A series of Sm3+-doped Na2O–ZnO–MgO–B2O3 glasses was synthesized by melt-quenching techniques. X-ray
diffraction confirmed the amorphous (non-crystalline) nature of the glassy systems. The impact of Sm2O3 concentration
on the physical, structural, and optical properties was investigated. Both molar volume and density
exhibit a positive correlation, indicating an upward trend. The structural change correlated with an increase in
density and molar volume. FT-IR spectroscopy demonstrated the transmutation of BO4 units to BO3 units as the
content of Sm2O3 increased, resulting in a rise in non-bridging oxygens (NBOs). The optical band gap (Eopt)
decreased from 3.39 eV to 2.71 eV as the Sm3+ content increased, indicating an escalation in disorder within the
glass network. Under 403 nm excitation, the photoluminescence spectra exhibited four intense emission peaks at
562, 598, 646, and 709 nm, corresponding to the 4G5/2 → 6H5/2, 6H7/2, 6H9/2, and 6H11/2 transitions of Sm3+
ions, respectively. The prominent orange-red emission at 598 nm (4G5/2 → 6H7/2) was the most significant
feature. The CIE chromaticity coordinates indicated a brilliant reddish-orange emission, with CCT within the
warm-light spectrum 1860–2759 K. The synthesized Sm3+-doped borate glasses are promising candidates for
orange-red-emitting solid-state lighting and photonic applications. |
