Synthesis and Characterization of Silica Coated CdSe/CdS Core/Shell Quantum Dots

A great deal of interest has been dawn on the colloidal chemistry based semiconductor nanocrysallites, also known as quantum dots (QDs). Because of the strong quantum confinement, quantum dots have unique size-dependent optical properties, which are much more superior to the conventional organic fluorescence materials. In addition, strong chemical resistant makes inorganic semiconductor QDs ideal candidate for next-generation of bio-labels and drug delivery vehicles. This report presents a user friendly approach to synthesize high quality biocompatible CdSe QDs in aqueous solution. Size of the dots can be controlled by adjusting the temperature, pH of the solution, and ratio of the precursors. A thin CdS layer was grown on CdSe QDs, forming a CdSe/CdS core/shell structure, to improve the photoluminescence. In order to use these QDs in-vivo, a more chemically robust coating, silica, was grown on the core/shell structure QD. The optical properties of the QDs were characterized by absorption and photoluminescence spectra. X-ray diffraction and transmission electron microscopy were conducted to verify the QDs composition and structure.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Electrical and Computer Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2005

Author dc:creator

• Xu, Yang

Chair dc:contributor.committeechair

• Meehan, Kathleen

Committee members dc:contributor.committeemember

• Guido, Louis J.
• Lu, Guo-Quan
• Wyatt, Christopher L.
• Love, Nancy G.

• CdS
• Silica
• semiconductor nanocrystal
• quantum dots
• CdSe

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-12072005-112723

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/29974