Fraunhofer FEP presents functional films for printed electronics

Flexible OLED of Fraunhofer COMEDD, built upon and encapsulated with functional films of Fraunhofer POLO

The Fraunhofer FEP presented vacuum technologies for the production of functional films for organic and printed electronics at the international trade fair and conference LOPE-C 2013 in Munich.

Printed electronics, for example in solar cells, sensors or displays, are becoming increasingly popular on the mass market. Apart from the possibility of new functions and designs, productive deposition methods and the flexible materials used promise significant reductions in production costs. The short lifetime of the products has often been an obstacle to their widespread commercialization up to now. The main reason for this is the high sensitivity of the electronic functional materials inside the devices, which can be damaged by water vapour and oxygen.

The Fraunhofer Institute for Electron Beam and Plasma Technology FEP in Dresden develops vacuum processes to productively seal polymer films roll-to-roll with so-called high-barrier and functional layers. A standard polymer film would allow large amounts of water vapour and oxygen to pass through. Permeation barrier layers prevent gas diffusion and thus protect the active, organic materials. In addition to the barrier function, the film can also be enhanced through further, application-related functional layers. For example, the optical properties of the film can be adapted or transparent electrodes can be added on top of a barrier stack.

Dr. John Fahlteich, an expert for high-barrier films at the Fraunhofer FEP, presented productive roll-to-roll coating processes for films with extremely good barrier at the LOPE-C in Munich. With the help of a multilayer system made from sputtered zinc-tin-oxide (ZTO) layers and ORMOCER^® hybrid-polymer, water-vapour permeability’s of less than 8 • 10^-5 g / (m²d) can be achieved at room temperature. This corresponds to roughly one drop of water seeping through an area of the size of a football pitch in one month. The layer system, which was developed within the Fraunhofer Polymer Surfaces Alliance (POLO) in cooperation with the Fraunhofer ISC (ORMOCER^® development) and Fraunhofer IVV (ORMOCER^® application), is currently one of the systems produced in a roll-to-roll process with the lowest water-vapour permeability properties in the world.

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