Luminescence characterization of cerium doped yttrium gadolinium aluminate phosphors
Introduction
The rapidly expanding market for solid-state lighting creates a need for new phosphors with high conversion efficiencies, excellent thermal quenching behavior and emission in a spectral range that will make it possible to adapt the color points of the emitted light over a wide range (from ‘cool’ to ‘warm’ white).
Yttrium aluminum garnet Y3Al5O12 (YAG) is one of the most important optical materials with a wide range of applications such as a laser host material, optical lens, and thermal barrier coating owing to high thermal stability, chemical stability, a relatively stable lattice and a high temperature mechanical strength [1]. The rare earth doped YAG crystals are the most widely used solid-state laser materials. YAG materials are promising phosphor candidates in cathode-ray tubes (CRTs), field emission displays (FEDs), scintillation, vacuum fluorescent displays (VFDs) and electroluminescent (EL), due to the discovery of stimulated emission in Nd doped yttrium aluminum garnet (YAG) crystal [2], [3]. Yttrium aluminum garnet (Y3Al5O12 or YAG) doped with Ce3+ is at present one of most important luminescent materials that is applied in white light LEDs. YAG:Ce was first introduced as phosphor for fast cathode ray tubes. Ce doped yttrium aluminum garnet is a yellow phosphor widely used as scintillator for alpha particles and gamma rays as well as LED. However, gadolinium aluminum garnet (GAG) is not a familiar material as a host contrasted to YAG since it is very difficult to synthesize by conventional method at a temperature above 1600 °C. The chemical and physical characteristics of GAG are very similar to YAG. In addition GAG is also a suitable host material for the replacement of rare earth ions [3], [4], [5].
In this study, photoluminescence (PL), radioluminescence (RL), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of yttrium gadolinium aluminate phosphors doped with cerium ((Y1−xGdx)3Al5O12:Ce) concentration are reported. A need for information on the results of Gd doping has thus motivated the present work.
The aim of this studies is to the synthesize cerium doped yttrium gadolinium aluminum garnets ((Y1−xGdx)3Al5O12:Ce) phosphors both for superior photoluminescence performances required in white LED lighting using wet-chemical route via the reagent simultaneous addition technique (WCS-SimAdd).
Section snippets
Sample preparation
Yttrium gadolinium aluminum garnets doped cerium (Y1−xGdx)3Al5O12:Ce3+ phosphors were synthesized by homogeneous precipitation, using the WCS-SimAdd technique. Two (Y,Gd)3Al5O12:Ce3+ sample series with 0; 25; 50; 75 and 100 mol% gadolinium were synthesized with and without NH4Cl as flux, in order to prepare YAG:Ce, YGAG:Ce and GAG:Ce phosphors. For this purpose, Y–Al–Ce precursors were prepared from Y2O3 (99.9%; Fluka), Gd2O3 (99+, Merck); Al(NO3)3.9H2O (98%; Alfa Aesar), Ce(NO3)3.6H2O
Results and discussion
The present study is involved in the synthesis and characterization of cerium doped yttrium gadolinium aluminum garnet phosphors having different gadolinium and yttrium concentrations. Photoluminescence (PL), radioluminescence (RL), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of cerium doped yttrium gadolinium aluminum garnets results are studied.
Conclusions
We have investigated the effects of composition changes in YAG:Ce by substituting Y with Gd on luminescence properties. This substitution of atoms induces lattice expansion and changes the local crystal-field interaction of Ce. The red shift of the emission bands in PL is mostly related to Gd incorporation. The partial substitution of Y by Gd in YAG:Ce causes a significant red shift of the emission (from 583 nm to 602 nm). Prepared material shows leading PL peak at 530 nm typical for the Ce doped
Acknowledgment
This research is supported by the grants from The Scientific and Technical Research Council of Turkey (TUBITAK) Contract No. 111M222.
References (16)
- et al.
J. Lumin.
(2010) - et al.
Opt. Mater.
(2008) - et al.
J. Alloy Comp.
(2002) - et al.
Opt. Mater.
(2011) - et al.
Mater. Res. Bull.
(2008) - et al.
J. Phys. Chem. Solid
(2004) - et al.
J. Alloy Comp.
(2009) J. Lumin.
(2000)
Cited by (25)
Research progress of gadolinium aluminum garnet based optical materials
2021, Physica B: Condensed MatterCitation Excerpt :In GdAG transparent ceramics, Y3+ can also occupy three different cationic sites in garnet. GYAG has high expectations because of its cubic system and crystal structure similar to the widely studied YAG [14,118–122]. Hirano et al. synthesized Ce-doped (Gd0.32Y0.68)3Al5O12 transparent ceramics by vacuum sintering and studied the scintillation characteristics of transparent ceramics [106].
Rapid synthesis of garnet structured aluminosilicate phosphors
2019, Journal of LuminescenceCitation Excerpt :Modifying the YAG formula keeping the garnet structure intact was the most sought after way for improvement [19]. Substitutions at Y or Al sites had been studied in earlier efforts [20–25]. Kuru et al. had noticed that simultaneous aliovalent substitutions at both Y and Al sites increase the solubility limits [26].
Study of Gd-induced shift of luminescence spectra of YGAG:Ce micropowders as a function of grain size
2018, Journal of LuminescencePreparation and characterization of Yttrium based luminescence phosphors
2017, Optical MaterialsScintillation properties of Ce-doped (Gd<inf>0.32</inf>Y<inf>0.68</inf>)<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> transparent ceramics
2017, Optical MaterialsCitation Excerpt :The ratio of the concentration of Gd ion to that of Y is 1/2, therefore one-third of the rare earth sites are substitute by Gy. Previous studies showed scintillation properties of Ce:(GdXY1-X)AG single crystal (X = 0, 0.2, 0.4, 0.6, 0.8, 1.0) [22] and Ce:(GdXY1-X)AG transparent ceramics (X = 0.5) [10], and photoluminescence (PL) properties of Ce:(GdXY1-X)AG ceramics (X = 0.25, 0.50, 0.75, 1.0) [23] and nanoparticles (X = 0.1, 0.3, 0.6, 0.99) [24]. However, we hardly found a report on scintillation properties of Ce:GYAG transparent ceramics with the composition of Gd:Y = 1:2.