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 sp³ 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 GΩ sq⁻¹, resulting in graphene field-effect transistors with on/off current ratios of 10⁸ 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 sp² to sp³ hybridization, are confirmed by in situ Raman spectroscopy, supported by first-principles calculations.

石墨烯因其高电子迁移率、灵活性和稳定性而在下一代电子产品的开发中备受关注。然而，由于没有带隙，石墨烯晶体管的开/关电流比很差。引入能隙的一种方法是使用氢化反应，该反应将石墨烯转变为具有sp ³键合的绝缘石墨烷。在这里，我们展示了电场可用于通过在含有离解氢离子的有机液体电解质中进行可逆电化学氢化来控制微米级石墨烯中导体到绝缘体的转变。完全氢化的石墨烯表现出 200 GΩ sq ^-1的较低薄层电阻极限，导致石墨烯场效应晶体管的开/关电流比为 10⁸在室温下。这些器件还具有很高的耐用性，开关周期可达 100 万次。在双层石墨烯中也观察到类似的绝缘行为，而三层石墨烯在氢化后仍保持高导电性。原位拉曼光谱证实了石墨烯晶格的变化，以及从sp ²到sp ³杂化的转变，并得到了第一性原理计算的支持。