Due to their special properties, rare earths are a component of many high-tech products. Scientists at the Karlsruhe Institute of Technology (KIT) are working on new options for using the elements. The team produces so-called sandwich complexes with rare earths, which could in future 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, the properties of which are still largely unknown. The connections consist of two ring structures, between which a single metal atom is “clamped”. Simplified, the complexes look like tiny sandwiches. In order to research whether the molecules are suitable as an innovative basis for future materials, Professor Peter Roesky, head of the Chair for Inorganic Functional Materials at the Institute of Inorganic Chemistry (AOC) and his team in the laboratory produce different variants of the sandwich complexes. The scientists use various elements from the rare earth group as metal atoms in the middle of the connections. The test molecules also differ in the type of their ring structures. In addition to carbon, the rings consist of 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 what influence the structure of the sandwich complexes has on its physical properties," explains Roesky. "In particular, we research the magnetism and luminescence of the molecules."
So far, rare earths have generally been integrated into solid materials that are used in high-tech products. The elements can be found, for example, in LED lights, cell phone displays or magnets from wind turbines. With the production of the molecular compounds with rare earths that he planned, Roesky is pursuing an approach that has so far hardly been considered in the application.
Ideally, the scientists could receive molecules that behave like tiny magnets. Such connections are also referred to as single-molecule magnets. One day, the new types of complexes could be used to manufacture storage media that have greatly increased storage capacities with the same physical size. Roesky and his team are also experimenting with rare earth elements that are already used in phosphors. Sandwich complexes containing these elements could later be used to produce optimized displays. "Our project serves to create a basic understanding of these new 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 specifically promotes such high-risk projects, thereby giving established researchers the opportunity to implement innovative ideas. Across all subjects, only eight of them were funded in Germany in 2019 by a Reinhart Koselleck project. With Roesky, a KIT scientist was the first to receive this financial support. The funds, which are designed for five years, can be freely used.