We use a range of hybrid nanostructures composed of semiconductor nanocrystals combined with metal nanoparticles and organic molecules to photocatalytically split water or reduce carbon dioxide to usable fuels such as methanol or methane. These structures absorb light and utilize the energy of the incident photon to drive thermodynamically up-hill reactions. The major benefit of such approach is that the solar energy can be not only harvested but also stored in the form of chemical bonds of the fuels. At present, our main interest is in narrow band gap cadmium chalcogenide nanoparticles and nanorods as well as in sensitized wide band gap metal oxide semiconductors. We examine the full process, starting from the synthesis of the structures through the optical and electronic characterization to the measurement of the efficiency of photocatalysis (GC, GC-MS) upon monochromatic or broad spectrum illumination. We strive to develop more efficient materials, but our focus here is on understanding the mechanism and the kinetics of the photocatalytic processes on semiconductors. To this end, we additionally employ several ultrafast time-resolved spectroscopy techniques.
The Nanoplasmonics group studies the optical and plasmonic properties of metal nanoparticles as well as hybrid nanosystems containing metal nanoparticles and organic molecules or semiconducting nanocrystals. Our investigations are performed both on the ensemble and the single-object level. Hybrid materials are of particular interest since they allow for enhancing and modifying the properties of the single components or can even induce behavior that neither of the components exhibits on its own. These properties include Raman scattering, fluorescence, kinetic properties and many more.
We are interested in the physical chemistry of bio-inorganic hybrid nanomaterials and their application to living systems. Our research efforts encompass the synthesis and characterization of nanostructured materials with a particular emphasis on non-conventional self-assembly based nanofabrication techniques and synthetic phospholipid membranes. With this combination we are able to mimic biological interfaces with defined chemical composition and physical properties to imbue nonliving matter with the functionality of dynamic living systems.
OPTOELECTRONICS OF ORGANIC MATERIALS
Our research deals with the optical properties of molecular and quasi-molecular semiconductors such as organic conjugated polymers, which possess a one-dimensional delocalised pi-electron system, dendrimers and colloidal semiconductor nanoparticles. Organic semiconductors are highly suited to making optoelectronic devices such as photodiodes, light-emitting diodes or lasers. In contrast to conventional crystalline inorganic semiconductors they may be processed from solution, greatly simplifying device fabrication.