Researchers from Germany's TU Darmstadt University developed new glowing fibers by coating them with white OLED emitters. They call their technology reproducible rotational coating and they envision all sorts of possibilities in the area of smart textiles, as in the future it'll be possible to coat all sorts of semiconductor components (such as transistors or solar cells) on fibers.
The researchers use vacuum deposition and small-molecule OLEDs for this process. They deposit seven different layers but the whole OLED is just 200 nanometers thick. OLEDs require a very smooth substrate and so currently they use glass fibers - which aren't really useful in wearable applications as they are too brittle to be woven into textiles. They are now starting to experiment with polymer-coated glass fibers that may be flexible enough to be used in textiles.
Another problem is the encapsulation. They still haven't solved this issue and so these OLEDs won't last very long. In any case the scientists want to patent this development.