Color-tunable photoluminescence and energy transfer of (Tb1-x Mn x )3Al2(Al1-x Si x )3O12:Ce3+ solid solutions for white light emitting diodes.

Abstract

(Tb1−xMnx)3Al2(Al1−xSix)3O12:Ce3+ solid solution phosphors were synthesized by introducing the isostructural Mn3Al2(SiO4)3 (MAS) into Tb3Al5O12:Ce3+ (TbAG). Under 456 nm excitation, (Tb1−xMnx)3Al2(Al1−xSix)3O12:Ce3+ shows energy transfers (ET) in the host, which can be obtained from the red emission components to enhance color rendering. Moreover, (Tb1−xMnx)3Al2(Al1−xSix)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 (ηT, 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).