Facile preparation and broadband microwave absorption of multilayered materials based on thin films of reduced graphene oxide

Microwave absorption (MA) materials have received extensive attention for their wide applications in both civil and military areas. However, many MA materials have a large thickness, high filling ratio, and narrow effective microwave absorption bandwidth (Reflection Loss, RL <= -10 dB) (EAB), and are prepared by complex processes. In this work, a reduced graphene oxide (RGO) film is prepared for the first time by an approach involving floating-dipping and chemical reduction. Compared with previous micrometers-thick RGO films, the present 200 nm-thick dense RGO film is critical for improving not only the impedance matching but also the capability of the material to attenuate incident microwaves. Based on such a thin RGO film, a multilayered material with a jaaumann structure is constructed with individual RGO layers alternating between low dielectric polyethylene terephthalate (PET) sheets. With the superb impedance matching, multilayer attenuation, and multi-cavity resonance, the present multilayered material can achieve a wide EAB of 13.75 GHz with a minimum reflection loss of -47.69 dB using only 3 layers of RGO films. This study provides a new and simple strategy for the development of layered materials with a thin thickness, low filling ratio, and strong absorption with a wide EAB.