Synthesis and luminescence properties of RMgPO_4:Mn~(2+) (R = Li, Na, and K) red phosphor

摘要

RMgPO_4:Mn~(2+) (R = Li, Na, and K) phosphors are synthesized by a solid-state reaction method in air. The crystal structures and luminescence properties are investigated. A broad emission band peaking at 638 nm of RMgPO_4:Mn~(2+) (R = Li and Na) phosphors with excitation 408 nm is observed in the range of 550-800 nm owing to the ~4T_1(G) → ~6A_1 transition of the Mn~(2+) ion. KMgPO_4:Mn~(2+) phosphor with excitation 416 nm shows a broad emission band peaking at 658 nm in the range of 550-800 nm owing to the ~4T_1(G)→~6A_1 transition of the Mn~(2+) ion. The optimal Mn~(2+) ion concentration in RMgPO_4:Mn~(2+) (R = Li, Na, and K) phosphors is about 5 mol%. The lifetimes of RMg_(0.95)PO_4:0.05Mn~(2+) (R=Li, Na, and K) phosphors is ~6.21, 6.03, and 6.28 ms, respectively. The luminous mechanism is explained by Tanabe-Sugano diagram of Mn~(2+) ion.