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

Abstract

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 BaMgSiO₄∶Eu²⁺, Eu²⁺ ions occupy three different lattice sites by substitution for Ba²⁺ 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.