discs had electric conductivities that were nearer to multi-layered graphene and greater

than carbon nanotubes and reduced graphene oxide materials in experiments [26].

Furthermore, the presence of functional groups and the number of layers were found to

enhance resistivity values. As a result, the simulated conductivities are often higher than

those measured experimentally.

Due to changes in d-spacing, defect concentration between MXenes flakes, surface

functional groups, and their lateral diameters generated by each etching technique,

Ti3C2Tx observed electrical conductivities ranging from 850 to 9,880 S/cm. In general,

MXenes with lower HF concentrations and etching periods have fewer defects and

greater lateral diameters, resulting in higher electronic conductivity. Furthermore, hu­

midity in the environment may affect their conductivities, indicating the potential for

relative humidity sensing material applications [27].

Modification of surfaces using alkaline and thermal treatments is a good way to im­

prove electrical characteristics. Conductivities increase by two orders of magnitude, ac­

cording to their findings. The removal of functional groups (particularly –F) and

intercalated molecules are responsible for this rise [28].

15.3.2.4 Magnetic Properties

In contrast to MAX phases, investigations of MXenes’ magnetic characteristics were broa­

dened due to the potential of magnetization. Magnetic moments are expected in several

virgin compounds, including Ti4C3, Ti3N2, Ti3CN, Zr2C, Fe2C, Cr2C, Ti2N, and Zr3C2.

However, after terminations, each MXene and functionalization group must be examined

individually. For example, the functional groups make Ti3CNTx and Ti4C3Tx non-magnetic,

whereas the OH and F groups make Cr2CTx and Cr2NTx ferromagnetic at ambient tem­

perature, and Mn2NTx is ferromagnetic regardless of the surface terminations [29].

15.3.2.5 Optical Property

Photovoltaic, photocatalytic, transparent conductive electrode devices, and optoelectronic

all benefit from visible and UV light absorption. Ti3C2Tx films absorbed light in the

UV–vis range and had a transmittance of up to 91.2% at 5 nm thickness. In addition,

depending on the film thicknesses, it may have an intense and wider absorption band at

roughly 700–800 nm, which produces a pale greenish film hue and is important for

photothermal treatment (PTT) applications. It’s worth noting that the transmittance va­

lues could be improved by adjusting the thickness and ion intercalation [30].

The optical properties of these two-dimensional materials could be altered by the func­

tional groups, according to first-principles calculations. In reality, unlike oxygen termina­

tions, fluorinated and hydroxyl terminations have identical properties. When compared to

virgin MXene, the fluorine and hydroxyl terminations lower absorption and reflectivity in

the visible range, while all terminations increase reflectivity in the UV range. Furthermore,

the absorbance value could be decreased by reducing the lateral flake size of MXenes [31].

MXenes are intriguing prospects for flexible transparent electrode applications because

of their optical transparency in the visible range and metallic conductivity, but their

significant reflection in the ultraviolet range signals anti-ultraviolet rays coating mate­

rials. Finally, a remarkable 100% light-to-heat conversion efficiency was achieved, which

is critical for biomedical and water evaporation applications. To improve MXenes’ ap­

plications, certain optical qualities such as luminescence efficiency, emission colors,

plasmonic, and non-linear optical aspects must be addressed [32].

MXenes-Based Polymer Composites

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