Orange-red luminescence of samarium-doped bismuth-germanium-borate glass for light-emitting devices

Samarium (Sm³⁺ )-doped glass has sparked a rising interest in demonstrating a noticeable emission in the range of 400-700, which is advantageous in solid-state lasers in the visible region, colour displays, undersea communication, and optical memory devices. This study reports the fabrication of Sm³⁺ -doped bismuth-germanium-borate glasses were established using a standard melt-quenching technique and inspection by absorption, steady-state luminescence, and transient studies. The typical peaks of Sm³⁺ ions were detected in the visible range under 403 nm excitation. A strong emission band was detected at 599 nm that resembles the ⁴ G_5/2 →⁶ H_7/2 transition of Sm³⁺ ions for BGBiNYSm_0.5 glass. Furthermore, a reddish-orange (coral) luminescence at 646 nm that resembles the ⁴ G_5/2 →⁶ H_9/2 transition was also perceived. The stimulated emission cross-section of ⁴ G_5/2 level for BGBiNYSm_0.5 glass was 0.39 × 10^-22  cm² . Lifetime of the ⁴ G_5/2 level was enhanced for the BGBiNYSm_0.5 glass and decreased with an increase in active ion concentrations. The lifetime quenching of ions at the metastable state was because of energy transfer among Sm³⁺ ions by cross-relaxation channels. Commission Internationale de l'Éclairage (CIE) coordinates were evaluated from the emission spectra. Moreover, all the findings recommend these glass as light-emitting materials in the coral region at 599 nm for solid-state lighting applications.