Rare-earth free broadband Ca3Mg3P4O16:Mn2+ red phosphor: Synthesis and luminescence properties

Rare-earth-free red-emitting Ca3Mg3P4O16:Mn2+ (CMPO:Mn2+) phosphor is synthesized by high temperature solid-state reaction method in air. The crystal structures and luminescence properties are investigated. Broad emission band peaking at ~ 625 nm of CMPO:Mn2+ phosphor with excitation 410 nm is observed in the range of 510 − 790 nm due to the 4T1(G) → 6A1 transition of the Mn2+ ion. The full width at half-maximum is ~ 120 nm. Excitation bands are assigned to the [6A1 → 4E(4D), 4T2(D), [4A1(G), 4E(4G), and 4T1(G)] transitions, respectively. The optimal Mn2+ ion concentration in CMPO:Mn2+ phosphor is ~ 5 mol%. The lifetime of CMPO:0.05Mn2+ phosphor is ~ 5.75 ms. The luminous mechanism of Mn2+ ion in CMPO:Mn2+ phosphor is explained by Tanabe-Sugano diagram and the simple energy level diagram of Mn2+ ion. The paper content is helpful for the research of novel Mn2+-doped materials.