Enhanced White Light Emission And Energy Transfer Studies Of Dy3+/Ce3+ Co-doped YAl3(BO3)4 Phosphors For White Light Emitting Diodes

¹Department of Physics, Sri Venkateswara University, Tirupati 517 502, India

²Department of Physics, Chadalawada Venkata Subbaiah Engineering College, Tirupati 517 506, India

³Department of Materials and Ceramics Engineering, CICECO, University of Aveiro, Campus Santiago, 3810-193 Aveiro, Portugal

Adv. Mater. Lett., 2013, 4 (11), pp 841-848

DOI: 10.5185/amlett.2013. 3453

Publication Date (Web): Nov 02, 2013

Copyright © IAAM-VBRI Press

E-mail: bcjamal@hotmail.com

Abstract

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 1200^oC/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⁺:⁴F_9/2 → ⁶H_15/2,_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.

Keywords

Phosphors, white light emission, solid state reaction, optical properties, luminescence.