Luminescence properties of Ca3Si2O7: Dy3+ phosphor for white light-emitting diodes

A new white Ca3-xSi2O7: xDy(3+) (x = 0.03, 0.05, 0.07, 0.10) phosphor with various Dy3+ concentrations was prepared and its photoluminescent properties were investigated. The XRD results show that the Dy3+ substitution of Ca2+ does not change the structure of Ca3Si2O7 host for x 0.10. The SEM image displays that phosphors aggregate obviously, and the shape of the phosphor particle is irregular. The EDX results reveal that the phosphors consist of Ca, Si, O and Dy elements. Luminescence spectra excited by 350 nm consist of two characteristic blue and yellow bands, which correspond to F-4(9/2)-> H-6(15/2) and F-4(9/2)-> H-6(13/2) transitions of Dy3+, respectively. The yellow-to-blue emission intensity ratio under excitation of 350 nm increases with the elevated Dy3+ concentrations, and the evaluated color coordinates of the investigated samples fall in the white light region. The energy transfer style between Dy3+ ions is dipole-dipole interaction for higher concentration Dy3+ doped Ca3Si2O7 phosphor. The quantum efficiency for x = 0.05 sample excited by 365 nm is 15.16%. (C) 2012 Elsevier B.V. All rights reserved.