Tunable Terahertz Properties of Reduced Graphene Oxide by Ionic Liquid Intercalation

Dynamic manipulation of terahertz waves is crucial for advancing rapidly evolving terahertz technologies. Recently, intercalation in 2D materials has emerged as a powerful strategy for tuning their physical and chemical properties, enhancing their potential for terahertz modulation applications. However, the terahertz-band response during intercalation and the underlying optical response mechanisms remain poorly understood. Herein, the tunable terahertz properties of the reduced graphene oxide films are investigated via ionic liquid intercalation and elucidate the associated terahertz response mechanism. The free charge carriers transport characteristics during the intercalation process are extracted using Drude–Smith model. The mechanism behind the terahertz response primarily stems from the intercalation of ionic liquid into the reduced graphene oxide films, resulting in an increase in the number of free carriers responding to terahertz waves. These results provide valuable insights for graphene-based tunable terahertz wave control and open a route toward exploring the intercalation mechanism in 2D materials.