A stretchable self-powered triboelectric tactile sensor with EGaIn alloy electrode for ultra-low-pressure detection

Self-powered tactile and pressure sensor is one of the key components for new smart electronic devices which can sense various external physical stimuli without external power supplies. With the potential application in detection of health conditions and sport performances, self-powered tactile sensors have attracted broad attentions. Still, fabrication of self-powered tactile sensors with stretchability, flexibility and low detection limit remains challenge. In this work, a self-powered triboelectric tactile sensor with multi-level structured polydimethylsiloxane (PDMS) triboelectric layer and PDMS/Eutectic Gallium-Indium (EGaIn) alloy composite electrode is demonstrated with simple fabrication process and low-cost. The detection limits of 0.23 Pa (experimental) and 7 mPa (calculated) are the state of art for reported self-powered triboelectric tactile sensor. With this excellent characteristic, monitoring of human wrist pulses is demonstrated by this self-powered triboelectric tactile sensor. Moreover, due to the working mechanism of the triboelectric nanogenerator, this self-powered triboelectric tactile sensor exhibits uncompromising resilience to stretching and even significant damage.