Organic LEDs produce saturated, bright-red light-emission spectra

Researchers at the Optical Sciences Center of the University of Arizona have fabricated efficient organic-light-emitting devices with saturated red-light-emission spectra. The interesting aspect of these devices is that they are hybrids and use a more stable cathode such as aluminum (Al) instead of calcium or magnesium. Current state-of-the-art devices, based on the phosphorescent dopant platinum octaethylporphyrin and magnesium silver alloy cathode, emit saturated red light with luminance of about 1 cd/m² at an external efficiency of 5.6%. These same devices also have an external efficiency of 2.2% at a luminance level of 100 cd/m², a level more suited for display applications. The hybrid devices with Al cathode allow for the emission of saturated red color and have external quantum efficiency approaching 9% at forward light output of about 14 cd/m². At about 100 cd/m², these devices have an external quantum efficiency approaching 7%. More optimization is also underway to push the performance even higher.