Saint-Gobain and Novaled develop new OLED contacts

Jan. 15, 2008
Saint-Gobain and Novaled have demonstrated the feasibility of large area OLEDs, based on a new high-performance metallic anode.
The goal of a two-year research cooperation programme between both partners has been to develop basic technologies for high-performance white OLEDs. Researchers at Saint-Gobain Recherche (SGR) have created a highly-conductive transparent electrode named Silverduct™, bringing up to 10 times better surface conductivity than traditional ITO (Indium Tin Oxide).

Using Novaled PIN OLED™ technology for high efficiency OLEDs, samples were successfully manufactured on large area surfaces. SGR and Novaled now see the possibility to produce homogeneous OLED devices up to 100 cm2, 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 centimetres. Therefore, 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 30 Ohm/sq).

The new anode Silverduct™ has a sheet resistance of less than 4 Ohm/sq, thus enabling large area OLEDs without additional metal grids. This is an important step especially 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.

“Saint-Gobain has world-class expertise in manufacturing metallic layers on glass. Our researchers have developed Silverduct which is well-suited to the promising OLED market”, says Didier Roux, VP Research of Saint-Gobain Group.

“When combining the remarkable advantages of Novaled PIN OLED technology with our specific electrode, we achieved lab samples with an increased efficiency of +30%. 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”.

“We have been pleased to work with Saint-Gobain, a global player in the glass industry with innovative metal layers for large lighting areas.” says Gildas Sorin, CEO of Novaled. “This cooperation illustrates our strategy of engaging with the key players to sustain a solid OLED business ramp-up. 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” he adds.