Journal of Inorganic Materials, Volume. 39, Issue 2, 129(2023)
Figures & Tables(13)
![Schematic illustration of a THz-TDS system for electromagnetic interference shielding efficiency (a) and reflection loss measurements (b)[57]](/Images/icon/loading.gif){kind=icon}
3. Schematic illustration of a THz-TDS system for electromagnetic interference shielding efficiency (a) and reflection loss measurements (b)[57]
4. Enhanced THz electromagnetic shielding phenomenon of MXene based on gold nano-slit antenna[59]
6. Layer-dependent terahertz (THz) conductivity observed in self-assembled Ti3C2Tx films[65]
7. Synthesis of MWP, and viscosity and EMI SE measurements of different MXene filler content MWP[57]
8. High-temperature terahertz electromagnetic shielding composite film of MXene and layered montmorillonite utilizing a water-oxygen adsorption competition mechanism[76]
9. Terahertz absorption characteristics of Ti3C2Tx and its composite porous absorber
10. Terahertz absorption properties of Ti3C2Tx and its composite porous hydrogels and directional freeze-dried aerogels
Table 1. Terahertz electromagnetic shielding and absorption mechanism[37-38]
View tableView in ArticleTable 1. Terahertz electromagnetic shielding and absorption mechanism[37-38]
Classification Absorbing mechanism Remark Salisbury screen 
A resistive sheet is placed in front of a metal ground plane, usually separated by some lossless dielectrics. The reflectivity drops to zero due to destructive interference between the scattering paths in the device. (a) Narrow band(b) Destructive interference(c) Easy to process Jaumann absorber 
The Jaumann absorber, an extension of the Salisbury screen, primarily comprises multiple thin impedance layers, lossless dielectric layers, and a metal layer. The electromagnetic characteristics of each impedance layer and the thickness of the dielectric layer are designed to operate at distinct frequencies, enabling destructive interference absorption across multiple frequency points and achieving broadband absorption. (a) Broadband frequency(b) Destructive interference(c) Substantial thickness and intricate processing methods Dällenbach absorber 
The impedance matching layer is designed for specific high imaginary part of dielectric constant and permeability, while matching the free-space impedance. (a) High imaginary part of dielectric constant and permeability ,(b) Free-space impedance matching(c) The absorption bandwidth is related to the conduction-frequency characteristics(d) Easy to process Classification Absorbing mechanism Remark Impedance gradient multilayer absorber 
Similar to the Dällenbach absorber, the layer-by-layer impedance matching design minimizes the reflected component of the interface when waves are incident. (a) Gradient interface impedance matching(b) The absorption bandwidth is related to the conduction- frequency characteristics(c) Complicated process Pyramidal type absorber 
The pyramidal-type absorber, an evolution from the Dällenbach absorber framework, adopts a specific angle design to maximize incident wave capture, minimizing reflection. Electromagnetic waves undergo multiple reflections along the cone structure. Both pyramidal and tetrahedral pyramidal configurations exhibit reduced demands concerning the polarization direction of electromagnetic waves. (a) The macrostructure captures the incident wave and reduces scattering (b) The absorption bandwidth is related to the conduction- frequency characteristics(c) Easy to process Metamaterial absorber 
The resonant response exhibited by distinctive metamaterial structure serves the purpose of dissipating incident electromagnetic waves. Owing to the notably high degree of freedom within this characteristic structure, metamaterials can be engineered for either single-frequency or wide-band resonant absorption. To achieve broadband absorption, multiple distinct single-frequency resonant structures are employed and combined. However, due to practical limitations in the manufacturing process, there remains a gap in absorption between the multiple resonant frequencies, leading to partial absorption within specific frequency bands. (a) Electromagnetic resonance characteristic structure(b) Adjustable electromagnetic parameters ()(c) The processing difficulty is related to the wavelength Coherent perfect absorber 
When two normal incidence plane waves with an odd times π phase difference enter the impedance layer from both ends, interference cancelation occurs, and all electromagnetic waves will be absorbed. (a) Coherent wave(b) Phase difference:(c) The absorption bandwidth is related to the conduction- frequency characteristics Artificial blackbody 
In the domain of artificial black holes, spheres and cylinders stand as prevalent design frameworks. Multi-layer spheres and cylinders are designed to increase the dielectric constant of the medium layer by layer from the outside to the inside. The center is full of material with high imaginary part of dielectric constant, and the incident wave is deflected to the center layer by layer and converges and loses. (a) Gradient dielectric constant(b) The overall geometry is larger than the wavelength diffraction limit
Table 2. MXenes fitting parameters for terahertz electron relaxation time and backscattering based on the Drude-Smith model [60⇓-62,64-65]
View tableView in ArticleTable 2. MXenes fitting parameters for terahertz electron relaxation time and backscattering based on the Drude-Smith model [60⇓-62,64-65]
MXenes Film fabrication method Thickness/nm $\tau $ /fsc Ref. Ti3C2Tx (MILD) Interfacial thin film technology 16 6±1 -0.97±0.03 [ 60 ]Ti3C2Tx (MILD) Interfacial thin film technology 25±5 19±1 -0.68 [ 62 ]Ti3C2Tx / / 67±3 ~ -0.65 [ 64 ]Al-Ti3C2Tx Self-assemble technology 3.0±0.2 9.62±0.1 -0.82±0.0015 [ 65 ]6.4±0.3 10.61±0.2 -0.79±0.0016 8.0±0.7 10.73±0.2 -0.76±0.0019 10.2±0.1 10.98±0.2 -0.72±0.0016 11.8±0.5 12.60±0.2 -0.68±0.0013 13.3±0.5 12.59±0.1 -0.66±0.0012 Mo2Ti2C3Tx (HF TBAOH) Spin-coating technology ~80 16±3 -0.941±0.007 [ 61 ]Annealing-Mo2Ti2C3Tx (HF TBAOH) Spin-coating technology ~80 20±4 -0.875±0.013 [ 61 ]Mo2TiC2Tx (HF TBAOH) Drop-cast technology ~1300 36±4 -0.864±0.007 [ 61 ]Annealing-Mo2TiC2Tx (HF TBAOH) Drop-cast technology ~1300 31±3 -0.895±0.005 [ 61 ]Nb4C3Tx-few layer (HF TMAOH) / / 52±4 ~ -0.7 [ 64 ]
Table 3. Terahertz electromagnetic shielding and absorption properties of MXenes and their composites [57,59,62,76,78⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ -89]
View tableView in ArticleTable 3. Terahertz electromagnetic shielding and absorption properties of MXenes and their composites [57,59,62,76,78⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ -89]
Composition Density/(g·cm-3) Thickness/μm SE/dB SSE/t/(dB·cm2·g-1) Absorption /(RL·dB-1) Frequency band/THz Ref. Compact & laminated structure Ti3C2Tx / 0.15 20 / / 1.0 [ 59 ]Ti3C2Tx ca. 2.39 0.025 ~2.5 ~7×105 / 0.25-2.25 [ 62 ]Ti3C2Tx / 25 55~70 / / 0.3-0.7 [ 78 ]Ti2CTx/PDMS / / ~6 / / 0.2-3 [ 79 ]PAN/Ti3C2Tx/AgNPs / 3.85 9.11 / / 0.2-1.2 [ 80 ]Ti3C2Tx/copolymer-polyacrylic / 38.3 64.9 / / 0.2-1.6 [ 57 ]PVA/Ti3C2Tx/MWCNT / 42 23~36 / / 0.2-2.0 [ 81 ]Ti3C2Tx/extracted bentonite / 11 47 / / 0.2-1.3 [ 76 ]Ti3C2Tx/ polyaramids / 20 52.7 / / 0.2-1.6 [ 82 ]Porous structure Ti3C2Tx/GO / 4000 / / 37 dB 0.2-2.0 [ 83 ]Zn2+/Ti3C2Tx/GO 0.11 85 51 451.0 / 0.2-2.0 [ 84 ]Ti3C2Tx/polyurethane / 2000 / / 99.99% 0.3-1.65 [ 85 ]Ti3C2Tx/PAA/ACC nanoparticle / 130 45.3 / 23.2 0.2-2.0 [ 86 ]Ti3C2Tx/polyurethane/SCA/silica / 2000 / / 99.6% 0.3-1.2 [ 87 ]Ti3C2Tx/rGO / 148 ~30 / 99.999% 0.37-2.0 [ 88 ]Ti3C2Tx/polysiloxane / 2500 / / 27.3 0.2-1.4 [ 89 ]
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Hujie WAN, Xu XIAO.
Paper Information
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Received: Oct. 5, 2023
Accepted: --
Published Online: Jul. 8, 2024
The Author Email: XIAO Xu (xuxiao@uestc.edu.cn)
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