Generation of nickel-oxide nanoparticles by CW laser ablation in liquid

Pulsed laser ablation in liquid (PLAL) has been widely applied for the generation of nanoparticles (NPs). However, until now, there is no reported work on the successful generation of Ni oxide NPs by laser ablation of nickel target in aqueous environments. This paper reports our recent investigation on generation of Ni oxide NPs using a continuous wave (cw) high-power and high-brightness fibre laser source at wavelength of 1070nm. Characterisation of such NPs in terms of size distribution, shape, chemical composition and phase structure was carried out by transmission electron microscopy (TEM), high-resolution TEM equipped with energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The results revealed the formation of NiO NPs in water with an average size of 12.6 nm. The addition of anionic surfactant sodium dodecyl sulphate (SDS) reduced the size of NiO NPs down to 10.4 nm. The shape of the NPs was also affected by the SDS, showing the change of shapes from spherical domination in water to tetragonal with increased SDS concentrations. In addition, the NiO NPs generated in water and SDS solutions were dual-phase containing both cubic and rhombohedral structures.