Research Interests and Projects
Thin Film Solar Cells:
These projects focus on a deeper understanding of the chemical and electronic structure of interfaces in Cu(In,Ga)(S,Se)2, CdTe, and Si-based thin film solar cells. Particular focus is on the determination of electronic surface band gaps and interface band alignments, as well as a study of the impact of chemical treatments on the various surfaces and interfaces.
In these projects, we help to understand and optimize the surface properties of materials in photoelectrochemical devices for hydrogen production. Furthermore, we help in the development of oxide layers that show suitable band edge energies and stability in their respective electrolysis environments.
To improve life time and reduce costs, one of the primary topics in fuel cell research is to find novel catalyst materials with optimized properties. Using our tool chest, we help in the development of such novel catalysts by investigating the electronic and chemical properties of Pt-based and Pt-free nanocatalysts and how they are influenced by the formation of core-shell structures and chemical treatments. Furthermore, we collaborate with partners to understand the electronic structure of metal oxide films in solid oxide fuel cells.
Devices in organic electronics require an optimization of charge carrier transport across molecular layers and interfaces. We use our spectroscopic methods to aid in the development of novel organic materials, as well as in the tailoring of organic/organic and organic/inorganic interfaces for charge carrier injection, separation, and/or extraction.
Inorganic Semiconductor Devices:
The electronic structure of semiconductor surfaces and interfaces is of large interest in various electronic applications (e.g., in (In,Ga,Al)N layers for green LEDs). The electronic surface band gaps of numerous materials have not been experimentally investigated, especially when nanoscale dimensions are employed. Furthermore, the formation of suitable metal contacts on semiconductors is an art that would benefit from further microscopic insight. In this project, we team up with partners that require detailed knowledge of the electronic structure at surfaces and interfaces to optimize a variety of thin-film electronic devices.
Bio-interfaces and Liquids:
In this project, we are part of an international collaboration that studies the electronic structure of liquids, solutions, and bio-interfaces with soft x-ray spectroscopy. By developing novel experimental approaches, new insights into the fascinating world of water and its importance for biomaterials in native environments can be obtained. These approaches include high-efficiency soft x-ray spectrometers and the development of novel in-situ cells to study non-vacuum processes for a variety of different applications. Exploring the Structure of Aqueous Solutions with SALSA