Researchers from the University of Tokyo developed a new technology to bond polyimide films to glass so it can easily be peeled off by applying heat. Polyimide is widely used today as a flexible OLED substrate, which is indeed produced on glass and then de-laminated at the end of the deposition process. This is an expensive process today (which requires a laser) with low yields.

The new bonding technology (which they call surface activated bonding) makes it easier to remove the polyimide film. In the new process an argon io beam is used to remove the oxide and adsorption films and flatten the surfaces. A 5-20 nm thick silicon layer is formed between the glass and the polyimide by ion beam sputtering. An iron adhesion layer (1 nm thick) is formed on the silicon to reinforce the bonding.

Heating the resulting glass-polyimide film to 400 Celsius for about an hour reduces the bonding strength which makes it easy to separate the films. The researchers estimate that this technology can be commercialized within a few years, and this may result in cheaper flexible OLED production. This technology can also be modified to be used in roll-to-roll processes.

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The OLED won't like the 400 Celcius though...

If the substrate really has to be heated to 400 (!) degree Celcius for an hour in order to separate the PI from the glass, it's hard to imagine how this technique would be suitable for fabrication of OLEDs. An OLED deposited on the glass-PI substrate would not be likely to withstand this sort of temperature treatment.

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