Synthesis of thermally stable orange light-emitting phosphors: characterization and investigations of Sm ³⁺ -doped CsCaF ₃ phosphors for solid-state-lighting applications

In this study, we synthesized and characterized pure CsCaF3 and CsCaF3 doped with samarium (Sm3+) ions using a solid-state method. X-ray diffraction analysis was employed to examine the crystal structure, while field emission scanning electron microscopy analyzed the surface morphology of the doped sample. A color coordinate graph was used to calculate the color, with the Commission Internationale de l'Eclairage (CIE) fitting the color of both pure and doped samples. Upon excitation at 405 nm (6H5/2→6F7/2 transition), the doped CsCaF3 emitted an orange light. The CsCaF3:Sm3+ sample (0.8 mol%) displayed 86% color purity and a color temperature of 2191 K, making it suitable for lighting applications. The thermoluminescence (TL) curve of the beta-irradiated CsCaF3:Sm3+ (0.8 mol%) sample showed peaks at 174 °C and 297 °C. Preheating techniques eliminated the low-temperature peak, and the peak temperature of maximal TL intensity (Tm) was 297 °C. The activation energy (Ea) and frequency factor (s) were determined using the peak shape method and varying heating rates. The dosage response of CsCaF3:Sm3+ (0.8 mol%) was examined for potential dosimetry applications.