title: Structural and luminescent properties of KY(1-x)DyxBO3 phosphors.
abstract: Yttrium borate phosphors (KY(1-x)DyxBO3) doped with Dy(3+) ions were synthesized by the solid-state reaction method. The structural and morphological characteristics were studied by XRD, FTIR and SEM measurements. Luminescent properties of different concentrations of KY(1-x)DyxBO3 phosphors were investigated from the excitation, emission and decay analyses. The emission spectra exhibited characteristic blue (460-500nm) and yellow (555-610nm) bands of Dy(3+) ions which combines to give white light. The evaluated color co-ordinates (x, y) were found to lie within the white light region of CIE chromaticity diagram. All the decay curves of Dy(3+) ions exhibited non-exponential nature and the experimental lifetimes for the (4)F9/2 excited level were found to decrease from 0.87, 0.47, 0.35, 0.26 and 0.13ms with the increase of Dy(3+) ion concentrations from 0.05, 0.1, 0.15, 0.2 and 0.3mol%, respectively. In order to understand the energy transfer mechanism, the decay curves were fitted to Inokutti-Hirayama model and found that the energy transfer is of dipole-dipole type. From the results of these investigations, it is concluded that the KY(1-x)DyxBO3 phosphors are more useful for white light emitting diodes.
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
authors.forename: Sowjanya
authors.initials: S
authors.lastname: G
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India; Department of Physics, Chadalawada Ramanamma Engineering College, Renigunta Road, Tirupati 517 506, India. Electronic address: lrmphysics@yahoo.co.in.
authors.forename: Rama Moorthy
authors.initials: RM
authors.lastname: L
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
authors.forename: Basavapoornima
authors.initials: B
authors.lastname: Ch
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
authors.forename: Jayasankar
authors.initials: J
authors.lastname: C K
keywords: Chromaticity; KY((1−x))Dy(x)BO(3) phosphor; Luminescent properties; Solid-state reaction; White light emission