MXene is typically exfoliated by selective etching the A layer of MAX phase. [1] One example of MXene, Ti 3 C 2 F x , satisfies the stoichiometric ratio of n + 1/n, in which M, X, and T stand for transition metals, carbon or nitrogen, terminal groups at surfaces, respectively. The MXene has exhibited extraordinary electrical, [2][3][4] optical, [5] mechanical, [6][7][8] and electrochemical properties [9] since its first discovery, [10] which has become an emerging material for sensing, [11,12] communication, [13,14] energy, [15,16] environmental, [17] and healthcare applications. [18][19][20] There are many reviews existing for electrochemical energy storage, including supercapacitors, lithium ion batteries, [21][22][23] sodium ion batteries, zinc ion batteries, [24][25][26] lithium-sulfur batteries, and energy conversions, [27][28][29] includingThe Internet of Things era has promoted enormous research on sensors, communications, data fusion, and actuators. Among them, sensors are a prerequisite for acquiring the environmental information for delivering to an artificial data center to make decisions. The MXene-based sensors have aroused tremendous interest because of their extraordinary performances. In this review, the electrical, electronic, and optical properties of MXenes are first introduced. Next, the MXene-based sensors are discussed according to the sensing mechanisms such as electronic, electrochemical, and optical methods. Initially, biosensors are introduced based on chemiresistors and field-effect transistors. Besides, the wearable pressure sensor is demonstrated with piezoresistive devices. Third, the electrochemical methods include amperometry and electrochemiluminescence as examples. In addition, the optical approaches refer to surface plasmonic resonance and fluorescence resonance energy transfer. Moreover, the prospects are delivered of multimodal data fusion toward complicated human-like senses. Eventually, future opportunities for MXene research are conveyed in the new material discovery, structure design, and proof-of-concept devices.

Human beings perceive the world through the senses of sight, hearing, smell, taste, touch, space, and balance. The first five senses are prerequisites for people to live. The sensing organs upload information to the nervous systems, including the brain, for interpreting the surrounding environment. Then, the brain sends commands to muscles reflexively to react to stimuli, including light, gas, chemicals, sound, and pressure. MXene, as an emerging two-dimensional material, has been intensively adopted in the applications of various sensors and actuators. In this review, we update the sensors to mimic five primary senses and actuators for stimulating muscles, which employ MXene-based film, membrane, and composite with other functional materials. First, a brief introduction is delivered for the structure, properties, and synthesis methods of MXenes. Then, we feed the readers the recent reports on the MXene-derived image sensors as artificial retinas, gas sensors, chemical biosensors, acoustic devices, and tactile sensors for electronic skin. Besides, the actuators of MXene-based composite are introduced. Eventually, future opportunities are given to MXene research based on the requirements of artificial intelligence and humanoid robot, which may induce prospects in accompanying healthcare and biomedical engineering applications.

Graphene remains of great interest in biomedical applications because of biocompatibility. Diseases relating to human senses interfere with life satisfaction and happiness. Therefore, the restoration by artificial organs or sensory devices may bring a bright future by the recovery of senses in patients. In this review, we update the most recent progress in graphene based sensors for mimicking human senses such as artificial retina for image sensors, artificial eardrums, gas sensors, chemical sensors, and tactile sensors. The brain-like processors are discussed based on conventional transistors as well as memristor related neuromorphic computing. The brain−machine interface is introduced for providing a single pathway. Besides, the artificial muscles based on graphene are summarized in the means of actuators in order to react to the physical world. Future opportunities remain for elevating the performances of human-like sensors and their clinical applications.

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The electronic and optoelectronic properties of 2D materials and their stacking heterostructures have inspired enormous interests. WSe2, as a p-type semiconductor, represents a foremost building block in the p-n junctions. WSe2 shall possesses the features of large area, homogeneity, and precise layer control. To date, there is yet an ideal synthesis method ever reported. First, we present a facile approach to prepare high-quality wafer-scale homogenous WSe2 full films. In brief, we first deposit a thin layer of metal and then do the selenization. We can control the film thickness of WSe2 in a chemical equilibrium environment. Second, we present a facile approach to prepare high-quality large-area homogenous WSe2 full films. In brief, we developed a pre-seeding strategy for depositing W-containing precursors over dielectric substrates, which form well-distributed particles as seeding center. Upon the salt-assisted sublimation of tungsten oxides, the WSe2 forms over the seeded substrates (at high temperature) in the Se-rich atmosphere. Eventually the high quality of the synthetic film has been reflected on the high performances of photodetectors and field-effect transistors. Our finding may pave the way of wafer scale integration of transition metal dichalcogenides in the integrated flexible electronics.