Graphene quantum dots interfacial-decorated hierarchical Ni/PS core/shell nanocapsules for tunable microwave absorption

Graphene quantum dots interfacial-decorated hierarchical Ni/PS core/shell nanocapsules were successfully synthesized by three-step liquid chemical method . The morphologies and electromagnetic properties were carefully studied in order to investigate the dielectric shells modulated tunable microwave absorption in 1–18 GHz (L–Ku), based on the anisotropic nanoflakes assembled magnetic core. With different GQDs/PS ratio in the shells, the dielectric attenuation can be flexibly tuned by the interfacial polarizations deriving from the density modulation of interfacial-decorated polar GQDs in the nonpolar insulative PS matrix. The calculated impedance matching maps, microwave absorption efficiencies ( R E ), reflection loss ( RL ) and simulations illustrated the coincident effect with an obvious rise-fall performance in X–Ku band. The tunable RL value in fixed frequency of X band and shifting absorption peaks from Ku to X band were achieved in different absorber thickness with the minimum RL below −42.5 dB and the effective absorption bandwidth ( RL  < −10 dB) above 2.04 GHz.