Poster presented at the First International Meeting on Applied Physics - Applied Physics 2003, Badajoz, Spain

Del Rosario, G.

Mančić, Lidija

Milošević, Olivera

Ohara, Satoshi

Del Rosario, Gilberte

Serbian Academy of Science and Arts Digital Archive (DAIS)

CHARACTERIZATION OF YAG:Ce POWDERS THERMAL TREATED AT DIFFERENT TEMPERATURESINTRODUCTIONThe homogeneity of materials obtained by synthesized through aerosol create process of energy transfer well defined that contribute in the quantum efficiency of luminescent materials.  The objective was to establish the relations between composition, structure and morphology of powders. A comparative study of the characteristics of the powders treated at different temperatures 1000-1200ºC helps to understand the evolutions of the system with the temperatures.YAG:Ce is considered to be interesting for several applications: (e.g. field emission display (FED), cathode-ray tubes (CTRs), LED and pigments and thermal barrier coatings (TBC).L.Mancic, O. MilosevicInstitute of Technical Sciences of Serbian Academy of Science and Arts, K.Mihajlova 35/IV, 11000 Belgrade, Serbia and MontenegroE-mail: oly@itn.sanu.ac.yuG. del RosarioTechnological Support Center, University Rey Juan Carlos Tulipan s/n. Móstoles Madrid. 28933, SpainE-mail: grosario@escet.urjc.esS. OharaInstitute of Multidisciplinary Research for Advanced Materials,Tohoku University, 2-1-1 Katahira, Aoba-ku,Sendai, 980-8577, JapanE-mail: s-ohara@mail.tagen.tohoku.ac.jpXRD pattern of YAG:Ce powder after thermal  treatment at 1000ºC (a), 1100ºC (b), 1200ºC (c). Details of crystallographic directions 420 overlap pattern and the results of the crystallite size calculated for: (a) 318 Å, (b) 407 Å and (c) 474 Å.X-Ray diffraction analysis. The average crystallite size of the powder heated to different temperatures was determined from the broadening observed for the peak corresponding to the (420) reflection using the Scherrer formula. The diffracted intensity is function of the volume irradiated and the crystallite sizes grow with the temperature, it was possible to correlate these values, that have parabolic form with maximum at 1100°C.300 330 360 390 420 450 480 5100,040,080,120,160,200,240,28T = 1200ºCT = 1100ºCT = 1000ºC   Average Particle Volum ( μm 3 )Average Crystallite Size (Aº)0 10 20 30 40 50 60 70 80 900300600Intensity (arb. units)2Theta (º)a0 10 20 30 40 50 60 70 80 900300600900b0 10 20 30 40 50 60 70 80 900300600900120015001800 c31 32 33 34 35 36 370300600900120015001800abc(422)(420) Intensity (arb. units)2Theta (º)Luminescence properties. The curves exhibit broad emission in the range from 450-700 nm with the luminescent peak maximum at 533nm (∼18.76x103 cm-1), attributed to the Ce3+ intershell transition (5d→4f ) in YAG lattice. The average distance (dCe-Ce ) between centers of luminescence is calculated from the average volume that Ce atom occupies, assuming ideal dispersion. dCe-Ce = 2[VCe / (4/3π)]1/3where:  VCe = (1/Na )(Vm /XCe )   Vm : is a molar volume calculated from the weighed-out composition.       (YAG = 130.38 cm3/mol). Na : is Avogardo number. XCe : is molar fraction1) PL spectra for powders of YAG-Ce treated to: 1000ºC (a), 1100ºC (b), 1200ºC (c). 2) The distance of luminescent centers (dCe-Ce ) as a function of energy emission (E em ) and intensity normalised emission for a wavelength fix of 533 nm.00,20,40,60,81400 450 500 550 600 650 700Wavelength (nm)PL Intensity (a.u.)acb29,4 29,6 29,8 30,0 30,2 30,40,00,20,40,60,8T=1200ºCT=1000ºCT=1100ºCIntensity dCe-Ce[A]18,6818,7018,7218,7418,76E em  [*10 3  cm-1 ]1 2a300nm 10nmb0.486nmTEM images of powder samples. a) Low magnification show particles transparent to electron beam. b) High-magnification image of sample treated at 1100 ºC. a bbabaStructural image of a particle treated to 1000ºC, show two zones with different orientations and interplannar spacing. Details of these zones make clear these differences. SAED patterns denoted cubic symmetry in both zones.TEM analysis, was applied in order to evaluate the changes of crystallinity with temperature. Fig.a, show inner particle structure, composing of differently oriented primary particles (< 60nm) with nanoporosity, is revealed. CONCLUSIONSThe most relevant change was observed at 1100 ºC, increasing luminescence properties. The tendency of the phase Y3 Al5 O12 to order crystalline with the temperature is confirmed by the high growth rate of crystallite size (0.78 Å.ºC-1). TEM analyses provides details of inner part of the particle and XRD confirms the cubic symmetric structure of the predominant phase observed. The homogeneity  of the structure is obtained to temperature up to 1000ºC. RESULTS AND DISCUSSIONMorphological characterization by SEMAt (%)1000º C1100º C1200º CO K 53,09 52,71 53,22Al K 27,92 28,17 27,92Y  L 17,23 17,50 17,40Ce L 1,56 1,62 1,46Note: Detector type (UTW), 20 Kv, Lsec 100dSEM photomicrographs of powder after thermal treatment at 1000ºC (a), 1100ºC (b) and 1200ºC (c). EDS spectra and quantitative analysis of YAG-Ce powder (d)cba0 500 1000 1500 20000246810121416NumberDiameter of Particle (nm)a) Histogram of the diameter distribution of YAG : Ce powder at 1100ºC. b)Reconstruction in 3D of the surface of a particle treated to 1100ºCaStatistical analysis of the particle sizes. The equivalent surface and volume were estimated based on the average particle diameter. The histogram of frequency, fig a, reveals uniform in their shape for this sample in comparison to the samples treated at 1000 and 1200ºC.Treatment(ºC)Diameter Mean (nm)Se(yEr±)AverageVolume (μm3)Roughness Average surface Sa (nm)SurfacesArea RatioSdr (%)Area surface (m2)Mass by particle (g)Relation (m2/g)1000ºC 664 32 0.154 68.0 37.9 52.6 10-12 7.0 10-13 74.51100ºC 788 44 0.257 78.9 73.9 144.3 10-12 1.2 10-12 122.31200ºC 599 36 0.112 71.6 32.1 36.2 10-12 5.1 10-13 71Note: Se is standard error of the meanUsed density: (Dx-YAG) 4.553 g.cm-3 (JCPDS- International Centre for Diffraction data. 33-0040)(Dx-Ce) 6.814 g.cm-3 (JCPDS- International Centre for Diffraction data. 78-0638)The roughness parameters give information about the average surface of particle,  fig. b. These results are summarised in the following table. The growth of the surface in the sample treated to 1100ºC, implies higher reactivity and provides better uniformity of layers.bCarrier gas ExhaustAerosol generator(twin-fluid,10-100 μm ultrasonic, 1-10μm, etc.)Evaporation- Precipitation- Drying- Decomposition-Sintering Droplet Solid particledm/dt=F(D,Δp, ΔT, δ)dT/dt=ϕ(D, ΔT, δ)High surface reaction. Stoichiometry retention to the droplet scale. Molecular level of compositional homogeneity EXPERIMENTAL INSTALLATIONAcknowledgements: This research was financially supported through the NEDO International Joint Research Grant Program 01MB7: ”Wetability of solid by liquid at high temperatures”, the Ministry of Education, Science, Sports and Culture, through Grant-in-Aid for the COE project, Giant Molecules and Complex, 2003, Japan as well as Republic of Serbia Science Foundation project 1832. 

English

Characterization of YAG:Ce powders thermal treated at different temperatures

Digital Repository of the Institute of Technical Sciences of SASA

CHARACTERIZATION OF YAG:Ce POWDERS THERMAL 
TREATED AT DIFFERENT TEMPERATURES
INTRODUCTION
The homogeneity of materials obtained by synthesized through aerosol create process of 
energy transfer well defined that contribute in the quantum efficiency of luminescent 
materials.  The objective was to establish the relations between composition, structure 
and morphology of powders. A comparative study of the characteristics of the powders 
treated at different temperatures 1000-1200ºC helps to understand the evolutions of the 
system with the temperatures.
YAG:Ce is considered to be interesting for several applications: (e.g. field emission 
display (FED), cathode-ray tubes (CTRs), LED and pigments and thermal barrier 
coatings (TBC).
L.Mancic, O. Milosevic
Institute of Technical Sciences of Serbian Academy of Science 
and Arts, K.Mihajlova 35/IV, 11000 Belgrade, Serbia and 
Montenegro
E-mail: oly@itn.sanu.ac.yu
G. del Rosario
Technological Support Center, University Rey Juan Carlos 
Tulipan s/n. Móstoles Madrid. 28933, Spain
E-mail: grosario@escet.urjc.es
S. Ohara
Institute of Multidisciplinary Research for Advanced Materials,
Tohoku University, 2-1-1 Katahira, Aoba-ku,
Sendai, 980-8577, Japan
E-mail: s-ohara@mail.tagen.tohoku.ac.jp
XRD pattern of YAG:Ce powder after thermal  treatment at 1000ºC (a), 1100ºC 
(b), 1200ºC (c). Details of crystallographic directions 420 overlap pattern and the 
results of the crystallite size calculated for: (a) 318 Å, (b) 407 Å and (c) 474 Å.
X-Ray diffraction analysis. The average crystallite size of the powder heated 
to different temperatures was determined from the broadening observed for the 
peak corresponding to the (420) reflection using the Scherrer formula. The 
diffracted intensity is function of the volume irradiated and the crystallite sizes 
grow with the temperature, it was possible to correlate these values, that have 
parabolic form with maximum at 1100°C.
300 330 360 390 420 450 480 510
0,04
0,08
0,12
0,16
0,20
0,24
0,28
T = 1200ºC
T = 1100ºC
T = 1000ºC  
 
Av
er
ag
e 
Pa
rt
ic
le
 V
ol
um
 ( 
μm
 3
 )
Average Crystallite Size (Aº)
0 10 20 30 40 50 60 70 80 90
0
300
600In
te
ns
it
y 
(a
rb
. u
ni
ts
)
2Theta (º)
a
0 10 20 30 40 50 60 70 80 90
0
300
600
900
b
0 10 20 30 40 50 60 70 80 90
0
300
600
900
1200
1500
1800 c
31 32 33 34 35 36 37
0
300
600
900
1200
1500
1800
a
b
c
(422)
(420)
 
In
te
ns
it
y 
(a
rb
. u
ni
ts
)
2Theta (º)
Luminescence properties. The curves exhibit broad emission in the range from 
450-700 nm with the luminescent peak maximum at 533nm (∼18.76x103 cm-1), 
attributed to the Ce3+ intershell transition (5d→4f ) in YAG lattice. The average 
distance (dCe-Ce ) between centers of luminescence is calculated from the average 
volume that Ce atom occupies, assuming ideal dispersion. 
dCe-Ce = 2[VCe / (4/3π)]1/3
where:  VCe = (1/Na )(Vm /XCe )   Vm : is a molar 
volume calculated from the weighed-out 
composition.       (YAG = 130.38 cm3/mol). Na : is 
Avogardo number. XCe : is molar fraction
1) PL spectra for powders of YAG-Ce treated to: 1000ºC (a), 1100ºC (b), 1200ºC (c). 
2) The distance of luminescent centers (dCe-Ce ) as a function of energy emission (E em ) 
and intensity normalised emission for a wavelength fix of 533 nm.
0
0,2
0,4
0,6
0,8
1
400 450 500 550 600 650 700
Wavelength (nm)
P
L
 
I
n
te
n
s
i
t
y
 
(
a
.
u
.
)
a
c
b
29,4 29,6 29,8 30,0 30,2 30,4
0,0
0,2
0,4
0,6
0,8
T=1200ºC
T=1000ºC
T=1100ºC
In
te
ns
ity
 
dCe-Ce[A]
18,68
18,70
18,72
18,74
18,76
E e
m
  [
*1
0 
3  c
m
-1
 ]
1 2
a
300nm 10nm
b
0.486nm
TEM images of powder samples. a) Low magnification show particles transparent 
to electron beam. b) High-magnification image of sample treated at 1100 ºC. 
a b
b
a
b
a
Structural image of a particle 
treated to 1000ºC, show two 
zones with different 
orientations and interplannar 
spacing. Details of these zones 
make clear these differences. 
SAED patterns denoted cubic 
symmetry in both zones.
TEM analysis, was applied in order to evaluate the changes of crystallinity with 
temperature. Fig.a, show inner particle structure, composing of differently oriented 
primary particles (< 60nm) with nanoporosity, is revealed. 
CONCLUSIONS
The most relevant change was observed at 1100 ºC, increasing luminescence 
properties. The tendency of the phase Y3 Al5 O12 to order crystalline with the 
temperature is confirmed by the high growth rate of crystallite size (0.78 Å.ºC-1). 
TEM analyses provides details of inner part of the particle and XRD confirms the 
cubic symmetric structure of the predominant phase observed. The homogeneity  of 
the structure is obtained to temperature up to 1000ºC. 
RESULTS AND DISCUSSION
Morphological characterization by SEM
At 
(%)
1000º 
C
1100º 
C
1200º 
C
O K 53,09 52,71 53,22
Al K 27,92 28,17 27,92
Y  L 17,23 17,50 17,40
Ce L 1,56 1,62 1,46
Note: Detector type (UTW), 20 Kv, Lsec 100
d
SEM photomicrographs of powder after thermal treatment at 1000ºC (a), 1100ºC (b) and 
1200ºC (c). EDS spectra and quantitative analysis of YAG-Ce powder (d)
c
ba
0 500 1000 1500 2000
0
2
4
6
8
10
12
14
16
N
um
be
r
Diameter of Particle (nm)
a) Histogram of the diameter distribution of YAG : Ce powder at 1100ºC. 
b)Reconstruction in 3D of the surface of a particle treated to 1100ºC
a
Statistical analysis of the particle sizes. The equivalent surface and volume were 
estimated based on the average particle diameter. The histogram of frequency, fig a, 
reveals uniform in their shape for this sample in comparison to the samples treated at 
1000 and 1200ºC.
Treatment
(ºC)
Diameter 
Mean 
(nm)
Se
(yEr±)
Average
Volume 
(μm3)
Roughness 
Average 
surface Sa (nm)
Surfaces
Area 
Ratio
Sdr (%)
Area surface 
(m2)
Mass by 
particle (g)
Relation 
(m2/g)
1000ºC 664 32 0.154 68.0 37.9 52.6 10-12 7.0 10-13 74.5
1100ºC 788 44 0.257 78.9 73.9 144.3 10-12 1.2 10-12 122.3
1200ºC 599 36 0.112 71.6 32.1 36.2 10-12 5.1 10-13 71
Note: Se is standard error of the mean
Used density: (Dx-YAG) 4.553 g.cm-3 (JCPDS- International Centre for Diffraction data. 33-0040)
(Dx-Ce) 6.814 g.cm-3 (JCPDS- International Centre for Diffraction data. 78-0638)
The roughness parameters give information about the average surface of particle,  
fig. b. These results are summarised in the following table. The growth of the surface 
in the sample treated to 1100ºC, implies higher reactivity and provides better 
uniformity of layers.
b
Carrier gas Exhaust
Aerosol generator
(twin-fluid,10-100 μm ultrasonic, 1-10μm, etc.)
Evaporation- Precipitation- Drying- Decomposition-Sintering 
Droplet Solid particle
dm/dt=F(D,Δp, ΔT, δ)
dT/dt=ϕ(D, ΔT, δ)
High surface reaction. Stoichiometry retention to the droplet scale. Molecular level of 
compositional homogeneity 
EXPERIMENTAL INSTALLATION
Acknowledgements: This research was financially supported through the NEDO International Joint Research Grant Program 01MB7: ”Wetability of solid by liquid at high temperatures”, the Ministry of Education, Science, Sports and Culture, through Grant-in-Aid for the COE project, Giant Molecules and Complex, 
2003, Japan as well as Republic of Serbia Science Foundation project 1832. 


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Characterization of YAG:Ce powders thermal treated at different temperatures

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