Researchers from the UK's UCL and Italy's IIT developed OLED-based smart temporary tatoos. Similar to children's "sticker" type tatoos, these small devices can be transferred to the skin by being pressed and washed with water.
Such devices could in the future be used to short-term sensors (for example to detect when an athlete is dehydrated during an event) or in fruit packaging to signal when a product has passed its expiry date.
The OLED device itself adopts a simple structure - a polymer-emitting material between two electrodes, protected by an insulating layer. The PLED emitter is deposited using spin coating.
Last year researchers from Yonsei University in Korea developed a full-color wearable AMOLED display that can be placed directly on human skin. The device can be flexed and stretched as needed.