Akademik Veri Yönetim Sistemi
MATERIALS SCIENCE & ENGINEERING B: SOLID-STATE MATERIALS FOR ADVANCED TECHNOLOGY, cilt.323, ss.118776, 2026 (SCI-Expanded)
In this study, Eu3+-activated Ca2Gd1 xVO6 and Sr2Gd1 xVO6 (x = 0–30 mol%) red-emitting phosphors were
synthesized via a conventional solid-state reaction route and systematically characterized to assess the effect of
A-site variation on their structural and photoluminescence properties. X-ray diffraction results confirmed the
single phase formation of monoclinic-Ca2GdVO6 (P21/n) and monoclinic-Sr2GdVO6 (P2/m) structures, as further
corroborated by full Rietveld refinements that yielded low-residual fits and reliable lattice parameters. SEM
micrographs revealed similar grain morphologies with marginal differences in average grain sizes. Photoluminescence
excitation spectra exhibited a broad charge transfer band (CTB) centered near 256 nm, attributed
to O2 → Eu3+ transitions, along with sharp f–f transitions and characteristic Gd3+ absorptions. Emission spectra
under blue excitation (λex = 467 nm) demonstrated dominant 5D0 → 7F2 electric dipole transitions, with higher
asymmetry ratios observed in the Ca-based system, indicating a more distorted local environment. Judd–Ofelt
(JO) analysis further confirmed this distinction through elevated Ω2 parameters, particularly at low doping
levels. The quantum efficiencies (ηQE) calculated using the Judd–Ofelt formalism were 99.56 % and 78.05 % for
the most luminescent Ca-based and Sr-based samples, respectively, while the experimentally measured IQE/EQE
values were 79.82 %/41.69 % (Ca-based) and 65.58 %/36.66 % (Sr-based). Additionally, colorimetric evaluation
revealed that both phosphor systems emitted warm reddish light with high color purity (up to ~85 % for Cabased
and ~96 % for Sr-based) and low correlated color temperature (CCT ~ 1600–2500 K), suitable for
warm-white LED and display applications. These findings highlight the tunable nature of Eu3+-activated vanadate
perovskites via A-site engineering, enabling their use in solid-state lighting, displays, and optical security.