The effect of binary glass composition on the Eu-ions luminescence properties

Abstract Eu 2 O 3 -doped Ca 1- x Ba x O-2SiO 2 glasses were prepared using standard melt-quenching technique at 1500 °C in CO-rich atmosphere. The changes of the Eu 2+ /Eu 3+ ratio as a function of Ba content ( x ) were investigated by optical absorption, photoluminescence (PL), radioluminescence (RL) and electron paramagnetic resonance (EPR) methods. The increase of x leads to a monotonic decrease of the absorption band related to Eu 2+ . On the other hand, the glass samples with a dominating Ca 2+ content exhibit the strongest Eu 2+ luminescence. Altogether this may point out the domination of the energy transfer from Eu 2+ to Eu 3+ . A weak Eu 2+ - and Eu 3+ -related emission in mixed glasses with 1- x = 0.5, 0.75 can be the result of some kind of quenching due to the mutual Ca 2+ and Ba 2+ influence introduced to the nearest environments of Eu ions. The role of x in the glass structure modification was confirmed also by infrared spectroscopy (IR) methods. Specific Eu 2+ signals were detected in EPR spectra measured in all the glass samples with the exception of the BaO–2SiO 2 one, so only the europium 3+ charge state is expected to be present in this glass. EPR measurements thus correlate well with optical observations.