Adjusting N-doping to balance conductivity and polarization for superb electromagnetic wave absorption properties of SiO2

Abstract

Due to its low relative permittivity and basically non-electromagnetic loss characteristics, SiO2, a typical electrical insulator, is frequently employed as a wave-transparent material. Hence, using SiO2 as a wave-absorbing material is a novel concept. In this study, a composite (SiO2-Nx) was created using a one-step solvothermal process, doped with N atoms and bound by Si-N bonds. Based on SiO2's imbalanced polarization ability, this research modifies the material's conductivity loss by doping it with N, which successfully balances the polarization and conductivity and turns SiO2-Nx into a wave-absorbing material. The resulting SiO2-N4 composite has a low matched thickness and a wide absorption band of 5.28 GHz with a minimum reflection loss value of -34.48 dB (2.5 mm). The addition of doped-N atoms, which on the one hand improves the impedance matching properties of SiO2-Nx, results in the balanced polarization relaxation and conductivity. The two dielectric loss mechanisms of polarization and conductivity loss, on the other hand, are enhanced to varying degrees by N-doping, which completes the improvement of the wave absorption capability. These outstanding findings offer original suggestions for the creation of SiO2-based electromagnetic wave absorption materials.