Upscaling Pulsed Laser Fragmentation in Liquids by Advanced Free‐Flow Setups

ABSTRACT

Among the various nanoparticle synthesis techniques to address the growing demand for nanoparticles, pulsed laser fragmentation in liquids (PLFL) stands out as a simple, versatile, and sustainable method for obtaining nanoparticles (NPs) with unprecedented purity. Despite the potential to tailor the size, composition, structure, and defects of NPs via laser irradiation of a free‐flowing colloid jet, upscaling PLFL is oftentimes realized by employing costly high‐power laser sources. Herein, two improved flat‐film setups are introduced and compared with the conventional PLFL setup for the synthesis of ZnO NPs, which represent a promising model material for manifold applications. Indeed, a twofold reduction of average NP size down to less than 7 nm at 60% productivity increase and constant energy input can be achieved. Moreover, the microparticle conversion efficiency increases up to 65%, while crucial upscaling criteria, such as colloid heating, are optimized to prevent NP ripening and colloid evaporation. Numerical simulations reveal that a flat liquid surface reduces nonlinear interactions and provides more consistent irradiation conditions. The results emphasize the potential of synergistic optimization of the laser and liquid parameters for upscaled PLFL as a competitive technique for obtaining ligand‐free, green, and ultra‐small NPs.