초록 |
Two-dimensional (2D) MXenes are a newly discovered family of transition metal carbides, nitrides, and carbonitrides. Their outstanding electrical conductivities of >104 S cm−1 in 2D morphology, low density, mechanical flexibility, easy processability, and structural controllability extends their application scope to compete with existing conventional 2D materials. Ti3C2Tx, the representative candidate of the MXene family, exhibits an EMI shielding effectiveness of 92 dB at 45 micrometer thickness, whereas a 55 nanometer thick film can provide 99% shielding against EMI, which is outstanding for highly-compacted electronics. A transition metal carbonitride, Ti3CNTx MXene, with a moderate electrical conductivity provides a higher shielding effectiveness compared to more conductive Ti3C2Tx or metal foils of the same thickness. This exceptional shielding performance of Ti3CNTx was achieved by thermal annealing and is attributed to an anomalously high absorption of electromagnetic waves in the layered metamaterial-like porous structure. With high absorption of EM waves at minimal thickness, MXenes are ideal for real applications in smart 5G electronics. |