Surface Functionalization of Silicon Nanoparticles Produced by Laser-Driven Pyrolysis of Silane followed by HF-HNO_3 Etching

摘要

CO_2 laser induced pyrolysis of sílané was u?ed to produce silicon nanoparticles with an average diameter as smáli as 5 nm at high rates (up to 200 mg/h).Etching these particles with a mixture of hydrofluoric acid (HF) and nitric acid (HNO_3) reduces their size and passivates their surface such that they exhibit bright visible photoluminescence (PL).This páper describes the attachment of organic molecules to hydrogen-terminated and hydroxyl-terminated surfaces of these nanoparticles.Stable particle dispersions in various solvents were obtained by treatment of hydrogen-terminated surfaces with octadecene or undecylenic acid and by treatment of hydroxyl-terminated surfaces with octadecyltrimethoxysilane.Transmission electron microscopy showed that the surface-functionalized particles were well dispersed and crystalline.FTIR spectroscopy confirmed the expected reactions of the organic molecules with the particle surfaces.Photoluminescence measurements showed that surface treatment significantly stabilized the PL properties of the nanoparticles against degradation.Size selective precipitation was applied to particle dispersions and allowed some narrowing and tuning of the PL spectrum.