Organic Light-Emitting Devices

"Researchers working on organic light-emitting devices (OLEDs) have made a critical jump that could finally call lights out time for the humble bulb. Since OLEDs are transparent when switched off, the prospect is of whole surfaces like walls, windows, or even curtains flooding rooms with brilliant white light.

University of Southern California Professor Mark Thompson said: "This process will enable us to get 100 percent efficiency out of a single, broad spectrum light source."

The American team's breakthrough was to make OLEDs able to emit the daylight-style white light needed in homes and offices. Previous efforts had had struggled to get the full spectrum of wavelengths required."

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Current incandescent interior lighting, which has been in development for over 125 years, has an efficiency of approximately 15 lumens per watt. Electrophosphorescent white OLEDs have already demonstrated efficiencies of approximately 20 lumens per watt at levels bright enough for room illumination. We recently demonstrated in our labs that by combining phosphorescence and more conventional fluorescence, we can make a single OLED structure that produces nearly 30 lumens per watt, with the possibility of 50 to 60 lumens per watt in the near future. This device operates at lower voltage than a pure electrophosphorescent white OLED, resulting in improved efficiency.

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