Saint-Gobain, Novaled demo large-area OLEDs
Saint-Gobain and Novaled have presented the feasibility of large-area OLEDs, based on a new high-performance metallic anode.
The two-year research cooperation program aimed to develop basic technologies for high-performance white OLEDs. Researchers at Saint-Gobain Recherche (SGR) have created a highly conductive transparent electrode dubbed "Silverduct", bringing up to 10 times better surface conductivity than traditional indium tin oxide (ITO). Coupled with Novaled's PIN OLED technology for high efficiency OLEDs, samples were successfully manufactured on large-area surfaces. SGR and Novaled tout the possibility to produce homogeneous OLED devices up to 100cm², which will ease the manufacturing of large OLED lighting products.
Traditional ITO coated glass impedes the race to large area OLED, due to its limited ability to carry current over distances longer than a couple of centimeters. For large area OLEDs, the ITO layer must be topped with a thick metallic grid to prevent gradient of light emission caused by the sheet resistance of ITO alone (typically 30Ω/sq). The new anode Silverduct has a sheet resistance of less than 4Ω/sq, enabling large area OLEDs without additional metal grids. This is an important step for transparent and bottom emission OLEDs in which the metal grid is visible. Additionally, by eliminating the metal grid Silverduct offers significant potential for reducing manufacturing costs.
"Our researchers have developed Silverduct which is well-suited to the promising OLED market," says Didier Roux, VP research of Saint-Gobain Group. Roux added that combining the Novaled PIN OLED technology with Silverduct, they were able to achieve lab samples with an increased efficiency of 30 percent. "The lack of metallic grid makes the whole processing much easier. Furthermore, improved lifetime has been demonstrated, as compared to the equivalent OLED device based on ITO."
"This cooperation illustrates our strategy of engaging with the key players to sustain a solid OLED business ramp-up," said Gildas Sorin, CEO of Novaled. "Our technology offers the advantage of being able to be combined with any substrate surface and electrode structure while providing OLED devices with highest energy saving and longest lifetime."