High-Sensitive Bubble Level-Based Triboelectric Sensor for Motion Monitoring

The self-powered motion sensor based on solid friction electrification has attracted more and more attention since its independent and sustainable operation without an external power source in vibration monitoring. However, the measurement accuracy of these sensors is often affected by the large friction force and instability of the friction between solids, which highly limits their practical applications. Here, a novel high-resolution bubble level-based triboelectric sensor (BL-TES) is proposed to detect weak vibrations basing on liquid–solid triboelectrification and the inertial oscillations of the bubble. The results indicate that the electric signal of the BL-TES can detect the motion information in real time with high sensitivity. Compared with the solid-based triboelectric sensors dominated by threshold static solid–solid friction force, the BL-TES is dominated by the solid–liquid friction with very small friction force and the high-pressure differential driven force, which result in a high resolution of 0.35 m s⁻² and sensitivity of 6.35 nA s⁻² m⁻¹. Given its easy fabrication and high-sensitive property, this type of BL-TES has promising potential applications in scavenging weak mechanical energy and detecting weak vibration.