title: Gilded nanoparticles for plasmonically enhanced fluorescence in TiO2:Sm3+ sol-gel films.
abstract: Silica-gold core-shell nanoparticles were used for plasmonic enhancement of rare earth fluorescence in sol-gel-derived TiO2:Sm3+ films. Local enhancement of Sm3+ fluorescence in the vicinity of separate gilded nanoparticles was revealed by a combination of dark field microscopy and fluorescence spectroscopy techniques. An intensity enhancement of Sm3+ fluorescence varies from 2.5 to 10 times depending on the used direct (visible) or indirect (ultraviolet) excitations. Analysis of fluorescence lifetimes suggests that the locally stronger fluorescence occurs because of higher plasmon-coupled direct absorption of exciting light by the Sm3+ ions or due to plasmon-assisted non-radiative energy transfer from the excitons of TiO2 host to the rare earth ions.
  78; 78.67.-n; 78.67.Bf.
authors.forename: Siim
authors.initials: S
authors.lastname: Pikker
authors.forename: Leonid
authors.initials: L
authors.lastname: Dolgov
authors.forename: Siim
authors.initials: S
authors.lastname: Heinsalu
authors.affiliation: V, Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, Kyiv 03680, Ukraine. smamykin@gmail.com.
authors.forename: Sergii
authors.initials: S
authors.lastname: Mamykin
authors.forename: Valter
authors.initials: V
authors.lastname: Kiisk
authors.forename: Sergei
authors.initials: S
authors.lastname: Kopanchuk
authors.forename: Rünno
authors.initials: R
authors.lastname: Lõhmus
authors.forename: Ilmo
authors.initials: I
authors.lastname: Sildos