Influence of dysprosium incorporation strategies on borotellurite glass properties for white light emission

Abstract

Two series of dysprosium borotellurite glasses, with the base composition (0.4Li2O 0.4MgO)0.2Bi2O3(1.4B2O30.6TeO2), are synthesized. Two incorporation strategies are explored: substituting Bi2O3 or the glass networkitself. Comprehensive characterization using X-Ray Diffraction (XRD) confirms the amorphous nature of theglasses, while Differential Thermal Analysis (DTA) demonstrates their thermal stability and glass transitiontemperature (Tg). Fourier-transform infrared (FTIR) spectroscopy identifies the presence of BO3, BO4, TeO3, andTeO4 units, providing insights into the glass structure. Optical analysis using the Tauc and DASF methodsconfirms the allowed direct inter-band electronic transitions in the glasses. Photoluminescence analyses revealcharacteristic Dy3+ emission peaks in the blue and yellow regions. It is observed that photoluminescence intensityincreases with Dy3+ concentration in the bismuth-substituted series (BixDy), but remains constant in thenetwork-substituted series (BTxDy). This stable PL output in the BTxDy series demonstrates that the host networkeffectively inhibits Dy3+ micro-clustering, thereby suppressing concentration quenching mechanisms even athigh concentrations. Finally, Judd-Ofelt analysis and CIE chromaticity coordinates confirm that all glasses emitcold white light, positioning them as promising materials for white light-emitting diodes (WLEDs).