Solution synthesis of alkyl- and alkyl/alkoxy-capped silicon nanoparticles via oxidation of Mg2Si

Alkyl-capped and alkyl/alkoxy-capped silicon nanocrystals have been prepared by the oxidation of magnesium silicide with bromine. High-resolution transmission electron microscopy confirmed the crystalline nature of the nanoparticles and provided an average diameter of 4.5 (2.0) nm for the alkyl-capped and for the alkyl/alkoxy-capped nanoparticles. Energy-dispersive X-ray spectroscopy showed that the nanoparticles are composed of silicon, with no evidence of unreacted bromine. FTIR spectra were consistent with alkyl- and alkyl/alkoxy-capped surfaces. Fluorescence spectroscopy indicated strong ultraviolet-blue photoluminescence, which was attributed to both quantum confinement and surface termination. These nanoparticles displayed long-term stability and no degradation of the photoluminescence was observed for a period of 1 year.