Synthesis of silicon nanoparticles by laser ablation at low fluences in water and ethanol

Colloidal silicon nanoparticles (Si-nc) where synthesized by laser ablation of a solid Si target in water and ethanol. The target was immersed in a vessel containing the solvent and irradiated during 5 and 10 min at different fluences: 0.530, 0.608, 0.687 J cm−2. Ablation was carried out using a laser wavelength of 1064 nm. The obtained colloidal nanoparticles were irradiated after the synthesis to evaluate if laser fragmentation could be produced. In addition, a series of nanoparticles using ethanol as liquid medium was synthesized ablating with 532 nm. Colloidal nanoparticles were structurally characterized by Raman spectroscopy and Transmission Electron Microscopy. Size of the Si-nc were calculated by the theorical models: Bond Polarizability Model (BPM) and One-Phonon Confinement Model (PCM), where nanocrystals ranging from 2 to 11 nm were found.