MXenes and Their Applications in Wearable Sensors

Abstract

MXenes, a kind of two-dimensional material of early transition metal carbides and carbonitrides, have emerged as a unique class of layered-structured metallic materials with attractive features, as good conductivity comparable to metals, enhanced ionic conductivity, hydrophilic property derived from their hydroxyl or oxygen-terminated surfaces, and mechanical flexibility. With tunable etching methods, the morphology of MXenes can be effectively controlled to form nanoparticles, single layer, or multi-layer nanosheets, which exhibit large specific surface areas and is favorable for enhancing the sensing performance of MXenes based sensors. Moreover, MXenes are available to form composites with other materials facilely. With structure design, MXenes or its composite show enhanced mechanical flexibility and stretchability, which enabled its wide application in the fields of wearable sensors, energy storage, and electromagnetic shielding. In this review, recent progress in MXenes is summarized, focusing on its application in wearable sensors including pressure/strain sensing, biochemical sensing, temperature, and gas sensing. Furthermore, the main challenges and future research are also discussed.

Retracted: Emerging 2D MXene/Organic Heterostructures for Future Nanodevices

“…Moreover, such heterostructures can be very suitable for use in wearable health care devices such as sweat based glucose/electrolyte sensors, pulse sensors, etc., for early medical diagnosis. [ 252 ] MXenes also exhibit considerable magnetization effects, even at room temperature. [ 253 ] Therefore, strong magnetic manipulation can be expected in these heterostructures, which can lead to design appealing 2D spintronic devices.…”

“…2D MXenes or its composites show enhanced mechanical flexibility and stretchability, which has enabled its wide application in the fields of wearable sensors. [211,275] Toward the use of 2D organic materials for wearable sensors, 2D metal organic framework layer based nanodevices have been demonstrated for various functional sensory purposes. [276] In particular, the abundant accessible active sites available on such organic frames could play a vital role for sensing applications.…”

Tuning the Magnetic Properties of Two-Dimensional MXenes by Chemical Etching

“…3 The high elastic mechanical strength 4 , electronic conductivity 5,6 , chemical stability [7][8][9] , and hydrophilicity 10,11 of MXenes have opened broad prospects for their applications in a variety of industrial and technological areas including energy storage, optoelectronics, spintronics, catalysis, and sensing. [12][13][14][15][16][17][18][19][20][21][22][23] Although there is significant research effort in the optical 24,25 and electronic 11,26,27 properties of MXenes, the magnetic properties of these materials for spintronic application is relatively unexplored. 28 The intrinsic properties of MXenes are mainly determined by the transition metal in the MAX phase.…”

MXene-Based Nanocomposite Sensors

“…For example, Ti 2 C MXene was theoretically and experimentally investigated for gas sensor applications. 22 Simulation studies confirmed that single-layer Ti 2 C shows higher sensibility for NH 3 than for CO 2 , O 2 , H 2 , and CH 4 when its surface is enriched with oxygen functional groups. In addition, fabricated flexible Ti 2 C/polyimide sensors showed excellent NH 3 detection.…”

“…The grafting of poly(2-(dimethylamino)ethyl methacrylate) on the V 2 C surface allowed for the fabrication of sensors that are sensitive to CO 2 and temperature. 22 …”