Japan's Oji Paper developed a new microfabrication technology that can be used to enhance the light extraction efficiency of OLEDs. The idea is to use microparticle coating to form a regular pattern that is several-nanometer-wide on the surface of the metal part of the negative electrode in an OLED panel. The nanostructure turns the plasmon energy (that is sometimes released from an OLED) into light.

Oji paper says that this technology was used to improve a red OLED's light extraction efficiency by about 100%!

They are now working to apply this to a white OLED:

http://www.oled-info.com/new-microfabrication-technology-can-enhance-oled-light-extraction-efficiency