Color-Stable White Organic Light-Emitting Diodes Utilizing a Blue-Emitting Electron-Transport Layer

We have fabricated efficient and color-stable white organic light-emitting diodes (WOLEDs) based on a simple double-layer device structure consisting of a blue-emitting oligoquinoline electron-transport layer and a poly­(N-vinyl carbazole) layer doped with phosphorescent green and red iridium emitters. Pure white color with the CIE coordinates from (0.30, 0.31) to (0.34, 0.37) in the whole operating bias voltage range and luminous efficiency higher than 7 cd/A at a brightness up to 12 000 cd/m² was achieved. These results demonstrate a new strategy to realizing easily processable, highly efficient, and color-stable WOLEDs with a simple structure.