Abt. Hochfrequenztechnik

Materialsynthese und Charakterisierung

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.