Carbon nanolayer-mounted single metal sites enable dipole polarization loss under electromagnetic field

Abstract

Surface modulation strategies have spurred great interest with regard to regulating the morphology, dispersion and flexible processability of materials. Unsurprisingly, customized modulation of surfaces is primed to offer a route to control their electronic functions. To regulate electromagnetic wave (EMW) absorption applications by surface engineering is an unmet challenge. Thanks to pyrolyzing surface-anchored metal-porphyrin, here we report on the surface modulation of four-nitrogen atoms-confined single metal site on a nitrogen-doped carbon layer (sM(N4)@NC, M = Ni, Co, Cu, Ni/Cu) (sM=single metal; NC= nitrogen-doped carbon layer) that registers electromagnetic wave absorption. Surface-anchored metal-porphyrins are afforded by attaching them onto the polypyrrole surface via a prototypical click reaction. Further, sM(N4)@NC is experimentally found to elicit an identical dipole polarization loss mechanism, overcoming the handicaps of conductivity loss, defects, and interfacial polarization loss among the current EMW absorber models. Importantly, sM(N4)@NC is found to exhibit an effective absorption bandwidth of 6.44 and reflection loss of −51.7 dB, preceding state-of-the-art carbon-based EMW absorbers. This study introduces a surface modulation strategy to design EMW absorbers based on single metal sites that enable fine-tunable and controlled absorption mechanism with atomistic precision. In this work, Cheng et al. report a unique electromagnetic wave (EMW) dipole-dominated loss model excluding other redundant EMW loss, opening an avenue for exploring future academic studies and industrially applicable EMW absorbing materials.