Saint-Gobain (Courbevole, France) and Novaled (Dresden, Germany) have demonstrated the feasibility of large-area, high-performance, white OLEDs, based on a new, high-performance, metallic anode, with Saint-Gobain Recherche technology and Novaled OLED proprietary developments.
Researchers at Saint-Gobain Recherche (SGR) have created the Silverduct™, a highly conductive, transparent electrode, with, the companies claim, up to 10 times better surface conductivity than traditional indium tin oxide (ITO). Thanks to Novaled PIN OLED™ technology for high-efficiency OLEDs, samples were manufactured on large-area surfaces. SGR and Novaled now see the possibility to produce homogeneous OLED devices up to 100 sq. cm, which will ease the manufacturing of large, OLED-lighting products.
Traditional, ITO-coated glass can’t carry current over distances longer than a few centimeters. Therefore, for large-area OLEDs, the ITO layer must be topped with a thick, metallic grid to prevent light-emission gradient caused by ITO sheet resistance (typically 30 Ohm/sq). Silverduct’s sheet resistance of less than 4 Ohm/sq enables large-area OLEDs without adding more metal grids. (The metal grid is visible in transparent and bottom-emission OLEDs.) Additionally, by eliminating the metal grid, Silverduct can reduce manufacturing costs.
Pr. Didier Roux, Saint-Gobain Group’s VP of research, said, “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.”
As background, OLEDs are semiconductors that comprise thin (a few nanometers thick), organic-material layers. They emit light in a diffuse way to form an area light source. In a fast-growing display market, OLEDs are being incorporated in paper-thin, highly efficient displays, where they produce brilliant colors and enable flexible designs. OLEDs offer the potential to outstrip CFL bulbs’ energy savings.