Luminescence characteristics of Sr_1−<i>x</i>Ba_<i>x</i>Si₂O₂N₂:Eu²⁺ phosphors for white light emitting diodes

Abstract

Abstract Sr 1− x Ba x Si 2 O 2 N 2 :Eu 2+ phosphors were synthesized using high temperature solid state reaction. The effect of Ba incorporation on the structural and luminescence characteristics of SrSi 2 O 2 N 2 :Eu 2+ phosphors were studied. The phosphors were crystallized in triclinic crystal structure and the cell volume increases monotonically with Ba addition. The PL emission peak wavelength red shifts with Ba up to x = 0.50 beyond which no red shift is observed. The XPS analysis shows that nitrogen is being incorporated into the host lattice along with Ba addition up to x = 0.50. The as synthesized phosphors show high thermal stability. Phosphor converted light emitting diodes were realized using Sr 1− x Ba x Si 2 O 2 N 2 :Eu 2+ phosphors ( x = 0 and x = 0.40) showing luminance efficacies of 108 and 101 lm W −1 . magnified image The CIE chromaticity coordinates of Sr 1− x Ba x Si 2 O 2 N 2 :Eu ( x = 0 and x = 0.40) phosphors.