Holey graphene films intercalated with iron nanoparticles for efficient electromagnetic wave shielding

With excellent electrical conductivity and engineering feasibility, graphene materials have attracted increasing attention in the application of electromagnetic interference (EMI) shielding, where graphene-based composites are considered to achieve a better EMI shielding effectiveness (EMI SE) than the bare graphene films. In this study, holey graphene films intercalated with iron nanoparticles (FRGO) are fabricated through a two-step filtration and thermal annealing method, in which the initially intercalated BiFeO 3 microparticles are thermally decomposed to iron nanoparticles and create microholes in graphene simultaneously. Due to multiple reflections within microholes and the magnetic loss generated by the iron nanoparticles in response to electromagnetic waves, the FRGO-6:40 film (where 6:40 represents the mass ratio of BiFeO 3 to graphene oxide in the precursor mixture) with a thickness of 71 μm reaches an excellent EMI SE of 38.64 dB at 9.9 GHz within the X-band range (8.2–12.5 GHz). We find that although the electrical conductivity of the holey graphene film decreases when intercalated by iron nanoparticles, the EMI SE increases, attributed to the enhancement in electromagnetic wave absorption contributed by iron nanoparticles and microholes.