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

Abstract

It is highly desirable to red-shift the emission of Y3Al5O12:Ce 3+ phosphor in order 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 reported the red-shifted emission of Y3MgSiAl3O12:Ce 3+ garnet phosphor for w-LEDs through a chemical unit co-substituting in solid solution design strategy. The fabrication temperature of the Y3MgSiAl3O12:Ce 3+ powder was optimized at 1600 ºC and its structure, photoluminescence properties, micromorphology, decay curves, quantum yield, as well as the thermal stability of the samples were investigated in details. The as-prepared Y3MgSiAl3O12:Ce 3+ phosphors displayed a broad excitation band ranging from 300 to 520 nm (centered at 450 nm), and presented an intense Ce 3+ 5d-4f emission band in the yellow light region (λem=564 nm, obviously red-shifted away from Y3Al5O12:Ce 3+). This can be explained by the increase of the crystal field splitting in the Ce 3+ 5d levels due to the chemical unit co-substitution of Al 3+ (I) and Al 3+ (II) ions by Mg 2+ and Si 4+ ions. The quantum yield of the Y2.92MgSiAl3O12:0.08Ce 3+ phosphor was measured as 61.8%. Further investigation on the packaged w-LEDs lamp by combining Y2.92MgSiAl3O12:0.08Ce 3+ phosphors on a blue InGaN chip exhibit a lower CCT and higher CRI compared to the commercial Y3Al5O12: Ce 3+ based device, indicating their outstanding strengths for potential applications in w-LEDs.

Achieving ferromagnetic insulating properties in La0.9Ba0.1MnO3 thin films through nanoengineering

“…Even though Ce filling of La vacancies tends to enlarge the LBMO lattice (c = 3.900 Å in the 23 nm NC, as compared to 3.883 Å of the A phase in the 21 nm PF), the lattice is still smaller than the vacancy-free La 0.9 Ba 0.1 MnO 3 bulk (a = 3.92 Å), because the Ce n+ (n = 3 or 4) has a smaller ionic radius than La 3+ . 57,72 With increasing the thickness, i.e. for the 46 nm film, as observed by the shoulder peak shifting to the left hand side of the STO (003) peak in Fig.…”

Yellow Emission Obtained by Combination of Broadband Emission and Multi-Peak Emission in Garnet Structure Na2YMg2V3O12: Dy3+ Phosphor

“…The phase compositions and crystal structures of the as-prepared powder samples were characterized at room temperature. The XRD patterns of Na 2 (Figure 1a), corresponding, respectively, to the (2 1 1), (2 2 0), (4 0 0), (4 2 0), (3 3 2), (4 2 2), (4 3 1), (4 4 4), (6 4 0), and (6 4 2) facets of a single garnet structure with a cubic Ia3d (No. 230) space group.…”

“…The results are shown in Figure 4. The decay curves of Na2YMg2V3O12:xDy 3+ were well fitted to the following exponential function [37]: (2) where It and I0 are the emission intensities at time t and the initial time, respectively, and A is a constant. τ determines the decay time.…”

“…For several years, phosphor-converted white light-emitting diodes (pc-WLEDs) have been recognized as the most promising replacements of traditional incandescent and fluorescence lamps [1][2][3][4][5]. These solid-state light sources deliver high luminescence efficiency and an excellent operation lifetime (>10,000 h) while conserving energy and lowering the pollution risk.…”

Massive red shift of Ce3+in Y3Al5O12incorporating super-high content of Ce

“…Recently, it was reported that double substitution by Mg 2+ -Si 4+ induced a signicant red shi. [21][22][23][24] Du et al reported a massive red shi to 598 nm in Y 3 Mg x Al 5À2x Si x O 12 :Ce transparent ceramic, 23 which was the largest red shi achieved till date in cationsubstituted YAG:Ce.…”