Researchers have developed an ultra flexible and thin film designed to be worn on the human skint and provide health-monitoring information. The smart "e-skin" system includes health-monitoring sensors, displays, and ultraflexible PLEDs. It is conformable to wear and includes three-color, highly efficient polymer light-emitting diodes (PLEDs) and organic photodetectors (OPDs). The total thickness of the devices, including the substrate and encapsulation layer, is only 3 μm, which is one order of magnitude thinner than the epidermal layer of human skin.

By integrating green and red PLEDs with OPDs, the researchers at the university of Tokyo fabricated an ultraflexible reflective pulse oximeter. The device unobtrusively measures the oxygen concentration of blood when laminated on a finger. On-skin seven-segment digital displays and color indicators can visualize data directly on the body.

Ultimately, flexible organic optical sensors may be directly laminated on organs to monitor the blood oxygen level during and after surgery.