A dual-excited emission phosphor Eu3+/Eu2+ co-doped Ca4Si2O7F2: Lattice occupancy and luminescence characterization

A novel adjustable dual excited emission Eu 2+ /Eu 3+ co-doped Ca 4 Si 2 O 7 F 2 phosphor are reported. Unlike most of Eu 2+ doped inorganic compounds , in the host lattice Ca 4 Si 2 O 7 F 2 , partial Eu 3+ can still exist stably even in reducing atmosphere. The adjustable dual excited emission from blue light to red light can be found by changing the wavelength of excitation emission or the concentration of europium doped ion. The mechanism by which the two ions Eu 2+ and Eu 3+ can coexist in Ca 4 Si 2 O 7 F 2 is revealed through the bond energy theory. Eu 2+ and Eu 3+ in Ca 4 Si 2 O 7 F 2 system can be demonstrated to occupy the Ca1 lattice of Ca 4 Si 2 O 7 F 2 .