Crystal structures, tunable emission and energy transfer of a novel GdAl12O18N:Eu2+,Tb3+ oxynitride phosphor

Abstract

We have synthesized a series of Eu²⁺ and Eu²⁺/Tb³⁺ activated novel GdAl₁₂O₁₈N oxynitride phosphors by a traditional solid state reaction. The structural and photoluminescence properties related to the crystal of GdAl₁₂O₁₈N:Eu²⁺/Tb³⁺ phosphor are investigated. Rietveld structure refinement and photoluminescence properties of the obtained phosphor indicate that the GdAl₁₂O₁₈N host has only one type of Gd site. GdAl₁₂O₁₈N:Eu²⁺,Tb³⁺ samples exhibit a blue emission band that peaks at 460 nm and a green line that peaks at 550 nm, originating from the Eu²⁺ and Tb³⁺ ions, respectively. This energy transfer from Eu²⁺ to Tb³⁺ was confirmed by the decay times of energy donor Eu²⁺. In addition, the mechanism of energy transfer from Eu²⁺ to Tb³⁺ ions is demonstrated to be a dipole–quadrupole mechanism by the Inokuti–Hirayama (I–H) model. All the results indicate that the Eu²⁺ and Tb³⁺ activated phosphor may be a good candidate for blue-green components in UV white LEDs.