Nanostructures and Optical Materials
Crucial targets of nanoscience are new materials and devices. They can be based on known physical phenomena improving them, or they can apply completely new principles. New materials, physical phenomena, new principles - in this triangle we move with our research projects. Our fields of interest are photonic crystals, especially artificial opals, hierarchical materials, self-assembly and self-organization, directed self-assembly, alternative principles for solar cells, and Grätzel cells.
Our fields of interest are:
• Photonic crystals, especially artificial opals
• Hierarchical materials
• Self-assembly and self-organization
• Alternative principles for solar cells, Grätzel cells
• NLO and switchable materials
For regenerative energy sources, not only high efficiencies but also economical facts are important. Therefore, the well-developed high-efficiency solar cells are not competitive to traditional energy sources without financial support....
Opals are not only beautiful gemstones, they also have fundamental significance as prototypes for photonic crystals. They may lead to new photonic and photocatalytic materials. The crucial problems of these materials are the spontaneous defects and the desired incorporation of specially designed defects. In the works below, we described basic ideas and our approaches to special topics.
This research area was active in our research group until 2013, but it has still an influence on the on-going research.
Many synthesis techniques deliver interesting brick stones for nanotechnology, but how can we assemble them in a reasonable manner? Very likely, there is not a single universal procedure to construct nano devices. Such devices have...
This research area was active in our research group until 2007, but it has still an influence on the on-going research.
A prerequisite for an efficient „molding the flow of light“ by photonic crystals is the molding of materials in desired nanostructures. Very often, conventional materials and processing techniques cannot fulfill the theoretical requirements for the materials and structures. Sol-gel methods enable material processing in opal pores and the controlled introduction of pores into materials. The porosity can be used for lowering the refractive index, for soft processing of the materials and for stress relaxation. Examples for this approach are ultra-low refractive index films used as supports for 2D photonic crystals, inverse opals with a skeleton-like unit cell filling and ferroelectric films with high transparency. Especially...
Metal-organic frameworks (MOFs), Covalent-organic frameworks (COFs) and similar materials have attracted a great deal of attention in the last few years. Potential areas of application include catalysis, gas adsorption, switchable systems, sensor technologies and many more. In our workgroup we investigate guest molecules inside the pores that can be influenced by external stimuli. The possibility to freely align azobenzene molecules with linearly polarized light could be demonstrated.