Enhanced White Light Emission And Energy Transfer Studies Of Dy3+/Ce3+ Co-doped YAl3(BO3)4 Phosphors For White Light Emitting Diodes
G.V. Lokeswara Reddy, L. Rama Moorthy, T. Chengaiah, B.C. Jamalaiah
Volume 4, Issue 11, Page 841-848 | DOI: 10.5185/amlett.2013. 3453
Phosphors; white light emission; solid state reaction; optical properties; luminescence.
We reported the structure, photoluminescence and energy transfer studies of Dy3+/Ce3+ co-doped YAl3(BO3)4 (YAB) phosphors prepared by solid-state reaction method at 1200oC/3h. Upon 273 nm UV excitation, the YAB:Ce3+ phosphor exhibits a sharp emission band with peak maximum at 380 nm related to the parity and spin allowed Ce3+:5d → 4f transition. When excited with 352 nm, the broad emission band of Ce3+ contains two components at 390 and 417 nm due to the electric dipole transitions from 5d excited state to the two splitting ground 2F5/2,7/2 states, respectively. The incorporation of Ce3+ enhances the luminescence intensity of Dy3+ due to efficient energy transfer from Ce3+ to Dy3+. The emission spectra of Dy3+/Ce3+ co-doped phosphors under 273 nm excitation display the Dy3+:4F9/2 → 6H15/2,13/2,11/2 and the Ce3+:5d → 4f transitions. The emission colour can be tuned from blue-to-white as a function of Ce3+ concentration and/or excitation wavelength. Colour perception has been analyzed by evaluating the Commission International de I’Eclairagein (CIE) chromaticity coordinates. The YAB:Dy3+/Ce3+ phosphors can be significant for current generation UV excited white light emitting diodes. Copyright © 2013 VBRI press.