Flexible transparent electrodes made of electrochemically exfoliated graphene sheets from low-cost graphite pieces

Graphene is a highly promising candidate to replace oxide-based conducting materials for fabrication of transparent electrodes used in flexible displays and electronic devices. However, so far an appropriate method is still not found to provide high-quality, low-cost graphene in a large quantity. To overcome this issue, we demonstrate that massive graphene sheets can be synthesized by electrochemical exfoliation process using artificial graphite as a starting material. The product is mainly composed of bilayer thin graphene sheets. Their lateral size can be up to several to 20 μm, and the quality determined by Raman spectroscopy is better than the reduced graphene oxide derived from graphene oxide. The transparent conducting films made of electrochemically exfoliated graphene can be simply prepared by an airbrush spraying method, which is easy to scale up for large-area deposition, and compatible with flexible polymer substrates.