Color-tunable photoluminescence and energy transfer of (Tb1−xMnx)3Al2(Al1−xSix)3O12:Ce3+ solid solutions for white light emitting diodes

Abstract

(Tb_1−xMn_x)₃Al₂(Al_1−xSi_x)₃O₁₂:Ce³⁺ solid solution phosphors were synthesized by introducing the isostructural Mn₃Al₂(SiO₄)₃ (MAS) into Tb₃Al₅O₁₂:Ce³⁺ (TbAG). Under 456 nm excitation, (Tb_1−xMn_x)₃Al₂(Al_1−xSi_x)₃O₁₂:Ce³⁺ shows energy transfers (ET) in the host, which can be obtained from the red emission components to enhance color rendering. Moreover, (Tb_1−xMn_x)₃Al₂(Al_1−xSi_x)₃O₁₂:Ce³⁺ (x = 0–0.2) exhibits substantial spectral broadening (68 → 86 nm) due to the 5d → 4f transition of Ce³⁺ and the ⁴T₁ → ⁶A₁ transition of Mn²⁺. The efficiency of energy transfer (η_T, Ce³⁺ → Mn²⁺) gradually increases with increasing Mn²⁺ content, and the value reach approximately 32% at x = 0.2. Namely, the different characteristics of luminescence evolution based on the effect of structural variation by substituting the (MnSi)⁶⁺ pair for the larger (TbAl)⁶⁺ pair. Therefore, with structural evolution, the luminescence of the solid solution phosphors could be tuned from yellow to orange-red, tunable by increasing the content of MAS for the applications of white light emitting diodes (wLED).