Femtosecond ligand/core dynamics of microwave-assisted synthesized silicon quantum dots in aqueous solution

Tonya M. Atkins, Arthur Thibert, Delmar S. Larsen, Sanchita Dey, Nigel D. Browning, Susan M. Kauzlarich

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


A microwave-assisted reaction has been developed to produce hydrogen-terminated silicon quantum dots (QDs). The Si QDs were passivated for water solubility via two different methods: hydrosilylation produced 3-aminopropenyl-terminated Si QDs, and a modified Stöber process produced silica-encapsulated Si QDs. Both methods produce water-soluble QDs with maximum emission at 414 nm, and after purification, the QDs exhibit intrinsic fluorescence quantum yield efficiencies of 15 and 23%, respectively. Even though the QDs have different surfaces, they exhibit nearly identical absorption and fluorescence spectra. Femtosecond transient absorption spectroscopy was used for temporal resolution of the photoexcited carrier dynamics between the QDs and ligand. The transient dynamics of the 3-aminopropenyl-terminated Si QDs is interpreted as a formation and decay of a charge-transfer (CT) excited state between the delocalized π electrons of the carbon linker and the Si core excitons. This CT state is stable for ∼4 ns before reverting back to a more stable, long-living species. The silica-encapsulated Si QDs show a simpler spectrum without CT dynamics.

Original languageEnglish (US)
Pages (from-to)20664-20667
Number of pages4
JournalJournal of the American Chemical Society
Issue number51
StatePublished - Dec 28 2011

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry


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