| Abstract: A series of phosphors Ca0.955-xAl2Si2O8:0.045Eu2+, xMn2+ (x=0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.325, 0.35, 0.375, 0.40, 0.425) were prepared via solid-state reaction. As Mn2+ was substituted for Ca2+ into the crystal lattice, the effect on its lattice parameters and spectral properties were discussed. The results show that complete solid solutions were formed in the whole range for x while Mn2+ enterers CaAl2Si2O8 lattice and substitutes for Ca2+. The samples belong to triclinic system, and P1 space group. The lattice parameters (a, b, c, γ) and unit cell volume of phosphors Ca0.955-xAl2Si2O8:0.045Eu2+, xMn2+ decreased linearly, and the lattice parameters (α, β) increased linearly as Mn2+ content increased in the phosphors. When Mn2+ substitutes for Ca2+ the most obvious change is in cell parameter a, the second is c, and the minimum is b. When excited by 357 nm, the Ca0.955-xAl2Si2O8:0.045Eu2+, xMn2+ phosphors exhibited two emission peaks centered at 433 and 567 nm, which are ascribed to 5d→4f and 4T1(4G)→6A1(6S) transition of Eu2+ and Mn2+, respectively. The results show that the existence of efficient energy transfer between Eu2+ and Mn2+ in phosphors Ca0.955-xAl2Si2O8:0.045Eu2+, xMn2+, the critical distance is calculated to be 0.947 1 nm. The energy transfer between Eu2+ and Mn2+ was due to the electric dipole-dipole interaction of the resonance transfer. Under the effective excitation of the ultraviolet chip, by changing the amount of Mn2+ doping, the color of the emitted light of the phosphors can be gradually shifted from blue light (0.158 2, 0.086) to near white light (0.295 3, 0.298 9). UV-excited single-phase white light-emitting phosphors for white LEDs were available. |
