A transparent and biocompatible single-friction-surface triboelectric and piezoelectric generator and body movement sensor

Abstract

With the development of wearable electronics, flexible energy devices are now paid more attention, aiming at efficiently converting a variety of physical motion energy of the human body into electricity. This work innovatively proposes a flexible and biocompatible single-friction-surface triboelectric and piezoelectric hybrid generator (TPG) with good transparency. The novel TPG uses Al:ZnO (AZO) as transparent electrodes, P(VDF-TrFE) as the piezoelectric functional layer and PDMS with micro-fabricated pyramids as the triboelectric layer. The proposed TPG can effectively harvest bending and movement energy from human skin under piezoelectric and triboelectric mechanisms. The typical stress–strain curve and transmittance testing of TPG indicates that TPG has outstanding stretchability and transmittance. The generator has an open-circuit output voltage of 25 V under the triboelectric mechanism and a piezoelectric open-circuit output voltage of 2.5 V under the piezoelectric method. The total output voltage and power density of this device are 26 V and 751.1 mW m⁻², respectively. In addition, this device would scavenge the mechanical energy from the different parts of the body, such as the human neck, finger, elbow and ankle into electric energy with various signal forms owing to the different contacting moving modes on the friction surface, which will be deployed as a body moving sensor.