Ultrasensitive and Highly Stretchable Multifunctional Strain Sensors with Timbre‐Recognition Ability Based on Vertical Graphene

Abstract

Stretchable/wearable strain sensors are attracting growing interest due to their broad applications in physical and physiological measurements. However, the development of a multifunctional highly stretchable sensor satisfying the requirements of ultrahigh sensitivity (able to distinguish sound frequency) remains a challenge. An ultrasensitive and highly stretchable multifunctional strain sensor with timbre-recognition ability based on high-crack-density vertical graphene (VGr) is fabricated using an ultrasonic peeling (UP) method. It can distinguish frequencies of sounds higher than 2500 Hz. Detailed microscopic examinations reveal that their ultrahigh sensitivity stems from the formation of high-density nanocracks in the graphitic base layer, which is bridged by the top branched VGr nanowalls. These nanocracks cut the VGr film into a large number of nanopieces, which increase the natural frequency of the sensors, enabling the sensors to distinguish the sound frequency. Demonstrations are presented to highlight the sensors' potential as wearable devices for human physiological signal and timbre detections. This is the first multifunctional highly stretchable strain sensor with timbre-recognition ability.

Fully Inkjet-Printed Short-Channel Metal-Oxide Thin-Film Transistors Based on Semitransparent ITO/Au Source/Drain Electrodes

“…Thanks to the relatively large gap between the isolated sub-microscale Au particles, the water will fill the gap during ultrasonic treatment. As a result, the sub-microscale Au particles can be easily stripped from the substrate with the help of cavitation bubble collapse under ultrasonic bath [23]. Figure 3c shows the microscope image of prepared short-channel ITO/Au electrode pairs, while Figure 3d shows an enlarged image of a pair of electrode with a channel length of 1.67 µm.…”

Mechanical sensors based on two-dimensional materials: Sensing mechanisms, structural designs and wearable applications

“…It vibrates synchronously with high-frequency dynamic force stimulation. For example, high-crack-density vertical graphene was able to distinguish frequencies of acoustic signal higher than 2500 Hz ( Deng et al., 2019 ).…”

Remote Recognition of Moving Behaviors for Captive Harbor Seals Using a Smart-Patch System via Bluetooth Communication

“…However, in the present work, the proposed system, which enables detecting movement, direction, and amplitude of the targeted animals according to sensor signals from pressure sensors, is highly beneficial for understanding muscle movement and its output in wild animals. This is attributed to main platforms which can detect a rate of change while subjecting animals to relatively less stress [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. In this work, to overcome the limitations of conventional methods (e.g., passive or active markers), a strain measurement system was implemented using RA18 devices (Marveldex inc., Korea), which are commercially available, to detect muscle changes.…”