Luminescence properties of Sr2Mg3P4O15:Mn2+ phosphor and the improvement by co-doping Bi3+

Sr 2 Mg 3 P 4 O 15 :R (R = Bi 3+ , Mn 2+ , and Bi 3+ /Mn 2+ ) phosphors are synthesized by a solid-state reaction method in air. Sr 2 Mg 3 P 4 O 15 :Bi 3+ phosphor with excitation 380 nm shows blue light and its emission band peaking at ∼445 nm is observed. Under excitation at 355 and 416 nm, Sr 2 Mg 3 P 4 O 15 :Mn 2+ phosphor shows red emission with a single broad emission band peaking at ∼630 nm in the range of 500–800 nm owing to the 4 T 1 (G) → 6 A 1 transition of the Mn 2+ ion. The optimal Mn 2+ ion content in Sr 2 Mg 3 P 4 O 15 :Mn 2+ phosphor is ∼0.05 and the lifetime of Sr 2 Mg 2.95 P 4 O 15 :0.05Mn 2+ phosphor is ∼6.17 ms. After Bi 3+ ion is co-doped, emission intensity of Sr 2 Mg 3 P 4 O 15 :Mn 2+ phosphor can be enhanced obviously due to energy transfer (ET) from Bi 3+ to Mn 2+ , which is confirmed by the luminescence properties and lifetimes of Sr 2 Mg 3-x P 4 O 15 :Bi 3+ , Mn 2+ phosphor. Luminous mechanism and ET process of Sr 2 Mg 3-x P 4 O 15 :Bi 3+ , Mn 2+ phosphor are explained by the simple energy level diagram of Bi 3+ and Mn 2+ ions.