Structure, configuration and sizing of Ni nanoparticles generated by ultrafast laser ablation in different media

DAVID MUÑETÓN ARBOLEDA; JESICA M. J. SANTILLÁN; LUIS JOAQUÍN MENDOZA HERRERA; MARCELA B. FERNÁNDEZ VAN RAAP; DIEGO MURACA; DANIEL C. SCHINCA ; LUCÍA B. SCAFFARDI

San Diego, California, Estados Unidos

Congreso; SPIE Optics + Photonics 2015, San Diego, USA, 9 al 13 de Agosto de 2015; 2015

SPIE

In recent years, nickel nanoparticles (Nps) have increased scientific interest because of their extensive prospects in catalysts, conducting pastes, information storage, large-scale batteries and biomedicine. Several works on Ni Nps generation by laser ablation have appeared in the literature in the last years, using different pulsed laser regimes and different media have been published recently. However, there are no works reporting on the use of fs-regime laser ablation of Ni in liquids and the corresponding characterization of the obtained colloids. In this work we analyze the characteristics of species, structure (bare core or core-shell),configuration and size distribution of Nps generated by fs pulse laser ablation over a Ni solid target in n-heptane and water. We report the presence of NiO-Ni core-shell and hollow Ni Nps in these colloids obtained, discussing a mechanism for the formation of different species present in the colloidal suspensions. These were experimentally characterized using AFM and TEM microscopy, as well as Optical Extinction Spectroscopy (OES). Extinction spectra were modeled using Mie theory through an appropriate modification of the complex experimentaldielectric function, taking into account a size-dependent corrective term for each free and bound electron contribution.Experimental UV-visible-NIR spectra were reproduced considering a size distribution of bare core, hollow and core-shell structures Nps. In both media, Ni Nps shape and size distribution agrees with that derived from TEM and AFM analysis.