Enhanced white light emission and energy transfer studies of Dy 3+ /Ce 3+ co-doped YAl3(BO3)4 phosphors for white light emitting diodes

We reported the structure, photoluminescence and energy transfer studies of Dy 3+ /Ce 3+ co-doped YAl3(BO3)4 (YAB) phosphors prepared by solid-state reaction method at 1200 o C/3h. Upon 273 nm UV excitation, the YAB:Ce 3+ phosphor exhibits a sharp emission band with peak maximum at 380 nm related to the parity and spin allowed Ce 3+ :5d → 4f transition. When excited with 352 nm, the broad emission band of Ce 3+ contains two components at 390 and 417 nm due to the electric dipole transitions from 5d excited state to the two splitting ground 2 F5/2,7/2 states, respectively. The incorporation of Ce 3+ enhances the luminescence intensity of Dy 3+ due to efficient energy transfer from Ce 3+ to Dy 3+ . The emission spectra of Dy 3+ /Ce 3+ co-doped phosphors under 273 nm excitation display the Dy 3+ : 4 F9/2 → 6 H15/2,13/2,11/2 and the Ce 3+ :5d → 4f transitions. The emission colour can be tuned from blue-to-white as a function of Ce 3+ concentration and/or excitation wavelength. Colour perception has been analyzed by evaluating the Commission International de I’Eclairagein (CIE) chromaticity coordinates. The YAB:Dy 3+ /Ce 3+ phosphors can be significant for current generation UV excited white light emitting diodes. Copyright © 2013 VBRI press.