Effect of Mg doping in Sr 2 SiO 4 :Eu 2 + nanophosphors for blue and white emission at near-UV excitation.

Nanophosphors of (Sr0.98-x Mgx Eu0.02 )2 SiO4 (x = 0, 0.18, 0.38, 0.58 and 0.78) were prepared through low temperature solution combustion method and their luminescence properties were studied. The emission peak for Eu2 +  -doped Sr2 SiO4 nanophosphor is observed at ~490 nm and ~553 nm corresponding to two Sr2 + sites Sr(I) and Sr(II) respectively for 395 nm excitation. However the addition of Mg2 + dopant in Sr2 SiO4 leads to suppression of ~553 nm emission peak due to absence of energy levels of Sr (II) sites which results in a single broad emission at ~460 nm. It was shown that the emission peak blue shifted with increase in Mg concentration which may be attributed to change in crystal field environment around Sr(I) sites. Therefore, the (Mg0.78 Sr0.20 Eu0.02 )2 SiO4 nanophosphor can be used for blue emission and the Sr2 SiO4 :Eu0.04 2+ for green-yellow emission at 395 nm excitations. The Commission International de L'Eclairage (CIE) chromaticity coordinates for mixed powders of (Mg0.78 Sr0.20 Eu0.02 )2 SiO4 and Sr2 SiO4 :Eu0.04 2+ (in a 1:1 ratio) fall in the white region demonstrating the possible use of the mixture in white light generation using near-UV excitation source.