Enhancing the emission intensity and decreasing the full widths at half maximum of Ba3Si6O12N2:Eu2+ by Mg2+ doping

Abstract

The promising green oxynitride phosphor, Ba_3−xMg_xSi₆O₁₂N₂:Eu²⁺ was synthesized by the solid-state reaction method. The effect of Mg²⁺ doping on the structure and photoluminescence (PL) properties of Ba₃Si₆O₁₂N₂:Eu²⁺ was investigated systematically. The results reveal that the phosphor retains the single phase of Ba₃Si₆O₁₂N₂, with the lattice expanding upon increasing the Mg²⁺ concentration, in an appropriate range. This suggests that a large portion of Mg²⁺ enters into the interstitial sites of the crystal lattice. At a certain concentration, Mg²⁺ doping can greatly enhance the absorption and PL intensity and decrease the full widths at half maximum (FWHM) of Ba₃Si₆O₁₂N₂:Eu²⁺ phosphors. The green phosphor Ba_2.87Eu_0.1Mg_0.03Si₆O₁₂N₂ exhibited a small thermal quenching, which remained 82% of the initial emission intensity when measured at 150 °C. The quantum efficiency measured at 400 nm excitation was 38.5%. All the results indicate that the solid solution Ba_3−xMg_xSi₆O₁₂N₂:Eu²⁺ can be a good candidate for phosphors applicable in n-UV LEDs for solid-state lighting.