Synthesis and Photophysics of Dendronized Nanomaterials

With luminescence quantum efficiencies ranging from §5 to 15%, Cadmium selenide (CdSe) quantum dots (QDs) §are stronger emitters than many organic fluorescent §dyes. Inorganic coated ODs such as (CdSe)ZnS further §increase quantum yield by fully coordinating free §unbound surface electrons by reducing the occurrence §of nonradiative transitions. The electron hole is §confined to the QD core, while the electrons are §delocalized throughout the core/shell structure. §Surface modification of QDs with covalently attached §dendrons offers a means to not only modify §luminosity of the quantum dot, but to also modify §its soluibility. In this dissertation, the synthesis §of CdSe QDs with covalently bound thiol dendrons is §presented. While covalently bonding the dendrons to §the QD did not increase the quantum efficiency or §emission lifetime, the dendrons did effect the §morphology of the quantum dot by replacing the §surface Selenium with Sulfur from the dendron §attachment effectively creating an organically §coated core/shell QD. Elemental analysis is §presented amongst other data as evidence for the §composition of the (CdSe)CdS-Dendron compounds.