Luminescence and Site Occupancy of Eu²⁺ in Ba₂ Ca(BO₃)₂

A green phosphor Ba₂Ca(BO₃)₂:Eu²⁺ was synthesized by a high temperature solid–state reaction method under a reductive atmosphere. The luminescence and site occupancy of Eu²⁺ in Ba₂Ca(BO₃)₂ are investigated. Ba₂Ca(BO₃)₂:Eu²⁺ shows one green band (537 nm) under 400 nm near ultraviolet excitation which is suitable for UV LED. Ca²⁺ and Ba²⁺ ions in Ba₂Ca(BO₃)₂ are replaced by Eu²⁺ ions, the Ba₂Ca(BO₃)₂:Eu²⁺ shows a dissymmetrical emission band. The influence of Eu²⁺ doping concentrations on the emission intensity of Ba₂Ca(BO₃)₂:Eu²⁺ is studied. It is found that the emission intensity is influenced by the Eu²⁺ concentration and reaches the maximum value at 2% Eu²⁺. According to the Dexter theory, the concentration quenching mechanisms of Eu²⁺ in Ba₂Ca(BO₃)₂ are the d–dinteraction.