Laser Ablation based "Green" Synthesis of multilayer Graphene and Graphene Oxide nanosheets

In this experimental investigation, a simple and efficient technique is presented for the carbonic nanostructures fabrication-in particular, Graphene Oxide (GO) and Graphene nanosheets- based on the pulsed laser ablation of graphite target inside the Cetyltrimethylammonium bromide (CTAB) (0.1 M) and liquid nitrogen environments using the pulsed nanosecond Q-switched Nd:Y3Al5O12 (Nd:YAG) laser at 532 nm. X-ray diffraction (XRD) pattern, Raman spectrum, Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and Field emission scanning electron microscopy (FE-SEM) were used to characterize the ablation products. Results represent the formation of multilayer graphene and GO nanosheets in liquid nitrogen medium and CTAB solution, respectively. In liquid nitrogen medium, the graphene nanosheets includes the largest SP2 domain size and the least defects, while the size distribution of SP2 domains of GO nanosheets decreased noticeably in CTAB solution that can be related to the breaking of crystallites with oxidation. The XRD spectra of the produced samples showed the well-defned crystalline structure of the hexagonal phase of CNx in liquid nitrogen medium and also the formation of GO and other new carbonic structures in CTAB solution. In addition, the stretching vibrations of C=O and C-O in carboxylic groups of GO structure and vibrations of graphitic domains (C=C bonds) in graphene nanosheets was observed by FTIR spectra. Our experimental results can be useful guidance toward the production of graphene nanosheets with desired attributes.