Organic LEDs are especially useful in blue because blue is a primary color for producing white light. Blue OLEDs are also the hardest hue to achieve. As part of a project sponsored by the Department of Energy, materials engineer Franky So recently demonstrated an exceptionally efficient blue OLED, which could mean a bright future for these little lights.

From the U.S. Department of Energy...

Researchers at the University of Florida have demonstrated a blue phosphorescent organic light-emitting diode with a peak power efficiency of 50 lm/W and a peak external quantum efficiency of 29 percent, using no external light extraction techniques. This accomplishment is believed to be the world record in blue OLED efficiency.

Blue OLEDs are important in the creation of white light suitable for solid-state general illumination applications, but high-efficiency blue OLEDs with good lifetime and stability have represented a significant technical hurdle. Most phosphorescent OLEDs including this particular type of blue small molecule possess an inherent imbalance of charge carriers that limits internal quantum efficiency.

The UF team has demonstrated very high-efficiency blue OLEDs using a unique charge carrier material with special electrical properties. The team will continue to exploit certain light extraction techniques and special down-converting phosphors that will produce white light from the high-efficiency blue OLEDs developed in their lab.

For more information, see the DOE SSL Project Portfolio.