Structure and luminescent properties of Sm/Dy-doped Sr2MgSi2O7 glass–ceramics

Sm³⁺-doped and Sm³⁺/Dy³⁺ codoped SiO₂–SrO–MgO glasses were prepared by conventional melt quenching and Sr₂MgSi₂O₇ based glass–ceramics from sintering and crystallization of the glass powders. The thermal, structural, and optical properties of the glasses and glass–ceramics were investigated as a function of the dopant concentration. The optical characterization includes the photoluminescence spectra and the lifetimes of the ⁴G_5/2 (Sm³⁺) and ⁴F_9/2 (Dy³⁺) excited states. In Sm³⁺ single-doped samples, the emission intensity increases up to a concentration of 0.3 mol% Sm³⁺ ions and then decreases due to nonradiative energy transfer processes. The emission spectra in the glass–ceramics show a more resolved structure and higher intensity compared to the glass samples, suggesting a different and crystalline environment for the Sm³⁺ ions. The non-radiative processes also influence the experimental decays of the glass samples which deviate from a single exponential with lifetimes decreasing as Sm³⁺ concentration increases. The emission and excitation spectra of the codoped samples do not show significant energy transfer between Sm³⁺ and Dy³⁺ ions. Different emitting colors can be obtained in the codoped glasses by changing the excitation wavelength. The studied glass–ceramics could be applied as enamels on ceramic or metallic substrates.