Overview
Project 01
Project 02
Project 04
Project 06
Project 07
Project 08
Project 10
Project 11
Project 12
Project 13
Project 14

Project 02 – Design and application of tunable surfaces based upon photoreactive molecules

Wolfgang Kern, Mag.Dr.tech.Univ.Prof.

This project aims at thin layers and self-assembled monolayers (SAMS) of photoreactive organic molecules on selected substrates. The general idea is to modify the properties of these surface layers by UV induced reactions which will allow lateral patterning by lithographic techniques. Focus will be on molecules for which UV-light can induce a permanent change in chemical structure, reactivity and polarity by photo-isomerizations and photo-cleavages. By this way the properties of inorganic surfaces and their interactions with an organic active layer can be tuned in a spatially resolved fashion. Bi-functional molecules containing both a designed photoreactive unit and a suitable headgroup for inorganic surfaces (e.g. Au, SIO₂, TIO₂) will be synthesized and characterized. Examples for envisaged photoreactions are UV induced isomerization of organic thiocyanates R-SCN, photocleavage of sulfones (to give sulfinic acids) and also the cleavage of selected carboxylic acid esters.

Differences in the properties of irradiated and non-irradiated zones (chemical composition, reactive binding groups, surface energy) of the layers will allow selective reactions including coupling of functionalized molecules and selective growth processes.Selected photoreactive surface layers and SAMS will be structured by lithographic techniques (masks, UV laser interference) to obtain patterns with polar / non-polar as well as reactive / inreactive features.

Grating structures at interfaces will be explored as injection gratings to tune the emission wavelength and light-outcoupling from OLEDS. Using scanning nearfield optical techniques (SNOM), patterns on a nanometer scale are aimed at.