title: Luminescent Properties of Eu(III) Chelates on Metal Nanorods.
abstract: In this article, we report the change of optical properties for europium chelates on silver nanorods by near-field interactions. The silver rods were fabricated in a seed-growth method followed by depositing thin layers of silica on the surfaces. The europium chelates were physically absorbed in the silica layers on the silver rods. The silver rods were observed to exhibit two plasmon absorption bands from longitudinal and transverse directions, respectively, centered at 394 and 675 nm, close to absorption and emission bands from the Eu(III) chelates. As a result, the immobilized Eu(III) chelates on the silver rods should have strong interactions with the silver nanorods and lead to greatly improved optical properties. The Eu-Ag rod complexes were observed to have enhanced emission intensity up to 240-fold in comparison with the Eu(III) chelates in the metal-free silica templates. This enhancement is much larger than the value for the Eu(III) chelates on the gold rods or silver spheres indicating the presence of stronger interactions for the Eu(III) chelates with the silver rods. The interactions of Eu(III) chelates with the silver rods were also proven by extremely reduced lifetime. Moreover, the Eu-Ag rod complexes exhibited a polarized emission, which was also due to strong interactions of the Eu(III) chelates with the silver rods. All of these features may promise that the Eu(III)-Ag rod complexes have great potential for use as fluorescence imaging agents in biological assays.
authors.affiliation: Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, United States.
authors.forename: Krishanu
authors.initials: K
authors.lastname: Ray
authors.affiliation: College of Chemistry and Molecular Engineering, Peking University, Beijing National Laboratory for Molecular Sciences, Beijing 100871, P. R. China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, United States.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lakowicz