Oxygen plasma modulates the interfacial impedance of microwave reduced graphene oxide for enhanced microwave absorption

Abstract

As a classic two-dimensional material, graphene has attracted worldwide attention in the fields of electromagnetic shielding and microwave absorption. However, the excellent electrical conductivity makes it challenging to achieve impedance matching, which significantly limits its application microwave absorption. Here, we propose a strategy for the modification of graphene by low-temperature oxygen plasma that precisely regulates the electromagnetic parameters of the graphene material by adjusting the plasma irradiation time. This approach controls the electrical conductivity of graphene for impedance matching and creates enriched defects that effectively improve the material permittivity loss capability. Owing to these advantages, the sample (O-MW-rGO-60) irradiated by plasma for 60 min showed excellent microwave absorption properties with a minimum reflection loss of −54.11 dB at a matched thickness of 1.7 mm and an effective absorption bandwidth of 5.68 GHz at a thin thickness of 2.0 mm. In addition, CST simulation is used as an intelligent design strategy to verify a product's radar wave absorption capability under realistic conditions. The RCS values of the model covered with the O-MW-rGO-60 sample coating are significantly lower than those of the metal substrate, which confirms its excellent microwave absorption properties and provides new insights into the future development of microwave absorbing materials.