Bioinspired Microspines for a High-Performance Spray Ti₃C₂T_x MXene-Based Piezoresistive Sensor

Abstract

Recently, wearable and flexible pressure sensors have sparked tremendous research interest, and considerable applications including human activity monitoring, biomedical research, and artificial intelligence interaction are reported. However, the large-scale preparation of low-cost, high-sensitivity piezoresistive sensors still face huge challenges. Inspired by the specific structures and excellent metal conductivity of a family of two-dimensional (2D) transition-metal carbides and nitrides (MXene) and the high-performance sensing effect of human skin including randomly distributed microstructural receptors, we fabricate a highly sensitive MXene-based piezoresistive sensor with bioinspired microspinous microstructures formed by a simple abrasive paper stencil printing process. The obtained piezoresistive sensor shows high sensitivity (151.4 kPa −1 ), relatively short response time (<130 ms), subtle pressure detection limit of 4.4 Pa, and excellent cycle stability over 10,000 cycles. The mechanism of the high sensitivity of the sensor is dynamically revealed from the structural perspective by means of in situ electron microscopy experiment and finite element simulation. Bioinspired microspinous microstructures can effectively improve the sensitivity of the pressure sensor and the limit of the detectable subtle pressure. In practice, the sensor shows great performance in monitoring human physiological signals, detecting quantitatively pressure distributions, and remote monitoring of intelligent robot motion in real time.

Advances in MXene Films: Synthesis, Assembly, and Applications

“…This sensor was ultrathin, flexible, and highly sensitive, and therefore easy to attach to the skin for detecting human activities and human-computer interaction ( Fig. 17d) [178]. MXenes films can also be utilized for detecting various gases and biologically important molecule because of the active surface functional groups and layered structures.…”

Anisotropic Boron–Carbon Hetero‐Nanosheets for Ultrahigh Energy Density Supercapacitors

“…Considering these impressive electrochemical performance together with high mechanical flexibility, we design an actual use of wearable energy‐sensor system to detect the physiological signals by making the connection of FSC, Ti 3 C 2 T x MXene mechanical sensor and Bluetooth device (Figure 5 a). In this wearable system, the FSC is utilized as a high energy supply to stably power mechanical sensor, thereby efficiently monitoring the human activities with steadily physiological signals [40] . As shown in Figure 5 b (Supporting Information, Movie S1), two pulse signals of normal and after exercise are recorded by attaching the wearable system on wrist.…”

“…In this wearable system, the FSC is utilized as ah igh energy supply to stably power mechanical sensor, thereby efficiently monitoring the human activities with steadily physiological signals. [40] As shown in Figure 5b (Supporting Information, Movie S1), two pulse signals of normal and after exercise are recorded by attaching the wearable system on wrist. It was showed that the normal pulse frequency is around 78 times per min, whereas it raises to around 120 times per min with an enhanced intensity after exercise.S pecially,t hose physical signals can be read out on mobile phone in real time,w hich exhibit two significantly distinguishable peaks (strong peak indicating the systolic process and weak peak revealing the diastolic behavior).…”

Controlled Assembly of MXene Nanosheets as an Electrode and Active Layer for High‐Performance Electronic Skin

“…[ 29,30 ] For example, Cheng et al. successfully fabricated an MXene‐based pressure sensor with bioinspired microspinous microstructures through a printing process, which exhibited a high sensitivity of 151.4 kPa −1 and short response time of 130 ms. [ 31 ] In addition, a single‐layer MXene has a high specific surface area and good surface hydrophilicity, which significantly enhances the force of binding with the contact substrate for better cyclic stability. Therefore, it is a good electrode material candidate for flexible devices.…”