Photoenhancement of lifetimes in CdSe/ZnS and CdTe quantum dot-dopamine conjugates.

Phys Chem Chem Phys

Department of Biomedical Engineering, McGill University, 3775 Rue University, Montreal, QC H3A 2B4, Canada.

Published: June 2009

The response of water-soluble, mercaptocarboxylic acid-capped fluorescent semiconductor nanoparticles, or quantum dots (QDs), to extended visible-light irradiation is variable and poorly described. Here we use time-resolved spectroscopy to investigate the photoluminescence intensities and lifetimes of CdSe/ZnS and CdTe QDs as a function of blue light illumination. Conjugates of the particles to the electron donor dopamine were also investigated, and the effect of the antioxidant beta-mercaptoethanol was explored. Both types of QD showed signs of direct electron transfer to the conjugate, but enhancement was much more pronounced in CdSe/ZnS. A model of the two different types of enhancement is proposed.

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http://dx.doi.org/10.1039/b820602cDOI Listing

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