Surface Modification of Photoluminescent Silicon Nanocrystals

摘要

This thesis describes the surface modification of silicon nanocrystals, investigating the influence of surface species on photoluminescent and solution behaviour. Photochemical hydrosilylation of hydride-terminated silicon nanocrystals with alkenes affords a well-dispersed, colloidal suspension with strong luminescent character. First, the photoluminescent stability of silicon nanocrystals with respect to ambient oxidation was investigated. Upon exposure to ambient atmosphere, changes in photoluminescent behavior over time were explained based on the formation of surface species as detected by infrared spectroscopy. Secondly, water-soluble silicon nanocrystals were prepared via hydrosilylation with alkenes containing a distal carboxylic acid. The photoluminescent and solution stability of the resulting functionalized materials were investigated as a function of the alkenyl chain length. It was conclusively shown that the longer chain length imparts a greater photoluminescent and solution stability in aqueous systems.