Organic light-emitting diodes (OLEDs) are promising candidates for use in portable devices such as cellular phones and personal organizers. And as with all previous such technologies the natural progression is from monochrome to colour. This has been achieved with OLEDs, but it has not been possible to make them using convenient solution-based methods. A new process based on electroluminescent polymers that act like 'photoresist' materials - becoming soluble under ultraviolet light so that exposed areas can be washed away with a solvent - now makes it possible to fabricate colour matrix displays using OLEDs. Pixelated devices can be constructed with these polymers, displaying red, green and blue. The blue emitter performs well, though the red and green will need to be improved before the devices become a practical proposition. Link