▎ 摘　　要

An electric-field-induced reversible hydrogenation reaction, which relies on a hydrogen-ion electrolyte, can be used to create graphene field-effect transistors with on/off current ratios of 10(8) and endurance of up to 1 million switching cycles. Graphene is of interest in the development of next-generation electronics due to its high electron mobility, flexibility and stability. However, graphene transistors have poor on/off current ratios because of the absence of a bandgap. One approach to introduce an energy gap is to use a hydrogenation reaction, which changes graphene into insulating graphane with sp(3) bonding. Here we show that an electric field can be used to control the conductor-to-insulator transitions in microscale graphene via reversible electrochemical hydrogenation in an organic liquid electrolyte containing dissociative hydrogen ions. The fully hydrogenated graphene exhibits a lower sheet resistance limit of 200 G omega sq(-1), resulting in graphene field-effect transistors with on/off current ratios of 10(8) at room temperature. The devices also exhibit high endurance, with up to 1 million switching cycles. Similar insulating behaviours are also observed in bilayer graphene, while trilayer graphene remains highly conductive after hydrogenation. Changes in the graphene lattice, and the transformation from sp(2) to sp(3) hybridization, are confirmed by in situ Raman spectroscopy, supported by first-principles calculations.