Microwave absorbing property and complex permittivity and permeability of graphene-CdS nanocomposite

The graphene-CdS (G-CdS) nanocomposite with enhanced microwave absorption was directly synthesized from graphene oxide (GO) via a facile hydrothermal approach, during which the formation of CdS nanoparticles and the reduction of GO occured simultaneously. The morphology, structure, microwave absorbing property, complex permittivity and permeability of G-CdS nanocomposite were systematically investigated by transmission electron microscope, X-ray diffraction and the coaxial line method. The complex permittivity of G-CdS nanocomposite presents triple dielectric relaxations with constructing a good structural graphene-CdS interface. The triple dielectric relaxations were critical to improve the microwave absorption of G-CdS nanocomposite. The G-CdS nanocomposite achieved a reflection loss below -10 dB in the frequency range of 5.2-18 GHz when adjusting the thicknesses from 2 to 5 mm, which was mainly ascribed to the proper electromagnetic matching of the CdS nanoparticles and graphene sheets, and the triple dielectric relaxations. The G-CdS nanocomposite is promising as a lightweight and wide-frequency microwave absorber. (C) 2013 Elsevier B.V. All rights reserved.