Dynamics of Complex Fluids and Interfaces
The research focus of this HI ERN research unit is the development of simulation and modeling techniques for printing and coating processes for thin film production. The results of this work are supposed to enable an optimized production of solar cells and electrocatalytic active films. The theoretical work of this section perfectly connects the HI ERN research areas “printable photovoltaics” and “hydrogen as secondary energy source”.
The central challenge about thin liquid films and their conversion into solid films is how to tailor their microstructures, which influence the electronic, optical, and mechanical properties. For example, the relation between the microstructure, the functional properties of the thin films and the process variables in the printing process is currently not sufficiently understood for the manufacturing of a printed solar cell and for electrochemical systems. For this reason the theoretical activities of this research group link fundamental scientific research with the well-defined application of mass-printing highly efficient electrochemical systems and solar cells. Based on the fundamental physical and chemical properties of the used materials and processes, an in-depth understanding of structure-property and process-structure relationships shall be developed. Thus, modeling and simulation of the structure formation processes during printing, drying and post-processing will address the following aspects:
- Wetting and spreading of liquids, dispersions or emulsions during printing by means of thin film equations and mesoscale simulation methods
- Rheological models of highly filled dispersions adapted to shear rates in the printing device
- Statistical mechanics of the dynamic evolution of interactions between the building blocks – molecules and nanoparticles – which determine the thin-film rheology via aggregation and self-organization
- Heat and mass transfer coupled to structure formation processes during deposition and drying including the important issue of crack formation
- Effect of post-processing in various environments on defect states
Modeling and simulation of structure-property relationships of thin films
Once predictive models of structure-property and process-structure relationships for thin film formation have been developed, mathematical optimization is used as the tool for developing highly efficient printing processes. The predictive models are supposed to be validated by cooperating with the experimental groups (e.g. at the Energiecampus Nürnberg).