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- Carbon nanotubes
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Preparation of graphene oxide with large lateral size and graphene/polyimide hybrid film via in situ “molecular welding” strategy
摘要： In this letter, we report an "ultrasonication-free" direct exfoliation method to obtain graphene oxide with large lateral size (LGO). The average size of LGO sheets is about 50 lm * 50 lm. The g-LGO film shows a superior in-plane thermal conductivity after the graphitization treatment. Furthermore, the in situ "molecular welding", using polyimide (PI) to weld up the GO sheets, is conducted to improve the performance of hybrid thermal conducting film. The thermal conductivity of g-LGO/PI film is 1053.975 ± 8.762 W m-1 K-1, superior to that of the g-LGO film and g-SGO/PI. The direct preparation method to obtain GO with large lateral size, followed by such an in situ "molecular welding" strategy by PI, provides a promising way to fabricate graphene-based film for efficient thermal management.
关键词： Molecular welding,In situ polymerization,Large lateral size,Thermal properties,Carbon material
更新于2025-09-23 15:23:52
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Enhancing Diamond NV Center Density in HPHT Substrate and Epitaxy Lateral Overgrowth Layer by Tungsten Pattern
摘要： The Nitrogen Vacancy (NV) center distribution in epitaxial lateral overgrowth (ELO) single crystal diamond layer grown on tungsten patterned HPHT substrate by microwave plasma chemical vapor deposition (CVD) system has been investigated. It has been found that in ELO diamond layer densities of NV0 and NV- center above the tungsten metal are enhanced. Meanwhile, in patterned high-pressure and high-temperature (HPHT) substrate the density of NV- center beneath the tungsten metal is much higher than that of NV0. The HPHT substrate doesn't contain NV centers before CVD growth, and there is almost no NV center in the region without tungsten metal after growth.
关键词： Defects,Carbon materials,Epitaxial growth,Luminescence,Crystal growth
更新于2025-09-23 15:23:52
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One-pot synthesis of visible-light-driven photocatalyst for degradation of Rhodamine B: graphene based bismuth/bismuth(III) oxybromide
摘要： A ternary photocatalyst, graphene based bismuth modified bismuth(III) oxybromide (Bi/BiOBr/G), was synthesized via a facile one-step solvothermal method using only ethylene glycol as both solvent and reducing reagent. Bi/BiOBr/G exhibits higher photocatalytic activity than bismuth(III) oxybromide (BiOBr) on degradation of Rhodamine B under visible-light illumination, and the photodegradation rate is 4.9 times that of BiOBr. The enhanced photocatalytic activity is attributed to the synergistic effect among Bismuth, graphene and BiOBr, which can effectively promote the visible-light absorption of Bi/BiOBr/G and the separation of photogenerated charge carriers. The conditions influencing the photocatalytic performance of Bi/BiOBr/G were also investigated in detail, as well as the photocatalytic mechanism of the degradation.
关键词： Nanocomposites,Semiconductors,Carbon materials,Photocatalytic activity,Visible light
更新于2025-09-23 15:23:52
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New measurements of Mαβ, Mγ and total M-shell X-ray production cross sections induced by carbon ions on Bi and Pt targets
摘要： In this work X-ray and elastic backscattered spectra from Pt and Bi thin targets were simultaneously measured using C4,3+ ions in the energy range 2.5 MeV to 5 MeV. Mαβ, Mγ and total M-shell X-ray production cross sections were extracted from collected X-ray and backscattered particle spectra using calibrated SDD X-ray and silicon solid state particle detectors. The obtained cross section values are compared to theoretical values employing commonly used datasets for fluorescence yields, emission rates, Coster-Kronig transitions and M-shell ionization cross sections based on the Semi-classical Approximation (United Atom and Separated Atom limits), PWBA (Plane Wave Born approximation), and ECPSSR models. The ISICS code was used for PWBA and ECPSSR calculations.
关键词： Carbon ions,M-shell cross section,SCA (UA and SA),Pt,Bi
更新于2025-09-23 15:23:52
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Highly conductive, transparent and metal-free electrodes with a PEDOT:PSS/SWNT bilayer for high-performance organic thin film transistors
摘要： Conductive organic materials including polymers, small molecules, and carbon nanotubes (CNTs) are a promising alternative to inorganic materials in electronic devices. Conventionally, organic electrodes employing CNTs are designed using functionalization of their surfaces or formation of nanocomposites with a conductive polymer. However, phase separation limits the concentration of CNTs in a polymer matrix, hindering the formation of highly dense CNT networks and leading to poor electrical conductivity. In this paper, we introduce bilayer electrodes comprising poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and single-walled CNTs (SWNTs) chemically modified by HNO3 treatment. Impressive conductivities of 2432 and 2438 S cm?1 are found for the SWNT/PEDOT:PSS (S/P) and PEDOT:PSS/SWNT (P/S) electrodes, respectively. Further, an increase in the work function of the electrodes after HNO3 treatment lowers the hole injection barrier, which facilitates hole injection from pentacene. The smooth surface of PEDOT:PSS also contributes to growth of large pentacene grains; consequently, the field-effect mobility of pentacene-based thin film transistors is 1.88 cm2 V?1 s?1 when the P/S electrode is employed. The metal-free electrodes also exhibit a high optical transparency of 88.7%, which suggests that they have great potential for applications in optoelectronics.
关键词： Electrode,PEDOT:PSS,Carbon nanotube,Pentacene,Thin film transistor
更新于2025-09-23 15:23:52
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Fracture strength of silicon torsional mirror resonators fully coated with submicrometer-thick PECVD DLC film
摘要： In this work, we attempted to enhance the torsional fracture strength of single crystal silicon (SCS) resonators for micro mirrors application by introducing a 300 nm-thick diamond-like carbon (DLC) coating. The SCS torsional beams of the resonators were 20 μm wide and 9 μm thick, and fully coated with DLC films using plasma enhanced chemical vapor deposition (PECVD) at three different deposition bias voltages. The resonators were driven by a piezoelectric actuator and their angular amplitude was measured by a custom-made torsional test system. Average nominal torsional fracture strength of DLC coated resonators was 11.1–30.0% higher than that of bare SCS, reaching a value of 2.93 GPa. The torsional fracture strength of resonators exhibited a good agreement with the tensile fracture strength. Deviations in torsional strength were reduced with increasing deposition bias voltage due to the compressive residual stress of DLC films.
关键词： Single crystal silicon,Micro mirror resonator,Diamond-like carbon film,Strength deviation,Torsional fracture strength
更新于2025-09-23 15:23:52
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Facile synthesis of two-dimensional tailored graphitic carbon nitride with enhanced photoelectrochemical properties through a three-step polycondensation method for photocatalysis and photoelectrochemical immunosensor
摘要： Graphitic carbon nitride (g-C3N4) is an ideal alternative two-dimensional (2D) nanostructure for photocatalysis and photoelectrochemical (PEC) application, while controllably fabricating 2D shaped g-C3N4 nanolayers/nanosheets is still facing challenges. On the basis of temperature-dependent polymorphic characters, herein, a 2D extending g-C3N4 (g-CNS3) is synthesized from dicyandiamide as the precursor by operating the condensation temperature in a continuously three-step thermal polycondensation procedure. The g-CNS3 with film-like morphology showed improved visible-light absorption ability and enhanced PEC performance compared to g-CNS1 synthesized via the traditional one-step thermal polymerization method. Benefiting from its excellent PEC properties, the g-CNS3 exhibited high photocatalytic activity to removal MB with fast kinetics and served as the photoactive layer to construct a PEC immunosensor with high sensitivity and specificity for subgroup J avian leukosis virus detection. A linear range from 102.14 to 103.35 TCID50/mL and a detection limit of 102.08 TCID50/mL were obtained for the PEC immunoassay of the target virus. This work might provide a novel protocol for tailoring shaped 2D g-C3N4 nanosemiconductor with superior properties and shed light on its promising PEC applications.
关键词： Two-dimensional material,Photocurrent response,Graphitic carbon nitride,Photocatalysis,Photoelectrochemical immunosensor
更新于2025-09-23 15:23:52
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Diamond like carbon films with embedded Cu nanoclusters deposited by reactive high power impulse magnetron sputtering: Pulse length effects
摘要： In the present study diamond like carbon films with embedded Cu nanoclusters (DLC:Cu films) were deposited by reactive high power impulse magnetron sputtering (HIPIMS). HIPIMS pulse length (pulse on time) effects were considered. The dependence of the chemical composition on pulse length was found. Structure of diamond like carbon matrix of the nanocomposite films studied by Raman scattering spectroscopy has indicated weak increase of the sp3/sp2 carbon bond ratio with HIPIMS pulse length. Studies of the shape and dimensions of copper nanoclusters performed by He ion microscopy have shown that increase of the HIPIMS pulse on time resulted in increased number of the nanoclusters and subsequent increase of the Cu nanoclusters size. Study of optical properties revealed surface plasmon resonance effect in all investigated films. Correlation between the optical absorption spectra and photoexcited charge carrier relaxation time recorded by the pump probe spectroscopy was found. The highest relaxation time was observed at the excitation wavelength close to the absorption surface plasmon resonance peak wavelength The highest maximum relaxation time was observed for the DLC:Cu film deposited by using HIPIMS pulse of 400 μs on time. It was explained by the dependence of the relaxation time on Cu nanocluster size.
关键词： Pulse length,Diamond-like carbon,High-power pulsed magnetron sputtering,Structure,Optical properties,X-ray photoelectron spectroscopy,Copper,Nanoclusters
更新于2025-09-23 15:23:52
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Heterobimetallic (Fe <sup>II</sup> /Pt <sup>II</sup> )-Based Supramolecular Coordination Complexes Using 1,1′-Ferrocene Dicarboxylate: Self-Assembly and Interaction with Carbon Dots
摘要： The synthesis and characterization of a new pyrazine-based ditopic organoplatinum(II) complex having a bite angle of 180° is reported. The facile and efficient syntheses are described of three discrete neutral Fe(II)/Pt(II) heterobimetallic SCCs with Pt(II) acceptor clips of different binding angles, 0, 120, and 180°. These new SCCs were characterized by multinuclear NMR and mass spectrometry. Electrochemical response of these ferrocene containing self-assembled ensembles was studied using cyclic voltammetry. The diplatinum acceptor organometallic clips significantly quench the fluorescence of highly emitting carbon quantum dots (CD), while the self-assembled macrocycles tend to nullify the quenching effect of the organometallic clips. Interestingly, the inefficient quenching of CD fluorescence by these SCCs was found to be directly related to the angular disposition of the binding sites in the Pt(II) based organometallic clips.
关键词： carbon dots,heterobimetallic,electrochemical response,self-assembly,supramolecular coordination complexes,fluorescence quenching,ferrocene
更新于2025-09-23 15:23:52
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Fullerene-to-MWCNT Structural Evolution Synthesized by Arc Discharge Plasma
摘要： The growth of multi-walled carbon nanotubes (MWCNTs) has been extensively studied using electron microscopy. The ex situ structural behavior was examined to investigate the growth of the MWCNTs under different environments and pressures using electron microscopy. The arc discharge plasma technique was applied to synthesize the MWCNTs by evaporating carbon through the arc plasma between two cylindrical graphite rods, with a background pressure of 10?2 to 102 mbar, inside a vacuum chamber under different ambient environments. The results showed that long MWCNT structures were successfully grown. We suggest that the mechanism involves: (i) fullerene formation; (ii) the elongation of fullerenes; and (iii) the growth of MWCNTs. Agglomeration with other structures then forms MWCNT bundles. We note that the pressure and environment in the vacuum chamber can affect the structure of the MWCNTs.
关键词： arc discharge,electron microscopy,carbon nanotube,nanostructured
更新于2025-09-23 15:23:52