title: Photoenhancement of lifetimes in CdSe/ZnS and CdTe quantum dot-dopamine conjugates.
abstract: 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.
authors.affiliation: Department of Biomedical Engineering, McGill University, 3775 Rue University, Montreal, QC H3A 2B4, Canada. daniel.cooper@mail.mcgill.ca
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Cooper
authors.forename: Diana
authors.initials: D
authors.lastname: Suffern
authors.forename: Lina
authors.initials: L
authors.lastname: Carlini
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Clarke
authors.forename: Rupesh
authors.initials: R
authors.lastname: Parbhoo
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Bradforth
authors.forename: Jay L
authors.initials: JL
authors.lastname: Nadeau
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D004298:Dopamine / Q000737:chemistry*; D049449:Luminescence; D010100:Oxygen / Q000737:chemistry; D017785:Photons; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry*; D013691:Tellurium / Q000737:chemistry*; D013997:Time Factors; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide; D013691:Tellurium; D010100:Oxygen; C028337:cadmium telluride; D004298:Dopamine