Akademik Veri Yönetim Sistemi
Journal of Luminescence, cilt.286, 2025 (SCI-Expanded, Scopus)
Rare-earth (RE) activated double perovskite phosphors have emerged as promising candidates for advanced optoelectronic applications due to their superior photoluminescence and high quantum efficiency. In this study, the structural, morphological, and spectroscopic properties of Ca2Gd1-xMO6:xEu3+ (M = Nb, Ta and x = 2.5–50 mol%) double perovskites were systematically investigated to assess their suitability for red-emitting laser phosphor applications. X-ray diffraction (XRD) confirmed a stable single-phase monoclinic structure with successful Eu3+ substitution at Gd3+ sites up to 50 mol% for both host lattices. Scanning electron microscopy (SEM) revealed that Ca2GdNbO6:Eu3+ formed irregular micron-sized grains, while Ca2GdTaO6:Eu3+ developed larger, oval-shaped particles. Photoluminescence measurements showed enhanced emission intensities up to 40 mol% Eu3+, followed by quenching at 50 mol% due to concentration quenching effects. Increasing Eu3+ concentration strengthened the hypersensitive 5D0→7F2 electric dipole transition, reflected in higher asymmetry ratios and increasing Judd–Ofelt parameters (Ω2, Ω4), indicating a gradual reduction in local symmetry and ligand electron density. Notably, Ca2Gd0.6NbO6:0.4Eu3+ exhibited a higher stimulated emission cross-section (71.783 × 10−22 cm2) and optical gain (3.242 × 10−24 cm2 s) compared to its Ta-based counterpart, along with superior quantum efficiency (ηQE = 100 %). Good agreement between theoretical and experimental quantum efficiency values (within 0–6 % deviation) validated the Judd–Ofelt analysis. Chromaticity evaluations demonstrated high color purity (∼95 %) and low correlated color temperatures (CCTs), making these materials attractive for warm white and red-light-emitting devices. Overall, the results underscore the strong red emission, structural tunability, and optical amplification potential of Eu3+-doped Ca2GdNbO6 and Ca2GdTaO6 phosphors, confirming their viability as efficient red laser materials and photonic components.