Triboelectric Nanogenerator Tattoos Enabled by Epidermal Electronic Technologies

With the high flexibility, good conformability and lightweight, the next-generation energy harvesters could exist in the format of epidermal electronics. They are able to convert the mechanical energy from daily body motions into electrical signals for energy harvesting and human-machine interfaces. Triboelectric nanogenerators (TENGs) have proven to be excellent candidates for wearable energy harvesters, however, the reported TENGs commonly face the hurdles of poor adhesion to skin and relative thick in geometry up to several cm. Herein, a series of ultrathin, soft, tattoo-like triboelectric nanogenerators (TL-TENGs) with well-designed aesthetic patterns are introduced. With the ultrathin materials applied and state of art processing techniques in epidermal electronics, the TL-TENGs present an outstanding mechanical property of high robustness and thickness of tens of μm. Besides, TL-TENGs own remarkable electrical characteristics, the open-circuit voltage and short circuit current can reach up to ≈180 V and ≈2.2 μA under constant tapping (≈16 kPa), respectively. With the well structural mechanics designs, the TL-TENGs can be customized into various tattoo patterns, such as twelve Chinese zodiac signs. Demonstrations of TL-TENGs in energy harvesting and the human-machine interface indicate great potential in next generation wearable nanogenerators and internet of things.