Synthesis of photoluminescent colloidal silicon nanoparticles by pulsed laser ablation in liquids

Abstract

We performed pulsed laser ablation (PLA) of a silicon target in liquid environment to prepare a silicon colloid solution. The nanoparticles were observed by SEM and TEM measurements. The result of Raman scattering indicates that this particle is mainly composed of silicon nanocrystallites. The optical gap energies of the colloid solutions varied by changing the solvents; 2.9 and 3.5 eV for colloids prepared in water and hexane, respectively. These colloid solutions showed efficient PL intensity. Since Si-(CH3)n related bonds were observed for the specimen prepared in hexane, surface effects other than the quantum confinement effect should be taken into account for the origin of the PL. Our results indicate that new kinds of Sibased colloid solutions can be prepared by PLA in solvent. Since the PL peak energies were sensitive to the surface conditions, these colloid solutions are promising for biological applications such as bio-sensors.