Pressure sensors for monitoring human movement are receiving increasing attention, and there is an urgent need for wearable devices with good flexibility and high sensitivity in the field of motion monitoring. In this article, a team led by Professor Ke Chen and Researcher Kai Pan from Beijing University of Chemical Technology published a paper titled "Flexible Laser Reduced Graphene with Gradient Wrinkled Microstructure for Piezoresistive Pressure Sensors" in the journal ACS Appl. Nano Mater. They studied the fabrication of a graphene based pressure sensor by combining pre stretching and laser reduction strategies.This method not only gives the graphene oxide layer a gradient wrinkled structure, but also introduces an expanded porous structure. The multi-level microporous gradient shrinkage structure enables the sensor to have a wide detection range (33 Pa-6.67 kPa), low detection limit (33 Pa), and high sensitivity (125.9 ± 10.8 kPa-1). In addition, the sensor also has good mechanical stability and short response time. More importantly, the potential application of the prepared sensor in monitoring large-scale movements, such as bending movements of fingers and wrists, has been confirmed.

We have developed a flexible gradient wrinkled graphene piezoresistive sensor using a simple PS&LR method. Due to its unique structure, the flexible piezoresistive sensor has excellent sensitivity of 125.9 ± 10.8 kPa-1 in the low pressure resistance range (0.033-0.333 kPa) and high sensitivity of 42.8 ± 7.6 kPa-1 in the high pressure resistance range (0.333-6.67 kPa). The minimum detection limit of the sensor is 33 Pa, and it can maintain initial mechanical stability even after more than 5000 fatigue tests. The prepared piezoresistive sensor can be used to test finger bending and gesture recognition, such as the numbers represented by gestures. In short, this work provides a practical method for manufacturing high-performance piezoresistive sensors that have the potential to be applied in a wide range of human activity monitoring and gesture recognition, opening up new possibilities for information transmission.

Source: Sensor Expert Network