Preparation, Characterization And Nonlinear Optical Properties Of Graphene-Carboxymethyl Cellulose Nano-composite Materials

Graphene is a nanomaterial with a single layer of aromatic carbon, has one of the strongest in-plane bonds among all materials, as well as superior electronic, optical, thermodynamic, and physical chemistry properties, Which make graphene have great potential application in the field of healing drugs, bioimaging, and solar cells etc. Especially, the interband optical transitions in graphene depend only on the fine structure constant rather than frequency. Its nonlinear optical (NLO) effect covers wide laser wavelengths, so it is a promising optical limiting (OL) material. Carboxymethyl cellulose (CMC), a water-soluble derivative of cellulose, cheap and available, can be widely applied in various fields. When choose CMC as a film formation agent, it also acts as a surfactant so we do not need to add extra surfactant to the system. In the molecular chain of CMC, there are many carboxyl and hydroxyl groups, which provide a large number of chemical modifications sites and lay a foundation for its functional design.In this paper, we choose three different dimension graphene-based materials:graphene nanosheets (GNSs), graphene nanoribbons (GNRs) and graphene quantum dots (GQDs) as the doping starting materials and Carboxymethyl Cellulose (CMC) as the film-forming matrix to form graphene-CMC nano-composite films by solution casting method. The products were characterized by Transmission electron microscopy, X-ray diffraction, Raman spectroscopies and Fourier-transform infrared. The influence of different doping factors on structure, morphology, and composition of film nanostructures were investigated. Thermal Gravity Analysis, Fluorescence spectroscopy, Ultraviolet visible absorbance and Z-scan technology were used to investigate the properties of composite films with different morphologies, especially the nonlinear optical property. Finally, this paper was offered as a preliminary probe into a study on the preparation mechanism of different dimension graphene-based nanomaterials.Results indicate that we successfully prepared GNSs with single layer, CNTs with different unzipping stages, GQDs with blue fluorescence and free-standing films with uniformity and transparency. Various properties of composite films changed and enhanced when compared with pure CMC film. After explored the optical performance of these graphene based materials in solution and after being immobilized by CMC, we found:the NLO effect of GNSs-CMC films increase with the dosage concentration significantly. Liquid CNTs with three different unzipping stages and the corresponding solid composite films have no obvious NLO changes. Liquid GQDs have no obvious NLO effect under low incidence laser energy, but after energy increase it will appear obvious effects and increases with the energy. GQDs-CMC films behave the similar fluorescent property with liquid GQDs.