Energy transfer in Y₃Al₅O₁₂:Ce³⁺, Cr³⁺ and Y₃Al₅O₁₂:Ce³⁺, Pr³⁺, Cr³⁺ phosphors

Triply doped Y₃Al₅O₁₂:Ce³⁺, Pr³⁺, Cr³⁺ phosphors with Ce³⁺ and Pr³⁺ substituting for Y³⁺ sites and Cr³⁺ substituting for Al³⁺ site are prepared by solid state reaction. A broad emission spectrum composed a yellow emission band from Ce³⁺, a light red emission line from Pr³⁺ and a deep red emission line from Cr³⁺, which are generated through energy transfer among the dopant ions. The study of photoluminescence and fluorescence decay indicates that there exist energy transfers from Ce³⁺→Cr³⁺ and Ce³⁺→Pr³⁺→Cr³⁺. The effect of energy transfer on relative intensities of the three emissions is analyzed. A white LED is fabricated using a blue LED chip coated with the triply doped phosphor and shows a color rendering index of 81.4 and 80.4, respectively.It is higher than that either using Ce³⁺ and Cr³⁺ doubly doped phosphor or Ce³⁺ singly doped phosphors.