- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2018
- energy distribution
- graphene edge
- vacuum transistor
- Field emission
- Optoelectronic Information Science and Engineering
- Naval Research Laboratory
- KeyW Corporation
- Pohang University of Science and Technology (POSTECH)
-
Silver Nanostructures on Graphene Oxide as the Substrate for Surface-Enhanced Raman Scattering (SERS)
摘要： Nanosized surface-enhanced Raman scattering (SERS) substrates fabricated by the controlled growth of metal nanostructures on water-dispersed two-dimensional nanomaterials can open a new avenue for SERS analysis of liquid samples in biological fields. In this work, regular and uniform Ag nanostructures were grown on the surface of graphene oxide (GO) through a microwave-assisted hydrothermal method. Polyamidoamine (PAMAM) dendrimers were assembled on the surface of GO to form GO/PAMAM templates for growing Ag nanostructures, which are primarily comprised of Ag dimers and trimers. The prepared Ag/GO nanocomposites are highly dispersed and stable in aqueous solution and may be used as substrates for enhanced Raman detection of rhodamine 6 G (R6G) in aqueous solution. This special substrate provides high-performance SERS and suppresses R6G fluorescence in aqueous solution and is promising as a nanosized material for the enhanced Raman detection of liquid samples in biological diagnostics.
关键词： graphene oxide (GO),Surface-enhanced Raman scattering (SERS),polyamidoamine (PAMAM) dendrimers,transmission electron microscopy (TEM),Fourier transform infrared (FTIR) spectroscopy,rhodamine 6G (R6G)
更新于2025-09-23 15:23:52
-
Reconfigurable metasurface lens based on graphene split ring resonators using Pancharatnam–Berry phase manipulation
摘要： A reconfigurable graphene based metasurface is presented to controllably focus a circularly polarized incident plane wave. The unit cell of the proposed metasurface consists of split ring resonators on both sides of a dielectric layer. The required phase shift for focusing purpose is achieved by concurrent rotation of the elements to obey to the Pancharatnam–Berry concept. Convergence/Divergence of the transmitted wave can be controlled by handedness of the impinging plane wave and direction of the elements’ rotation. The operating frequency of the designed lens and its focal length can be adjusted by properly exploiting to the unique property of graphene, i.e. by tuning its chemical potential.
关键词： metasurface,Graphene,Pancharatnam–Berry phase,reconfigurable lens
更新于2025-09-23 15:23:52
-
Graphene electrode diagnostic with IR imaging of Joule heat emission
摘要： Conductive graphene electrode of large area is required for some applications like for example photovoltaics or touch screens. Such large area graphene membrane needs specific test methods to assess defects which may obstacle its performance. In this work the infrared imaging of Joule heated graphene was proposed to estimate its uniformity and mechanical continuity. Thermal signatures of the typical mechanical defects like scratches and local resistivity inhomogeneity were identified. Distribution of the heat emission around such defects were simulated using finite elements method and then experimentally verified by recording of thermal landscape around the corresponding real graphene defects. Proposed method gives micrometric resolution and ability to inspection of large area electrodes depending on applied optics. Presented results give suggestions how graphene imperfections generate observed hot points related to graphene layer defects.
关键词： Finite elements,Joule heat,Defect,Graphene,Infrared
更新于2025-09-23 15:23:52
-
Scalable modulation of reduced graphene oxide properties via regulating graphite oxide precursors
摘要： Here we demonstrate the scalable modulation of reduced graphene oxide (RGO) properties by regulating graphite oxide (GtO) precursors. Our findings show the thickness and loose degree of GtO precursors act as key roles in flame activation process. Interestingly, the looser GtO transforms into RGO with a lower specific surface area (SSA); RGO from the thinner GtO paper shows a higher SSA. By regulating GtO precursors, SSA from 1030.5 to 335.3 m2 g?1, defect degree, oxidation degree, and pore volume from 4.61 to 1.36 cm3 g?1 can be tuned. The corresponding structural properties are translated into unique supercapacitor (SC) performances such as high specific capacitance (the highest value of 576 F g?1) and coulombic efficiency. Additionally, this method indicates great potential to prepare RGO-based metal oxide composites with good homogeneity and good SC behaviors.
关键词： Flame,Energy efficiency,Reduced graphene oxide,Precursor,Supercapacitor
更新于2025-09-23 15:23:52
-
Ultraviolet-light-assisted heterogeneous Fenton reaction of Ag-Fe3O4/graphene composites for the degradation of organic dyes
摘要： In this study, Fe3O4/graphene and Ag-Fe3O4/graphene composites with varying content of graphene and Ag were prepared and used as a heterogeneous Fenton catalyst for the degradation of MO and MB under UV-light irradiation. The physicochemical properties of the obtained catalysts were used for the Fenton reaction. In addition, the effects of graphene and Ag content, pH, H2O2 concentration, catalyst loading, and initial MO and MB concentrations on the degradation by the UV-Fenton process were evaluated. Results revealed that the highest removal efficiency of MO and MB is achieved at graphene and Ag concentrations of 10 and 25 wt%, respectively. Furthermore, Ag-Fe3O4/graphene composites were used to assess the degradation of a mixture of MO and MB and other anionic and cationic dyes. Results revealed that Ag-Fe3O4/graphene composites can be used as a broad-spectrum catalyst with good efficiency for the removal of several dye contaminants in water. Moreover, the effect of the addition of ascorbic acid (AA) on dye degradation was investigated. AA accelerated the degradation of organic dyes compared to that without AA. The obtained results revealed that Ag-Fe3O4/graphene composites exhibit stable catalytic activity and reusability after four successive runs.
关键词： Heterogeneous Fenton reaction,Organic dyes,Ag/Fe3O4/graphene
更新于2025-09-23 15:23:52
-
Limitations of graphene nanocoated optical tapers for high-power nonlinear applications
摘要： In this letter, we investigate the limitations of graphene as a saturable absorber for high-power nonlinear optical applications. The response of graphene nanocoated optical tapers against the average optical power injected is tested. We point out that the power handled by such components is limited and their nonlinear properties are strongly and permanently modified when exposed to high optical power. The origin of the degradation of the components is discussed.
关键词： nonlinear optics,mode-locking,fiber laser,Graphene,optical tapers
更新于2025-09-23 15:23:52
-
Effect of Au2Cl6 Doping on Stability and Work Function of Graphene
摘要： The first-principles method based on the density functional theory are used to study the work function and stability of the bilayer graphene doped with the Au2Cl6. The results show that the Au2Cl6 interlayer doping, like the common surface doping method, significantly increases the work function of graphene and successfully obtains p-type graphene. In addition, p-type graphene obtained by interlayer doping has better stability than surface doping. Considering the poor stability is a major problem faced in the practical application of surface-doped p-type graphene, this study shows that the interlayer doping of Au2Cl6 is a promising preparation method for p-type graphene.
关键词： first principle,graphene,Au2Cl6 molecule,work function
更新于2025-09-23 15:23:52
-
How doping configuration affects electron transport in monolayer zigzag graphene nanoribbon
摘要： The electrical conductance of hybrid monolayer graphene/h-BN ribbon with zigzag edges is numerically investigated using density functional theory. Our findings reveal that transmission of graphene/h-BN hybrid structure is sensitive to the arrangement of its component. The result also shows that replacing carbon atoms with boron and nitrogen totally reduces the transmission. Three different arrangement of BN domains have been investigated: replacing carbon atoms with boron and nitrogen in the transport direction, perpendicular to the transport direction and diagonal direction. We find that combination of many factors such as edge effect, additional charge carrier, interface of BN and carbon domains can alter transmission significantly.
关键词： Density functional theory,Doping configuration,Graphene/h-BN hybrid,Electronic transport
更新于2025-09-23 15:23:52
-
Quantum regime for dielectric Cherenkov radiation and graphene surface plasmons
摘要： In this article, we propose a quantum regime for Cherenkov free-electron laser (CFEL) and surface plasmon polaritons (SPPs) excited in dielectric and multilayer graphene waveguides, respectively. This quantum regime is realized when the momentum spread induced in the interaction is smaller than the photon recoil. The discrete momentum exchange characterizing this interaction yields a significantly narrow single emission line. To determine the condition of the quantum regime, we derive an expression for the gain in the Cherenkov effect using a quantum mechanical treatment. It is assumed that the effective spread in momentum is due to the finite interaction length L (or the propagation length in the case of SPPs). For both cases, CFEL and SPPs, the effects of electron beam and waveguide parameters on the possibility of the quantum regime are studied. We conclude that the quantum regime can be basically verified at low electron beam energy (<40 keV) and at emission wavelengths in the near infrared range (<5 μm) when L is in the order of millimeters. In the case of SPPs, we also show that the feasibility to realize quantum SPPs is enhanced by increasing the chemical potential and number of graphene layers.
关键词： Quantum light,Surface plasmon polaritons,Graphene,Cherenkov radiation
更新于2025-09-23 15:23:52
-
One-pot self-assembly of 3D CdS-graphene aerogels with superior adsorption capacity and photocatalytic activity for water purification
摘要： Graphene-based three-dimensional (3D) aerogel hybrids have recently emerged as a new class of functional materials and applied in many fields. In this work, we assemble the spherical CdS nanoparticles in situ in graphene aerogel (GA) by a facile one-pot hydrothermal method. The resultant CdS-GA hybrids possess a hierarchical porous structure and there is strong electronic interaction between CdS and GA, which enhances the adsorption capacity and photocatalytic activity for the elimination of organic contaminants in water under visible light irradiation, such as rhodamine B (RhB), methylene blue (MB), acid chrome blue K (AcbK), methyl orange (MO), and ciprofloxacin (CIP). The removal efficiencies of CdS-GA for MO, MB, CIP, RhB, AcbK are 15.6, 6.6, 4.4, 2.8, and 2.2 times of pure CdS, respectively. Meanwhile, the resultant CdS-GA hybrids display good reusability. In addition, a photocatalytic mechanism is also discussed. This provides a valuable alternative to explore semiconductor-GA hybrids with outstanding adsorption capacity and superior visible-light induced photocatalytic activity.
关键词： Graphene aerogel,Adsorption,Photocatalysis,Hybrids,CdS nanoparticle,organic contaminants
更新于2025-09-23 15:23:52