23 Feb 2007
Top emission OLEDs are the future of display and lighting applications, says the company that has just improved outputs of these devices.
Novaled claims to have achieved "groundbreaking" results in lifetime, voltage and efficiency of top-emitting RGB stacks with its PIN OLED technology. Lifetimes for blue OLEDs are up to 16,000 hours, for red and green up to 100,000 hours at an initial brightness of 500 cd/m2.
This latest performance means that green OLED devices are now outperforming their bottom emission reference samples by a factor of 2.5. White top emission devices achieved a lifetime of 18,000 hours at a driving voltage of 3 V and a starting luminance of 1,000 cd/m2.
Moreover, the lowest ever reported operating voltage has been achieved for green top-emission OLED stacks of 2.5 V at 1,000 cd/m2. At 95 cd/A, the current efficiency is higher than for comparable bottom emission devices. These green devices are based on "standard" emitter material Ir(ppy)3.
Top emission OLED structures emitting light away from the substrate are a key feature of future OLED applications, Novaled asserts: the top emission design increases the aperture ratio above 50% for displays and paves the way for more powerful, large area active-matrix displays. When used in lighting devices, top emission OLEDs enable manufacturers to use cheap non-transparent and flexible substrates.
"Top emission OLEDs are the future of display and lighting applications," said Jan Blochwitz-Nimoth, CTO of Novaled. "Our technology is currently being tested by different OLED manufacturing companies preparing their entry into mass production."