Lay summary

The objective of this Marie Heim-Vögtlin project is to investigate self-organisation processes for the design of structured/patterned materials with application to the energy sector, for example photoelectrodes for solar water splitting. Solar energy driven splitting of water by heterogeneous photocatalysts is a promising green technology for hydrogen fuel production and can be obtained in a single step process in photoelectrochemical cells. Nanostructured materials as electrodes perform better than planar electrodes, therefore, adding structure to the material is of great interest.

The conventional methods to nanostructure materials are the so called 'top-down' techniques, where structures are produced by removing parts of the material, i.e. lithography methods. Recently considerable attention has been devoted to the so called ‘bottom-up’ techniques where the structure is spontaneously
built from building blocks using self-organization/self-assembly techniques. Reaction-diffusion-precipitation processes are very promising candidates for building complex
structures because the location of the self-organised chemical pattern is locked once it is formed. Another promising self-organization process is the formation of ordered nanopillar arrays in a very thin layer of molten polymer driven by electrohydrodynamic  instability. The advantage of this technique is that it does not require a template with relief pattern because the pillars form spontaneously. 

New research on self-organizing systems is combined with nanoscale materials science in this project. Mixed metal self-organized planar microstructures and core-shell nanopillar arrays is synthesised. The structures is transfered to ceramic systems and photoelectrochemical characterisation is performed. Results from structural and morphological studies enable us to understand the mechanism of the formation of these structures and develope a model.