EU project TREASORES finishes successfully
In November 2012, the TREASORES project (Transparent Electrodes for Large Area Large Scale Production of Organic Optoelectronic Devices) started with the aim of developing technologies to dramatically reduce the production costs of organic electronic devices such as solar cells and LED lighting panels. Funded with €9M from the European Commission and an additional €6M from the project partners, the project has since then produced seven patent applications, a dozen peer-reviewed publications and provided inputs to international standards organisations. The TREASORES project united nine companies with six research institutes from five countries and was led by Frank Nüesch from the Swiss Federal Laboratories for Materials Science and Technology (Empa) who is ”very much looking forward to seeing the first commercial products made using materials from the project in 2016.”
Most importantly, the project has developed and scaled up production processes for several new transparent electrode and barrier materials for use in the next generation of flexible optoelectronics. Three of these electrodes-on-flexible substrates that use either carbon nanotubes, metal fibres or thin silver are either already being produced commercially, or expected to be so as of this year. The new electrodes have been tested with several types of optoelectronic devices using rolls of over 100m in length, and found to be especially suitable for next-generation light sources and solar cells. The roll of OLED light sources with the project logo was made using roll-to-roll techniques at Dresden-based Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology (FEP) on a thin silver electrode developed within the project by Rowo Coating GmbH.
Such processing techniques promise to make light sources and solar cells much cheaper in future, but require flexible and transparent electrodes and water impermeable barriers – which have also been developed by the TREASORES project. The electrodes from the project are technically at least as good as those currently used (made from indium tin oxide, ITO) but will be cheaper to manufacture and do not rely on the import of indium. Tomasz Wanski from Fraunhofer FEP said that because of the new electrodes, the OLED light source was very homogeneous over a large area, achieving an efficiency of 25 lumens per watt - as good as the much slower sheet to sheet production process for equivalent devices. In the course of the project, new test methods were developed by the National Physical Laboratory in the UK to make sure that the electrodes would still work after being repeatedly bent – a test that may become a standard in the field.
A further outcome of the project has been the development, testing and production scale-up of new approaches to transparent barrier foils (plastic layers that prevent oxygen and water vapour from reaching the sensitive organic electronic devices). High performance low-cost barriers were produced and it is expected that the Swiss company Amcor Flexibles Kreuzlingen will adopt this technology after further development. Such high performance barriers are essential to achieve the long device lifetimes that are necessary for commercial success – as confirmed by a life cycle analysis (LCA) completed during the project, solar cells are only economically or ecologically worthwhile if both their efficiency and lifetime are high enough. By combining the production of barriers with electrodes (instead of using two separate plastic substrates), the project has shown that production costs can be further reduced and devices made thinner and more flexible.