Defect Enhanced Efficient Physical Functionalization of Graphene with Gold Nanoparticles Probed by Resonance Raman Spectroscopy

Abstract

We demonstrate efficient physical functionalization of single layer graphene with Au nanoparticles mediated by in-plane defects in graphene grown by a chemical vapor deposition technique. The effect of an ultrathin Au layer on the single layer, bi layer, and few layer graphene with intrinsic defects was studied by resonance Raman spectroscopy and high resolution transmission electron microscopy (HRTEM). We observed a striking enhancement in the intensity of sharp D and D′ bands after sputter deposition of an ultrathin Au layer on graphene. In contrast, G and 2D bands show a lower enhancement in intensity and a change in line width due to the charge transfer from Au to the graphene and strong interaction between the Au and graphene layers, respectively. X-ray photoelectron spectroscopy (XPS) analysis shows a 40% decrease in integrated intensity ratio of sp 3 and sp 2 bands in C-1s spectra after Au functionalization indicating bonding of Au atoms preferentially at the defect sites in graphene. This was further substantiated by HRTEM imaging and position dependent Raman spectral line shape analysis. The calculations of interdefect distance and areal defect density from the Raman analysis on the graphene−Au hybrid are in close agreement with the HRTEM analysis. Further, Raman spectral line shape dependence of Au functionalization on the number of layers in graphene reveals that Au functionalized single layer graphene behaves like a pristine bi layer graphene due to strong interaction between Au and the graphene layer. These results open up possibilities for efficient physical functionalization of graphene with foreign atoms through defect engineering for novel applications of graphene in catalysis, biosensors, and optoelectronic and photonic devices.

Reducing and multiple-element doping of graphene oxide using active screen plasma treatments

“…[54] For the plasma treated samples, the G and D bands exhibit the similar characteristics to those of the as-cast GO, while the 2D and D+G bands are too weak to be identified. It is known [25,55] that the G band is related to the vibration of sp 2 -hybridized carbon, and the prominent D band corresponds to the structural imperfections created partly by the attachment of oxygen, hydroxyl and epoxide groups to the carbon backbone. The area under the D band was integrated from 1250 to 1450 cm -1 and that under the G band was integrated from 1500 to 1650 cm -1 as demonstrated in Figure 6, and the area ratio of D/G is shown in the parenthesis for each spectrum.…”

Strong visible and near infrared photoluminescence from ZnO nanorods/nanowires grown on single layer graphene studied using sub-band gap excitation

“…The full experimental details on the graphene growth and clean transfer of graphene were reported elsewhere. 15,24 Subsequently, various ZnO nanostructures were grown on the above prepared graphene substrates by using a physical vapor deposition system for different pretreated substrates. At first, an $5 nm thick Au film was deposited on the graphene substrate, bare oxidized Si (Si/SiO 2 ), and quartz substrates by radio frequency (RF) magnetron sputtering.…”

Graphene–Noble Metal Nano-Composites and Applications for Hydrogen Sensors

“…Biroju and P.K. Giri [23] reported on the role of defects in graphene on the physical functionalization of graphene grown by the chemical vapor deposition technique ( Figure 6). The effect of intrinsic defects in graphene on the ultra-thin gold layer, deposited on different layers (SLG, BLG, TLG etc.)…”