Photoluminescence Properties of Ce ³ ⁺ ‐Doped RbCaMgF ₃ Phosphor for White LEDs

We report the first successful synthesis and comprehensive optical characterization of Ce 3 + ‐doped RbCaMgF 3 nanophosphors, highlighting their potential for next‐generation white LED applications. Structural analysis confirms the incorporation of Ce 3 + ions into the cubic perovskite lattice without phase segregation, maintaining lattice integrity across all doping levels. FTIR spectra validate the stability of Mg–F and Ca–F bonding networks, while FE‐SEM and EDAX reveal uniform nanocrystals with homogeneous elemental distribution. UV–vis diffuse reflectance spectroscopy shows a redshift in the absorption edge and a bandgap narrowing from 3.00 to 2.72 eV with increasing Ce 3 + content, enabling efficient UV‐to‐visible energy conversion. The incorporation of Ce 3 + ions into the host lattice modified the optical band gap, resulting in a significant enhancement of the emission intensity. Enhanced emission intensity is observed due to bandgap modulation, with a broad blue‐green emission centered at 441.5 nm under 401 nm excitation, attributed to the 5d→4f transition of Ce 3 + in a symmetric crystal field. The chromaticity coordinates ( x = 0.33, y = 0.27) and correlated color temperature (5300 K) place the emission in the cool‐white region of the CIE 1931 diagram.