Green synthesis of few-layered graphene from aqueous processed graphite exfoliation for graphene thin film preparation

The development of an approach for producing a very low defect graphene with simple and green technique is essential for highly conductive graphene thin film preparation. This paper describes the preparation of graphene thin film from aqueous processed graphene dispersion using alkaline lignin (AL) as surfactant, a low cost route to produce high yield (0.72 ± 0.05 mg/mL) with free structural defect of graphene sheets. In this work, the cationic properties of AL adsorbed on the exfoliated graphene sheet surfaces are easily removed via centrifugation, thermal and annealing treatments so that prepared graphene thin films exhibit good electrical conductivity and defect ratio reduction. Using optimum AL solution with concentration of 0.5 mg/mL, the precursor graphite is successfully being exfoliated into few layer graphene sheets (