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Efficient Singlet Fission in a Pentacene-Based Nanotube
摘要： Angew. Chem. Int. Ed. 2019, DOI: 10.1002/anie.201812976.
关键词： pentacenes,singlet fission,nanotubes
更新于2025-09-19 17:15:36
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On the nanoscale behaviour of single-wall C, BN and SiC nanotubes
摘要： The paper presents a numerical study of defect-free single-wall carbon, boron nitride and silicon carbide armchair and zigzag nanotubes, through a simple stick-and-spring model, based on Morse and cosine potential functions. The study investigates the relaxed configuration of the tubes and gives a comprehensive evaluation of their elastic constants, which is performed by framing tensile, torsional and radial tests within the membrane behaviour of a Donnell thin shell model. Extensive comparisons with reference ab-initio results are given and used to refine some parameters of the potential functions for hexagonal silicon carbide nanomaterials.
关键词： ab-initio comparisons,mechanical behavior,elastic constants,stick-and-spring model,nanotubes
更新于2025-09-19 17:15:36
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Effect of thermal condensation temperature on electrochemical capacitive properties of g-C3N4 supported on reduced TiO2 nanowires/nanotubes array
摘要： In this work, effect of processing temperature in electrochemical capacitors was investigated for g-C3N4. The g-C3N4 materials (CN) were synthesized by thermal condensation of melamine precursor at different temperature (450, 550 and 650 °C). Then, the g-C3N4 materials were deposited on electrochemically reduced TiO2 nanowires/nanotubes arrays (rTWTA)/Ti substrate. The g-C3N4/rTWTA/Ti electrodes were used as supercapacitor electrodes. Morphology, crystal structure and chemical composition of the g-C3N4/rTWTA/Ti electrodes were studied by FESEM, XRD, FTIR and elemental analysis. Based on galvanostatic charge/discharge measurements, the CN(450)/rTWTA/Ti electrode exhibited the highest specific capacitance up to 22 mF/cm2 at 0.3 mA/cm2 with long cyclic durability at 96.8% capacitance retention after 500 cycle. This effect was attributed to the existence of higher nitrogen content, more active sites, the improved hydrophilicity and three-dimensional morphology of the CN(450)/rTWTA/Ti electrode as compared to the other electrodes. This research introduces the optimum thermal condensation temperature of the melamine for synthesis of the g-C3N4 with great potentials in supercapacitors.
关键词： Supercapacitor,TiO2 nanowires/nanotubes array,Processing temperature,g-C3N4,Specific capacitance
更新于2025-09-19 17:15:36
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Why it is so hard to detect Luttinger liquids in angle resolved photo-emission spectroscopy?
摘要： The problem of photoemission from a quasi-1D material is studied. We identify two issues that play a key role in the detection of gapless Tomonaga–Luttinger liquid (TLL) phase. Firstly, we show how a disorder—backward scattering as well as forward scattering component—is able to significantly obscure the TLL states, hence the initial state of angle resolved photo-emission spectroscopy (ARPES). Secondly, we investigate the photo-electron propagation towards a sample’s surface. We focus on the scattering path operator contribution to the final state of ARPES. We show that, in the particular conditions set by the 1D states, one can derive an exact analytical solution for this intermediate stage of ARPES. The solution shows that for particular energies of incoming photons the intensity of photo-current may be substantially reduced. Finally, we put together the two aspects (the disorder and the scattering path operator) to show the full, disruptive force of any inhomogeneities on the ARPES amplitude.
关键词： nanotubes,Fresnel diffraction,quasi-1D materials,disorder,ARPES,Tomonaga–Luttinger liquids
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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Ag-La loaded protonated carbon nitrides nanotubes (pCNNT) with improved charge separation in a monolithic honeycomb photoreactor for enhanced bireforming of methane (BRM) to fuels
摘要： Well-designed Ag-La modified protonated graphitic carbon nitride nanotubes (pCNNT) are fabricated via a template-free sonicated assisted one-pot hydrothermal method. The structure and properties of the catalyst samples are obtained by XRD, SEM, TEM, EDX, N2-sorption, XPS, UV-Vis DRS and PL spectroscopy characterization techniques. The effect of Ag-La-modified pCNNT is evaluated for different CH4 reforming processes such as dry reforming of methane (DRM) and bi-reforming of methane (BRM), carried out in a fixed-bed and monolithic honeycomb photoreactor systems under UV and visible light irradiations. The optimized 3%Ag-5%La/pCNNT performance displayed increased productivity under UV-light due to more production of charges with strong ability for cleaving both stable CO2 and CH4 molecules. More importantly, the performance of Ag-La loaded pCNNT is 1.45 and 2.10 folds higher for CO and H2 production, respectively compared with Ag-La loaded pCN nanosheets. CO and H2 evolutions prevailed in a monolith photoreactor compared to fixed-bed reactor. Besides, the amount of CO, H2 and CH3OH are 1.79, 2.12 and 2.13 folds higher in BRM compared to DRM. The improved performance can be ascribed to effective interfacial carrier separation due to Ag-La synergistic effect with suitable redox potentials for BRM process. The quantum yield is significantly enhanced with BRM in the monolithic honeycomb photoreactor loaded with Ag-La modified pCNNTs due to greater photon energy utilization, larger illuminated surface area, improved sorption process and surface reactions with efficient charge carrier utilization for CO2 reduction and CH4/H2O oxidation. Reaction mechanism is proposed to commensurate with the performance of Ag-La/pCNNT for BRM process based on characterization analysis and experimental results. The experimental results could provide guidance for further development of advanced and highly efficient hetero-structures for photocatalytic BRM applications.
关键词： Synthesis gas (CO/H2),Monolithic structure,Photocatalytic dry reforming,pCN nanotubes,Bi-reforming
更新于2025-09-19 17:15:36
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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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An Efficient Room Temperature Ethanol Sensor Device Based on p-n Homojunction of TiO <sub/>2</sub> Nanostructures
摘要： In this paper, an efficient room temperature ethanol sensor device based on p-n homojunction of p-TiO2 nanoparticles (NPs) and n-TiO2 nanotubes (NTs) is reported. p-TiO2 NPs were prepared by low-temperature sol–gel method and coated on n-TiO2 NTs (NPs) grown by electrochemical anodization. Field emission scanning electron microscopy and X-ray diffraction authenticated the formation of stable homojunction between p-type anatase TiO2 NPs and n-type anatase TiO2 NTs. Current–voltage characteristics of the device, in the lower voltage range (0–1.26 V) for 30 °C, followed nonlinear characteristics (Schottky). With increase in voltages (>1.26 V) and temperature (40 °C–100 °C) such nonlinear behavior moves toward more linear ones. The gas sensing performance of the homojunction device was studied at room temperature with alcohols as the test species. The device offered the maximum response magnitude of ～57% (toward ethanol) at 100 ppm with appreciably fast response time and recovery time of ～30 and ～16 s, respectively. Dramatic increase in the effective depletion region area distributed throughout the nanotubular voids and the associated localized electric filed originated from the electrostatic charge separation therein (which helps in easy dissociation of target species) is possibly responsible for such efficient room temperature sensing performance.
关键词： room temperature,Ethanol sensing,fabrication and characterization,p-TiO2 nanoparticles (NPs)/n-TiO2 nanotubes (NTs),homojunction
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