Structural, optical, luminescence spectroscopy and radiation shielding properties of Eu3+:borophosphotellurite glasses

Abstract

Recently much effort is being paid to study the rare earth ions in multi component glass formers as they exhibit high enhancement in the efficiency of luminescence properties. In this direction, the present study focuses on the preparation and analysis of novel glass batches with composition of (in mol %) BPTCZEu: 40B2O3+20P2O5+15TeO2+ 10CaO+(15−x)ZnO + xEu2O3, x = 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5. The important spectroscopic techniques such as optical absorption, luminescence, excitation and decay curves are taken to analyse the BPTCZEu glasses. Luminescence spectrum of BPTCZEu comprise of emission from excited (5D0) to the lower multiplets (7FJ (J = 0−4)), among these, 5D0 → 7F2 (red luminescence) at 612 nm found to be very intense. Judd−Ofelt characteristics, Ω2, Ω4 and Ω6, were derived from different constraints. To know the site symmetry around Eu3+, the fluorescence intensity ratio of 5D0 → 7F2 vs. 5D0 → 7F1 were analysed. Exciting 7F0 → 5L6 and monitoring 5D0 → 7F2, the lifetime of 5D0 level is determined to be 2 ms which is independent of Eu3+ content. The colour coordinates for all the Eu3+ concentrations are estimated to fall in the reddish−orange region. Theoretical radiation shielding results showed that substituting Eu2O3 for ZnO in the glasses lowers photon number that can pass via the material, enhancing the glass system's trend to shield high energy radiation. These stimulated results are compared with experimental measurements of mass attenuation coefficient with respect to energy up to 662 KeV using Cs−137 source. All these findings obtained from title glasses are compared and discussed with respect to reported Eu3+:glasses and no systematic variation has been noticed either with single, bi− or multi−component glass formers and therefore needs further systematic work to relate Eu−radiation−ligand interaction.