Effect of codoping Ce³⁺ on the luminescence properties of Sr₉Mg_1.5(PO₄)₇:Eu²⁺ orange–yellow phosphor

Abstract

Sr 9 Mg 1.5 (PO 4 ) 7 :Eu 2+ has recently been reported as a promising blue light-excited orange-yellow phosphor that can be used in white LED device. Here, Ce 3+codoping is found to be an effective strategy to improve the luminescence performance of Sr 9 Mg 1.5 (PO 4 ) 7 :Eu 2+ phosphor. The coexistence of Eu 2+ and Eu 3+ ions has been verified via photoluminescence spectral analysis. The reduction of Eu 3+ to Eu 2+ in Sr 9 Mg 1.5 (PO 4 ) 7 lattice cannot be completed in a reducing atmosphere, but can be promoted through codoping with Ce 3+ ions to a great extent, which finally increase the effective concentration of Eu 2+ in the crystal lattice. The Eu 3+ −Eu 2+ reduction mechanism is analyzed using a charge compensation model. This work not only achieves enhanced luminescence of the Sr 9 Mg 1.5 (PO 4 ) 7 :Eu 2+ phosphor by codoping with Ce 3+ ions, but also provides new insights into the design of Ce 3+ /Eu 2+ codoped luminescent materials. K E Y W O R D Sdefects, doping, europium, LED, optical materials

Luminescence Enhancement of Red‐Emitting Sr9MnK(PO4)7 Phosphor via Energy Transfer and Charge Compensation

“…O for charge compensation in the SMKP host. As Eu ions are introduced in the SMKP host, K vacancies can be stabilized by Eu ions instead of V According to our previous experiments, [20,21,24] Eu ions are difficult to reduce completely in some phosphate hosts with β-Ca 3 (PO 4 ) 2 -type structure, which limits and impedes the study of whitlockite-like phosphors. Eu 2þ/3þ ions in phosphors can be clearly distinguished from their PLE and PL profiles.…”

“…According to our previous experiments, [ 20,21,24 ] Eu ions are difficult to reduce completely in some phosphate hosts with β‐Ca 3 (PO 4 ) 2 ‐type structure, which limits and impedes the study of whitlockite‐like phosphors. Eu 2+/3+ ions in phosphors can be clearly distinguished from their PLE and PL profiles.…”

“…The Mn 2þ emission intensity of SMKP:0.01Eu 2þ sample was about 13.7 times stronger than that of the SMKP sample. It was reported that Sr 9 MgK(PO 4 ) 7 :Eu 2þ phosphor [24][25][26] exhibited broad emission bands (450-700 nm) due to 4f 6 5d 1 !4f 7 transition of Eu 2þ ions occupied at various Sr sites with different CNs. The red emission of Mn 2þ (Figure 4a) is clearly increased with the doping of Eu 2þ .…”

Effect of [Ln3+–Si4+] (Ln = Y, La, Gd, Lu) Cosubstitution on the Structure and Luminescence Property of Sr9Mg1.5(PO4)7:Eu2+ Phosphor

“…The coexistence of Eu 2þ and Eu 3þ has been witnessed in the Sr 9 Mg 1.5 (PO 4 ) 7 host. [9][10][11][12] Both Eu 2þ and Eu 3þ ions randomly occupy Sr1, Sr2, and Sr3 sites. As shown in Table 1, the ionic radius of Eu 3þ ion is quite smaller than that of Eu 2þ ion.…”

“…[9] Upon excitation at 460 nm, Sr 9 Mg 1.5 (PO 4 ) 7 :Eu 2þ phosphor exhibits an emission band from 470 to 850 nm. In addition, it is found that Eu 2þ and Eu 3þ ions coexist in the phosphor, [10] making the luminescence behavior quite complicated. Meanwhile, several cation-substitution strategies have been designed to improve the luminescent performance.…”