title: Photophysical behaviors of single fluorophores localized on zinc oxide nanostructures.
abstract: Single-molecule fluorescence spectroscopy has now been widely used to investigate complex dynamic processes which would normally be obscured in an ensemble-averaged measurement. In this report we studied photophysical behaviors of single fluorophores in proximity to zinc oxide nanostructures by single-molecule fluorescence spectroscopy and time-correlated single-photon counting (TCSPC). Single fluorophores on ZnO surfaces showed enhanced fluorescence brightness to various extents compared with those on glass; the single-molecule time trajectories also illustrated pronounced fluctuations of emission intensities, with time periods distributed from milliseconds to seconds. We attribute fluorescence fluctuations to the interfacial electron transfer (ET) events. The fluorescence fluctuation dynamics were found to be inhomogeneous from molecule to molecule and from time to time, showing significant static and dynamic disorders in the interfacial electron transfer reaction processes.
authors.affiliation: Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland School of Medicine, 725 Lombard Street, Baltimore, MD 21201, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland School of Medicine, 725 Lombard Street, Baltimore, MD 21201, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland School of Medicine, 725 Lombard Street, Baltimore, MD 21201, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lakowicz
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D015034:Zinc Oxide
keywords: interfacial electron transfer; radiative decay rate; single molecule spectroscopy; zinc oxide nanostructures