Synthesis of ZnS quantum dots and CoFe 2 O 4 nanoparticles co-loaded with graphene nanosheets as an efficient broad band EM wave absorber

In order to obtain the high-performance electromagnetic (EM) wave absorber, nanocomposites have been applied to absorbing field. In our research, hybrid reduced graphene oxide (RGO)/CoFe2O4/ZnS nanocomposites were successfully synthesized via a facile hydrothermal process in combination with the co-precipitation route. The crystal structure, chemical composition and morphology of the as-prepared nanocomposites have been detailedly investigated. The ZnS quantum dots and CoFe2O4 nanoparticles with an average diameter of 3–8 nm and 10–20 nm, respectively, were homogeneously anchored on graphene sheets. Moreover, the EM parameters of both RGO/CoFe2O4 and RGO/CoFe2O4/ZnS nanocomposites were measured using a vector network analyzer. The EM wave absorption properties of RGO/CoFe2O4/ZnS nanocomposites are significantly improved compared with RGO/CoFe2O4 nanocomposites, with the maximum reflection loss as high as −43.2 dB at only 1.8 mm and the maximum absorption bandwidth (<−10 dB) of 5.5 GHz (from 10.2 to 15.7 GHz) at 2.0 mm. And the absorption bandwidth (<−20 dB) is up to 6.3 GHz with a thickness in the range of 1.5–2.5 mm. Moreover, the absorption bandwidth (<−10 dB) almost covers the whole frequency range (from 3.6 to 18.0 GHz) with the thickness range of 1.5–5.0 mm. Consequently, it is believed that the as-prepared nanocomposites could be used as promising materials for stealth camouflage techniques.