Syntheses and Luminescent Properties of CaAl2Si2O8: Eu2+, Mn2+ Phosphors for White LED

Aluminosilicate-based luminescent materials, a series of CaAl2Si2O8: Eu2+ samples were prepared by using a solid-state reaction method. The X-ray diffraction patterns of the samples confirmed their triclinic structure after annealing at 1100. degrees C. The excitation spectra of CaAl2Si2O8: Eu2+ exhibited a broad band ranging between 220 to 420 nm with a point peak at a longer wavelength. Moreover, a shift in the broad band was also recorded with increasing Eu2+ concentration. The emission spectrum of CaAl2Si2O8: Eu2+ consists of a broad band from 390 to 550 nm with a maximum intensity at about 438 nm, which can be ascribed to the electric-dipole-allowed 4f(6)5d(1-8) S-7/2(4f(7)) transition of the Eu2+ ions. A series of Eu2+ and Mn2+ co-activated CaAl2Si2O8 samples were synthesized at 1400. degrees C. The CaAl2Si2O8: Eu2+, Mn2+ samples had a wide emission band ranging from blue to yellow and peaking at 438 and 550 nm under an excitation wavelength of 352 nm. The PL spectrum of the CaAl2Si2O8: Eu2+, Mn2+ samples reveal an effective energy transfer from Eu2+ to Mn 2+ in CaAl2Si2O8. By utilizing the principle of energy transfer, we also demonstrated that with appropriate tuning of the activator content, CaAl2Si2O8: Eu2+, Mn2+ phosphors exhibit great potential as a phosphor for white-light-emitting diodes.