Wearable Pressure Sensor Array with Layer-by-Layer Assembled MXene Nanosheets/Ag Nanoflowers for Motion Monitoring and Human–Machine Interfaces

Abstract

Recently, wearable sensors and electronic skin systems have become prevalent, which can be employed to detect the movement status and physiological signals of wearers. Here, a pressure sensor composed of mesh-like micro-convex structure polydimethylsiloxane (PDMS), MXene nanosheet/Ag nanoflower (AgNF) films, and flexible interdigital electrodes was designed by layer-by-layer (LBL) assembly. The unique microstructure of PDMS effectively increases the contact area and improves sensitivity. Moreover, AgNFs were introduced into the MXene as a “bridge,” and the synergistic effect of the two further enhanced the performance of the sensor. The pressure sensor has high sensitivity (191.3 kPa–1), good stability (18,000 cycles), fast response/recovery time (80 ms/90 ms), and low detection limit (8 Pa), so it can be used for all-round monitoring of the human body. Sensing arrays were integrated with a wireless transmitter as an intelligent artificial electronic skin for spatial pressure mapping and human–computer interaction sensing. Moreover, we develop a smart glove by a simple method, combining it with a 3D model for wireless accurate detection of hand poses. This provides ideas for hand somatosensory detection technology, leading to health monitoring, intelligent rehabilitation training, and personalized medicine.

Graphene Capping of Cu Back-End-of-Line Interconnects Reduces Resistance and Improves Electromigration Lifetime

“…Another solution is to replace the conventional capping and barrier materials in the Cu interconnect structure with materials with improved specularity and better reliability. To date, Co-based capping layers have been widely used, but their role was limited to the improvement of EM properties. , To replace Co with thinner, better materials, low-dimensional materials such as carbon nanotube (CNT), MXene, and graphene are promising materials for the capping of Cu. − Among them, graphene capping on Cu has been proposed as an effective way to reduce its resistivity. − Mehta et al reported that electron scattering at the surface is partially changed from inelastic to elastic by graphene capping, lowering the Cu resistivity along the same dimension . Other studies have proposed that the resistivity of graphene itself can also contribute to the total resistance reduction of graphene/metal lines. , Like these, the exact role of graphene in reducing resistivity in Cu interconnects is controversial.…”

In Situ Polymerized MXene/Polypyrrole/Hydroxyethyl Cellulose-Based Flexible Strain Sensor Enabled by Machine Learning for Handwriting Recognition

“…In recent years, flexible strain sensors have become a hot research topic, and many related research results have been reported. The researchers shifted their research focus from the basic performance of sensors to the practical application of sensors and made breakthroughs in many fields such as soft robotics, , electronic skin, − human–computer interaction, − and medical monitoring. − Generally speaking, flexible strain sensors have realized real-time sensing applications in human health and motion detection due to their excellent elasticity and toughness, as well as their perfect fit with human skin. A strain sensor that comprehensively detects human motion activities needs to meet the characteristics of high sensitivity to minor signals, extremely high linearity, stable dynamic performance, and ultrafast response.…”

Flexible Pressure Sensors Based on Molybdenum Disulfide/Hydroxyethyl Cellulose/Polyurethane Sponge for Motion Detection and Speech Recognition Using Machine Learning

“…Flexible sensors have outstanding characteristics, such as softness, lightweight, and easy wearing. In recent years, it has been widely used in the fields of wearable devices, , electronic skin, , human–machine interaction, , and health monitoring. − Due to the high-performance requirements of sensors in practical applications, flexible pressure sensors with different mechanisms such as piezoresistive, , capacitive, , and piezoelectric , have been widely studied. Among them, piezoresistive flexible pressure sensors are considered as ideal candidates for next-generation sensors due to their advantages of simple fabrication, easy signal reading, low energy consumption, and excellent static pressure detection capability. , To improve sensitivity, various sensor microstructures are designed and reported, such as pyramids, domes pillars, and fibers .…”

“…Flexible sensors have outstanding characteristics, such as softness, lightweight, and easy wearing. In recent years, it has been widely used in the fields of wearable devices, 1,2 electronic skin, 3,4 human−machine interaction, 5,6 and health monitoring. 7−9 Due to the high-performance requirements of sensors in practical applications, flexible pressure sensors with different mechanisms such as piezoresistive, 10,11 capacitive, 12,13 and piezoelectric 14,15 have been widely studied.…”