Search results for "Raphe"

A reliable procedure for the preparation of graphene-boron nitride superlattices as large area (cm x cm) films on arbitrary substrates or powders (gr…

2019

[EN] Herein, a reliable procedure for the preparation of graphene-boron nitride superlattices, either as films or powders, consisting of the pyrolysis at 900 degrees C of polystyrene embedded pre-formed boron nitride single sheets is reported. The procedure can serve to prepare large area films (cm x cm) of this superlattice on quartz, copper foil and ceramics. Selected area electron diffraction patterns at every location on the films show the occurrence of the graphene-boron nitride superlattice all over the film. The procedure can also be applied to the preparation of powdered samples on a gram scale. Comparison with other materials indicates that the superlattice appears spontaneously as…

Supramolecular assembly of pyrene-tetrathiafulvalene hybrids on graphene: Structure-property relationships and biosensing activity

2021

Two different molecular receptors (1 and 2) incorporating one and three pyrene units to promote the π–π interaction with the basal plane of graphene are reported. In order to modulate the electronic properties of graphene, the new receptors are endowed with an electron-donor tetrathiafulvalene moiety (exTTF). The resulting non-covalent hybrids have been characterized by different analytical, spectroscopic and microscopic techniques (TGA, Raman, UV-Vis absorption, TEM and XPS), and the supramolecular interaction of the molecular systems with graphene has been investigated by theoretical calculations. The electrochemical behavior of the pyrene-exTTF hybrids onto distinct graphene-based materi…

Simulation of electromagnetic properties in carbon nanotubes and graphene-based nanostructures

2012

As carbon nanotubes (CNT) and graphene nanostructures (GNR) constitute the basis of high-speed nanoelectronics and nanosensors, we examine the fundamental properties of var- ious CNT-metal (Me), GNR-Me, and CNT-graphene interconnects. The cluster approach based on the multiple scattering theory as well as effective medium approximation were used to model the dispersion law, electronic density of states (DOS), and conductivity, etc. Multiple scattering problems were solved for nanostructures with radial (quantum dots) and axial (nanowires, nano- tubes) symmetry. Interconnect capacitances and impedances have been evaluated in the GHz and THz regimes. Parametrical numerical simulations of cond…

Nonlinear photo-oxidation of graphene and carbon nanotubes probed by four wave mixing imaging and spectroscopy (Presentation Recording)

2015

Graphene has high potential for becoming the next generation material for electronics, photonics and optoelectronics. However, spatially controlled modification of graphene is required for applications. Here, we report patterning and controlled tuning of electrical and optical properties of graphene by laser induced non-linear oxidation. We use four wave mixing (FWM) as a key method for imaging graphene and graphene oxide patterns with high sensitivity. FWM produces strong signal in monolayer graphene and the signal is highly sensitive to oxidation providing good contrast between patterned and non-patterned areas. We have also performed photo-oxidation and FWM imaging for air suspended carb…

Controllable coverage of chemically modified graphene sheets with gold nanoparticles by thermal treatment of graphite oxide with N,N-dimethylformamide

2013

Abstract We describe a simple chemical method to reduce and functionalize graphite oxide by reaction with dimethylformamide under controlled heating. Our experiments suggest that the reaction conditions assist the decomposition of the solvent to produce dimethylamine molecules that can react with the oxygen-rich functional groups covering the surface of the exfoliated layers of graphene, therefore generating chemically modified graphene (CMG). These N-functionalities have been next used as anchoring points for the grafting of Au nanoparticles. Given that the functionalization extent can be controlled with the temperature and reaction time, our approach can be considered as a straightforward…

Synthesis and studying of reduced few-layered graphene coatings in gas sensor applications

2019

In this work reduced few-layered graphene (rFLG) nanoparticles were synthesized using electrochemical pulse exfoliation method from waste graphite crucibles. The regular change in voltage polarity in the synthesis process ensures both the separation of graphite in layers and the reduction of graphene oxide. A method for synthesizing free-standing rFLG and nitrocellulose (NC) composite film has been developed involving creation of rFLG-NC ink that can be deposited on various substrates. It has been observed that a successful synthesis of a free-standing composite coating is possible with the mass ratio of rFLG:NC at least 9:1 of which resistivity is on the order of approximate 10 ohm-centime…

Inside Back Cover: Rational Chemical Multifunctionalization of Graphene Interface Enhances Targeted Cancer Therapy (Angew. Chem. Int. Ed. 33/2020)

2020

Innenrücktitelbild: Rational Chemical Multifunctionalization of Graphene Interface Enhances Targeted Cancer Therapy (Angew. Chem. 33/2020)

2020

Atomic Layer Deposition of Localized Boron- and Hydrogen-Doped Aluminum Oxide Using Trimethyl Borate as a Dopant Precursor

2020

Atomic layer deposition (ALD) of boron-containing films has been mainly studied for use in two-dimensional materials and for B doping of Si. Furthermore, lithium-containing borates show great promi...

Self-Passivating Edge Reconstructions of Graphene

2008

Planar reconstruction patterns at the zigzag and armchair edges of graphene were investigated with density functional theory. It was unexpectedly found that the zigzag edge is metastable and a planar reconstruction spontaneously takes place at room temperature. The reconstruction changes electronic structure and self-passivates the edge with respect to adsorption of atomic hydrogen from molecular atmosphere.