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

Nanophosphors of (Sr Mg Eu ) SiO (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 Eu  -doped Sr SiO nanophosphor is observed at ~490 nm and ~553 nm corresponding to two Sr sites Sr(I) and Sr(II) respectively for 395 nm excitation. However the addition of Mg dopant in Sr SiO 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 (Mg Sr Eu ) SiO nanophosphor can be used for blue emission and the Sr SiO :Eu for green-yellow emission at 395 nm excitations. The Commission International de L'Eclairage (CIE) chromaticity coordinates for mixed powders of (Mg Sr Eu ) SiO and Sr SiO :Eu (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.