Spectral properties and Judd–Ofelt analysis of novel red phosphors Gd2InSbO7:Eu3+ with high color purity for white LEDs

Gd₂InSbO₇:Eu³⁺ red phosphors were successfully synthesized via high-temperature solid–state reaction. The phase purity, particle size, and luminescence properties of obtained phosphors were measured and analyzed in detail. The Gd₂InSbO₇ lattice possesses cubic structure with F_d-3m (227) space group. The phosphors emit bright red emission at 628 nm under 393 nm excitation, and this phenomenon is attributed to the ⁵D₀–⁷F₂ transition. The Judd–Ofelt parameters (Ω₂, Ω₄), transition ratio, and branching ratios (β) of Eu³⁺-doped Gd₂InSbO₇ phosphor were calculated on the basis of the emission spectra and decay lifetimes. The optimal content in Gd₂InSbO₇:xEu³⁺ is identified to be 15 mol%. The thermal quenching of Gd₂InSbO₇:Eu³⁺ is found to be over 500 K, and its activation energy is 0.26 eV. The Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of Gd₂InSbO₇:15%Eu³⁺ are (0.629, 0.371), which are close to ideal red chromaticity coordinates (0.670, 0.330). The fabricated w-LED exhibits good color rendering index (R_a) (86), correlated color temperature (CCT) (6997 K), and CIE chromaticity coordinates (0.302, 0.330). The obtained results demonstrate that Gd₂InSbO₇:Eu³⁺ phosphors have potential applications in white LEDs.