Red-Shifted Emission in Y3MgSiAl3O12:Ce3+ Garnet Phosphor for Blue Light-Pumped White Light-Emitting Diodes

It is highly desirable to red shift the emission of Y₃Al₅O₁₂:Ce³⁺ phosphor to obtain a warmer correlated color temperature (CCT) in applications for blue-light pumped white-light emitting diodes (w-LEDs) with high color rendering index (CRI). In this paper, we report the red-shifted emission of Y₃MgSiAl₃O₁₂:Ce³⁺ garnet phosphor for w-LEDs through a chemical unit cosubstituting in a solid solution design strategy. The fabrication temperature of the Y₃MgSiAl₃O₁₂:Ce³⁺ powder was optimized at 1600 °C, and its structure, photoluminescence property, micromorphology, decay curve, quantum yield, as well as the thermal stability of the samples are investigated in detail. The as-prepared Y₃MgSiAl₃O₁₂:Ce³⁺ phosphors display a broad excitation band ranging from 300 to 520 nm (centered at 450 nm) and present an intense Ce³⁺ 5d–4f emission band in the yellow light region (λₑₘ = 564 nm, obviously red-shifted away from Y₃Al₅O₁₂:Ce³⁺). This can be explained by the increase of the crystal-field splitting in the Ce³⁺ 5d levels owing to the chemical unit cosubstitution of Al³⁺(I) and Al³⁺(II) ions by Mg²⁺ and Si⁴⁺ ions. The quantum yield of the Y₂.₉₂MgSiAl₃O₁₂:0.08Ce³⁺ phosphor is measured as 61.8%. Further investigation on a lamp packaged w-LEDs combining Y₂.₉₂MgSiAl₃O₁₂:0.08Ce³⁺ phosphors on a blue InGaN chip shows it to exhibits a lower CCT and higher CRI compared to those of the commercial Y₃Al₅O₁₂:Ce³⁺-based devices, indicating their appealing strengths for potential applications in w-LEDs.