Graphene-Based Nanostructures Produced by Laser Ablation Assisted by Electric Field.

The properties of carbon-based materials with nanometric size support their use in numerous applications, such as optoelectronics and energy devices, bioimaging, photodetectors, and sensors. Among the various nanostructure fabrication methods, pulsed laser ablation in liquids (PLA) is widely recognized for its simplicity and rapid processing. It is considered an environmentally friendly synthesis, as it enables nanostructure fabrication in pure liquids without chemical reagents, activators, or vacuum systems, in line with the increasing interest in sustainable and green nanotechnologies. A great challenge of PLA is the reproducibility of the size and shape of the produced structure. This can be accomplished by selection of the proper laser parameters and characteristics of the used liquid. This study is focused on the comparison of the synthesis of graphene-based nanostructures by electric-field-assisted pulsed laser ablation of a graphite target immersed in distilled water and deionized water, used as separate liquid media, without the use of chemical reagents. This is an innovative and environmentally friendly approach for the production of graphene nanoparticles. The laser parameters were kept constant throughout the experiments, while different voltage values were applied between the electrodes immersed in the liquid medium. The applied electric field significantly influences plasma dynamics, cavitation bubble evolution, and post-ablation nanoparticle growth processes, enabling controlled tuning of nanoparticle size and morphology. The optical properties of the obtained suspensions were evaluated by UV-Vis and FTIR spectroscopies. Atomic force microscopy revealed the composition, morphology, and quality of the formed structures.