Spectroscopic properties of Dy3+ doped tellurite glass with Ag/TiO2 nanoparticles inclusion: Judd-Ofelt analysis

Abstract

Silver (Ag) and Titania (TiO2) nanoparticles (ATNPs) co−embedded and dysprosium (Dy3+) ions doped magnesium−zinc−tellurite glasses were synthesized via melt quenching method. As−prepared samples were characterized using various analytical tools. Nanoparticles concentration dependent spectroscopic properties of the prepared glasses were evaluated using Judd−Ofelt (J−O) analysis. XRD pattern verified the amorphous nature of as−quenched samples. The UV–Vis spectra revealed six absorption bands centred at 1690, 1283, 1097, 904, 800 and 755 nm, assigned to the transitions from the ground level to different excited levels of Dy3+ ions. The photoluminescence (PL) emission spectra of the glass system displayed three emission bands positioned at 482 (blue: 4F9/2 → 6H15/2), 574 (yellow: 4F9/2 → 6H13/2) and 664 nm (weak red: 4F9/2 → 6H11/2). For all the bands, the PL intensities of the studied glasses were more pronounced than singly embedded sample (either ANPs or TNPs). Furthermore, the enhancement in the PL peak intensity due to the inclusion of metallic NPs was attributed to the surface plasmon resonance mediated local field effect in the proximity of Dy3+ ions. Ligand bonding of Dy3+ showed the ionic nature of the prepared glasses. The absorption and emission spectral data were used to evaluate the J−O intensity parameters (Ωλ (λ = 2, 4, 6)) and radiative properties. Values of Ωλ (λ = 2, 4, 6) for glass with 0.1 mol% of TNPs exhibited the trend of Ω2>Ω6>Ω4 while all other glasses revealed Ω2>Ω4>Ω6. It was demonstrated that by combining two types of NPs (Ag and TiO2) hot spot with intense electromagnetic field could be created in the neighbourhood of Dy3+ ion to achieve enhanced optical attributes of the proposed glasses. The attainment of large quality factors and quantum efficiency (≈100%) in the ATNPs co−embedded glasses were established to be beneficial for the development of solid state lasers and other photonic devices.