Printing electronic displays like newspapers
At the InnovationLab in Heidelberg, Germany, the worlds of science and industry are pursuing a common goal. Companies and universities are working together to develop luminous wallpaper, solar cells, and integrated circuits that can be printed in the same way as a newspaper. EMD is involved in four of the innovation projects and is providing them with new types of ink.
Andreas Taugerbeck heads the EMD team at the InnovationLab in Heidelberg
Nowadays people can choose checked or woodchip wallpaper, depending on their individual taste. In the future, they may also be able to choose wallpaper that emits light. Such wallpaper will be like a huge display composed of organic light-emitting diodes (OLEDs) that provide lighting or present images. It will be possible to roll up and print these displays like newspapers and affix them like wallpaper to various surfaces.
How to print electronic displays
The PrintOLED project provides preliminary answers to the question of how this vision can become reality. For this purpose, EMD has teamed up with universities and leaders of the global lighting industry to create a research network at the InnovationLab.
“Our task is to develop formulations for printing large electronic components onto films,” says Andreas Taugerbeck, who heads the EMD team of four employees. They are assisted by doctoral candidates, graduate students, and interns. What is unusual about the new approach is that the electronics are not made of the usual semiconductor material silicon, which is brittle, but of organic or inorganic components that can be printed like ink onto a surface.
The Heidelberg InnovationLab is an application-oriented research and transfer platform located in the Rhine-Neckar metropolitan area. Besides EMD, the shareholders include the companies BASF (chemistry), Heidelberger Druckmaschinen (printing technology), and SAP (IT), as well as the universities of Heidelberg and Mannheim.
In addition, several universities and renowned companies from a variety of sectors participate in individual InnovationLab projects. In 2008 the German Ministry of Education and Research (BMBF) provided the key impetus for the creation of this network when it promised to give the lab’s leading-edge cluster, Forum Organic Electronics, a total of up to €40 million in funding over a period of five years. Since then, InnovationLab partners have been intensely studying how luminous wallpaper, solar cells, and integrated circuits can be printed onto flexible thin substrates. EMD is involved in four of these projects.
A lab like a newspaper printing room
At the heart of the research center is a 650-square-meter cleanroom lab that was planned and built according to the latest technological standards. The facility houses all of the currently available ink printing technologies, which are used here for testing purposes. The equipment ranges from screen printing and flexographic printing systems to inkjet printers and offset printing machines. The star of the ensemble is a 17-meter roll-to-roll printing machine like those that are normally found only in newspaper printing rooms.
However, this system prints not on paper but on sheets of film, and for this purpose it uses completely new types of ink. These inks contain long chains of organic compounds (polymers) and, in some cases, smaller inorganic molecules, which have insulating, semi-conducting or conducting properties, depending on their chemical makeup. Conventional mass printing processes are used here to apply the inks to surfaces.
Besides focusing on printable OLEDs, research at the InnovationLab focuses on printable solar cells. The researchers hope that this innovative technology will help them apply thin layers of materials (e.g. compounds of copper indium gallium diselenide) onto flexible substrates. This would reduce the cost of manufacturing solar cells, because the materials would no longer have to be deposited onto glass at high temperatures, as is the case today. The cells’ light weight would allow them to be installed not only on rooftops but also on building façades. As a result, much larger areas than the ones used today could potentially be used to generate electricity.
A future goal: the “Internet of Things”
Another focus is on printable integrated circuits. One day these circuits could connect many small items of daily life with the Internet, for example in the form of radio-frequency labels on clothing or food packaging. In this “Internet of Things,” every item would have its own IP address. These addresses would close the gap between real life (e.g. parcels) and the IT world so that items could be optimally distributed. However, two very specific challenges have to be overcome before the “Internet of Things” can become reality.
The first challenge is to develop materials that are sufficiently dissoluble (which makes them easy to print) and also have a high level of conductivity. EMD is currently searching for appropriate solutions in the joint Morpheus project. For this project the researchers are also using the InnovationLab’s extensive range of systems for directly analyzing and simulating electronic components so that they can immediately integrate the results into new formulations.
At the InnovationLab in Heidelberg, companies and universities work together to develop printable OLEDs and printable solar cells
© InnovationLab GmbH
Concepts for manufacturing
The second challenge is to create effective design guidelines and manufacturing processes for organic circuits. This is because the more complex circuits are, the more likely it is that certain components will not harmonize with one another. That is why the researchers working on the Polytos project are creating a modular technology set that consists of components and processes that can be combined in various ways. This set should make it easier for companies to start manufacturing integrated organic circuits. This concept has been successfully employed in the conventional microelectronics sector for years.
Taugerbeck is satisfied with the results that have been achieved to date. “We have reached all of our interim goals,” he says. The main aim now is to define new projects and goals, because the funding from the BMBF will cease at the end of the year. However, Taugerbeck has plenty of ideas for further funding. “The current projects have raised a sufficient number of new questions,” he says.