Functional assemblies of semiconductor nanocrystal quantum dots on 1-D nanostructures using dielectrophoresis

Semiconductor nanocrystal quantum dots (NQDs) have attracted considerable interest for use in photovoltaics and optoelectric sensor applications. The ability to transport extracted carriers from the NQDs is essential for the development of NQD incorporated device applications. Coupling of NQDs to one-dimensional nanostructures such as single wall carbon nanotubes (SWNTs) or various types of nanowires is expected to produce a composite material which facilitates selective wavelength absorption, charge transfer to 1-D nanostructures, and efficient electron transport. We assembled prepared CdSe (core and core/shell with ZnS) semiconductor nanocrystal quantum dots on successfully aligned single walled carbon nanotubes using a new approach, dielectrophoresis (DEP), to demonstrate the efficient charge transfer. By monitoring electrical signatures from NQD decorated SWNTs when illuminated with polarized light, we were able to characterize the charge transfer from photoexcited NQDs to SWNTs.