Ultrafast piezoresistive flexible pressure sensor for vibration and sound detection with a bandwidth over 20 kHz

Flexible pressure sensors hold great potential for electronic skins and wearable devices. However, conventional piezoresistive flexible pressure sensors often lack the ability to detect high-frequency dynamic stimuli. Here we present a piezoresistive flexible pressure sensor by combining porous materials with a pyramid array composite hierarchical structure. The sensor significantly improve the response-relaxation time and can accurately capture dynamic stimuli exceeding 20 kHz with a frequency resolution of 0.1 Hz. Meanwhile, the sensor can detect a minimum pressure of 1 Pa and has a wide pressure sensing range from 1 Pa to 1000 kPa. In addition, we developed a structural vibration detection system, a sound detection system, and a human motion detection system to verify the broadband multifunctional detection capability of the sensor. This work provides innovative ideas for the development of flexible wearable devices and electronic skins.