Nickel and cobalt nanoparticles produced by laser ablation of solids in organic solution

Nanoparticles of nickel (Ni) and cobalt (Co) have been produced through laser ablation in organic solution. Pure Ni, Ni50Co50 alloy, and Co metal plates as the targets, respectively, have been irradiated under 532 nm Nd:YAG laser in ethylene glycol (EG). The produced metal nanoparticles are stabilized with poly (N-vinyl-2-pyrrollidone) (PVP) in EG. Under the same laser fluence and irradiation time, the average particle size of Ni nanoparticles is 8 nm in diameter, smaller than 22 nm of Co nanoparticles. The laser-induced structural transition at interface of bulk metal and liquid has been investigated. It has been found that laser-generated Co nanoparticles show fcc structure, while the target of laser ablation is hexagonal Co bulk. In addition, the surface plasmon resonance (SPR) absorptions of Ni and Co nanoparticles stabled by PVP in EG are 355 nm and 510 nm, respectively. This research demonstrates that laser ablation in liquid, a one-step, non-catalyst process, can produce stable Ni and Co nanoparticles.