Influence of Nb2O5 on the luminescent and structural properties of nanostructured phosphate glasses doped with RE3+ ions

Niobium pentoxide (Nb₂O₅) in glasses doped with RE³⁺ ions has garnered significant interest in developing luminescent materials for optical devices. This study explores a phosphate glass nanostructured with CdS and doped with Nd³⁺ and Eu³⁺ ions, focusing on the impact of Nb₂O₅ addition. Using optical absorption, photoluminescence (PL), time–resolved photoluminescence, and Raman Scattering, the structural and luminescent properties were characterized. Nb₂O₅ was found to significantly influence the matrix, acting as a network–forming agent, and reducing phonon energy from ∼1060 to 900 cm^-1. Structural changes were also evidenced by an increase in the asymmetric ratio of Eu³⁺ ions from ∼5 to 8. PL decay curves indicated Nd³⁺ ions distributed across sites with different symmetries, with Nb₂O₅ reducing the lifetime of the ⁴F_3/2 level from 337 to 282 μs. The findings demonstrate that Nb₂O₅ can modulate the structural and luminescent properties of phosphate glass, making it a promising for advanced photoluminescent materials.