title: Photoluminescence and energy transfer studies of Dy(3+)-doped fluorophosphate glasses.
abstract: Dy(3+)-doped fluorophosphate glasses with composition (in mol%) (56-x/2)P(2)O(5)+17K(2)O+(15-x/2)BaO+8Al(2)O(3) + 4AlF(3)+ xDy(2)O(3), x=0.01, 0.05, 0.1, 1.0 and 2.0, have been prepared by melt quenching technique. The luminescence spectra and lifetimes of (4)F(9/2) level of Dy(3+) ions in these glasses have been measured using the 457.9 nm line of argon ion laser as an excitation source. The free-ion calculation and Judd-Ofelt analysis have been performed. The room temperature emission spectra corresponding to (4)F(9/2)-->(6)H(J) (J=7/2, 9/2, 11/2, 13/2 and 15/2) transitions of Dy(3+) ions were measured. The fluorescence decay from (4)F(9/2) level have been measured by monitoring the intense (4)F(9/2)-->(6)H(13/2) transition. The lifetime of the decay is obtained by taking the first e-folding times of the decay curves and is found to decrease with increase in Dy(3+) ions concentration due to concentration quenching. The decay curves are found to be perfectly single exponential for samples with low Dy(3+) ion concentration. The non-exponential decay curves observed for higher concentrations are well fitted to the Inokuti-Hirayama model for S=6, which indicates that the energy transfer between the donor and acceptor is of dipole-dipole nature. The energy transfer parameter and donor to acceptor interaction increases with Dy(3+) ions concentration due to increase of energy transfer from Dy(3+) (donor) to unexcited Dy(3+) (acceptor) ions.
authors: Department of Physics, Sri Venkateswara University, Tirupati 517502, India.
authors: R
authors: R
authors: Praveena
authors: R
authors: R
authors: Vijaya
authors: C K
authors: CK
authors: Jayasankar
mesh_terms: D004419:Dysprosium / Q000737:chemistry*; D004735:Energy Transfer; D005459:Fluorides / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D049449:Luminescence; D008956:Models, Chemical; D010710:Phosphates / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D010710:Phosphates; C012980:fluorophosphate; D004419:Dysprosium; D005459:Fluorides