Enhancing Graphene Concentration in Organic Solvents with Salts and Additives

Abstract

The synthesis of graphene nanosheets by liquid-phase exfoliation of graphite in organic solvents is reported. The graphene concentration was enhanced with addition of salts and additives in organic solvents. Additives and salts intercalate into the edges of graphite which enhances graphene concentration significantly. It was found that by adding phenophthalein in cyclohexanone (CYN) organic solvent the graphene yield was increased nine times from 0.005 mg/ml to 0.045 mg/ml. Addition of organic and in-organic salt also affects the graphene concentration in organic solvents. It has been found that with addition of sodium citrate organic salt, the graphene concentration in dimethyl sulfoxide (DMSO) organic solvent was increased from 0.002 to 0.015 mg/ml. In 1-methyl-2-pyrrolidinone (NMP) organic solvent the effect of addition of anthracene in enhancing the graphene concentration was most prominent. The enhanced graphene concentration can be used for making graphene films and composites for various applications such as field effect transistors, flexible supercapacitors etc