Tunable blue–green–yellow emitting phosphor of Ba4Gd3Na3(PO4)6F2:Ce3+/Tb3+/Mn2+via energy transfer

Abstract

A series of tunable blue–green–yellow emitting Ba₄Gd₃Na₃(PO₄)₆F₂:Ce³⁺/Tb³⁺/Mn²⁺ phosphors have been synthesized by a traditional solid state reaction. The PL and PLE properties of Ba₄Gd₃Na₃(PO₄)₆F₂:Ce³⁺/Tb³⁺/Mn²⁺ have been investigated. Ba₄Gd₃Na₃(PO₄)₆F₂:Ce³⁺,Tb³⁺ exhibits two dominating bands situated at 356 nm and 547 nm, which originate from the allowed 5d–4f transition of the Ce³⁺ ions and the ⁵D₄ → ⁷F_J (J = 6, 5, 4, 3, 2) transition of Tb³⁺ ions, respectively. The Mn²⁺ ions substitute Ba²⁺ and emit orange light centered at 571 nm. The dominating energy transfer processes from Ce³⁺ to Tb³⁺ and Mn²⁺ in the Ba₄Gd₃Na₃(PO₄)₆F₂ host were investigated and have been demonstrated to be the resonant type via a dipole–quadrupole interaction mechanism. The critical distances of Ce³⁺ and Tb³⁺, and Ce³⁺ and Mn²⁺ are 9.97–13.29 Å and 7.67 Å, respectively. The blue, green, and yellow colors can be tuned by the ratio of Ce³⁺/Tb³⁺/Mn²⁺, indicating that the phosphor may potentially be used as a tunable blue–green–yellow emitting phosphor for UV light-emitting diodes.