LAUSR

DOI: 10.1002/adom.201701076 THz electronics and devices.[12] Recently, nonlinear optical phenomena using high power THz sources[13] and THz plasmonics[14] have been intensively explored. However, electromagnetic interference (EMI) often generated from those THz devices must be shielded in order to protect device and its surroundings.[15] In general, electrically conductive materials, such as carbon and their composites, have been used and shown to have promising EMI shielding capabilities in the range of THz frequencies.[15] Recently, 2D transition metal carbide (MXene) has shown excellent shielding performance in the microwave regime.[16–19] Among all, a thin film of Ti3C2Tx MXenes (≈1.5 μm) can block 99.99% EM waves showing the highest EMI shielding efficiency (EMI SE) for materials of comparable thicknesses.[19] Han et al. reported a composite of Ti3C2Tx in wax which delivers an EMI SE value of 76.1 dB with a thickness of only 1 mm.[18] Qing et al. reported the microwave absorption properties of a Ti3C2Tx filled polymer composite, where a reflection loss value of −11 dB was recorded in Ku band for a 1.4 mm thick sample.[17] Han et al., in another report, developed laminated carbon/TiO2 structures derived from Ti3C2Tx MXenes Terahertz (THz) shielding becomes increasingly important with the growing development of THz electronics and devices. Primarily materials based on carbon nanostructures or polymer–carbon nanocomposites have been explored for this application. Herein, significantly enhanced THz shielding efficiencies for 2D titanium carbide (Ti3C2 MXene) thin films with nanoscale THz metamaterials are presented. Nanoscale slot antenna arrays with strong resonances at certain frequencies enhance THz electromagnetic waves up to three orders of magnitude in transmission, which in turn enormously increases the shielding performance in combination with MXene films. Drop-casting of a colloidal solution of MXene (a few micrograms of dry material) can produce an ultrathin film (several tens of nanometers in thickness) on a slot antenna array. Consequently, THz waves strongly localized in the near-field regime by the slot antenna undergo enhanced absorption through the film with a magnified effective refractive index. Finally, the combination of an ultrathin MXene film and a nano-metamaterial shows excellent shielding performance in the THz range.