28.09.14

Getting blue PHOLEDs to live longer

AUTHOR: Inavate

Researchers at the University of Michigan have extended the lifetime of blue phosphorescent OLEDs (PHOLEDs) by a factor of 10.

There are two kinds ofOLEDs, phosphorescent OLEDs (PHOLEDs) and fluorescent OLEDs. The former are preferred to the latter due to the fact that their light producing mechanism is four times more efficient than the latter's. Displays use red and green PHOLEDs,but blue light is provided by fluorescent OLEDs as blue PHOLEDs has shorter lifetimes. This arrangement may be about to change thanks to the recent development.

The breakthrough comes from Stephen Forrest, the Paul G. Goebel Professor of Engineering at University of Michigan, and doctoral students from his group, Zhang and Jae Sang Lee. Blue PHOLEDs comprise of a thin light emitting material between two conductive layers. The solution keeps this design in tact but spreads out light producing energy further so that the blue PHOLEDs do not dim after use.

If the new blue PHOLEDs are employed in display product it is expected that the efficiency of the devices can be increased by five to 20 percent. The main beneficiaries are expected to be smartphone displays and commercial television sets which would be able to provide longer battery lives and lower power consumption respectively. More power efficient television screens may also increase the competition digital signage displays are facing from the commercial panels.