The High Frequency Technology and Photonics working group conducts basic research in the field of organic (semiconductor) materials as well as applied research and development of (organic) optical sources, transmission paths, and sinks.
The research group "Applied Organic Materials" of Dr. Johannes, located at the laboratory of electrooptics which is part of the institute of high frequency technology basically deals with three parts of modern chemistry and physics – OLEDs, sensors and photovoltaics. For this reason in our group eight chemists, two physicists and five engineers are employed in funded projects in cooperation with BMBF and partners from industry. The main field of activity is the development and improvement of new materials for Organic Light Emitting Diodes (OLEDs) like emitters and transport materials. Thereby, the main interest is not only focussed on the materials aspect with syntheses and characterisation, but also on new fabrication methods and device processing, for example RGB-structured OLED displays, passive and active matrix OLED displays and actually transparent OLED-displays. Together with Dr. Thomas Riedl the research on combining transparent transistors with transparent pixels in order to achieve transparent smart pixels was awarded with the “Kaiser Friedrich Forschungspreis“ in 2007.
Besides the OLED-technology group activity has got a second focus on sensor development. Since 1997 the Institute participates in the Collaborative Research Center 477 (SFB 477) which investigates the “Life Cycle Assessment of Structures via Innovative Monitoring”. In the projects C1a and T2 fibre optical and micro optical sensor systems for structure health monitoring are developed. For an in-situ measurement of chemical parameters like pH-value, humidity and chloride, which are important indicators for chemical attacks on reinforced concrete, changes of the optical properties (i.e. color changes) of tailor-made dyes are detected. The dyes are bound to a polymer matrix to resist the rough environment in concrete (pH 11-13) for at least decades.
In a further project sensor arrays consisting of conducting polymers are used to detect gases like methane, carbon monoxide and nitric oxide. The polymers, mainly doped polythiophenes, are deposited on one substrate by local electropolymerisation to result cheap to produce one device arrays. Groups main aim is to functionalise the monomers by recognition units, especially metalloporphyrins, in order to increase gas-sensitivity and selectivity of the resulting polymer films. Furthermore the scientist are challenging with finding optimal polymerisation conditions to improve long time stability and reliablility towards perturbations, such as temperature, humidity, etc.
Of course future work will be kept at the research field of organic electronics attending to photovoltaics and self aggregated monolayers (SAM), where some research was already done during the past.
Organic lasers are of enormous importance from many points of view. As compact, innovative, and prospectively cost-effective photon sources, their tunability in the entire visible and adjacent ultraviolet spectral range makes them predestined light sources for a variety of spectroscopic applications in which far more complex and thus more cost-intensive laser systems must be used today. Particularly in the increasingly important field of life sciences and bioanalytics, there is a growing need for tunable light sources that are inexpensive to manufacture and may also be suitable as consumables for disposable applications. The realization of the first electrically operated organic diode laser represents the greatest scientific and technological challenge to date.
Optical Spectroscopy on Planar Waveguide Structures
In this focus, among other things, waveguide-based measurement methods are developed that allow highly sensitive insights into the physical processes of organic semiconductors. Together with specially developed waveguide structures, very precise statements can be made about device-relevant molecular properties.
The new working group Bioelectronics is concerned with the research and development of components that combine the fields of electronics and biology. Such components are, for example, biosensors, which make it possible to convert biochemical signals into electrical signals and thus make them usable and analyzable.
Scientific Director
Prof. Dr.-Ing. Wolfgang Kowalsky
Laboratory for Electrooptics, Bienroder Weg 94, 38106 Brunswick
