Synthesis of submicron-dispersed carbon phases in water by Nd:YAG laser ablation of graphite

Abstract

Mixtures of micron to submicron complex carbon phases, namely, defective graphene, graphene-like (multi-layered graphene, graphene oxide etc.), graphite flakes etc. as fine suspensions were obtained by pulsed laser ablation of highly purified microcrystalline graphite targets immersed in double distilled water. The fundamental wavelength (λ = 1064 nm) and the fourth harmonic (λFHG = 266 nm) of a Nd:YAG laser system (15 ns pulse duration, 10 Hz pulse repetition rate) were used in the fabrication process. The laser fluence value corresponding to the onset of the ablation process, the one initiating optical breakdown in water and an intermediate value were used for each of the wavelengths mentioned above. The morphology of the particles dispersed in water was studied by scanning electron microscopy (SEM). Their phase composition and structure were explored by Raman spectroscopy. It showed the presence of some traces of polymerized hydrocarbons (polystyrene, polybutadiene etc.) in addition to the main carbon phases: defected graphene, reduced graphene oxide and graphite.