Printing technology possess the potential of accelerating and enabling the fabrication of optoelectronic applications in an unprecedented manner. However, the different device requirements in terms of device architecture and resolution will set the boundaries for the choice of printing fabrication technique. Particularly, organic light-emitting diodes (OLEDs) and organic photodetectors (OPDs) require a multilayer device architecture for an efficient performance. Therefore, a lot of care has to be placed in the ink formulation and processing of the materials to maximize device functionality.
In this talk, we will first discuss different approaches for the fabrication of OLED active layers by gravure printing. Moreover, we will present the fabrication of OLEDs utilizing solution processed electron injection layers (EIL) and the influence of the EIL molecular structure, thickness and film morphology on the device characteristics. Furthermore, we demonstrate a simple crosslinking step that improves device performance and enables processability of printed cathodes.
In the second part, we demonstrate a new direct-printed patterning technique comprising aerosol jet and inkjet printing, which allows for very precise, reproducible and deposition of multilayer devices with high registration accuracy and feature sizes down to a few micrometers. We apply this method for the fabrication of high performance bulk –heterojunction-based OPD arrays.
Finally, our recent efforts on the inclusion of biodegradable materials as passive and functional components of printed light-emitting devices will be presented.
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Gerardo Hernandez-Sosa received his PhD from the Johannes Kepler University Linz, Austria in 2009. Currently he is a research group leader of the Karlsruhe Institute of Technology, based in InnovationLab Heidelberg, Germany. His research group focuses in the development of printed optoelectronic devices and the use of biocompatible and sustainable materials in electronics. Prior to his current post, he worked in the Center for Polymers and Organic Solids of the University of California Santa Barbara, USA.