Research On Terahertz Shielding Materials Based On MXene

Terahertz has gradually being interested and received extensive attention with the delvelopment of technology.Because terahertz waves have many advantages such as good coherence characteristics,strong penetration performance,low radiation energy and broadband characteristics,is has shown great prospects in wireless communication,security inspection imaging,national defense and security.Moreover,the requirements for terahertz shielding materials with light weight,thin thickness,large bandwidth,high absorption and strong shielding are also increasing.However,most of the current terahertz shielding materials have one or several disadvantages of thicker thickness,heavier mass,stronger surface reflection,weaker absorption intensity and narrower shielding bandwidth.Based on the above background,this theis has carried out research on absorption-based terahertz shielding materials with large broadband,high absorption and strong shielding.The specific research results are as follows:First,this thesis analyzes and discusses PS sphere-based porous MXene films as terahertz shielding materials.The PS sphere-based porous MXene thin film terahertz shielding material was prepared by vacuum filtration followed by annealing to remove PS spheres,with a thickness of only a few micrometers.Then,the performance test proved that in the frequency range of 0.3THz～1.65 THz,the total electromagnetic shielding efficiency of the porous MXene film based on PS spheres is 43.71 d B,with high absorption rate（up to 98.7%）and low reflectivity（as low as 0.95%）,which strongly confirms that the PS sphere-based The porous Ti3C2 film is an absorption-dominant terahertz shielding material.Then,in order to reduce the reflectivity of MXene and improve the absorption rate,we prepared a 3D printing-based MXene-based wedge-shaped terahertz shielding material by mixing MXene dispersion and LA133 binder by freeze-drying.This material has the advantages of lighter mass density,ultra-high absorption rate,and simple fabrication process.We modeled the material with CST software and determined the size parameters of the wedge-shaped material by simulation.The experimental comparison shows that the wedge-shaped MXene achieved an ultra-high absorption rate of 99.97%,a very low reflectivity as low as 0.0218%,and a total electromagnetic shielding efficiency of up to 66.31 d B at a thickness of only 5.9mm in the frequency range of 0.3THz～1.65 THz.It is effectively confirmed that the wedge MXene prepared by us is an absorptiondominant terahertz shielding material.Finally,in order to further improve the shortcoming of the wedge-shaped MXene terahertz shielding material being easily broken,we combined the mixed solution of MXene dispersion and LA133 binder with the three-dimensional porous HTL resin material by vacuum filtration to prepare a 3D printed 3D porous MXene composite structure terahertz shielding material.This terahertz shielding material has the advantages of light density,ultra-high absorption rate,simple manufacturing process,and high hardness and unbreakable.By comparing the two variables of different thicknesses and different loadings of MXene nanosheets,it is finally shown that in the frequency range of0.2THz～1THz,the three-dimensional porous MXene polymer material with a thickness of only 2mm and a pore size of 500μm can achieve up to 99.86% ultra-high absorption rate,extremely low reflectivity as low as 0.129% and total electromagnetic shielding effectiveness as high as 50.61 d B.