Graphite-like carbon nitride (g-C3N4): A promising microwave absorber

During the last few years, the ever-increasing development of electronic devices using and/or producing electromagnetic waves has exited the global concern related to the electromagnetic pollution. As a result, based on the transmission line theory, widespread microwave absorbing materials have been architected operating according to their permeability and permittivity to mitigate the pollution and their emerged hazards. At frequencies above 1 GHz, dielectric nanostructures, having more specific surface area, gained the considerable attention due to their salient microwave absorbing characteristics, originated from the enhanced dipole, interfacial, and defect polarization, deduced by Debye relaxation and Maxwell-Wagner model. Among them, two-dimensional (2D) nanostructures are under the spotlight owing to their unique electromagnetic features. Interestingly, g-C3N4 nanosheets illustrated salient microwave absorbing properties generated from its special conjugated structure synthesized from a decussate arrangement of nitrogen and carbon. The lone pair electrons and sp2 hybridization develop π→π*, n→π*, and n→σ* transitions enhancing interfacial interactions, bringing its outstanding microwave properties. In this study, a comprehensive perspective ascribed to the defect engineering, doping, compositing, and medium, influencing the microwave absorbing properties of g-C3N4 have been scrupulously dissected. More significantly, the main origins behind the observed permeability of this type of materials were essentially discussed.