Research On Terahertz Shielding Properties Based On Two-dimensional MXene Materials

In recent years,terahertz technology has become a research hotspot in biosensing,spectroscopy,imaging,wireless communication and other fields based on the rapid development of electronics,laser and semi-conductivity.However,with the rapid development of terahertz technology,more and more terahertz radiation is generated.The electromagnetic radiation not only seriously affects the equipment performance,but also affects the communication security.Therefore,terahertz shielding materials are needed to reduce electromagnetic interference.Currently,research on terahertz shielding materials mainly focuses on four aspects:lightness,thinness,wide band and strong absorption.But many most of today's terahertz shielding materials cannot meet the above requirements at the same time,and many of them have problems such as high cost and poor stability,which prevent them from being used in practice for a long time.Thus,in order to improve the terahertz shielding effect of materials,the characteristics and structure of materials can be regulated.Two-dimensional transition metal carbonitride-MXenes have been gradually applied in terahertz shielding due to their strong mechanical properties,good electrical conductivity,large surface area,ultralight mass,and special physicochemical properties.In addition,adding a porous structure inside the shielding material can further improve the electromagnetic interference shielding performance of the shielding material.In this paper,three methods of suction filtration,spin coating and electrospinning were used to prepare Ti₃C₂T_x-MXene-based films with different thicknesses and contents of silver nanoparticles(Ag NPs)for terahertz shielding research.The details are as follows:(1)In this paper,Ti₃C₂T_x-MXene was prepared by top-down wet etching method,and then Ti₃C₂T_x-MXene films with different thicknesses were prepared on polyimide substrate by spin coating method for terahertz shielding research.The thickness of the film was controlled by changing the number of spin-coatings,and the terahertz shielding performance of the film was also enhanced by increasing the film thickness.When Ti₃C₂T_x-MXene film was only 12?m,the shielding effect was up to 17 d B.This result could be attributed to the intrinsic absorption of the two-dimensional structure of Ti₃C₂T_x-MXene,as well as its own high electrical conductivity,which was conducive to terahertz shielding.(2)In this paper,Ti₃C₂T_x-MXene and Ti₃C₂T_x-MXene/Ag NPs fiber membranes with different thicknesses and different Ag NPs contents were successfully prepared by electrostatic spinning technique using polyvinylpyrrolidone(PVP)and polyacrylonitrile(PAN)as spinning binders,respectively.According to the measurement of the terahertz time domain spectrum of the fiber membranes,it could be found that the terahertz shielding effect increased with the increase of Ag NPs content and thickness.When the content of Ag NPs was 1%,the shielding effect of the fiber membrane could reach 12d B.Among the three typical thicknesses selected,the thickest fiber membrane(3.85?m)exhibited the best terahertz shielding performance.The porous structure of the fiber membrane and the combination of Ti₃C₂T_x-MXene and Ag NPs not only enhanced the absorption of terahertz radiation by the fiber membrane,but also enhanced the electrical conductivity of the material.Meanwhile,the protection of the porous fiber skeleton by PAN made the fiber membranes have better thermal stability and stable terahertz shielding performance under high temperature environment.In conclusion,the Ti₃C₂T_x-MXene-based films prepared in this study are expected to provide potential ideas for the development of high-performance terahertz shielding materials,and further promote the application in real life.