Physical and spectroscopic properties of lithium-borosulfophosphate glasses doped with dysprosium and europium ions

Abstract

A study had successfully been conducted on lithium-borosulfophosphate glasses to examine the effect of dysprosium and europium ions upon their physical and spectroscopic properties. The glass samples were synthesized via convectional melt quenching technique and characterized using density, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), UV-Vis-NIR, and Photoluminescence (PL) measurements. The amorphous nature of the glass was confirmed using XRD studies. It is observed that the physical and optical properties of these glasses are found to be strongly influence by varying the glass composition. The glass density and refractive index increase proportionally with Dy2O3 and Eu2O3 concentration whereas the molar volume exhibits opposite behaviour. The result from FTIR spectra analysis indicates the presence of BO3, BO4, PO4 and SO42- groups in the host network structure. UV-Vis-NIR spectra of Dy3+ doped glass samples recorded seven absorption peaks while on the contrary, Eu3+ doped glass samples exhibits four peaks in UV-Visible region and two peaks in NIR region. The optical band gap was found to decrease gradually with increase in Dy3+ and Eu3+ concentration while the Ubach‘s energy shows inverse trend. Meanwhile the negative and positive value of the bonding parameters confirmed the corresponding ionic and covalent nature of Dy-O and Eu-O ligand bond in the host matrix. The luminescence spectra for Dy3+ doped samples at the excitation wavelength of 386 nm revealed two intense emission peaks at 494 nm (4F9/2?6H15/2), 585 nm (4F9/2?6H13/2) and a very weak peak at 673 nm (4F9/2?6H13/2). Conversely, doping the samples with Eu3+ ions gives rise to four emission peaks at 587 nm (5D0?7F1), 612 nm (5D0?7F2), 650 nm (5D0?7F2) and 698 nm (5D0?7F4) under the excitation wavelength of 394 nm. The superior features shown by the current glass material as a result of good correlations between the host network and dopant ions specifies its potentialities for lighting device applications.