Influence of organic solvent on optical and structural properties of ultra-small silicon dots synthesized by UV laser ablation in liquid

Year: 2012

Authors: Intartaglia R., Bagga K., Genovese A., Athanassiou A., Cingolani R., Diaspro A., Brandi F.

Autors Affiliation: Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy;
Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy;
Center for Biomolecular Nanotechnologies UniLe, Istituto Italiano di Tecnologia, via Barsanti, 73010 Arnesano Lecce, Italy

Abstract: 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. F (4) over bar 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.

Journal/Review: PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Volume: 14 (44)      Pages from: 15406  to: 15411

KeyWords: Silicon Nanoparticles; Nanocrystals; Hydrogen; Water; Toluene
DOI: 10.1039/c2cp42195j

Citations: 38
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