Influence of Gd³⁺ on structural and luminescence properties of new Eu³⁺-doped borate glass for photonics material

The Gd₂O₃–La₂O₃–ZnO–B₂O₃–Eu₂O₃ glasses with different Gd₂O₃ concentration (Gd:LaZnBEu) were studied in the physical, structural, optical and luminescence properties. The density and refractive index of glass increased with addition of Gd₂O₃ content. The FTIR spectra demonstrated the BO₃ and BO₄ borate complexes as the main construction in glass those were more disturbed by Gd₂O₃ increasing. The BO₄/BO₃ and bridging/non-bridging oxygen ratio, observed from XPS, changed by following the Gd₂O₃ concentration whose 10 mol% owned the highest values of both ratios. In the absorption spectra, glasses absorbed some photons in UV – NIR region. The excitation by O²⁻→Eu³⁺ charge transfer (240 nm), Gd³⁺→Eu³⁺ energy transfer (275 nm) and direct Eu³⁺ excitation (394 nm) caused the strongest Eu³⁺ photoluminescence at 613 nm (⁵D₀→⁷F₂). The glass with 5 mol%-Gd₂O₃, that possessed the optimum Eu³⁺ local site, exhibited the highest absorbance and photo-/radio-luminescence intensity. The CIE 1931 and UV lamp excitation revealed the strong reddish-orange emission of glasses. The photoluminescence decay time of Eu³⁺ in glasses were between 1.6 and 2.1 ms and decreased with added Gd₂O₃ amount. The Gd:LaZnBEu glasses have a potential for LED, laser, display, and X-ray detection devices with integration mode.