Product Code: ICAL08_N303

Production Technology for Transparent and Conducting Nano Layers
Authors:
Christian Vedder, Fraunhofer Institute For Lasertechnology; Aachen Germany
Jochen Stollenwerk, Fraunhofer Center for Laser Technology; Aachen Germany
Norbert Pirch, Fraunhofer Center for Laser Technology; Aachen Germany
Konrad Wissenbach, Fraunhofer Center for Laser Technology; Aachen Germany
Presented at ICALEO 2008

The paper describes the thermal laser treatment of printed transparent conductive oxide coatings (TCO) based on nanoscale indium tin oxide (ITO). Nanoparticulate dispersions have proven to be a powerful source for producing functional layers. ITO is used as a transparent anode material for e.g. organic LEDs (OLED). As the price of indium continues to increase it is crucial to decrease its loss in conventional masked sputtering processes for structured coatings. The application of nanoparticulate ITO layers onto glass or polymer substrates by e.g. ink jet printing is particularly challenging as the necessary thermal treatment of the dried films in order to achieve high conductivity often requires temperatures that exceed the temperature stability of the substrate or result in extensive grain growth in the layer material. The laser beam offers the possibility to overcome these drawbacks with high heating and cooling rates due to the high intensities and short interaction time between focused laser beam and work piece that can be achieved. Thus the post processing of those ITO layers with laser radiation is a key process step to obtain layers with appropriate functionality such as high conductivity and transparency.