Spontaneous reduction of europium ions below 250 °C in organic—inorganic hybrid low-melting phosphite glasses

Abstract

Europium-doped organic—inorganic hybrid low-melting phosphite glass was prepared from SnCl₂, Me₂SiCl₂, and H₃PO₃ (phosphonic acid) through the nonaqueous acid–base reaction process. The europium-doped glass melted at 250 °C showed fluorescence with a broad peak at 373 nm due to the 4f ⁶ 5d ¹ → 4f ⁷ transition of Eu²⁺ ions, whereas no fluorescence from the Eu³⁺ ions was observed. Almost all of the Eu³⁺ ions incorporated into the glasses could be successfully reduced to Eu²⁺ ions at a temperature as low as 250 °C by the strong reducing power of H₃PO₃.