The advent of decal, or tattoo-like, electronics is expected to benefit the manufacture and performance of wireless, wearable health monitoring devices.

Pressure-sensitive "e-stickers" contain all the functionality of traditional silicon circuits and can be fabricated into complex, flexible shapes. Credit: KAUSTResearchers at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia have devised a process that prints high-performance silicon-based computers on to soft, sticker-like surfaces that can be attached anywhere.

The researchers investigated various approaches to realize flexible printed circuits through a high-speed process and that conform to the human body. Their solution is a sensor containing narrow strips of aluminum foil that changes conductivity at different bending states.

Such devices could monitor a patient's breathing patterns or activity levels and feature high-mobility zinc oxide nanotransistors on silicon wafers thinned down lithographically to microscale dimensions for maximum flexibility. Silicon chips and foils are encapsulated into a polymer film backed by an adhesive layer by use of 3-D printing technology (see video).