Challenges with blue OLEDs

Lighting consumes one-fifth of the electricity generated in the United States. Solid-state lighting offers tremendous potential to improve the situation - once major research challenges are overcome.

 

The most promising technology is the organic light-emitting diode, or OLED. These multi-layered devices produce light by running an electrical current through a specially engineered host material into which light-producing phosphorescent molecules are embedded or "doped." The white light envisioned for large-scale applications, such as rooms and buildings, consists of red, green and blue light.

 

"The weakest link in OLED research is the absence of an efficient, long-lasting blue light to accompany the red and green," said Pacific Northwest National Laboratory scientist Asanga Padmaperuma. Development of better host materials to manage the flow of electricity through the device could help solve that problem.

 

Padmaperuma and his collegues have designed, synthesized and tested new materials that improve the power efficiency of blue OLEDs by at least 25 percent.

 

28.5% efficiency was reported last year by Japanese companies Sony and Idemitsu Kosan for internal quantum efficiency in deep blue fluorescent OLED devices. They claim that this is the world's highest efficiency, with previous fluorescent OLED devices limited to a maximum 25% IQE. They expect this increase in efficiency to significantly reduce the power consumption of OLED panels, contributing to the future development of large-size OLED TVs.

 

For more attend Printed Electronics Europe 2009 .