Structural, optical, and thermal traits of Sm3+-doped SrB2O4 phosphors for solid-state lighting applications

We synthesized Sm3+-doped SrB2O4 phosphors through a solid-state reaction method, varying the Sm3+ doping concentrations. Structural and morphological characteristics of material were investigated using Fouriertransform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) and scanning electron microscopy (SEM). Optical transitions were analyzed by recording the diffuse reflectance spectroscopy, while photoluminescent (PL) spectra were used to evaluate luminescence properties. The PL spectra revealed a strong orange emission at 598 nm under 402 nm excitation. The optimal Sm3+ doping concentration was determined to be 0.02 mol, beyond which concentration quenching occurred. This quenching is attributed to exchange-type interactions, which facilitate non-radiative energy relaxation. The CIE color chromaticity coordinates of all the synthesized phosphors fell within the orange region of the chromaticity diagram. Temperature dependent photoluminescence revealed lower activation energy and phonon energy. Thermal quenching temperature was calculated which is inline with commercially available LEDs. All of these results indicate the candidature of SrB2O4 phosphor doped with Sm3+ ions for solid state lighting and optical thermal sensing applications.