Origin of the nano-carbon allotropes in pulsed laser ablation in liquids synthesis.

Carbon-based materials are of great technological and scientific interest in materials science. Pulsed laser ablation in liquids (PLAL) is extensively used as a method to produce nanoparticles including nanodiamond and related materials. In this feature article, we will review the use of PLAL to tackle the challenges of synthesizing carbon-based nanostructures. Surprisingly, reported results have shown very poor reproducibility despite the use of similar experimental conditions. We use plasma spectroscopy and shadowgraph imaging to provide a picture of the thermodynamic properties, and then to better understand this apparent contradiction. Our study was carried out under traditional conditions which involve nanosecond laser, and radiant exposures from tens to thousands J/cm2. Prompted by these results, the different scenarios reported in the literature are discussed including shockwave induced phase transition, growth in high temperatures-high pressures like conditions, and vapor phase chemistry.