Raman, photoluminescence and EPR spectroscopic characterization of europium(III) oxide-lead dioxide-tellurite glassy network

Raman, photoluminescence and EPR spectroscopies were used to characterize some xEu2O3·(100−x)[4TeO2·PbO2] glasses with x=0-50 mol% obtained by melt quenching technique. Raman spectra of these glasses were interpreted in terms of vibration modes of deformed Te-O-Te linkages due to the intercalation of [PbOn] and [EuOn] entities produced by addition of Eu2O3 to the host lead-tellurite glass. Photoluminescence spectra of xEu2O3·(100−x)[4TeO2·PbO2] glasses reveal the presence of Pb2+, Eu2+ and Eu3+ ions. EPR data confirm the presence of Eu2+ ions in the europium-lead-tellurite glassy network and offer information about the compositional evolution of the Eu2+ ions local environment and Eu3+↔Eu2+ redox process. PL and EPR data show that the decrease of the Eu2+ ions luminescence intensity for the x≥40 mol% Eu2O3 region is not due to the clusterization of europium ions but is due the decrease of the amount of Eu2+ ions as result of changes in the Eu3+→Eu2+ redox equilibrium.