Influence of Sm3+ Ions on the Structural, Optical and Luminescent Properties of Zinc–Antimony–Boro–Germanate Glasses

Zinc–antimony–boro–germanate glasses highly doped with Sm2O3 were synthesized by the conventional melt-quenching method. Their structural, optical, and luminescent properties were systematically investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance UV–Vis (DR-UV–Vis), and photoluminescence (PL) spectroscopy. XRD analysis confirmed the amorphous nature of all prepared samples. XPS measurements were used to examine the surface chemical composition of the Sm2O3-doped glasses, with particular focus on verifying samarium incorporation and identifying its oxidation state after synthesis, since Sm ions act as the luminescent centers in these materials. For the sample containing the highest Sm2O3 concentration, the DR-UV–Vis spectrum exhibited ten absorption bands assigned to intra 4f electronic transitions. Based on these data, the nephelauxetic and bonding parameters were determined, indicating that increasing Sm2O3 content enhances the ionic character of the bonds within the glass network. PL spectra revealed three characteristic emission bands associated with Sm3+ luminescent centers. The emission intensity reached a maximum at 3 mol% Sm2O3, while further increases in samarium content led to luminescence quenching. The most intense emission band was in the yellow–orange region of the visible spectrum, highlighting the potential of these materials for yellow–orange-emitting solid-state laser applications. The excitation spectra show that the optical response is strongly dependent on concentration, with a sample doped with 3 mol% Sm2O3 exhibiting the highest excitation efficiency. The dominant excitation band centered near 402 nm, together with weaker bands in the blue region, indicating that these glasses are promising candidates for near-UV-pumped orange-emitting photonic devices.