Synthesis and luminescence properties of CaAl2O4:Mn4+ phosphor

CaAl 2 − y O 4 : y Mn 4+ ( 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, CaAl 3.99 O 7 :1%Mn 4+ and SrAl 1.99 O 4 :1%Mn 4+ 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 2 E   →   4 A 2 transition of Mn 4+ ion. The influence of crystal field to luminous intensity is discussed, and the possible luminous mechanism of Mn 4+ ion is explained by using energy level diagram of Mn 4+ ion. CaAl 1.99 O 4 :1%Mn 4+ , CaAl 3.99 O 7 :1%Mn 4+ , and SrAl 1.99 O 4 :1%Mn 4+ 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 Mn 4+ -doped phosphor for white LEDs.