Akademik Veri Yönetim Sistemi
Materials Science and Engineering: B, cilt.322, 2025 (SCI-Expanded, Scopus)
Rare-earth (RE) activated double perovskite phosphors are of growing interest due to their superior spectral features and high quantum efficiencies. This study explores the structural, morphological, and optical properties of Ca2Gd1-xSbO6:xEu3+ (x = 0–50 mol%) and Ca2Gd1-xSbO6:xEu3+, yB3+ (x = 50 mol%, y = 0–100 mol%) phosphors. XRD analysis confirmed a single-phase structure up to 50 mol% Eu3+, while higher B3+ co-doping induced a secondary ZrO2-type phase. SEM results showed similar morphology for Eu3+ doping, with microstructural changes emerging at high B3+ levels. The optical band gap (Eg) varied slightly with Eu3+ or B3+ concentration, ranging between 3.42 and 3.61 eV. Photoluminescence (PL) spectra under 465 nm excitation showed strong red emission centered at 612 nm (5D0→7F2), which aligns with the red spectral region desirable for display and lighting applications. Increasing Eu3+ concentration enhanced PL intensity without concentration quenching up to 50 mol%. While Eu3+ doping enhanced asymmetry and Judd-Ofelt (Ω2) parameter, B3+ co-doping preserved this effect up to 50 mol%. At higher B3+ levels, both Ω2 and Ω4 decreased notably, indicating a shift to a more symmetric and rigid environment, which weakens electric dipole transitions. The branching ratio (β), stimulated emission cross-section (σe), and the product σe×τ confirmed favorable emission characteristics. Notably, τ lifetimes increased significantly at 70–100 mol% B3+ due to the influence of the centrosymmetric secondary phase. Judd–Ofelt-derived quantum efficiencies (ηQE) remained above 100% across the entire B3+ doping range, including at high concentrations (70–100 mol%) where significantly extended decay times were observed. These findings demonstrate that Eu3+-and B3+-doped Ca2GdSbO6 phosphors possess strong red-emitting properties and desirable optical parameters for potential use in red-emitting phosphor devices.