Optical and Catalytic Properties of Metal Clusters


Within the scientific community, the production and investigation of nanoparticles and their properties is a fast growing field with increasing significance. Due to their size of only a few nanometers and the comparatively big surface area the properties of those clusters can strongly deviate from the bulk material. Because of that nanoparticles may pose very interesting opportunities for applications in a wide variety of fields including sensorics, catalysis, and medicine. To gain access to useful and unique properties on the nanoscale, it is a task for fundamental research to closely examine and investigate the physical and chemical behavior of the materials in question. In the Ernst Group here at the Institute of Experimental Physics (IEP) at Graz University of Technology we valuably contribute to the elucidation of the unique properties of metallic nanoparticles. We produce those metal clusters utilizing the unique helium droplet synthesis method. Metal atoms are thereby doped into cold, superfluid helium droplets, where they agglomerate to form clusters. This synthesis approach was established here at IEP a few years ago by building up the Cluster 3 laboratory. A major advantage of the helium droplet synthesis approach is the high purity of the nanoparticles, which is hard to accomplish with other synthesis procedures. Furthermore, the tailoring of core-shell structures made of two different metals is possible as well. To do successful science in a competitive international environment it is necessary and important to not only produce nanoparticles, but also to analyze them and find a theoretical description of their behavior. For that purpose, a close cooperation with the Hauser Group here at the IEP and with the Institute of Electron Microscopy and Nanoanalytics (FELMI) at Graz University of Technology has been established. The former are experts in the theoretic field of molecular physics and quantum chemistry, and the later enable us to image our particles with sub-nanometer resolution.  Besides the production of metallic nanoclusters and their visualization by means of electron microscopy, the research at our institute additionally covers a variety of scientific fields. In one project the catalytic properties of the metal clusters are intensively studied, while in another project bi-metallic cluster are investigated with a focus on alloying processes on the nanoscale. To gain information about optic and plasmonic properties of the particles, we apply a set of analytical methods from the field of atomic and molecular spectroscopy. A new analytic tool that we established 2018 at the IEP for that purpose is a photo-emission electron microscope. Here you can find further information on the individual fields of research.
All images © TU Graz/Institute of Experimental Physics