Synthesis and properties of biocompatible water-soluble silica-coated CdSe/ZnS semiconductor quantum dots

Daniele Gerion, Fabien Pinaud, Shara C. Williams, Wolfgang J. Parak, Daniela Zanchet, Shimon Weiss, A. Paul Alivisatos

Research output: Contribution to journalArticlepeer-review

1274 Scopus citations

Abstract

We describe the synthesis of water-soluble semiconductor nanoparticles and discuss and characterize their properties. Hydrophobic CdSe/ZnS core/shell nanocrystals with a core size between 2 and 5 nm are embedded in a siloxane shell and functionalized with thiol and/or amine groups. Structural characterization by AFM indicates that the siloxane shell is 1-5 nm thick, yielding final particle sizes of 6-17 nm, depending on the initial 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 quantum yields up to 18%, mainly determined by the quantum yield of the underlying CdSe/ZnS nanocrystals. Silanized nanocrystals exhibit enhanced photochemical stability over organic fluorophores. They also display high stability in buffers at physiological conditions (> 150 mM NaCl). The introduction of functionalized groups onto the siloxane surface would permit the conjugation of the nanocrystals to biological entities.

Original languageEnglish
Pages (from-to)8861-8871
Number of pages11
JournalJournal of Physical Chemistry B
Volume105
Issue number37
DOIs
StatePublished - 20 Sep 2001
Externally publishedYes

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