Laser synthesis emerges as a suitable technique to produce ligand-free nanoparticles, alloys and functionalized nanomaterials for catalysis, imaging, biomedicine, energy and environmental applications. In the last decade, laser ablation and nanoparticle generation in liquids has proven to be a unique and efficient technique to generate, excite, fragment and conjugate a large variety of nanostructures in a scalable and clean way. In this work, we give an overview on the fundamentals of pulsed laser synthesis of nanocolloids and new information about its scalability towards selected applications. Biomedicine, catalysis and sensing are the application areas mainly discussed in this review, highlighting advantages of laser-synthesized nanoparticles for these types of applications and, once partially resolved, the limitations to the technique for large-scale applications.

Utilizing a novel laser system consisting of a 500 W, 10 MHz, 3 ps laser source which is fully synchronized with a polygon scanner reaching scanning speeds up to 500 m/s, we explore the possibilities to increase the productivity of nanoparticle synthesis by laser ablation in liquids. By exploiting the high scanning speed, laser-induced cavitation bubbles are spatially bypassed at high repetition rates and continuous multigram ablation rates up to 4 g/h are demonstrated for platinum, gold, silver, aluminum, copper, and titanium. Furthermore, the applicable, ablation-effective repetition rate is increased by two orders of magnitude. The ultrafast ablation mechanisms are investigated for different laser fluences, repetition rates, interpulse distances, and ablation times, while the resulting trends are successfully described by validating a model developed for ultrafast laser ablation in air to hold in liquids as well.

The laser ablation of a bulk CoCrFeMnNi high-entropy alloy immersed in liquid yields colloidal nanoparticles with diameters below 5 nm. Both, the chemical composition and the crystal lattice of the bulk material is preserved in the nanoparticles.

Novel mechanisms of nanoparticle generation in laser ablation in liquids are revealed in atomistic simulations and verified in experiments.