Skin-integrated, stretchable triboelectric nanogenerator for energy harvesting and mechanical sensing

Due to the potential application of wearable electronics in human medical treatment and human machine interfaces, extensive investigations and research have been conducted recently. To provide sufficient and continuous power to the state-of-art flexible electronics, many wearable self-powered technologies have been developed. Triboelectric nanogenerators (TENGs) provide a prospective alternative option to efficiently transform mechanical energy during human daily movement into electricity, which can be utilized for motion capturing and energy harvesting. Here, we have developed a thin, skin-integrated stretchable triboelectric nanogenerator based on the contact-separation mode through a low-cost fabrication process. By adopting the serpentine designed Cu electrodes, the device has exhibited excellent flexibility and stretchability. To separate the two triboelectric layers, a flexible pillar array is built in the middle by screening printing, realizing the thin format of the TENG. Due to mechanical design, the TENG exhibits a wide pressure sensing range from ∼ 8.125 kPa to ∼ 43.125 kPa, corresponding to the open-circuit voltages ranging from ∼ 10 V to ∼ 80 V, allowing sensing to various external pressures, such as finger touching, tapping, and punching. At the external pressure of 43.125 kPa, the power output of the TENG could reach up to 300 μW/cm². Under a constant tapping by fingers, the energy yielded by the device could light 40 LEDs. Furthermore, a 4 × 4 arrayed TENG-based pressure sensor was further fabricated and demonstrates its potential applications in human motion monitoring and tactile mapping.