Large-area OLED lighting is an attractive technology for various applications in residential, architectural and automotive lighting segments. Sefar developed high conductive, transparent and flexible electrode substrates enabling large-area, homogenous lighting which is demonstrated by Fraunhofer FEP in a R2R process.
OLED for lighting applications enables new form designs (large area, flexible, lightweight and thin), is one of the closest light sources to natural light and has a low energy consumption.
"The new electrode substrate SEFAR TCS Planar is manufactured in a roll-to-roll process," explains Roland Steim, project manager at Sefar, "It is a foil like substrate with a very high conductivity of up to 0.01 Ohm/sq and a transparency above 87%. This outstanding high conductivity originates from embedded metallic wires with a diameter of currently 40 µm."
These metal wires reduce resistive losses in the transparent electrode substrate, which allows the design of larger and more homogeneous lighting solutions compared to conventional substrates like pure ITO. In addition, the embedded metallic wires are robust against bending of the substrate and less brittle then thick ITO layers on films. One challenge in the development of SEFAR TCS Planar was getting the surface as smooth as possible while parts of the metallic wires still emerge on the surface forming the electrical contact to the OLED.
Fraunhofer FEP has huge experiences in roll-to-roll processing of OLED and offers research and development services from concept studies to sample production in the field of R2R fabrication of organic-based devices on flexible substrates for industrial partners.
Stefan Mogck, head of department roll-to-roll organic technology at Fraunhofer FEP, adds, "We processed the OLED in vacuum in a roll-to-roll process on SEFAR TCS Planar substrates with a specific developed drying process and barrier film lamination. Altogether we deposited the OLED 30 m in length and 30 cm in width and OLED size up to 250 cm²."