Relationship between Eu3+ reduction and glass polymeric structure in Al2O3-modified borate glasses under air atmosphere

• The efficient reduction of Eu3+ to Eu2+ is observed in the B2O3–Na2O glasses.
• Eu2+ luminescence is significant enhanced in the Al2O3-rich glasses.
• The introduction of Al2O3 changed the network structure of the borate glasses.
• High polymeric borate groups in the glass matrix may be destroyed to the lower ones.

The reduction of Eu3+ to Eu2+ is realized efficiently in Eu2O3-doped borate glasses prepared under air condition by melting-quenching method. Luminescent spectra show an increasing tendency of Eu2+ emission with increasing Al2O3 concentration in B2O3–Na2O glasses. It is interesting that significant enhancement appeared of Eu2+ luminescence in the Al2O3-rich sample comparing to the samples of Al2O3 less than 6 mol%. FTIR and Raman scattering measurements indicated that some new vibration modes assigned to the low-polymerized structure groups decomposed from the slight Al2O3 dopant samples. These results demonstrated that the polymerization of the glass structure decreased with increasing incorporation of Al2O3 into the borate glasses, linking to the efficiency of Eu3+ self-reduction in air at high temperature.

graphical abstractA novel europium valence reduction phenomenon occurred in Al2O3 modified borate glasses, FTIR and Raman measurements revealed that high polymeric groups were destroyed to low polymery structures with Al2O3 addition.Figure optionsDownload as PowerPoint slide