1. Applied Voltage makes the current flow from the cathode towards the anode thorugh organic layers. This leads to removal of electrons from conductive layer and introduces electrons in the emissive layer.
Construction of an Oled
2. Removal of electrons from the conductive layer creates positively charged atoms called Holes which need one electron to form a stable atom.
3. The electrons from the emissive layer jumps to combine with the holes and in due process releases energy in the form of a light photon.
Kodak LS 633-the first camera to use OLED Screen
Samsung's 21" screen based on OLED. Expect more such screens in the near future
Small OLED screens made its way on the Samsung E700 cell phone