The field of epidermal electronics, or e-tattoos, covers a wide range of flexible and stretchable monitoring gadgets that are wearable directly on the skin. We have covered this area in multiple Nanowerk Spotlights, for instance stick-on epidermal electronics tattoo to measure UV exposure or tattoo-type biosensors based on graphene; and we also have posted a primer on electronic skin.
Taking the concept of e-tattoos a step further, integrating them with triboelectric nanogenerators (TENGs), for instance for health monitoring, could lead to next generation wearable nanogenerators and Internet-of-things devices worn directly on and powered by the skin.
In work reported in Advanced Functional Materials (“Triboelectric Nanogenerator Tattoos Enabled by Epidermal Electronic Technologies”), researchers report a tattoo-like TENG (TL-TENG) design with a thickness of tens of micrometers, that can interface with skin without additional adhesive layers, and be used for energy harvesting from daily activities.