Asia Sarycheva1 Alessia Polemi1 Yuqiao Liu1 Kapil Dandekar1 Babak Anasori1 Yury Gogotsi1

1, Material Science and Engineering, Drexel University, Philadelphia, Pennsylvania, United States

There is an ever-increasing need for portable and wearable electronics, because of the societal demand for active, efficient, and integrated devices. With the emerging Internet of Things, these devices require wireless communication devices that are lightweight and portable. Therefore, new fabrication techniques are needed to develop these unobtrusive wireless communication devices. Antennas for these novel devices are required to be conformal and compact, but retain good radio-frequency conductivity which is an essential property of antenna materials. Recently, nanomaterials such as graphene1, carbon nanotubes2, carbon onions3 and conductive polymers4 have come into play, but low conductivity is a limitation for their use. However, discovered in 2011, 2D titanium carbide MXene5 eliminates the problem of conductivity due to its metallic behavior. The conductivity of MXene Ti3C2 film reaches 10000 S/cm6 which makes it a promising candidate for portable wireless communication devices. Here we show a class of radio-frequency devices for wireless communication based on two-dimensional titanium carbide MXene prepared by a single step spray coating. We fabricated a transparent MXene antenna with less than 100 nm thickness with less than -10 dB reflection coefficient at a resonant frequency of 2.4 GHz. By increasing the antenna thickness to 8 µm, we achieved -70 dB of reflection coefficient. Additionally, we fabricated a 1-µm-thick MXene RFID tag in the 875 MHz band reaching a read range of 8 meters. Our finding shows that two-dimensional MXenes operate below the skin depth of copper or other metals as well as give an opportunity to produce transparent antennas. Being the most conductive among the solution processed two-dimensional materials, as well as water dispersible, MXenes opens new avenues for manufacturing various classes of radio-frequency devices. Using MXene as a conductor will thus be essential for the development of novel portable, flexible, and wearable electronic devices.

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3. N. A. Vacirca et al., Onion-like Carbon and Carbon Nanotube Film Antennas, Applied Physics Letters, 103 , 073301 (2013)
4. N. J. Kirsch et al., Optically transparent conductive polymer RFID meandering dipole antenna, 2009 IEEE International Conference on RFID 278-282 (2009)
5. M. Naguib et al., Two-dimensional nanocrystals produced by exfoliation of Ti3AlC2. Advanced Materials 23.37, 4248-4253 (2011)
6. C. J. Zhang et al., Transparent, flexible, and conductive 2D titanium carbide (MXene) films with high volumetric capacitance. Adv. Mater., 29, 4848-4856, (2017)