Spectroscopic evidence for nonradiative energy transfer between colloidal CdSe/ZnS nanocrystals and functionalized silicon substrates

摘要

We present the fabrication and properties of hybrid structures consisting of a monolayer of colloidal CdSe nanocrystals grafted on hydrogenated Si surfaces via amine modified carboxy-alkyl chain linkers. The wet chemical preparation ensures that Si surfaces are fully passivated with a negligible number of nonradiative surface state defects and that the separation between nanocrystals and Si is tightly controlled. An eightfold decrease in photoluminescence lifetime of nanocrystals on Si is observed as compared to glass. A quantitative analysis reveals that the nonradiative transfer from nanocrystals to Si is 65% efficient, demonstrating the potential of such hybrids for practical photovoltaic devices.