From red to blue: printing OLEDs in virtually any color

Karlsruhe – A modular system for fine-tuning the solubility and color of OLED emitters: cynora proposes an innovative concept for solution-based manufacturing of OLEDs for displays, lighting and flexible packaging. This paves the way for creating displays, light panels and flexible luminescent foil that for the most part can be manufactured using printing and coating processes. cynora recently published two scientific papers on these latest research findings in the industry journals Inorganic Chemistry and the Journal of Materials Chemistry.

Coloration, solubility and autocatalytic layer crosslinking

The ability to synthesize new luminescent materials will in future enable us to address the entire color spectrum. The modular OLED emitters are copper-based molecules, i.e. metal complexes. These metal complexes consist of a metal core surrounded by a ligand shell that plays a major role in determining the properties of the complex. By modifying the ligands it is possible to precisely modulate key properties such as color and solubility.

“Subtle modification of the structure and their corresponding electronic properties of the ligands enable us to fine-tune the color of the light being generated. And we can do that practically across the entire visible spectrum, from red to green to blue,” cynora CEO Thomas Baumann explains the research findings. Moreover, the solubility of the building blocks can be adjusted through further modifications as well – an aspect that is of central importance for the fabrication of OLEDs with solution-based processes. “Because manufacturing organic light-emitting diodes involves processing multiple layers on top of each other, it is especially critical that underlying layers are preserved when the new layer is applied,” says Baumann. “That is why it is important to be able to precisely influence the luminescent material’s solubility and adjust it to the fabrication process. That, in a nutshell, is what we managed to achieve.“

The innovative approach also offers the possibility of turning the applied layers insoluble, effectively preventing undesired blending of the functional layers. This crosslinking is achieved through autocatalytic networking of the copper complexes with a host matrix in the drying stage during processing. Baumann on the advantages of this approach: “The functional layer we obtain with this step is ideally suited for the solution-based processing of multilayer systems. It shows greater thermal stability than the non-modified metal complex, and becomes insoluble in all common organic solvents.”

Tobias Grab, co-CEO of cynora, places the new modular concept at the industry’s cutting edge: “The problems currently faced by major Asian manufacturers show only too clearly that OLED technology based on iridium complexes and vacuum processing is reaching its limits. New solutions are needed both in the display market and in the area of white light – readily available, efficient materials along with rapid and precise processing techniques. cynora continues to make strides on this path, as the recently published research papers demonstrate.”

The articles can be downloaded here: http://pubs.acs.org/doi/abs/10.1021/ic300979c (DOI 10.1021/ic300979c) and here: http://pubs.rsc.org/en/content/articlelanding/2012/jm/c2jm33291d (DOI 10.1039/C2JM33291D).

About cynora:

Founded in 2003, cynora GmbH came under new management in 2008. The company focuses on researching innovative organic semiconductors whose physical properties as white illuminants destine them for organic light-emitting diode (OLEDs) applications. From designing new functional molecules for OLEDs and solar cells all the way to manufacturing these components in a lab environment as well as testing them for physical suitability with advanced measurement technology and methods, cynora covers the entire spectrum of material and component development.
Besides exploring new ways of achieving additional efficiency gains, the young and dynamic team behind cynora with at the moment 14 employees also works on improving key aspects of OLED applications, such as cost-effective processing and lifetime. Printing optoelectronic components requires new, intelligent materials and approaches. Resulting products can be used as displays, light sources, design objects, solar cells for energy generation and for smart packaging.

For additional information: www.cynora.com

Media contact:
Daniel Volz, cynora GmbH, Hermann-von-Helmholtz-Platz 1, Geb. 717, D-76344 Eggenstein-Leopoldshafen, T: +49 (0)721/60829112, F: +49 (0)721/60829030, M: info@cynora.com

This release was published on openPR.