Influence of organic solvent on optical and structural properties of ultra-small silicon dots synthesized by UV laser ablation in liquid.
Ultra small silicon nanoparticles (Si-NPs) with narrow size distribution are prepared in a one step process by UV picosecond laser ablation of silicon bulk in liquid. Characterization by electron microscopy and absorption spectroscopy proves Si-NPs generation with an average size of 2 nm resulting from an in situ photofragmentation effect. In this context, the current work aims to explore the liquid medium (water and toluene) effect on the Si-NPs structure and on the optical properties of the colloidal solution. Si-NPs with high pressure structure (s.g. Fm3m) and diamond-like structure (s.g. Fd3m), in water, and SiC moissanite 3C phase (s.g. F4[combining macron]3m) in toluene are revealed by the means of High-Resolution TEM and HAADF-STEM measurements. Optical investigations show that water-synthesized Si-NPs have blue-green photoluminescence emission characterized by signal modulation at a frequency of 673 cm(-1) related to electron-phonon coupling. The synthesis in toluene leads to generation of Si-NPs embedded in the graphitic carbon-polymer composite which has intrinsic optical properties at the origin of the optical absorption and luminescence of the obtained colloidal solution.
Nanophysics, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy. romuald.intartaglia@iit.it
Romuald
R
Intartaglia
Komal
K
Bagga
Alessandro
A
Genovese
Athanassia
A
Athanassiou
Roberto
R
Cingolani
Alberto
A
Diaspro
Fernando
F
Brandi
D003102:Colloids / Q000737:chemistry; D007834:Lasers; D049449:Luminescence; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D055620:Optical Phenomena; D012825:Silicon / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D014050:Toluene / Q000737:chemistry*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*
D003102:Colloids; D012997:Solvents; D014867:Water; D014050:Toluene; D012825:Silicon