Synthesis and luminescence properties of CaAl2O4:Mn4+ phosphor

• CaAl2−yO4:yMn4+ phosphors are synthesized in air.
• PLE of CaAl2O4:Mn4+ phosphor from 220 to 550 nm is shown, and PL spectrum within the range 600–720 nm is observed.
• The influence of crystal field to luminous intensity and luminous mechanism are discussed, respectively.
• CIE chromaticity coordinates of CaAl1.99O4:1%Mn4+ phosphor is (0.7181, 0.2813).

CaAl2−yO4:yMn4+ (y = 0–1.6 mol%) phosphors are synthesized by a solid-state reaction method in air, and their crystal structure and luminescence property are investigated. To compare luminescence property, CaAl3.99O7:1%Mn4+ and SrAl1.99O4:1%Mn4+ phosphors are also synthesized at the same condition. Broad band excitation spectra are observed within the range 220–550 nm, and emission spectra cover from 600 to 720 nm with the strongest emission peak at ∼658 nm owing to the 2E → 4A2 transition of Mn4+ ion. The influence of crystal field to luminous intensity is discussed, and the possible luminous mechanism of Mn4+ ion is explained by using energy level diagram of Mn4+ ion. CaAl1.99O4:1%Mn4+, CaAl3.99O7:1%Mn4+, and SrAl1.99O4:1%Mn4+ phosphors under excitation 325 nm light emit red light, and their CIE chromaticity coordinates are (0.7181, 0.2813), (0.7182, 0.2818), and (0.7198, 0.2801), respectively. These contents in the paper are helpful to develop novel and high-efficient Mn4+-doped phosphor for white LEDs.