Strong visible photoluminescence from hollow silica nanoparticles

Abstract

Starting with crystalline silicon nanoparticles, which were produced by CO2\nlaser pyrolysis of silane in a gas flow reactor, we have synthesized\namorphous silica nanoparticles via oxidation. Upon excitation\nwith UV light, the novel nanostructured material gives rise to an intense red\nphotoluminescence (PL) which resembles that of some silicon\nnanostructures. Transmission electron microscopy studies and electron\nenergy loss spectroscopy confirm that the nanoparticles are composed of\namorphous silica and that the majority of them are hollow. The strong red\nPL is attributed to defects or molecular species located at the inner and outer\nsurfaces of the hollow nanoparticles. Its similarity to the PL of\nnanostructured silicon seems fortuitous.