title: Light-controlled molecular switches modulate nanocrystal fluorescence.
abstract: Spiropyran dyes were attached to fluorescent core-shell CdSe/ZnS nanocrystals via thiol-containing linkers. Photoisomerization of the dye to its merocyanine form by UV irradiation caused a dramatic loss in the intrinsic nanoparticle fluorescence, which was regained upon reversing the isomerization with visible light. The fluorescence quenching efficiency increased with increasing spectral overlap of fluorescence emission and merocyanine adsorption bands, consistent with FRET as the quenching mechanism. Typically, complete quenching required at least 80 bound dye molecules per particle.
authors.affiliation: Department of Chemistry and Center for Materials Research, Washington State University, Pullman, Washington 99164.
authors.forename: Linyong
authors.initials: L
authors.lastname: Zhu
authors.forename: Ming-Qiang
authors.initials: MQ
authors.lastname: Zhu
authors.forename: James K
authors.initials: JK
authors.lastname: Hurst
authors.forename: Alexander D Q
authors.initials: AD
authors.lastname: Li
mesh_terms: D001578:Benzopyrans / Q000737:chemistry / Q000528:radiation effects; D019187:Cadmium Compounds / Q000737:chemistry / Q000528:radiation effects; D003460:Crystallization; D005456:Fluorescent Dyes / Q000737:chemistry / Q000528:radiation effects*; D007211:Indoles; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry / Q000528:radiation effects*; D009574:Nitro Compounds; D018036:Selenium Compounds / Q000737:chemistry / Q000528:radiation effects; D013440:Sulfides / Q000737:chemistry / Q000528:radiation effects; D013997:Time Factors; D014466:Ultraviolet Rays; D017967:Zinc Compounds / Q000737:chemistry / Q000528:radiation effects
chemical_list: D001578:Benzopyrans; D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D007211:Indoles; D009574:Nitro Compounds; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C088184:spiropyran; C058667:cadmium selenide; C031238:zinc sulfide