Structural and visible fluorescence traits of Dy³⁺ ion activated Lu_1.5Y_1.5Al₅O₁₂ phosphors

In the current work, a series of Lu_1.5Y_1.5Al₅O₁₂ (LuYAG) phosphors doped with different Dy³⁺ ion concentrations (0.5, 1, 2, 3, 4, and 5 at% in nominal) have been synthesized by high-temperature solid-phase approach and characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy, transmission electron microscopy, optical absorption, emission, and decay lifetimes. The shape and position of Dy³⁺ ion absorption peaks were consistent in all samples, and the absorption peak intensity increased with enhancing Dy³⁺ concentration. Under λ_exci. = 448 nm, ⁴F_9/2 → ⁶H_15/2, _13/2, _11/2, _9/2 emission transitions have been identified in which the ⁴F_9/2 → ⁶H_13/2 transition possesses the highest intensity. Luminescence decay times were evaluated for Dy³⁺: ⁴F_9/2 level. Relying on the absorption and luminescence spectra, along with fluorescence decay patterns, the optimal doping concentration of 1 at% was identified. The energy transfer process between Dy–Dy ions was discussed and utilized to explain the concentration quenching phenomenon. Notably, 1 at% Dy: LuYAG could be used as a potential candidate for commercial yellow phosphors.