Growth, Transport and Functionalization of Noble Metal Nanoparticles Inside and Outside a Gas Aggregation Cluster Source: Uncovered by in-situ Diagnostics
The Haberland type gas aggregation cluster source (HGAS), which was invented in 1992 by Haberland et al., provides the opportunity to synthesize different types of NPs and tailor their properties by adjusting the operating parameters of the HGAS. Although nowadays the HGAS is used by many groups for the synthesis of NPs, the processes inside the HGAS are not fully understood until today. Therefore, the aim of this dissertation is to increase the understanding of the ongoing processes inside the HGAS, because this opens the way for new fields of applications. In order to gain a better understanding of the HGAS, in‑situ diagnostics with a good spatial and temporal resolution are essential. Five different in-situ methods were used, which together contribute to a better understanding of growth, transport and functionalization of NPs inside a HGAS. By combining different in-situ methods it was possible to investigate dynamic processes in a HGAS and thereby gain new insights into growth, transport and trapping of NPs. Furthermore, the reliability of the multicomponent target approach could be enhanced, which makes it an excellent tool for the fabrication of alloy NPs with tailored composition. Finally, a new approach for the production of core-shell NPs in the gas phase was developed, which is expected to open up new applications for core-shell NPs because of its outstanding flexibility in terms of material combinations and reliability
