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Multi-Walled Carbon Nanotubes/BiPO <sub/>4</sub> /BiOI Heterostructure Composite Photoelectrochemical Sensor in Detection of Salicylic Acid
摘要： In this work, BiOI, BiPO4, BiPO4/BiOI (M) and MWCNT/BiPO4/BiOI(MWCNT/M) heterostructure were synthesized through hydrothermal methods and served the function of fabricating photoelectrochemical (PEC) sensor for detection of Salicylic acid (SA). MWCNT covered with BiPO4/BiOI were observed with the aid of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Under visible light excitation, the low detection limit of 0.55 μM and working range of 1–320 μM and 480–3840 μM were obtained at the MWCNT/M/ITO. Moreover, it has excellent reproducibility and long-term stability. Meanwhile, results suggest that MWCNT/M developed herein offers a promising platform for the ultrasensitive detection of SA.
关键词： Multi-Walled Carbon Nanotubes,BiPO4/BiOI Heterostructure,Photoelectrochemical Sensor,Salicylic Acid
更新于2025-09-23 15:19:57
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Light-Induced Sulfur Transport inside Single-Walled Carbon Nanotubes
摘要： 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.
关键词： X-Ray spectroscopy,encapsulation,illumination,single-walled carbon nanotubes,sulfur,de-encapsulation
更新于2025-09-23 15:19:57
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Experimental observation of bound states of Q-switched fiber lasers mode-locked by carbon nanotubes
摘要： We demonstrate the experimental observation of bound states of Q-switched lasers mode-locked by carbon nanotubes. When bound states of Q-switched mode-locked lasers are formed, the Fourier transformation results into multiwavelength spectrum due to the small temporal interval induced by polarization controller. We find that the wavelength spacing is highly sensitive to pump power. A wavelength spacing tuning from ~0.057 nm to 1.569 nm with a pump power variation less than 4 mW is obtained. The wavelength spacing is also highly sensitive to the nonlinear phase induced by polarization controller. These findings enrich our understanding about the complex dynamics of the Q-switched mode-locked lasers.
关键词： carbon nanotubes,bound states,mode-locked,nonlinear phase,Q-switched fiber lasers
更新于2025-09-23 15:19:57
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Machine Learning Identification of the Sensing Descriptors Relevant in Molecular Interactions with Metal Nanoparticle-Decorated Nanotube Field-Effect Transistors
摘要： Carbon nanotube-based field-effect transistors (NTFETs) are ideal sensor devices as they provide rich information regarding carbon nanotube interactions with target analytes and have potential for miniaturization in diverse applications in medical, safety, environmental, and energy sectors. Herein, we investigate chemical detection with cross-sensitive NTFETs sensor arrays comprised of metal nanoparticle-decorated single-walled carbon nanotubes (SWCNTs). By combining analysis of NTFET device characteristics with supervised machine learning algorithms, we have successfully discriminated among five selected purine compounds – adenine, guanine, xanthine, uric acid, and caffeine. Interactions of purine compounds with metal nanoparticle-decorated SWCNTs were corroborated by density functional theory (DFT) calculations. Furthermore, by testing a variety of prepared, as well as commercial solutions with and without caffeine, our approach accurately discerns the presence of caffeine in 95% of the samples with 48 features using a linear discriminant analysis (LDA) and in 93.4% of the samples with only 11 features when using a support vector machine (SVM) analysis. We also performed recursive feature elimination and identified three NTFET parameters – transconductance, threshold voltage, and minimum conductance – as the most crucial features to analyte prediction accuracy.
关键词： support vector machine,linear discriminant analysis,sensor arrays,graphene,carbon nanotubes
更新于2025-09-23 15:19:57
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The technique of visualization and evaluation of the emission site distribution for large area field emitters
摘要： This paper presents a method for online treatment of the distribution pattern of emission sites on the emitter surface, combined with a multichannel registration and processing system of the IVC. Using computerized field emission projector we have studied nanocomposite emitter based on carbon nanotubes "Taunit M" and polystyrene. The distribution pattern of emission sites over the brightness level was obtained as well as the emission area of the sample was determined. Time dependences of the current level, the total brightness and the emission area were registered.
关键词： field emission,emission area,emission sites distribution,carbon nanotubes,nanocomposite emitter
更新于2025-09-23 15:19:57
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Optimizing and adjusting the photoluminescence of Mn <sup>4+</sup> -doped fluoride phosphors <i>via</i> forming composite particles
摘要： The occurrence of para-chloronitrobenzene (PCNB) in the environment due to increased agricultural and economic activities worldwide has raised serious concerns to human health and various environmental agencies, thus the qualitative and quantitative detection of PCNB is of great significance. In this work, a novel three-dimensional nanohybrid composed of carbon nanohorns and carbon nanotubes (CNHs-CNTs) was prepared via a simple ultrasonication process, and then, the obtained CNHs-CNTs nanohybrids were used to modify electrode for the electrochemical sensing of PCNB. Under the optimized conditions, the result showed that the CNHs-CNTs nanohybrids could exhibit electrochemical sensing performances toward PCNB detection due to the synergetic properties from CNHs and CNTs, and a wide linear range from 0.1 to 70.0 μM coupled with a low detection limit of 5.9 nM were obtained for the determination of PCNB. Finally, the developed method was successfully applied in the determination of PCNB in real water samples.
关键词： carbon nanotubes,carbon nanohorns,Electrochemical sensor,para-nitro chlorobenzene.
更新于2025-09-19 17:15:36
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Application of Raman Spectroscopy for Analysis of Carbon Nanotube Distribution in Living Cells
摘要： We have used Raman spectroscopy combined with confocal microscopy to study suspensions of single-wall and double-wall carbon nanotubes of different lengths and also multiwall carbon nanotubes. We have shown that the intensity of the G mode in the Raman spectrum of carbon nanotubes is directly proportional to the nanotube concentration, the exposure time, the exciting radiation power, and depth of focus in the transparent sample under study. We have established that the Raman spectra of longer carbon nanotubes (~1 μm) are characterized by higher intensity of the G mode compared with short carbon nanotubes (~250–450 nm). The dependences obtained were used to determine the local intracellular concentration of carbon nanotubes within the waist of the exciting laser beam, with the aim of mapping the carbon nanotube distribution inside the cells.
关键词： carbon nanotubes,local concentration,Raman spectroscopy,intracellular distribution,glioma cells
更新于2025-09-19 17:15:36
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Dielectric and Piezoelectric Properties of Composite Poly(vinylidene fluoride-trifluoroethylene) Copolymer with Carbon Nanotubes
摘要： Film samples of poly(vinylidene fluoride-trifluoroethylene) copolymer containing 2% of carbon nanotubes were synthesized. The temperatures of the ferroelectric phase transition and the value of permittivity at the frequency of 1 MHz were determined. The surface was visualized using scanning probe microscopy; the values of the effective piezoelectric coefficient were obtained. It was shown that incorporation of carbon nanotubes into the polymer matrix improves the values of the permittivity and piezoelectric coefficient of the polymer.
关键词： permittivity,copolymer,piezoelectric coefficient,carbon nanotubes
更新于2025-09-19 17:15:36
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Flash Sintering Samaria-Doped Ceria–Carbon Nanotube Composites
摘要： Composite ceramic green pellets were prepared by attrition milling a mixture of (CeO2)0.8(Sm2O3)0.2 (samaria-doped ceria, SDC) ceramic powder and carbon nanotubes (CNTs), followed by uniaxial and isostatic pressing. The pellets were sintered inside a dilatometer by applying AC electric fields at 850 °C and limiting the electric current to 1 A, achieving 20.2% final shrinkage. The SDC samples reached 13.3% shrinkage under the same conditions. Higher average grain sizes were measured in specimens flash sintered with CNTs. Impedance spectroscopy analyses show that the specimens flash sintered with addition of CNTs have higher electrical conductivity. Higher delivered Joule heating at the interfaces due to the presence of the electronic conductors (CNTs) are proposed as the main reason for that improvement of the electrical behavior.
关键词： flash sintering,solid electrolytes,carbon nanotubes,impedance spectroscopy,samaria-doped ceria
更新于2025-09-19 17:15:36
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Raman Spectroscopy as an Assay to Disentangle Zinc Oxide Carbon Nanotube Composites for Optimized Uric Acid Detection
摘要： Refluxed zinc oxide (ZnO) nanoparticles (NPs) were prepared and attached to carboxylic acid functionalized multi-walled carbon nanotubes (COOH-MWNTs) via sonication. Practical optimization of electrocatalysts using sonication to disentangle a carbon nanotube composite for monitoring uric acid (UA) is shown. Monitoring UA is important for the management of medical disorders. Selection of sonication time is a crucial step in producing the desired composite. We report, for the first time, the practical use of Raman spectroscopy to tune the sonication involved in tethering ZnO NPs to the multi-walled carbon nanotube (MWNT) surface. Maximum current for detecting UA, using chronoamperometry and cyclic voltammetry, correlated with the highest sp2-hybridized carbon signal, as seen in the integrated Raman G band peak areas denoting maximum COOH-MWNT disentanglement. An array of ZnO/COOH-MWNT composites were prepared ranging from 60 to 240 min sonication times. Optimum sonication (150 min) corresponded with both maximum measured current and MWNT disentanglement. The sensor was able to quantitatively and selectively measure UA at clinically relevant concentrations (100–900 μM) with rapid current response time (< 5 s).
关键词： chronoamperometry,zinc oxide nanoparticles,Raman spectroscopy,cyclic voltammetry,multi-walled carbon nanotubes,electrochemical sensing
更新于2025-09-19 17:15:36