Synthesis And Electromagnetic Wave Absorption Performance Of VSe₂-based Nanocomposites

At present,the wide application of electronic equipment,industrial equipment and satellite communication has caused serious electromagnetic radiation and electromagnetic pollution problems,which not only endanger human health,but also disrupt the normal operation of digital equipment.Therefore,in order to effectively prevent and control electromagnetic radiation,the preparation of good electromagnetic wave absorbing materials has been a great concern.Vanadium diselenide(VSe₂),as a two-dimensional semiconductor material with high carrier concentration and room temperature ferromagnetism,has a wide application prospect in the field of electromagnetic wave absorption.Meanwhile,carbon materials have been fully developed in the field of electromagnetic wave absorption with their light weight,low cost and stable chemical properties.Based on this,VSe₂nanosheets are compounded with carbon materials and the electromagnetic wave absorption properties are researched as follows:Firstly,the VSe₂nanosheets were prepared using a simple hydrothermal method.And its electromagnetic parameters were tested in the range of 2-18 GHz,and the reflection loss in this frequency range was obtained by calculation.The results show that the VSe₂nanosheet achieves the best reflection loss of-9.01 d B at 14.96 GHz for a thickness of 6.5 mm.Secondly,in order to optimize the electromagnetic wave absorption performance of VSe₂nanosheets,the composite of VSe₂nanosheets and carbon nanotubes(CNTs)was synthesized by one-step hydrothermal method.Since CNTs have a unique one-dimensional structure,good electrical conductivity and high carrier concentration,when they are compounded with VSe₂nanosheets,the doping ratio between VSe₂nanosheets and CNTs can be changed to achieve the modulation of the dielectric properties of the material,which enhances the dielectric loss of the composite while optimizing the impedance matching of the composite,thus obtaining excellent electromagnetic wave absorption performance.The optimum reflection loss value reaches-57.53 d B at a thickness of 4.16 mm,which is about 6 times that of VSe₂nanosheets.In addition,the VSe₂/CNTs composite sample has a dual-band absorption performance with a total effective absorption bandwidth(EAB)of 3.32 GHz.Finally,to investigate the effects of different carbon materials on the electromagnetic wave absorption performance of VSe₂nanosheets,VSe₂nanosheets and reduced graphene oxide(rGO)composites were also synthesized by hydrothermal method.It was found that the unique two-dimensional sheet structure of rGO enables multiple scattering and reflection of incident electromagnetic waves on its surface,and the large specific surface area enhances the contact between electromagnetic waves and the material so that the electromagnetic waves can enter the material to the maximum extent and be consumed inside the material,thus realizing excellent electromagnetic wave absorption performance.The VSe₂/rGO composite sample achieves a minimum reflection loss of-54.44 d B at 16.8 GHz at a thickness of 4.9 mm,while the reflection loss value is-44.01 d B at a thickness of 1.55 mm,with an EAB of 3.92 GHz.