Effect of Bi2O3 on the structural and spectroscopic properties of Sm3+ ions doped sodiumfluoroborate glasses

Erbium (III) ions- doped borate based glasses for 1.53 μm broad band applications

Designed and synthesized a novel erbium (III) ions doped borate based glasses (Er³⁺ : BCNF) by conventional melt-quenching technique. The glasses were characterized for their structural, vibrational and spectroscopic properties. The nephelauxetic ratio, bonding parameters, and Judd-Ofelt (JO) intensity parameters (Ω_λ λ = 2, 4 and 6) were determined by using absorption spectrum of 1 mol% Er₂ O₃ doped glass. These JO parameters were utilized to derive radiative properties for various excited states of Er³⁺ ions. Emission cross-section for ⁴ I_13/2 → ⁴ I_15/2 transition of erbium (III) ions was computed through McCumber theory. The decay curves for (² H_11/2 , ⁴ S_3/2 ) and ⁴ I_13/2 levels were recorded and analysed. All the results of Er³⁺ : BCNF glasses revealed that the studied glasses are efficient and thermally stable, could be suitable for display devices, optical amplification and green lasers applications.

Spectroscopic inquiry of CuO-doped borate glasses in the 50B2O3-25Li2O-25BaO ternary

Borate glasses with 50B₂O₃-25Li₂O-25BaO composition and CuO within 0.1-1.0 mol% relative to B₂O₃ have been prepared by the melting technique, and studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, optical absorption, and photoluminescence (PL) spectroscopy with decay kinetics assessment. A thermal dilatometric assessment was first carried out for the undoped glass, followed by a glass transition temperature (T_g) evaluation for all glasses by DSC. A propensity toward higher T_g values was indicated for high CuO concentrations, consistent with a higher BO₄ content being supported by copper ions as network modifiers. The glasses were all X-ray amorphous, whereas FT-IR spectra indicated the basic structural features of trigonal BO₃ units and BO₄ tetrahedra. Herein also, a tendency towards the 4-coordinated BO₄ units was indicated for the highest CuO contents concurring with the T_g trend. The optical absorption analysis showed that addition of CuO up to 1.0 mol% results in significant growth of the visible Cu²⁺ absorption band around 740 nm, with a decreasing trend in the optical band gap energies assessed through Tauc plots. Further analysis of the Urbach energies revealed declining values with copper doping indicating it favored a more uniform glass structure compatible with FT-IR data. An intrinsic luminescence was detected for the undoped borate glass displaying relatively long multi-exponential decay, which appeared to be quenched by Cu²⁺. The PL evaluation nevertheless supported the presence of Cu⁺ ions emitting broadly around 480 nm upon UV excitation at 250 nm. The decrease in the band gap energies is suggested to reflect the presence of ionic copper rather than an increase in non-bridging oxygens as commonly argued.

Investigations on Structural and Optical Properties of Various Modifier Oxides (MO = ZnO, CdO, BaO, and PbO) Containing Bismuth Borate Lithium Glasses

Bismuth based quaternary glasses with compositions BiBLM: 50Bi2O3–20B2O3–15Li2O–15MO (where MO = ZnO, CdO, BaO, and PbO) were processed by conventional melt quenching. The effectiveness of various modifier oxides on the optical and structural properties of the developed glasses was studied systematically by XRD, DSC, FTIR, Raman, and optical absorption (OA) measurements. The synthesized glass specimens were characterized by XRD and the patterns demonstrated an amorphous nature. The physical characteristics such as molar mass, density, and OPD values were found to increase with an increase in the molar mass of the modifier oxides, while there was a decrement in oxygen molar volume, thus resulting in decrement of complete molar volume of the prepared glasses. From DSC analysis, incorrigible reduction and enhancement of Tg and thermal stability among various modifier oxides in the glass network was noticed. Optical absorption data for glass specimens have confirmed the decrease in both direct and indirect optical band gap values among various modifier oxides incorporation. These investigations support the obtained Urbach energy (UE) and metallization criteria of synthesized glasses. The ionic characteristic for the glass specimens were confirmed by the values of electronic polarizability and electronegativity. The Raman and FT-IR spectra of the glass specimens displayed the existence of BiO3, BiO6, ZnO4, CdO4, BaO4, BO3, PbO4, and BO4 structural units within the glass matrix. These structural results can support the applications of as-developed glasses in the area of photonics.

Optical Spectroscopy and Excited-State Dynamics of Eu3+ -Doped Bismuth Borate Glasses Containing CuO

Bismuth borate glasses containing phosphors and luminescent rare-earths are of interest for applications in light-emitting devices. Herein, the influence of CuO impurities on red-emitting Eu³⁺ -doped bismuth borate glasses of the 25Bi₂ O₃ -15BaO-10Li₂ O-50B₂ O₃ type was investigated by various spectroscopic methods. The glasses were prepared by the melt-quench technique and characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, UV/Vis optical absorption (OA), and photoluminescence (PL) spectroscopy including decay kinetics assessment. The XRD data confirmed the amorphous nature of the glasses whereas FT-IR spectra indicated the basic structural features of trigonal BO₃ units and BO₄ tetrahedra. The OA analysis showed that addition of CuO up to 0.5 mol% results in significant growth of the visible Cu²⁺ absorption band around 715 nm, with slight decrease in the optical band gap energies assessed through Tauc plots. A drastic PL quenching of Eu³⁺ ions emission was evidenced concurring with the detrimental effect of Cu²⁺ . The assessment of the Eu³⁺ emission decay curves revealed significant lifetime decrease of the ⁵ D₀ emitting state with increasing CuO concentration. An analysis of quenching constants was finally performed comparing results from integrated PL data with the emission decay rates. It is argued that the bismuth borate glass system supports an effective Eu³⁺ →Cu²⁺ energy transfer (more so than phosphates) in connection with a strong spectral overlap between Eu³⁺ emission and Cu²⁺ absorption.