Ultrathin MXene film interaction with electromagnetic radiation in the microwave range

The quick progress in communication technologies demands superior electromagnetic interference (EMI) shielding materials. However, achieving a high shielding effectiveness (SE) with thin films, which is needed for microscale, flexible, and wearable devices, through absorption of EM radiation remains a challenge. 2D titanium carbide MXene, Ti (3) C (2) T x, has been shown to efficiently reflect electromagnetic waves. In this paper, we investigated the electromagnetic shielding of ultrathin printed Ti (3) C (2) T x films and recorded absorption up to 50% for 4 nm-thick films. This behavior is explained by impedance matching. Analysis of the sheet impedance in the X-band frequency range allows us to correlate the EMI shielding mechanism with the electrical conductivity measured within the same range. The average bulk in-plane conductivity for 4 to 40 nm-thick films reaches 10(6) S/m, while the average relaxation time is estimated at around 2.3 ps. Our figures of merit are similar to those reported for ultrathin metal films, such as gold, showing that an abundant MXene material can replace noble metals. We demonstrate that the MXene conductivity mechanism does not change from direct current to THz. The conventional method of reporting EMI SE is correlated with absolute values of transmitted, reflected, and absorbed power, which allows us to interpret previous results on MXene EMI shielding. Considering the easy deposition of thin MXenes films from solution onto a variety of surfaces, our findings offer an attractive alternative for shielding microscale devices and personal electronics.

Automated summary

This study investigates the electromagnetic shielding properties of ultrathin printed Ti (3) C (2) T x films and finds that these films can efficiently absorb electromagnetic radiation with absorption rates up to 50%. Analysis of the sheet impedance reveals the correlation between the electrical conductivity and the EMI shielding mechanism of the film. The study also shows that the MXene material's conductivity mechanism remains consistent from direct current to THz. These findings provide an attractive alternative for shielding microscale devices and personal electronics.