title: Host-sensitized luminescence properties in CaNb2O6:Ln(3+) (Ln(3+) = Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+)) phosphors with abundant colors.
abstract: A series of Ln(3+) (Ln(3+) = Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+)) ion doped CaNb2O6 (CNO) phosphors have been prepared via the conventional high-temperature solid-state reaction route. The X-ray diffraction (XRD) and structure refinement, diffuse reflection, photoluminescence (PL), and fluorescent decay curves were used to characterize the as-prepared samples. Under UV radiation, the CNO host present a broad emission band from about 355 to 605 nm centered around 460 nm originating from the NbO6 octahedral groups, which has spectral overlaps with the excitation of f-f transitions of Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) in CNO:Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) samples. They show both host emission and respective emission lines derived from the characteristic f-f transitions of activators, which present different emission colors owing to the energy transfer from the NbO6 group in the host to Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) with increasing activator concentrations. The decreases of decay lifetimes of host emissions in CNO:Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) demonstrate the energy transfer from the hosts to Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+). The energy transfer mechanisms in CNO:Eu(3+)/Tb(3+)/Dy(3+) phosphors have been determined to be a resonant type via dipole-dipole mechanisms. For CNO:Sm(3+), the metal-metal charge transfer transition (MMCT) might contribute to the different variations of decay lifetimes and emission intensity from CNO:Eu(3+)/Tb(3+)/Dy(3+) samples. The best quantum efficiency is 71.2% for CNO:0.01/0.02Dy(3+). The PL properties of as-prepared materials indicate the promising application in UV-pumped white-emitting lighting diodes field.
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Liu
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Li
authors.forename: Hongzhou
authors.initials: H
authors.lastname: Lian
authors.forename: Jun
authors.initials: J
authors.lastname: Lin
mesh_terms: D002118:Calcium / Q000737:chemistry*; D004735:Energy Transfer; D006801:Humans; D007700:Kinetics; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008029:Lighting / Q000295:instrumentation; D049449:Luminescence; D008163:Luminescent Measurements; D009556:Niobium / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics; D014466:Ultraviolet Rays
chemical_list: D028581:Lanthanoid Series Elements; D009556:Niobium; D002118:Calcium