Environmentally friendly approaches toward the production of processable graphene by exfoliation of graphite using ionic liquid.

A facile, low-cost and environmentally friendly method was developed to prepare processable graphene materials by direct exfoliation of expandable graphite flakes under wet ball milling conditions in ionic liquids. The graphene nano-sheets obtained in this method were characterized by AFM, Raman spectroscopy, UV-NIR. Thin-film field-effect transistors made from this graphene sheets exhibit ambipolar effect, an average hole mobility of -0.29 cm2 V(-1) s(-1), electron mobility of -0.57 cm2 V(-1) s(-1) was obtained.