Sm³⁺ ions doped Sm₂Si₂O₇-based glass ceramics: Crystallization, luminescence and energy transfer process through heat treatment

Sm³⁺ ions incorporated Sm₂Si₂O₇ crystalline phase formed in the aluminoborosilicate glass matrix synthesized via melting quenching technique followed by heat-treatment process is reported herewith. The preliminary confirmation on the obtained glass ceramics was made through X-ray diffration (XRD) studies. Formation of non-bridging oxygens (NBOs) in the glass network and the modes of vibrations of network units were analyzed through Fourier transform infrared spectroscopy (FTIR) studies. Surface morphology of heat-treated samples at varying temperatures was determined via a field emission scanning electron microscope (FESEM). The absorption studies on heat-treated samples signify the low bandgap values and high Urbach energy values due to improved crystallinity in the glass network. Judd–Ofelt intensity parameters identified for visible absorption transitions follow the trend of Ω₄ >Ω₂> Ω₆. Excitation and emission studies on heat-treated samples show improvement in their intensities compared to the unheated base glass. The thermal quenching is observed at higher temperatures (540 and 580 °C for 3 h) of heat-treated samples. Calculations based on luminescence spectra including radiative transition probability, stimulated emission cross-section and branching ratio show good results for glass ceramics prior to precursor glass. Longer lifetimes of Sm³⁺ ions (milliseconds) in the level ⁴G_5/2 are seen for glass ceramics. Color coordinates suggest the reddish-orange emissions from prepared glass ceramics. Thus, Sm³⁺ doped Sm₂Si₂O₇ glass ceramics are favorable materials for solid-state lighting and laser applications.