Valence state change of europium in barium aluminates glass ceramics fabricated by containerless processing

Divalent europium ions have been widely used as activators in phosphor materials for many applications, which are commonly obtained from the reduction of trivalent europium raw materials. In this work, barium aluminates are chosen as host materials for studying the change of the Eu valence state in glassy and crystal matrices. Eu-doped barium aluminates glass-ceramics are fabricated by containerless processing and subsequent heat treatment. The structural characteristics are observed and the change of Eu valence state is examined. Possible mechanisms of reduction from Eu3+ to Eu2+ are discussed.