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A room-temperature polymer-assisted transfer process is developed for large-area, single-layer graphene grown by means of chemical vapor deposition (CVD). This process leads to transferred graphene layers free of polymer contamination. The absence of polymer residues boosts the surface-enhanced Raman scattering (SERS) of the CVD graphene with gold nanoparticles (Au NPs) deposited atop by evaporation...
Graphene nanoscrolls (GNSs) are receiving intense interest because they are expected to possess some peculiar properties quite distinct from both graphene and carbon nanotubes. Research on GNS, however, has been hindered by limitations of the available preparation methods. Here we demonstrate a novel strategy for the large-scale preparation of GNSs from graphene oxide (GO) sheets by cold quenching,...
We study ultrafast dynamics in graphene grown by chemical vapor deposition, which presents a positive peak followed by a negative slow recovery process, and is different from the fully positive or negative dynamics reported. We discuss the diversity of ultrafast dynamics. A dynamic model of differential optical conductivity is developed to simulate ultrafast dynamics. It is found that the diversity...
N-doped graphene (NG) was synthesized by annealing reduced graphene oxide (RGO) in an ammonia atmosphere. The dependence of the nitrogen content on the annealing temperature and the type of doping of NG were investigated. The photoluminescence (PL) properties of the RGO and NG samples were studied. The results show that RGO exhibits strong ultraviolet (UV) PL at 367nm. The PL of RGO can be quenched...
We report a simple but highly-effective hydrohalic acid reducing method to reduce graphene oxide (GO) films into highly conductive graphene films without destroying their integrity and flexibility at low temperature based on the nucleophilic substitution reaction. GO films reduced for 1h at 100°C in 55% hydroiodic (HI) acid have an electrical conductivity as high as 298S/cm and a C/O ratio above 12,...
A method for the bulk growth of mono- to few-layer graphene on nickel particles by chemical vapor deposition from methane at atmospheric pressure is described. A graphene yield of about 2.5% of the weight of nickel particles used was achieved in a growth time of 5min. Scanning and transmission electron microscopy, Raman spectroscopy, thermogravimetry, and electrical conductivity measurements reveal...
The current–voltage characteristics of individual cup-stacked carbon nanotubes (CSCNTs) were investigated in situ inside the transmission electron microscope. Different from other quasi-1D carbon structures such as multi-walled carbon nanotubes, carbon nanofibers or graphitic fibers that normally behave as a metallic conductor of electrons, individual CSCNTs were found to exhibit unexpectedly semiconducting...
A simple and effective strategy is proposed to tune the number of graphene layers by selecting suitable starting graphite, using a chemical exfoliation method. It is found that both the lateral size and the crystallinity of the starting graphite play important roles in the number of graphene layers obtained. Using artificial graphite, flake graphite powder, Kish graphite, and natural flake graphite...
Various magnetic nanostructures such as Fe nanoparticles (Fe-NPs) adhering to single-walled carbon nanotubes, carbon-encapsulated Fe-NPs, Fe-NP decorated multi-walled carbon nanotubes (MWCNTs), and Fe-filled MWCNTs have been synthesized by the pyrolysis of pure ferrocene. It is found that the formation of the nanostructures can be selectively controlled by simply adjusting the sublimation temperature...
A simple method has been developed for direct synthesis of magnetic multi-walled carbon nanotubes (MWCNTs) homogeneously decorated with size-controllable Fe nanoparticles (Fe-NPs) encapsulated by graphitic layers on the MWCNT surface by pyrolysis of ferrocene. These composites have similar C/Fe atomic ratio of ∼10 and exhibit sufficiently high saturation magnetization for magnetic separation in a...
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