbon nanotube growth. Using a comprehensive set of methods (the analysis of differential mobility of the aerosol particles, optical spectroscopy, scanning and transmission electron microscopy, Raman spectroscopy, and atomic force microscopy) we have revealed the relation between the defectiveness, length, diameter distribution of carbon nanotubes and specific features of a generator such as electrode characteristics (breakdown voltage, composition, and current) as well as the nature of the surrounding media (carrier gas nature, flow rate). The design used has resulted in separation of the nanoparticle formation and carbon nanotube nucleation processes. This provides a mutual independence of the growth parameters and the diameter distribution of the single-walled carbon nanotubes enhancing the scalability of the process. For instance, the breakdown voltage has been shown to have nearly zero effect on diameter and length distribution of carbon nanotubes produced while strictly governing the yield. We focus here on producing specifically short carbon nanotubes (l < 500nm) of pronounced defectiveness for drug delivery and transistor applications.
关键词： single-walled carbon nanotubes,differential mobility analyzer,catalyst activation,spark-discharge generator,aerosol CVD,floating bed reactor
更新于2025-11-14 17:03:37
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Targeting carbon nanotubes based on IGF-1R for photothermal therapy of orthotopic pancreatic cancer guided by optical imaging
摘要： Pancreatic cancer is one of the most lethal malignancies worldwide. The existing therapeutic regimen in the clinic for advanced inoperable carcinomas are far from satisfactory, thus it is urgent to seek more effective anticancer strategies. In the pursuit of novel, more effective interventions, photothermal therapy (PTT) based on nanomaterials has attracted increased attention. Recent advances in related fields have catalyzed the generation of novel nanoprobes, such as organic dyes, metal nanoparticles. However, organic dyes are poorly stable and easy to quench while metal nanoparticles with potential metal toxicity are difficult to degrade, both of which have low light-to-heat conversion efficiency, broad spectrum of anti-tumor effects, and lack of tumor targeting specificity. Single-walled carbon nanotubes (SWNTs) can remedy the above inadequacies. Herein, we report our water-soluble, bio-stable and low-toxicity SWNTs with excellent photothermal conversion efficiency. Specific modifications can enable visualization of the aggregate characteristics of SWNTs at the macroscopic or microscopic level in tumors. The dye-conjugated SWNTs bound with targeting antibodies that can induce them specifically targeting to pancreatic tumors for purposes of performing dyes imaging-guided cytotoxic PTT. PTT using this method achieves precise and excellent curative effects with minimal adverse effects, thus providing a promising strategy for anticancer therapy.
关键词： Single-walled carbon nanotubes,Imaging,IGF-1R,Pancreatic cancer,Photothermal therapy
更新于2025-09-23 15:23:52
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Comparison of experimental and theoretical methods for determining the emission area of multitip field cathodes
摘要： The experimental and theoretical methods for obtaining the values of the emitting surface are considered. The obtained values of the emission area from the experimental current-voltage characteristic are compared with those derived using theoretical calculations and computer simulation.
关键词： Fowler-Nordheim plots,emission area,current-voltage data analysis,single walled carbon nanotubes,glow patterns,multi-tip field emitter
更新于2025-09-23 15:21:21
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Electrochemiluminescence revealing that HNO3-oxidized single-walled carbon nanotubes are essentially tubular graphene quantum dot-nanoassemblies
摘要： Graphene quantum dots (GQDs) as recently emerging 0-D graphitic nanomaterials, have attracted much attention due to their unique optical, electrical and catalytic properties. However, some properties of GQDs, such as very small size, low density, and excellent water-solubility, make it difficult to be separated and immobilized. This may limit the recycle and purification of GQDs, and thus their applications in catalysis and sensing. In this work, we prepared tubular GQD-nanoassemblies (t-GQD-NAs) by etching single-walled carbon nanotubes (SWCNTs) with concentrated HNO3. The synthesized t-GQD-NAs were characterized by TEM, SEM, XPS, Raman spectroscopy and electrochemiluminescence (ECL) in details. t-GQD-NAs were much shorter and slimmer in morphology, bore more oxygen-containing groups, and had a higher surface defect density compared with SWCNTs. t-GQD-NAs not only maintained good UV absorption property of SWCNTs but also showed strong infrared ECL emission and broad ECL spectrum, verifying that t-GQD-NAs were assembled from GQDs of various sizes and some graphene nanoribbons. This is for the first time that 0-D GQDs were reported to be assembled into 1-D tubular carbon structures. The t-GQD-NAs with abundant surface states and good ECL activity could be easily separated, purified, and immobilized, suggesting their promising applications in ECL sensing and catalysis.
关键词： Graphene quantum dots,Single-walled carbon nanotubes,Electrochemiluminescence,Tubular graphene quantum dot-nanoassemblies
更新于2025-09-23 15:21:01
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Nonlinear Luttinger liquid plasmons in semiconducting single-walled carbon nanotubes
摘要： Interacting electrons confined in one dimension are generally described by the Luttinger liquid formalism, where the low-energy electronic dispersion is assumed to be linear and the resulting plasmonic excitations are non-interacting. Instead, a Luttinger liquid in one-dimensional materials with nonlinear electronic bands is expected to show strong plasmon–plasmon interactions, but an experimental demonstration of this behaviour has been lacking. Here, we combine infrared nano-imaging and electronic transport to investigate the behaviour of plasmonic excitations in semiconducting single-walled carbon nanotubes with carrier density controlled by electrostatic gating. We show that both the propagation velocity and the dynamic damping of plasmons can be tuned continuously, which is well captured by the nonlinear Luttinger liquid theory. These results contrast with the gate-independent plasmons observed in metallic nanotubes, as expected for a linear Luttinger liquid. Our findings provide an experimental demonstration of one-dimensional electron dynamics beyond the conventional linear Luttinger liquid paradigm and are important for understanding excited-state properties in one dimension.
关键词： single-walled carbon nanotubes,Nonlinear Luttinger liquid,infrared nano-imaging,plasmons,electronic transport
更新于2025-09-23 15:21:01
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ZnO/Ag NANOPARTICLE-DECORATED SINGLE-WALLED CARBON NANOTUBES (SWCNTs) AND THEIR PROPERTIES
摘要： Raw single-walled carbon nanotubes (SWCNTs) were oxidized by using sulfuric acid and nitric acid at 3:1 ratio to produce oxygen functional groups attached to SWCNTs surfaces. Then, the oxidized SWCNTs are coated with zinc oxide and silver nanoparticles by chemical precipitation route to synthesize ZnO/Ag-SWCNTs nanocomposite material. The nanocomposite sample was analyzed via zeta potential analyzer, ultraviolet-visible (UV-Vis) spectrophotometer, ˉeld emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), X-ray di?raction (XRD), and Raman spectroscopy to investigate colloidal stability, optical, morphological, and structural properties. The SWCNT properties were found to be changed after the addition of ZnO/Ag nanoparticles. Hence, the new ZnO/Ag-SWCNTs nanocomposite is a good candidate for photocatalyst applications and biological applications.
关键词： biological applications,photocatalyst applications,Single-walled carbon nanotubes (SWCNTs),ZnO/Ag nanocomposite,chemical precipitation
更新于2025-09-23 15:21:01
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Nonresonant Polarized Raman Spectra Calculations of Nitrogen-Doped Single-Walled Carbon Nanotubes: Diameter, Chirality, and Doping Concentration Effects
摘要： Raman spectra of nitrogen-doped single-walled carbon nanotubes are calculated using the spectral moment’s method combined with the bond polarizability model. The influence of the nanotube diameter and chirality is investigated. We also address the important question of the effect of the N-doping concentration, and we propose an equation to estimate the doping concentration from the knowledge of the tube diameter and the frequency of the radial breathing mode.
关键词： spectral moment’s method,Raman spectra,N-doping concentration,nanotube diameter,nitrogen-doped single-walled carbon nanotubes,bond polarizability model,chirality
更新于2025-09-23 15:21:01
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Many-particle excitations in non-covalently doped single-walled carbon nanotubes
摘要： Doping of single-walled carbon nanotubes leads to the formation of new energy levels which are able to participate in optical processes. Here, we investigate (6,5)-single walled carbon nanotubes doped in a solution of hydrochloric acid using optical absorption, photoluminescence, and pump-probe transient absorption techniques. We find that, beyond a certain level of doping, the optical spectra of such nanotubes exhibit the spectral features related to two doping-induced levels, which we assign to a localized exciton X and a trion T, appearing in addition to an ordinary exciton E1. We evaluate the formation and relaxation kinetics of respective states and demonstrate that the kinetics difference between E1 and X energy levels perfectly matches the kinetics of the state T. This original finding evidences the formation of trions through nonradiative relaxation via the X level, rather than via a direct optical excitation from the ground energy state of nanotubes.
关键词： exciton,doping,optical absorption,pump-probe transient absorption,photoluminescence,trion,single-walled carbon nanotubes
更新于2025-09-23 15:19:57
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Silsesquioxane-Polythiophene Hybrid Copolymer as an Efficient Modifier for Single-Walled Carbon Nanotubes
摘要： One silsesquioxane-polythiophene hybrid copolymer, with combined star-like structure and intramolecular heterogeneity, was synthesized and sufficiently characterized via various methods, including FTIR, NMR, and SEC measurements. According to the exploration and characterization results, it was much more efficient at modifying SWNTs than its linear analogs in aqueous solution. The hydrophobic silsesquioxane core and PEDOT chains could locally anchor to the surface of the nanotubes, while the soluble flexible copolymer chains extended into the solution and rigid conjugated chains provided some π-π stacking effect to enhance adhesive force with the conjugated structure of the carbon nanotube, imparting steric stabilization to nanotube dispersion. The noncovalent interaction with SWNTs and solubility in aqueous solution improved the electrochemical characteristics of the modified-SWNT composite and availed for the preparation of a flexible and transparent electroactive film. Accordingly, this kind of silsesquioxane-polythiophene hybrid copolymer will be forwarded to apply to the assembling of flexible optoelectronic devices.
关键词： silsesquioxane-polythiophene hybrid copolymer,single-walled carbon nanotubes,noncovalent modification,electrochemical characteristics,aqueous solution
更新于2025-09-23 15:19:57
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Effect of purification on the electrical properties of transparent conductive films fabricated from single-walled carbon nanotubes
摘要： Transparent conductive films (TCFs) made of single-walled carbon nanotubes (SWCNTs) are usually fabricated using highly pure SWCNTs. Obtaining pure SWCNTs is an important step for harnessing their excellent electrical properties. Herein, we studied the effect of purification of SWCNTs by thermal and acid processes on the electrical properties of TCFs. These purification processes also affected the length and diameter of the SWCNT bundles. The purity of SWCNTs was determined by UV–visible-near-infrared spectroscopy and the metal content by thermogravimetric analysis. TCFs were made by spraying aqueous suspensions of SWCNTs having different purities onto polyethylene terephthalate substrates, and the ratios of dc to optical conductivities of the films were compared. Thermally purified (TP) SWCNT TCFs had a higher ratio than thermally and acid-purified (TAP) ones even though the purity of the TP-SWCNTs was lower than that of the TAP-SWCNTs. The conducting paths of the SWCNT bundle networks in the TP-SWCNT TCFs were well organized, because nanosized graphitic nanoparticles and metal catalysts occupied the spaces between the CNT bundles or networks without hindering the network connections. Although the SWCNT purity affected the conductivity of the SWCNT TCFs, the network property of lower junction resistance with smaller bundle diameter was more influential on film conductivity.
关键词： Transparent conductive films,Film network morphology,Purification,Single-walled carbon nanotubes,Purity evaluation
更新于2025-09-23 15:19:57