High-power UV-Laser Fragmentation System

• Subject Area: Materials Engineering
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 491146928

As a dispersion-based processing method, laser fragmentation allows the synthesis of colloidal inorganic nanoparticles in the size range of a few nanometers up to atomic clusters under highly pure conditions without molecular stabilizers. The continuous liquid jet process developed by the applicant enables material processing under steady-state conditions while precisely quantifying the energy input. Past studies on the fragmentation of oxides show a significant increase of catalytic activity after size reduction but are still limited to some niche applications. Especially due to the low absorptivity of the currently available high-power VIS- / IR laser pulses, fragmentation of oxides is still prone to low mass throughput. In contrast, UV laser pulses show a significantly larger absorption cross-section for most nanoparticles consequently allowing a significantly higher fragmentation efficiency and more material-variant research. Yet, the insufficiently low laser power (<20 W) of the UV-lasers available at the chair has been found to poses a major bottleneck in nanoparticle processing still limiting their application in scientific studies. With the existing equipment, the fragmentation of e.g. spinels and perovskites, high-melting hard materials (e.g. ZrB2, TiB2, TiC), or non-plasmonic precious metals (eg Pt, Pd) and high entropy alloys (eg Cantor alloy) is found to be possible but only in very low quantities (several 10th – 100th of mg). Based on the fundamental research conducted by combining the laser beam source with recently developed continuous flat-jet processing technology and its application perspectives including the required material quantities for functional testing (e.g. in heterogenous Catalysis or in 3D printing) an increase in productivity and throughput will create tremendous growth potential for the present research. This will have a direct impact on several research projects of the applicant including coordinated programs since the requested high-performance UV-laser fragmentation system has been found to occupy a key position, which has a leverage effect on the research spectrum at the chair. The specifications of the former are defined based on the materials and throughputs required in basic and applied research projects. Here, high-purity colloidal nanoparticles are needed on a 100 g scale. Accordingly, not only running projects will benefit from the new large-scale equipment but also novel project approaches in the field of laser powder bed fusion (several kg of nano-functionalized micro powders per batch) and catalyst development (several grams of catalyst nanoparticles required per series) will be made possible. Consequently, the applied continuously operated high-performance UV-laser processing technology for dispersions will be a unique selling point in the international scientific community.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Hochleistungs-UV-Laserfragmentierungssystem
• Instrumentation Group: 5740 Laser in der Fertigung
• Applicant Institution: Universität Duisburg-Essen
• Leader: Professor Dr.-Ing. Stephan Barcikowski