Multi-nanocavities and multi-defects synergetic enhancement for the electromagnetic absorption of the rGO-NG film

Abstract Dielectric loss is an important way to eliminate electromagnetic pollution. In order to achieve high dielectric loss, a graphene film reduced graphene oxide-N doped graphene (rGO-NG) was constructed from graphene oxide-Ni@polydopamine (GO-Ni@PDA) via the in situ synthesis of hollow graphene spheres between graphene sheets. This in situ was achieved by means of electrostatic self-assembly and metal-catalyzed crystallization. Owing to the synergetic effect of multi-nanocavities and multi-defects, the prepared rGO-NG film shows an average shielding effectiveness (SE) of 50.0 dB in the range of 8.2–12.4 GHz with a thickness of 12.2 μ m, and the SE reflection is only 7.3 dB on average. It also exhibits an average dielectric loss tangent (tan δ ) of 23.1, which is 26 and 105 times higher than those of rGO and rGO-Ni, respectively. This work provides a simple but effective route to develop high performance graphene-based materials for application as an electromagnetic interference shielding film in today’s electronic devices.