Electrodes and barriers
Organic semiconductors are key to many ‘System-in-Foil’ applications. But they’re extremely sensitive to the environment, requiring high-performance protection. In addition, many applications place stringent demands on electrodes. For example, in organic light emitting diodes (OLEDs), the cathode is very moisture sensitive. By replacing existing barrier and electrode materials, Holst Centre and its partners aim to reduce costs and maximize performance for flexible systems.
Most OLEDs and photovoltaic (PV) cells today are encapsulated in glass. This gives excellent environmental protection but isn’t flexible and is expensive – up to 50% of the cost of the finished system. Hence, this program aims to develop a low-cost, plastic barrier. It’s a huge challenge. The barrier must let through less than 1 microgram of water vapor per square meter per day. That’s 100,000 times less permeable than foil packaging for food.
The focus is on developing thin-film barriers using low-temperature deposition processes. Our main objectives are:
- encapsulation barriers that can be deposited directly onto the cathode of OLED and PV devices
- thin-film barriers on plastic foils which can be used as substrates for environmentally sensitive devices such as OLEDs and organic PVs
- alternative cathode deposition methods to increase throughput and reduce costs
- demonstrating the feasibility of manufacturing these layers at 1-10 meters per minute on a roll-to-roll pre-pilot line with a 30-cm-wide web.
To do this, the program brings together a wide network of partners including:
- foil and substrate manufactures
- materials suppliers
- equipment manufacturers
- integrated device manufacturers (IDMs)