Visibly emissive, hydride-terminated silicon nanoparticles (Si NPs) were obtained via high-temperature annealing of (HSiO1.5)n polymer, followed by chemical etching and thermal hydrosilylation with 1-decene. The decane-terminated Si NPs (dec-Si NPs) were subsequently re-dispersed in straight chain alcohols varying in carbon chain length (C1-C10).  The initial red photoluminescence observed from neat hexane dispersions of the dec-Si NPs disappeared upon exposure to the smallest alcohols, commensurate with an increase in blue photoluminescence intensity.  A comprehensive suite of spectroscopic and microscopic techniques was employed to correlate these dynamic changes in Si NP photoluminescence with size or composition changes. The results of these studies support that the observed red-to-blue photoluminescence switch results from dangling bond defect passivation by small alcohols, which introduces blue-emissive Si-O-related surface trap states. A simple energy level diagram is proposed to account for the key spectral and dynamic features observed in our work and in other recent works.

Red-to-blue photoluminescence switching in alcohol dispersions of alkyl-capped silicon nanoparticles: Insight into the origins of visible photoluminescence in colloidal nanocrystalline silicon

248th National Meeting (2014)

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