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  • 02 Aug 2012

Printed electronics research project moves into next phase

- Cost-effective production methods for printed electronics on flexible substrates are developed and tested in a joint cleanroom by leading industry names

BASF, Heidelberg and TU Darmstadt have commenced work on the NanoPEP2 development project after reporting successful results from their initial investigations into nano-based functional materials.

The trio are to continue their joint research work after the first phase of the "Nanostructuring and plastic electronics print platform" (NanoPEP) project resulted in the successful production of functional elements under cleanroom conditions.
Researchers at the participating companies have been working on nano-based functional materials and the related innovative printing methods for processing these since summer 2009.
Potential applications
The resulting applications in the field of organic electronics are based on conductive polymers and on smaller molecules of organic chemistry and are regarded as important technologies of the future offering considerable economic potential.
Possible areas of application extend from organic circuits and storage devices to photovoltaics and organic LEDs.
NanoPEP is one of the projects conducted by the Forum Organic Electronics cluster, which is promoted by the German Federal Ministry for Education and Research (BMBF). Links with other members of the cluster active in areas such as OLEDs, solar cells and printed circuits give it access to a broad range of technologies for developing possible applications.
Significant progress has already been made in the initial NanoPEP phase.
Rotary printing press
A rotary printing press based on the Gallus RCS 330 provided the platform for this. Initial functional elements have already been produced under laboratory conditions in the cluster's cleanroom using modified printing methods.
The task of transferring these processes to an industrial scale over the next two years is the primary purpose of the NanoPEP2 follow-up project.
In addition to the ongoing development of the nanostructured materials and the associated printing methods, practical demonstrators will be used to show the functionality of the printed components.
These can take the form, for example, of flexible OLEDs or solar cells produced in the cluster's joint cleanroom.
The printing press plays a key role in this work. It serves as the platform for modified or completely new printing or coating units and thus as an integrator for the newly developed processes.
The demands placed on the printing methods are very high. Being just a few nanometers thick, the printed layers must be extremely homogeneous and free of flaws.
To transfer these highly complex printing processes to a production scale, it is vital to precisely understand the processes that take place in a printing unit itself.
Consequently, the Institute for Printing Presses and Printing Methods (IDD) at Technische Universität Darmstadt is working on a model for defining the key production parameters.
The researchers are also examining the specific physical mechanisms that can lead to inhomogeneities in the printed organic semiconductor and dielectric layers and thus to the failure of the subsequent product.
New materials
Printable organic electronics require entirely new materials, which are developed by BASF experts in the field of nanostructuring.
Specially designed nanoparticles are used as building blocks for functional materials, which are built by new process technologies in a toolbox-like system.
In a subsequent step, these materials are processed into printable suspensions and tested by the project partners. The researchers rely on innovative hybrid materials consisting of inorganic and organic components allowing for perfect electronic functionality in the printed film.
Over the past three years, new integrated production processes for innovative hybrid materials have been developed in order to avoid intermediate process steps such as stabilization of the materials. The plants constructed for this purpose are able to produce the materials required for the printing tests on a kilogram scale.
Printable suspensions
In parallel, BASF researchers are developing printable suspensions for organic electronics that can be processed at low temperatures.
Again, this is a challenge for material development because the components and their interaction have to be adjusted to the printing conditions.
These materials should enable the production of components on inexpensive flexible polymer foils using the roll-to-roll printing method.
Heidelberg discusses its work within the Forum Organic Electronics in PPW issue #3. Read the interview online, here
Picture: Heidelberg presented an OLED demonstrator for organic electronics at Drupa 2012 | Image copyright: Heidelberger Druckmaschinen AG
Read more on Heidelberg here
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