Opsys Develops Dendrimer OLEDs

LONDON, March 26 -- High-efficiency organic light-emitting diodes (OLEDs) using pioneering dendrimer materials have been developed by scientists sponsored by display technology developer Opsys, which says the results have broad implications for the commercialization of OLED technology in the flat-panel display industry.

The Opsys-sponsored teams, led by Paul Burn of the University of Oxford and Ifor Samuel at the University of St. Andrews, have shown that dendrimers can be used to produce efficient solution-processed OLED devices with just a single layer of organic material between the electrodes. In contrast, existing phosphorescent materials require multiple layers of deposition by more expensive evaporation techniques.

Burn, who is also a consultant to Opsys, said, "Unlike light-emitting polymers (LEPs), dendrimers can incorporate the best features of small molecule materials, such as highly efficient phosphorescent-emitting cores, while also being solution processable. As such, dendrimers are a promising alternative to both small molecule and LEP approaches to OLEDs."

LEPs are the only OLED materials other than dendrimers that can be deposited by solution processing methods. However, LEPs are not as versatile, as the same chemical components of an LEP are responsible for both its light-emitting features and its processing features, Opsys said. In dendrimers, the surface groups may be tuned independently of the emitting core, providing flexibility in the processing properties.

The results were announced at the American Physical Society conference on March 22 and will be published in Applied Physics Letters on April 15 under the title "High-efficiency green phosphorescence from spin-coated single layer dendrimer LED structures."