ffg_Aufdampfprozesse - Nonlinear control of transient evaporation processes

The production of thin semiconducting organic layers, which e.g. can be used as active materials in organic electronic or optoelectronic devices, requires (beside other parameters) the observance of strict specifications for evaporation rate and layer thickness. Substantial for the accordant microcrystalline layer growth is an accurate control of the deposition rate because of the strong correlation of the microcrystalline structure and the charge transport in the solid state. Due to transient effects during the evaporation process it is very difficult to fulfil this demand. The proposed project is concerned with the model-based control of evaporation processes of organic semiconductor materials. Since in the relevant literature no approaches to the modelling of the transient effects exist, an extension of the mathematical model secured by appropriate experiments and numerical simulation is inevitable for the reproduction of these phenomena. On the basis of the found mathematical description suitable control concepts are to be developed, whose efficiency is to be proven experimentally with materials with very different evaporation behaviour.