Pulsed Laser System for Nanoparticle Production and Processing

• Subject Area: Materials Science
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 503865051

The methods of pulsed laser ablation in liquids and pulsed laser fragmentation in liquids enable the production and processing of colloidal nanoparticles under high-purity conditions. Due to the inherent high specific surface area of nanoparticles, surface purity is of great importance for the discrimination of surface functionality from surface adsorbate effects. The high surface purity is one of the great strengths of nanoparticle production by pulsed laser systems, which is why these laser-based methods have increasingly become the focus of research in recent years. While pulsed laser ablation in liquids has been applied to a broad range of materials. Investigation of pulsed laser fragmentation has been carried out mainly on model metal materials such as gold nanoparticles under resonant excitation of the surface plasmons (i.e., laser pulses in the visible wavelength). Further studies on oxide nanoparticles employed for additive manufacturing or tribology are severely limited in throughput and particle size due to the low absorption of VIS/IR laser pulses employed in existing high-power lasers. UV- laser pulses, in contrast, show a much larger absorption cross-section (especially for semiconductors, oxides, and most metal nanoparticles). Consequently, by using UV-lasers, a much more efficient and material-variant research of laser ablation and fragmentation is possible. With the existing IR-lasers in our group, fragmentation of, e.g., oxides (e.g., Y2O3, ZrO2), high melting hard materials (e.g., ZrB2, TiB2, TiC) or high entropy alloys (e.g., Cantor-Alloy) is only possible in insufficient quantity frameworks. The significant increase in throughput has considerable research potential due to the application perspective and the quantity requirement for functional testing (e.g., in additive manufacturing). The laser-produced and processed materials are applied in several research projects of the applicant, including coordinated programs. The proposed high-power UV laser system thus occupies a key position that exerts a leverage effect on the research spectrum at the newly appointed Chair of Materials Science and Additive Manufacturing. Meanwhile, it will strengthen the profile core “Materials.Inspire.Systems” of the University of Wuppertal. The specifications of this major instrumentation are defined based on materials and necessary throughputs relevant to basic and applied research projects. These require high-purity colloidal nanoparticles partly on a scale of 100 g. Accordingly, a whole series of ongoing projects at the Chair will benefit from the new instrument. In addition, further project approaches in the field of laser powder bed fusion (several kg of nanoadditivated micropowder per batch) will become feasible. The continuously operated high-performance UV laser production and processing technology for dispersions that can be implemented with the proposed equipment will represent a distinguishing feature internationally.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Uv Laser
• Instrumentation Group: 5700 Festkörper-Laser
• Applicant Institution: Bergische Universität Wuppertal
• Leader: Professor Dr. Bilal Gökce