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 Y 3 Al 5 O 12:Ce 3+ 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 Y 3 MgSiAl 3 O 12:Ce 3+ garnet phosphor for w-LEDs through a chemical unit cosubstituting in a solid solution design strategy. The fabrication temperature of the Y 3 MgSiAl 3 O 12:Ce 3+ 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 Y 3 MgSiAl 3 O 12:Ce 3+ phosphors display a broad excitation band ranging from 300 to 520 nm (centered at 450 nm) and present an intense Ce 3+ 5d–4f emission band in the yellow light region (λ em = 564 nm, obviously red-shifted away from Y 3 Al 5 O 12:Ce 3+ ). This can be explained by the increase of the crystal-field splitting in the Ce 3+ 5d levels owing to the chemical unit cosubstitution of Al 3+ (I) and Al 3+ (II) ions by Mg 2+ and Si 4+ ions. The quantum yield of the Y 2.92 MgSiAl 3 O 12:0.08Ce 3+ phosphor is measured as 61.8%. Further investigation on a lamp packaged w-LEDs combining Y 2.92 MgSiAl 3 O 12:0.08Ce 3+ phosphors on a blue InGaN chip shows it to exhibits a lower CCT and higher CRI compared to those of the commercial Y 3 Al 5 O 12:Ce 3+ -based devices, indicating their appealing strengths for potential applications in w-LEDs.