The reduction of Eu3+ to Eu2+ in BaMgSiO4:Eu prepared in air and the luminescence of BaMgSiO4:Eu2+ phosphor

The reduction of Eu3+ to Eu2+ in air has been observed in a silicate matrix for the first time in BaMgSiO4: Eu prepared by high-temperature solid-state reaction. Emission and excitation spectra were employed to detect the presence of Eu2+ ions in the compound and this reduction was explained by a charge compensation model proposed previously. In BaMgSi4 : Eu2+, Eu2+ ions occupy three different lattice sites by substitution for Bat2+ ions. Eu2+ ions on Ba(1) and Ba(2) sites gave emissions at about 500 nm while that on Ba(3) site showed an emission band at 398 nm. All the emissions of Eu2+ ions in BaMgSiO4: Eu2+ were not quenched at room temperature.