Enhanced green emission in Er3+–Doped alkali molybdenum boro tellurite glasses suitable for photonic and dosimeters applications

Abstract

The study explores, synthesis, structural, optical and luminescence investigations of trivalent erbium-loaded alkali molybdenum boro-tellurite glasses matrix, with special emphasis on the green visible range emission. The physical characteristics, like molar volume and density, were computed. Raman spectroscopy and X-ray diffraction (XRD) were used in the structural study. XRD patterns and Raman spectra corroborate the absence of a significant peak and the amorphous nature of all the specimens. Furthermore, increasing Er₂O₃ concentration led to systematic changes in density and molar volume, indicating structural compactness in the glass matrix. The refractive index increased with Er³⁺ doping. Additionally, energy dispersive X-ray spectroscopy (EDX) confirmed the incorporation of elements into the glass matrix. UV–Vis–NIR absorption data revealed distinct peaks attributed to f-f transitions of Er³⁺ ions, while Tauc plots showed increased in the band gaps from 2.84 to 2.99 eV. These findings underscore the structural adaptability of the glass system to host rare-earth ions efficiently. For the luminescence properties, the incorporation of Er³⁺ ions significantly enhance the luminescence characteristics of the glass matrix at 1 mol% of Er₂O₃-doped glass, with optimal emission observed at 530 nm and 548 nm, corresponding to the transitions from the excited states ²H₁₁/₂ and ⁴S₃/₂ to the ground state ⁴I₁₅/₂. The Judd-Ofelt theory was employed to calculate the spectroscopic parameters, yielding values of Ω₂ = 8.94, Ω₄ = 1.26, and Ω₆ = 3.02 ( × 10⁻²⁰ cm²), which correlate with the observed emission intensities and branching ratios. The strong luminescence emission intensity with the substantial values of transition probability and branching ratio, leads us to an ABLME1 glass is a suitable choice for visible laser applications.