Effect of Mg 2+ and fluorine on the network and highly efficient photoluminescence of Eu 3+ ion in MgF 2 –BaO–B 2 O 3 glasses

The glass structure and photoluminescence of new oxyfluoride glasses with the composition of x MgF 2 –(66.7−2 x /3)BaO–(33.3− x /3)B 2 O 3 ( x  = 10‐50 mol%) were investigated in this work. The structure of the glasses was investigated by magic‐angle spinning NMR , XAS , and Raman scattering spectroscopies. It was revealed that the glasses are mainly composed of BO 3 units with a disconnected borate network consisting mainly of ortho‐ and pyro‐borate units, and ortho‐borate increases with the addition of MgF 2 . The fluorine atoms are surrounded by Mg 2+ and Ba 2+ ions. The photoluminescence of Eu 3+ ‐doped samples were investigated. It was indicated that asymmetry of the Eu 3+ site increased with the addition of MgF 2 . The photoluminescence quantum yield ( η ) of the glasses are very high and increased with MgF 2 addition; red photoluminescence is observed with η  = 82% for 10MgF 2 and η  = 98% for 50MgF 2 for excitation at 393 nm.