White light emission in Pr³⁺, Tb³⁺:CaYAlO₄ phosphor

Abstract

In this work, the synthesis and photoluminescence characteristics of two new phosphors Pr³⁺: CaYAlO₄ (CYA) and Pr³⁺/Tb³⁺: CYA for light emitting diodes (LEDs) are investigated. 0.5% (atom percentage) Pr³⁺: CYA exhibits the largest bright yellow emission by varying the Pr³⁺ concentration, owing to the cross-relaxation process of ³P₀+³H₄ → ¹G₄+¹G₄. The energy level diagram in Pr³⁺: CYA, especially the positions of 4f5d level and ¹S₀ level, is discussed. By co-doping Tb³⁺ ions, the color coordinates of Pr³⁺/Tb³⁺: CYA phosphor can be tuned from yellow to white region. Finally, the strongest luminescence emission with color coordinates of (0.339, 0.364) located in the white region can be obtained in 0.3%Tb³⁺/0.5%Pr³⁺: CYA phosphor.

Keywords

White Region / Energy Transfer Efficiency / Energy Level Diagram / Energy Transfer Mechanism / White Light Emission