MXenes for Plasmonic Photodetection

Abstract

MXenes have recently shown impressive optical and plasmonic properties associated with their ultrathin‐atomic‐layer structure. However, their potential use in photonic and plasmonic devices has been only marginally explored. Photodetectors made of five different MXenes are fabricated, among which molybdenum carbide MXene (Mo2CTx) exhibits the best performance. Mo2CTx MXene thin films deposited on paper substrates exhibit broad photoresponse in the range of 400–800 nm with high responsivity (up to 9 A W−1), detectivity (≈5 × 1011 Jones), and reliable photoswitching characteristics at a wavelength of 660 nm. Spatially resolved electron energy‐loss spectroscopy and ultrafast femtosecond transient absorption spectroscopy of the MXene nanosheets reveal that the photoresponse of Mo2CTx is strongly dependent on its surface plasmon‐assisted hot carriers. Additionally, Mo2CTx thin‐film devices are shown to be relatively stable under ambient conditions, continuous illumination and mechanical stresses, illustrating their durable photodetection operation in the visible spectral range. Micro‐Raman spectroscopy conducted on bare Mo2CTx film and on gold electrodes allowing for surface‐enhanced Raman scattering demonstrates surface chemistry and a specific low‐frequency band that is related to the vibrational modes of the single nanosheets. The specific ability to detect and excite individual surface plasmon modes provides a viable platform for various MXene‐based optoelectronic applications.

Recent Advances in 2D MXenes for Photodetection

“…Alshareef and co‐workers in 2019 reported Mo 2 CT x photodetectors operated in the 400–800 nm visible spectral range, of which the performance was found to be enhanced by MXene surface plasmon induced hot carriers. [ 99 ] In their work, a sequence of different MXene phases were synthesized for better comparison through the same top‐down delamination approach, including Mo 2 CT x , Ti 3 C 2 T x , Nb 2 CT x , T 2 CT x , and V 2 CT x , while Figure a shows the as‐prepared TEM image of few‐layer Mo 2 CT x nanoflakes with good crystallinity (the inset). The authors carried out standard metallization on the MXene thin films to fabricate flexible photodetector arrays (Figure 8b), the active channels of which were shaped with a 1 mm width and a 70 µm length.…”

Engineering 2D Mesoporous Silica@MXene‐Integrated 3D‐Printing Scaffolds for Combinatory Osteosarcoma Therapy and NO‐Augmented Bone Regeneration

“…MXenes, as a new class of 2D nanomaterials, include a large group of carbides, nitrides, or carbonitrides, which have found their specific application in biomedicine. [ 32–36 ] MXenes are featured with extracting A‐element from the layered structure with MAX phase ceramics. In MXenes, “M” is a transition metal atom, “A” represents an A group element in element periodic table, and “X” is carbon or nitrogen.…”

MXene Printing and Patterned Coating for Device Applications

“…[ 24,99–101 ] On the other hand, MXenes have also exhibited intriguing optoelectronic and plasmonic properties owing to their ultra‐broadband absorption, which almost spans the whole electromagnetic spectrum from UV–visible, near‐infrared (NIR) and THz to radio‐frequency. [ 97,102–106 ] Nonetheless, their electronic and optical applications remain to be less than sufficient, and mostly limited to small‐area devices. Hence, the well‐controlled versatile patterning capability of printing is expected to promote the application of MXenes in electronics and optoelectronics greatly.…”