Wearable Triboelectric Sensors with Self-Powered Energy: Multifunctional Laser-Engraved Electrets to Activate Satellite Communication for Life-Emergency Alert in Pandemics

Abstract

Reliable sustainable power is inevitably a pillar resource for effective response to operate medical alert devices in pandemics. Only a few minutes of power outages can be a life-threatening event, especially for those who are vulnerable, such as bedridden patients and seniors with disabilities. This article addressed a self-powered wearable sensor that can send life-emergency requests instantly using satellite signals. The wearable sensor relied on a single-electrode triboelectric nanogenerator (SETENG) operated by a highly capacitive laser-engraved electret made of cuprite ions attached to graphene oxide [GO-Cu(II)] and coated on polytetrafluoroethylene. The multifunctional electret possessed the duality of negative triboelectric material and conductive GO-Cu(II) electrode that could generate self-power energy conversion when in contact with a positive triboelectric material of silk-Mg(II)–Ca(II). The voltage multiplier circuit (VMC) was integrated with the SETENG as an assistance unit to accelerate fast charge accumulation to capacitors, reaching 0.32 mC/m2 within a few minutes. Without the integration of VMC, SETENG itself exhibited intrinsically excellent stability and durability, obtaining a peak power density of 41 μW/cm2 and a high current density of 1.52 μA/cm2 under a loading force of 20 N. Besides, the electrical potential changes at different loading pressures on alphabetic electrets were further investigated using the finite element method. Hybrid quantum mechanics/molecular mechanics simulation revealed cationic ions on a finger bend electret segment via the translocation of cuprous ions in graphene voids. With the duality of high current density possessed by SETENG and the integrated VMC unit for fast charging, the SETENG wearable sensor can be self-powered using human finger pressures and can send a life-emergency signal via a satellite so the healthcare personnel can locate the person in distress and in need of immediate help.