Rare earths are a component of many high-tech products due to their special properties. Scientists from the Karlsruhe Institute of Technology (KIT) are working on new possibilities for the use of these elements. The team produces so-called sandwich complexes with rare earths, which in the future could serve as novel molecular materials for more powerful storage media or displays. The German Research Foundation (DFG) is funding the pioneering study with 500,000 euros as a Reinhart Koselleck project.
Sandwich complexes are chemical molecules whose properties are still largely unknown. The compounds consist of two ring structures between which a single metal atom is "clamped". In simple terms, the complexes look like tiny sandwiches. To investigate whether the molecules are suitable as an innovative basis for future materials, Professor Peter Roesky, head of the Department of Inorganic Functional Materials at the Institute of Inorganic Chemistry (AOC), and his team are producing different variants of the sandwich complexes in the laboratory. The scientists use different elements from the rare earth elements group as metal atoms in the middle of the compounds. The experimental molecules also differ in the nature of their ring structures. Thus, the rings consist of carbon and a variable proportion of other elements. The researchers are experimenting with different ring sizes. In the project, the size and nature of the rings are to be systematically varied in order to create a structure-effect principle. "We are investigating the influence of the structure of the sandwich complexes on their physical properties," explains Roesky. "In particular, we are studying the magnetism and luminescence of the molecules."
Up to now, rare earths have generally been integrated into solid state materials used in high-tech products. The elements are found, for example, in LED lights, cell phone displays or magnets in wind turbines. With the production of the molecular compounds with rare earths he is planning, Roesky is pursuing an approach that has hardly been considered in applications up to now.
Ideally, the scientists could obtain molecules that behave like tiny magnets, among other things. Such compounds are also known as single molecule magnets. One day, for example, these novel complexes could be used to produce storage media with greatly increased storage capacities for the same physical size. Roesky and his team are also experimenting with rare earth elements that are already used in fluorescent materials. Sandwich complexes containing these elements could later be used to produce optimised displays, for example. "Our project serves to create a basic understanding of these novel substances," explains Roesky.
Special funding for high-risk research
Since the scientists are at the very beginning of a new research area with their project, success is not guaranteed. Through Reinhart Koselleck Projects, the DFG provides targeted funding for such high-risk projects, thereby giving established researchers the opportunity to implement innovative ideas. Across all subjects, only eight of them were funded by a Reinhart Koselleck project in Germany in 2019. Roesky is the first KIT scientist who succeeded in obtaining this financial support. The funds, which are designed for a period of five years, can be used freely.
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