| Abstract
| - We describe the synthesis of water-soluble semiconductor nanoparticles and discuss and characterize theirproperties. Hydrophobic CdSe/ZnS core/shell nanocrystals with a core size between 2 and 5 nm are embeddedin a siloxane shell and functionalized with thiol and/or amine groups. Structural characterization by AFMindicates that the siloxane shell is 1−5 nm thick, yielding final particle sizes of 6−17 nm, depending on theinitial CdSe core size. The silica coating does not significantly modify the optical properties of the nanocrystals.Their fluorescence emission is about 32−35 nm fwhm and can be tuned from blue to red with quantumyields up to 18%, mainly determined by the quantum yield of the underlying CdSe/ZnS nanocrystals. Silanizednanocrystals exhibit enhanced photochemical stability over organic fluorophores. They also display high stabilityin buffers at physiological conditions (>150 mM NaCl). The introduction of functionalized groups onto thesiloxane surface would permit the conjugation of the nanocrystals to biological entities.
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