After the active organic layers were deposited on the first glass foil, an adhesive glass foil was applied through a continuous roll-to-roll lamination process, offering an hermetic barrier, free of defects while retaining the flexibility of thin glass.
The research was based on Nippon Electric Glass' G-Leaf ultra-thin glass which the company is able to manufacture as thin as 35μm.
“Encapsulation is not the only challenge for flexible large area OLEDs that need to remain stable over long periods. In order to get them to emit, a highly conductive, transparent oxide layer with good light coupling properties is required and reliable electrical contacts to the emitting layers with low contact resistance is essential," explains Dr. Stefan Mogck, Head of Roll-to-Roll Organic Technology at Fraunhofer FEP. “We are proud of having optimized our process, and that these layers can be applied very homogenously to the flexible glass.”
Making dependable electrical connections to the ultra-thin glass without damaging it was especially challenging.
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