Toward high volume solution based roll-to-roll processing of OLEDs

The large volume production of flexible electronics by solution based roll-to-roll (R2R) manufacturing technologies is a promising upscaling strategy for the organic electronics industry. Typical optoelectronic devices like organic light emitting diodes (OLEDs) consist of a complex stack of functional layers. Solution deposition of these structures eliminates the need for expensive vacuum processing. This contribution presents approaches for solution based R2R production methods of functional OLED layers on flexible polymer substrates. The development of a R2R line with two slot-die coating stations is discussed which can deposit two uniform layers consecutively in a single run (“tandem coating”) at web speeds up to 30 m/min. Furthermore, it offers the unique feature that there is no contact between the rollers and the top side of the substrate where the functional coating is deposited. Thereby, an important source of particle contamination and other damage to the device is eliminated. In addition to continuous deposition, stripe and intermittent coating techniques have been developed, allowing the production of patterned layers. Finally, examples will be shown of OLEDs where two functional materials are deposited by R2R processing from solution.