Luminescence properties of Ca3Si_2O_7: Dy~(3+) phosphor for white light-emitting diode

摘要

A new white Ca_3-_xSi_2O_7: _xDy~(3+) (x = 0.03,0.05, 0.07, 0.10) phosphor with various Dy~(3+) concentrations was prepared and its photoluminescent properties were investigated. The XRD results show that the Dy3+ substitution of Ca~(2+) does not change the structure of Ca_3Si_2O_7 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, 0 and Dy elements. Luminescence spectra excited by 350 nm consist of two characteristic blue and yellow bands, which correspond to ~4F_(9/2)→~6H_(15/2) and ~4F_(9/2)→~6H_(13/2) transitions of Dy~(3+), respectively. The yellow-to-blue emission intensity ratio under excitation of 350 nm increases with the elevated Dy~(3+) concentrations, and the evaluated color coordinates of the investigated samples fall in the white light region. The energy transfer style between Dy~(3+) ions is dipole-dipole interaction for higher concentration Dy3+ doped Ca_3Si_2O_7 phosphor. The quantum efficiency for x = 0.05 sample excited by 365 nm is 15.16%.