Tuning N-doping to balance conductivity and polarization relaxation: A strategy for converting SiO2 from an electromagnetic wave-transmitting to absorbing material

Abstract

Dielectric absorbing materials often need to adjust their conductivity and polarization effects to regulate their response to electromagnetic waves. Thus, the design concept often lies in improving the performance of conductive materials. On the contrary, using insulated wave-transmitting material as a wave-absorbing material and doping single atoms to improve conductivity are novel design mentalities. In this study, the SiO2 hybrid (N-SiO2-x), doped with N atoms and bound by Si-N bonds, was produced utilizing a one-step solvothermal technique without phase transition. 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 N-SiO2-x into a wave-absorbing material. The resulting N-SiO2-4 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). These novel findings offer original suggestions for the creation of SiO2-based wave-absorbing materials.