Structural and luminescent properties of KY(1-x)DyxBO3 phosphors.

Abstract Yttrium borate phosphors (KY (1−x) Dy x BO 3 ) 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) Dy x BO 3 phosphors were investigated from the excitation, emission and decay analyses. The emission spectra exhibited characteristic blue (460–500 nm) and yellow (555–610 nm) 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 F 9/2 excited level were found to decrease from 0.87, 0.47, 0.35, 0.26 and 0.13 ms with the increase of Dy 3+ ion concentrations from 0.05, 0.1, 0.15, 0.2 and 0.3 mol%, 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) Dy x BO 3 phosphors are more useful for white light emitting diodes.