MXene is widely used for electrode materials. However, the interfacial resistance between metal and semiconductor affects the device performance. The strain has become an effective strategy to improve interfacial properties. With the aim of revealing the interface mechanism and improving device performance, we use the first-principles calculation to investigate the electronic properties of Ti 3 C 2 T 2 /MoS 2 (T = F, O, OH) junctions and the effect of strain on the interfaces. The calculations show weak forces between Ti 3 C 2 T 2 and MoS 2 monolayer, and the interfacial interaction decreases in the order of Ti 3 C 2 (OH)

piezoelectricity, [21,22] and turboelectricity. [23,24] Among them, the resistivetype soft sensor is particularly prominent for its flexibility, stretchability, and simple support system. [1,[16][17][18] Resistive-type soft sensors normally consist of a conductive sensor film and a soft substrate. [1] Polydimethylsiloxane (PDMS) has become prevalent in using as flexible and stretchable substrate owing to its remarkable elasticity, simple processing, high thermal stability, and chemical inertness. [1][2][3]7,12,25] The most essential issue of strain sensor is the choice of sensitive material. Carbon nanotube (CNT) has been broadly used in strain sensors due to its excellent mechanical properties, chemical inertness, and low cost, [1,2,5,6,10] whose stretchability could reached 280% [7] or even 500%. [11] In order to make up some defects that carbon base materials often suffered, like low conductivity (sheet resistance of ≈4 kΩ sq −1 [5] ) and the relatively low sensitivity, [9,11] researchers has mixed CNT with metal materials. Takei and some researchers have mixed CNT with silver particles physically, [13] while Zhang and others using chemical methods produced AgNP modified CNTs. [26] Metal materials have good electrical properties [1,2,7,8,15] and high sensitivity (GF is easily achieved twice or even more times than CNTs [7,12] ), and can effectively supplement the shortage of CNT. Based on our previous researches, Ag@CNT synthesized by chemical reduction is a good material that combines the both advantages of CNTs and silver nanoparticles. [25] However, there are still some drawbacks here: pristine CNTs are insoluble in water or organic solvents and easily agglomerate; the bond between CNT and metal nanoparticle is not as tight and strong. On this basis, how to further improve the performance of Ag@CNT is an important and meaningful research direction. Researches on this aspect have not been reported as far as we know.In this study, we fabricated a stretchable and flexible strain sensor using Ag@COOH functionalized CNT. To get a better performance, three different CNTs were chosen for comparison: pristine CNT, COOH functionalized CNT, and OH functionalized CNT. In order to deeply compare the mechanism of binding energy and charge transfer ability, different Combining metal and carbon nanomaterials is an effective way to significantly enhance the performance of soft strain sensors. The role of carbon nanotubes (CNTs) functionalized with different chemical groups in improving the properties of nanosilver-coated carbon nanotubes (Ag@CNT) is investigated. The functionalized CNTs are first calculated with different chemical groups combined with the silver atoms. Ag@COOH-functionalized CNTs exhibit greater binding energy and a smaller bandgap, which leads to better hydrophilicity, stability, and stronger bonding. Ag@CNTs are then synthesized using pristine CNT, OH-functionalized CNT, and COOHfunctionalized CNT. Strain sensors are fabricated by wrapping the sensing material with polydimethylsiloxane (PDMS) to form a s...

We fabricated a flexible sensing system, including the preparation of sensors and construction of the signal processing computing platform, which enabled human health monitoring by collecting pulse signals.

Recently, highly stretchable strain sensors have attracted considerable attention. Identifying alternatives to sensitive unit materials and flexible substrates is critical in the fabrication of sensors.