Excitation-dependent photoluminescence and Eu3+ doping effects in BaZrO3 phosphors for red-emitting solid-state lighting

This study reports the successful synthesis of undoped and Eu 3+ doped BaZrO 3 phosphors via a high-temperature solid-state reaction technique. X-ray diffraction (XRD) measurements confirmed the phase purity and cubic structure of BaZrO 3 both with and without Eu 3+ ions. Fourier Transform Infrared (FTIR) and photoluminescence (PL) were used for optical characterizations. The PL excitation spectra showed dominant absorption at 296 nm, 314 nm, mainly due to the Eu 3+ -O 2- charge transfer band and oxygen vacancies and 393 nm of Eu 3+ ions. The PL emission spectra of Eu 3+ doped BaZrO 3 phosphor characterized by band at 484 nm (defect-related) along with an intense red emission at 595 nm and weak emission at 613 nm (Eu 3+ emission), which indicated a dominant magnetic dipole transition. This suggests that Eu 3+ ions primarily occupy centrosymmetric Zr 4+ sites within the cubic BaZrO 3 lattice under these specific excitations. Optimal emission intensity was achieved for 9 mol% Eu 3+ doped BaZrO 3 phosphor sample. Under excitation with 393 nm, the phosphor samples showed a significant tunable in emission intensity with intense red emission observed at 613 nm (electric dipole transition) and weaker emission at 595 nm. The CIE diagram showed that the color emission can be tuned from blue to red by varying the concentration of Eu 3+ ions under excitation with 296 nm. A significant color purity was observed for 9 mol% Eu 3+ doped BaZrO 3 phosphor sample: 31.1 % (under 296 nm excitation) and 88.43 % (under 393 nm excitation). Furthermore, correlated-color temperature (CCT) values below 5000 K were consistently observed, indicating their suitability for warm home lighting applications.