Polyol-mediated solvothermal synthesis and luminescence properties of CeF3, and CeF3:Tb3 nanocrystals

Article abstract of DOI:10.1016/j.jssc.2010.11.015

CeF₃ and CeF₃:Tb³ nanocrystals were successfully synthesized through a facile and effective polyol-mediated route with ethylene glycol (EG) as solvent. Various experimental techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectra as well as decay dynamics were used to characterize the samples. The results indicated that the content of NH ₄F and reactant concentrations were key factors in the product shape and size. Excessive NH₄F was necessary for the formation of hexagonal nanoplates. The specific morphology of product can be controlled by changing the NH₄F content and reactant concentrations. In addition, Tb ³ doped-CeF₃ sample shows strong green emission centered at 544 nm corresponding to the ⁵D₄⁷F ₅ transition of Tb³. Due to the decrease of nonradiative decay rate, the lifetime of ⁵D₄ level of Tb³ become longer gradually upon increasing the size of product.

Full text of DOI:10.1016/j.jssc.2010.11.015

Journal of Solid State Chemistry 184 (2011) 246–251
Contents lists available at ScienceDirect
Journal of Solid State Chemistry
journal homepage: www.elsevier.com/locate/jssc
Polyol-mediated solvothermal synthesis and luminescence properties
of CeF3, and CeF3:Tb3+ nanocrystals
Xuesong Qu a,b, Hyun Kyoung Yang a, Jong Won Chung a, Byung Kee Moon a, Byung Chun Choi a,
Jung Hyun Jeong a,n, Kwang Ho Kim c
a Department of Physics, Pukyong National University, Busan 608-737, South Korea
b Department of Physics, Changchun Normal University, Changchun 130032, China
c School of Materials Science and Engineering, Pusan National University, Busan 609-735, South Korea
a r t i c l e i n f o
a b s t r a c t
CeF3 and CeF3:Tb3+ nanocrystals were successfully synthesized through a facile and effective polyol-
mediated route with ethylene glycol (EG) as solvent. Various experimental techniques including X-ray
diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL)
spectra as well as decay dynamics were used to characterize the samples. The results indicated that the
content of NH4F and reactant concentrations were key factors in the product shape and size. Excessive
NH4F was necessary for the formation of hexagonal nanoplates. The specific morphology of product can be
controlled by changing the NH4F content and reactant concentrations. In addition, Tb3+ doped-CeF3
Article history:
Received 7 July 2010
Received in revised form
28 October 2010
Accepted 8 November 2010
Available online 21 November 2010
Keywords:
CeF3:Tb3+
Nanocrystals
PL
sample shows strong green emission centered at 544 nm corresponding to the 5D4–7F5 transition of Tb3+
.
Due to the decrease of nonradiative decay rate, the lifetime of 5D4 level of Tb3+ become longer gradually
upon increasing the size of product.
& 2010 Elsevier Inc. All rights reserved.
1. Introduction
Compared with the conventional oxide-based systems, RE
fluorides possess advantageous properties as fluorescent host
Recent years have seen considerable attention in the develop-
ment of inorganic luminescent nanocrystals (NCs) due to their
many potential applications such as light emitting devices, optical
amplifiers, biolabels, lowthreshold lasers, and so forth [1,2]. Among
various luminescent materials, rare earth (RE) doped materials
with nanoscale have stimulated more intense research interest
because of their unique optical, catalytic, and magnetic properties
[3,4]. Dramatic efforts have been dedicated to its design and
synthesis. To date, RE doped NCs with various shapes, including
zero-dimension (0D) isotropic nanoparticles [5]; 1D rods, wires,
tubes, and belts [6,7]; two-dimension (2D) plate, disk, and sheet
[8]; and hierarchical architectures such as nanoflowers [9], whisk-
broom [10], and shuttle-shaped [11] have been reported. It has
been demonstrated that the chemical and physical properties of
nanoscale regime materials are strongly related to their morphol-
ogy, dimensionality, and size [12–14]. It is expected to control and
manipulate the physical and chemical properties of materials and
therefore controlled fabrication ability is a challenging issue. To
synthesize NCs with uniform size and shape is both scientifically
and technically important.
materials such as low vibrational energies, and the subsequent
minimization of the quenching of the excited state of the RE ion
[15,16]. Furthermore, they exhibit high ionicity, electron-acceptor
behavior, high resistivity as well as adequate thermal and envir-
onmental stability and therefore are considered as ideal host
materials for luminescent RE ions. As an important inorganic
scintillator laser material, CeF3 is a luminescent material with
100% activator concentration [17,18]. Bulk CeF3 crystal possesses a
hexagonal phase structure with a space group of P3c1 (D43d), there
˚
are six molecules in the unit cell and lattice constants a¼7.13 A,
c¼7.29 A. The Ce3+ ion in the CeF3 crystal is coordinated by nine Fꢀ
˚
and has a C2 site symmetry [18]. So far, CeF3 nanomaterials have
been prepared via various wet chemical methods such as micro-
mulsion method [19], hydrothermal method [20], liquid–solid–
solution (LSS) procedure [21], and solvothermal methods [22], and
so forth [9,23]. Among the previous researches on synthesis of CeF3
NCs, particle and plate are of the two main shapes in which
the product can adapt to form. Agglomerated nanoparticles with a
15–20 nm diameter were obtained by micromulsion method [19];
round nanoplates were produced by a hydrothermal method using
NaF as the fluoride source [20]; oil-soluble CeF3 nanoparticles with
a 6–15 nm diameter were synthesized by LSS approach [21], which
is a new method and favor the control on the size and mono-
disperisity; polyol route employed by Wang et al. [22] only yielded
agglomerated nanoparticles rather than the regular hexagonal
n Corresponding author.
E-mail address: jhjeong@pknu.ac.kr (J.H. Jeong).
0022-4596/$ - see front matter & 2010 Elsevier Inc. All rights reserved.
doi:10.1016/j.jssc.2010.11.015

X. Qu et al. / Journal of Solid State Chemistry 184 (2011) 246–251
247
nanoplates reported herein. Nanodisks, rods, and dots were
produced by a mild ultrasound assisted route in an aqueous
solution [23]. Very recently, flowerlike CeF3 nanostructures were
collected via a microwave irradiation route [9].
In this work, we present a general polyol synthesis of fluoride
nanomaterials: 0D particles and 2D nanoplates CeF3 and CeF3:Tb3+
.
The influence of the reactants concentration, and ratio of reactant
on the morphology and size of the final products are studied. In
addition, the photoluminescent (PL) properties of as-prepared
samples with different shape and size are also investigated.
2. Experimental
CeF JCPDS:08-0045
3
2.1. Sample preparation
All chemicals were of analytical grade and were used as received
without further purification. In a typical procedure for the pre-
paration of CeF3 NCs, appropriate amounts of NH4F (6, 16, 24,
32 mmol) was dissolved in 20 mL of ethylene glycol (EG). After-
ward, a solution of 2 mmol Ce(NO3)3 ꢁ 6H2O in 20 mL of EG was
added into the above solution under vigorous stirring. After stirring
for 30 min, the mixed solution was transferred into a Teflon bottle
of 70 mL held in a stainless steel autoclave, sealed, and maintained
at 180 1C for 48 h. As the autoclave was cooled to room temperature
naturally, the precipitates were separated by centrifugation,
washed with deionized water and ethanol in sequence, and then
dried in air at 70 1C for 12 h.
10
20
30
40
50
60
70
80
2 Theta (Degree)
Fig. 1. XRD patterns of as-prepared CeF3 samples. The line spectrum corresponds to
the literature data of bulk CeF3. (JCPDS no. 08-0045).
S4
S3
CeF3:Tb3+ (10 mol%) were prepared in the same procedures
except for adding 1.8 mmol Ce(NO3)3 ꢁ 6H2O and 0.2 mmol
Tb(NO3)3 ꢁ 6H2O instead of 2 mmol Ce(NO3)3 ꢁ 6H2O.
In our experiments, different samples have been synthesized to
study the relationship between reaction condition and morphology
of product. It should be pointed out that when the effect of a
reaction condition was studied, the other reaction conditions were
kept same as those for the typical synthesis.
S2
S1
2.2. Measurements and characterization
X-ray diffraction (XRD) patterns of the samples were obtained
10
20
30
40
50
60
70
80
with a Philips XPert/MPD diffraction system with CuKa1 radiation
2 Theta (Degree)
˚
(l
¼1.54056 A). Field emission scanning electron micrograph
Fig. 2. XRD patterns of CeF3:Tb3+ S1–4 obtained with different NH4F content.
(FESEM) images were taken on a Hitachi S-4200 electron micro-
scope. The visible emissions were collected using a photon technol-
ogy international (PTI) fluorimeter using a Xe-arc lamp with a power
of 60 W. The fluorescence lifetimes were measured using a phos-
phorimeter attachment to the main system with a Xe-flash lamp
(25 W power) with a dominant excitation wavelength of 245 nm.
tendency of the crystallite size according to the Scherrer
equation (D ¼ kl=bcosy). Based on the XRD analysis, we can
conclude that the NH4F content play an important factor in
controlling the size and crystallographical growth. The morphology
of the as-prepared product is illustrated in Fig. 3. When the NH4F
content is stoichiometric, i.e., 6 mmol, sample is composed of
ꢂ35 nm nanoparticles which seems to be roughly spherical in
shape (Fig. 3A). As the NH4F content increases to 16 mmol,
hexagonal 2D nanoplates appear although the shape is irregular
(Fig. 3B). Upon further increasing the content of NH4F to 24 and
32 mmol, the shape of the nanoplates become more and more
regular and the size of the nanoplates become bigger and bigger.
The average diameters are 65, 140, and 210 nm and the average
thicknesses are 20, 40, and 70 nm, corresponding to samples S2, S3
and S4, respectively. This result demonstrates that excessive NH4F
was necessary for the formation of hexagonal nanoplates, and the
shape of nanoplates becomes more regular as increasing the NH4F
content. As shown recently, the anisotropic nature of building block
in crystal structure of NCs, the selective adsorption of surfactant
onto specific crystal planes as well as the balance between the
kinetic and thermodynamic growth regimes in solutions is three
3. Result and discussion
3.1. Structure and morphology
Fig. 1 shows XRD patterns of CeF3 sample (up) and the standard
data for CeF3 (down). According to the JCPDS standard card, the
pattern is in good agreement with hexagonal phase structure
(JCPDS Card 08-0045). In this paper, the samples synthesized with
NH4F contents of 6, 16, 24, and 36 mmol are denoted as S1, S2, S3,
and S4, respectively. Noted that except for NH4F contents, the other
reactants including amount of rare earth ions and volume of EG
were kept constant all the time. In Fig. 2, XRD patterns of S1–4 are
presented. It can be seen that all four samples crystallize in the
hexagonal structure. With increasing the NH4F contents from 6 to
32 mmol (from the top to the bottom in Fig. 2), the XRD patterns
become narrower and narrower, suggesting a gradually increased

248
X. Qu et al. / Journal of Solid State Chemistry 184 (2011) 246–251
Fig. 3. FE-SEM images of CeF3:Tb3+ samples: (A) S1, (B) S2, (C) S3, and (D) S4.
major driving forces for the crystal shape control of inorganic NCs
[24,25]. Herein, the hexagonal CeF3 seeds have anisotropic unit cell
structures, which can induce preferential growth along crystal-
lographically reactive directions. In addition, the increase of
monomer concentration can significantly enhance the crystal-
lization speed when the reaction was performed at high NH4F/
RE ratios. Previously reports [24–28] have shown that accelerated
crystallization process related to the high monomer concentrations
is another main driving force for anisotropic growth of inorganic
nanostructures, which is beneficial for growing well-crystallized
and regular-shaped NCs. As seen in the FESEM results of Fig. 3, our
study follows well this viewpoint, where when the NH4F/RE ratio
was around the stoichiometric value, only irregular spherical
nanoparticles appeared due to low monomer concentration; when
the NH4F/RE ratio was high enough, more regular and uniform
hexagonal-shaped nanoplates were observed. The results further
supported the monomer concentration-controlled kinetic model.
Furthermore, it can be seen (Fig. 3) that, the aspect ratio T/D
(thickness/diameter) in the 2D nanoplates has no obvious variation,
the values are 0.31, 0.29, and 0.30 for samples S2–S4, respectively. In
principle, crystal growth and morphology are governed by the degree
of supersaturation, the diffusion of the reactant species to the surface
of the crystals, the surface and interfacial energy, and the structure of
the crystals; that is the crystal structure, and the growth surround-
ings [29,30]. For the aspect ratio T/D, it is mechanistically determined
by the relative rates of growth along different crystallographic
directions. In general, faces perpendicular to the fast directions of
growth have smaller surface areas, and slow growing faces therefore
dominatethe final morphology [30]. For NCs with a hexagonal crystal
structure and hexagonal plate shape, the surfaces are typically {0001}
for top/bottom planes and a family of six energetically equivalent
consider that the relative rates of growth along the {0001} and
¯
{1010} face show no obvious change with increasing the content of
NH4F. As well documented in some literatures, influence of
Fꢀconcentration on size and shape of samples have been previously
investigated in other RE fluorides such as LaF3 and NaYF4. Qin et al.
[32] synthesized hexagonal LaF3 through a polyol route using NH4F as
F-source and found that excessive NH4F can capped on the {0001}
crystal surfaces of LaF3 NCs and lead to the anisotropic growth and
the aspect ratio evolution of product. Similarly, this phenomenon
was also observed by Li et al. [33] in the preparation of hexagonal-
shaped NaYF4 microcrystals using NaF and YCl3 as raw materials by
varying NaF to Y3+ ratio. By contrast, it is suggested that preferential
adsorption of Fꢀ on some nanocrystal facets of CeF3 be less important
in present solvothermal systems, which may be related to the change
of crystallographic structure and surface charge of NCs.
The effect of reactant concentration on morphology and size is also
investigated. In this paper, we take the ratio of NH4F to RE ion as 16 as
an example and fix the volume of EG (40 mL) to synthesize samples.
Three concentrations (NH4F/RE: 16 mmol/1 mmol, 32 mmol/2 mmol,
and 48 mmol/3 mmol) were selected and the samples are denoted as
samples C1–C3, respectively. Fig. 4 shows the XRD patterns and SEM
images of sample C1–3. XRD patterns revealed that three samples
adopted a hexagonal CeF3 structure and the crystallinity became
better and better with the increase in concentration. It is pointed out
that there is some difference from each other in the relative intensity
for (002), (110), (111), (300) and (113) reflections, especially the
intensity of (111) reflection relative to the others increased noticeably
in C3 sample, which may imply the shape anisotropy and/or preferred
growth along (111) orientation with higher reactant concentration.
From the SEM images, it can be observed that all of three samples
were characterized by hexagonal-shaped nanoplates but the size
decreased from samples C3 to C1. The average diameters are 75, 210,
and 300 nm and the average thicknesses are 25, 70, and 180 nm,
corresponding to samples C1–C3, respectively. It indicates that the
lower reactant concentration results in fewer monomers for the
growth of CeF3 nanoplates, which showed size shrinkage via the
‘‘defocusing’’ way [34].
¯
¯
¯
¯
¯
¯
{1010} side planes ((1010), (1010), (0110), (0110), (1100), and
¯
(1100)) on the basis of the known or similar models [31]. In the
¯
present work, the surface energy of {1010}side planes may be much
higher than that of {0001} top/bottom planes considering that CeF3
nanoplates preferentially extend along the former directions over the
whole growth process. With regard to the unchanged T/D, we

X. Qu et al. / Journal of Solid State Chemistry 184 (2011) 246–251
249
A
B
C3
C2
C1
10
20
30
40
50
60
70
80
2 Theta (Degree)
D
C
Fig. 4. (A) XRD patterns of the CeF3:Tb3+ samples with different reactants concentration. (B) and (C) FE-SEM images of CeF3:Tb3+ samples corresponding to the above XRD
result. (B) C1, (C) C2, and (D) C3.
lines induced by the small size effects [22]. Monitored with the
emission wavelength of 337 nm, the obtained excitation spectrum
consists of two broad bands with maxima at 263 and 286 nm,
337
263
λ =263 nm
which are associated with allowed 5d–4f transitions from the
ground state 2F5/2 of Ce3+ to different crystal field components of 5d
286
levels split by the crystal field [22,23,37].
As the CeF3 NCs are doped with Tb3+ ions, they exhibit strong
green luminescence under UV excitation. Fig. 6 shows the excita-
tion (A) and emission (B) spectra of sample S1–4. It can be seen that
excitation spectrum (Fig. 6A) monitored with the 544 nm emission
(5D4–7F5) of Tb3+, including a strong allowed 4f–5d transitions of
Ce3+, is almost identical to that of pure CeF3 nanoparticles (Fig. 5)
except that a weak forbidden f–f transitions of Tb3+ ions in the UV
range, which were associated with 7F6–5D3, 7F6–5GJ, and 7F6–5L6
transitions of Tb3+. Note that the above broad band should include
the contribution from Tb3+ ions given the case that Tb3+ ion also
suffers from the 4f–5d transition in the spectral range above
300 nm. Actually, we measured the excitation spectrum of bulk
TbF3 (not shown here), however, 4f–5d transitions are usually
weaker than its f–f transitions and narrower than that of Ce3+, like
those demonstrated in YPO4:Ce3+ and YPO4:Tb3+ [38]. In addition,
the 5f–4d transition bands of Ce3+ ion in four samples show a little
variation, the bands are located at 260.5, 286, 272.5 and 266.5 nm,
respectively, in the samples S1–4. Particularly for the nanoplates,
the reduced size from S4 to S2 was companied by the red shift of
excitation peak. These results may be related to the variations of 5d1
excited state of Ce3+ in different samples. The 5d1 excited electronic
configuration of Ce3+ is not shielded from the surroundings and is
very sensitive to the change surrounding Ce3+ ions at or near the
surface [36], which may descend when the grain size becomes
smaller and lead to a red shift in the excitation spectra [39].
However, with smaller size, the nanoparticles (sample S1) do not
follow the above trend to red shift further, which may be related
to the difference in shape. The shape-dependent luminescence
properties have been observed previously in CeF3 and CeF3:Tb3+
NCs [23].
200
250
300
350
400
450
Wavelength (nm)
Fig. 5. Excitation (left) and emission (right) spectra of CeF3 sample.
3.2. Excitation and emission spectra
CeF3 sample shows an emission in the UV region. Fig. 5 gives the
excitation (left) and emission (right) spectra of CeF3 nanoplates.
The emission spectrum of CeF3 nanoplates includes a broad band
ranging from 300 to 450 nm peaking at 337 nm, which can be
attributed to the 5d–4f transition of Ce3+ [19,20]. Note that the
profile of the spectrum is non-symmetrical, and should be con-
tributed by different components. It has been reported that two
well-resolved emission peaks were observed in the bulk [35] and
nanowires [36] of LaPO4:Ce3+ due to the ground-state splitting of
Ce3+ (2F5/2, 2F7/2). In the present CeF3 nanoparticles the splitting for
Ce3+ cannot be resolved clearly due to the broadening of spectral

250
X. Qu et al. / Journal of Solid State Chemistry 184 (2011) 246–251
4f-5d transition
of Ce
S1:λex= 260.5 nm
λ
=544 nm
S2:λex= 286 nm
S3:λex= 272.5 nm
S4:λex= 266.5 nm
f-f transition
of Tb
Ce3+
200
250
300
350
300
400
500
600
Wavelength (nm)
Wavelength (nm)
Fig. 6. Excitation (A) and emission (B) spectra of CeF3:Tb3+ upon excitation into the Ce3+ absorption bands at 260.5, 286, 272.5 and 266.5 nm in the samples S1–4, respectively.
S1: dot line; S2: dash line; S3: dash dot line; and S4: solid line.
In Fig. 6B, a weak emission of Ce3+ and a strong emission of Tb3+
ion can be both observed upon excitation into the Ce3+ absorption
bands at 260.5, 286, 272.5 and 266.5 nm in the samples S1–4,
respectively. The green emission is due to transitions from the
excited 5D4 level to the 7FJ (J¼3–6) ground states of Tb3+ ions,
which was labeled in Fig. 6B. This result indicates that an effective
energy transfer process from Ce3+ to Tb3+ occurs in CeF3:Tb3+
samples [22,23,37,40]. That is, the Ce3+ acted as a sensitizer which
absorbed UV light first and then transferred the energy to Tb3+
acceptor in the time scale of picosecond or faster, and then
nonradiatively relaxes to the excited 5DJ levels, yielding visible
fluorescence. As discussed above, although self-excitation of Tb3+
ions through the 4f–5d and f–f transition absorption can also
produce the green emission; however, the emission intensity
1.0
0.8
0.6
0.4
0.2
0.0
Color dots: experimental data
White solid line: fitted by I(t)=I exp(-t/τ)
should be two orders of magnitude weaker than that via Ce3+
–
Tb3+ energy transfer route due to an inherent low excitation
efficiency. Thereby, the strong green emission observed currently
should mainly originate from the Ce3+–Tb3+ energy transfer
process. It is well known that Tb3+ has a relatively simple 4f-
configurational energy level structure: low-energy states 7FJ (J¼6,
5, 4, 3, 2, 1, 0) and emitting levels of 5D3 and 5D4. In general, the blue
luminescence from the transitions of 5D3 to 7FJ dominates emission
spectra with a very low concentration of Tb3+ doped into host
matrix. With increasing Tb3+ concentration, the cross-relaxation
from 5D3 to 5D4 occurs due to the interaction between the
neighboring Tb3+ ions, which increases accordingly the population
of 5D4 energy level. In consequence, green-light emitting from the
transitions of 5D4 to 7FJ becomes dominant in the visible spectrum
range [37]. In this work, there is no emission from higher level (5D3)
observed because of the cross-relaxation phenomenon at the
present high doped concentration of Tb3+ ion (10 mol%) [37,41].
The blue emission of the 5D3–7FJ transition is also difficult to be
observed in other Ce3+ and Tb3+ co-doped system such as LaPO4/
0
10
20
30
40
Dacay time (ms)
Fig. 7. Luminescence decay curves from 5D4 level of Tb3+ in CeF3:Tb3+ NCs upon
excitation into the Ce3+ absorption bands at 260.5, 286, 272.5 and 266.5 nm in the
samples S1–4, respectively. S1: black dots; S2: red dots; S3: green dots; and S4: blue
dots. (For interpretation of the references to colour in this figure legend, the reader is
referred to the web version of this article.).
non-single-exponential decay behavior was frequently observed in
energy-transfer assisted luminescence route [42].Whereas in the
Ce3+–Tb3+ energy transfer induced luminescence single-exponen-
tial function can usually be used well to fit the luminescence decay
of energy acceptor of Tb3+ [22,23,38]. The lifetime is, respectively,
determined to be 4.75, 7.07, 7.77 and 8.62 ms for the samples S1–4,
that is, the value of lifetime increases gradually in the sequence
from S1 to 4. Generally, the luminescence lifetime of 5D4 level of
Tb3+ is in the order of millisecond magnitude. The above observa-
tion is similar to previous reports [22,23,37]. With respect to the
increase of lifetime, we consider that it can be attributed to the
Ce3+, Tb3+
.
3.3. PL decay dynamics
change of nonradiative decay rate since the fluorescent lifetime (
is dominated by the radiative (Wr) and nonradiative (Wnr) transi-
tion rates, which can be written as
known, in the NCs, surface defects such as broken bonds/dangling
bonds and a large number of surface adsorptions such as OH– and
CO2 bonds are generally involved. The surface defects may quickly
trap the energy from both by excited Ce3+ prior to energy transfer
t)
The room-temperature luminescent dynamics were also mea-
sured. Fig. 7 shows the luminescent decay curves of S1–4 by
monitoring the emission of Tb3+ at 544 nm. It can be seen that all of
the four curves can well fit with a single-exponential function
t¼1/(Wr+Wnr). As is well
as I¼I0 exp(ꢀt/
t) (t
is 1/e lifetime of the Tb3+ ion). In general, a

X. Qu et al. / Journal of Solid State Chemistry 184 (2011) 246–251
251
and excited levels of Tb3+ nonradiatively; such surface adsorption
groups have large phonon energy and can act as nonradiative
relaxation channels to bridge the emitting levels of Tb3+ and the
ground states, both giving rise to an increase of nonradiative
transition rate [43]. As stated above, samples S1–4 are synthesized
with different condition and therefore exhibit different morphol-
ogy and size. From samples S1 to S4, the size becomes larger
gradually, as a result, the surface to volume ratio decreases and the
surface contamination should be decreased, and the nonradiative
relaxation rate therefore decrease and the lifetime become longer
accordingly. The lifetime evolutions may support the remarkably
enhanced green emission from S1 to S4 (see Fig. 6B) observed under
the same measurement conditions. The present changes in photo-
luminescence intensity further indicate that luminescence proper-
ties of nanosized CeF3:Tb3+ are sensitive to the shape, particle size,
structural defects and surface chemistry of sample.
[3] X. Wang, Y. Li., Chem. Eur. J. 9 (2003) 5627–5635.
[4] B. Dubertret, P. Skourides, D.J. Norris, V. Noireaux, A.H. Brivanlou, A. Libchaber,
Science 298 (2002) 1759–1762.
[5] H. Mai, Y. Zhang, R. Si, Z. Yan, L. Sun, L. You, C. Yan., J. Am. Chem. Soc. 128 (2006)
6426–6436.
[6] X. Bai, H. Song, G. Pan, Z. Liu, S. Lu, W. Di, X. Ren, Y. Lei, Q. Dai, L. Fan., Appl. Phys.
Lett. 88 (2006) 143104.
[7] L. Wang, Y. Li., Chem. Mater. 19 (2007) 727–734.
[8] J.L. Lemyre, A.M. Ritcey, Chem. Mater. 17 (2005) 3040–3043.
[9] L. Ma, W. Chen, X. Xu, L. Xu, X. Ning, Mater. Lett. 64 (2010) 1559–1561.
[10] X. Xiao, B. Yan, Y. Song, Cryst. Growth Des. 9 (2003) 136–144.
[11] Z. Miao, Z. Liu, K. Ding, B. Han, S. Miao, G. An, Nanotechnology 18 (2007)
125605–12509.
[12] A.P. Alivisatas, Science 271 (1996) 933–937.
[13] Y.N. Xia, P.D. Yang, Y.G. Sun, Y.Y. Wu, B. Mayers, B. Gates, Y.D. Yin, F. Kim,
H.Q. Yan, Adv. Mater. 15 (2003) 353–389.
[14] H.X. Mai, Y.W. Zhang, L.D. Sun, C.H. Yan., J. Phys. Chem. C 111 (2007)
13730–13739.
[15] P. Rahman, M. Green, Nanoscale 1 (2009) 214–224.
[16] J.H. Zeng, Z.H. Li, J. Su, L. Wang, R. Yan, Y. Li, Nanotechnology 17 (2006)
3549–3555.
[17] A.J. Wojtowicz, M. Balcerzyk, E. Berman, A. Lempicki, Phys. Rev. B 49 (1994)
14880–14894.
[18] K. Wei, C.X. Guo, J. Deng, C.S. Shi., J. Elec., Spectrosc. Relat. Phenom. A 79 (1996)
83–85.
4. Conclusions
[19] H. Lian, M. Zhang, J. Liu, Z. Ye, J. Yan, C. Shi., Chem. Phys. Lett. 395 (2004)
362–365.
[20] C. Li, X. Liu, P. Yang, C. Zhang, H. Lian, J. Lin., J. Phys. Chem. C 112 (2008)
2904–2910.
In summary, 0D nanoparticles and 2D nanoplates CeF3 and
CeF3:Tb3+ have been successfully fabricated through a facile and
effective polyol process. The content of NH4F and reactant concen-
tration plays a critical role in controlling the final morphology and
size of the product. With low content of NH4F, 0D nanoparticles were
obtained. When the content of NH4F exceeded a certain value,
hexagonal and regular 2D nanoplates were formed. With increasing
the content of NH4F and reactant concentration the size of products
increases. Furthermore, PL spectra showed that the CeF3 and
CeF3:Tb3+ samples exhibited characteristic emissions of Ce3+ (5d–4f)
and Tb3+ (f–f), respectively. The lifetime of Tb3+ in CeF3:Tb3+
samples become longer with increasing the size of samples because
the nonradiative processes at or near the surface of the nanoma-
terials are much reduced. The as-synthesized luminescent product
may have some potential applications in the areas of light display.
[21] X. Wang, J. Zhuang, Q. Peng, Y. Li., Inorg. Chem. 45 (2006) 6661–6665.
[22] Z.L. Wang, Z.W. Quan, P.Y. Jia, C.K. Lin, Y. Luo, Y. Chen, J. Fang, W. Zhou,
C.J. O’Connor, J. Lin., Chem. Mater. 18 (2006) 2030–2037.
[23] L. Zhu, Q. Li, X.D. Liu, J.Y. Li, Y.F. Zhang, J. Meng, X.Q. Cao., J. Phys. Chem. C 111
(2007) 5898–5903.
[24] H.X. Mai, Y.W. Zhang, L.D. Sun, C.H. Yan, Chem. Mater. 19 (2007) 4514–4522.
[25] R. Si, Y.W. Zhang, H.P. Zhou, L.D. Sun, C.H. Yan., Chem. Mater. 19 (2007) 18–27.
[26] C.H. Liu, H. Wang, X. Li, D.P. Chen, J. Mater. Chem. 19 (2009) 3546–3553.
[27] C.H. Liu, H. Wang, X.R. Zhang, D.P. Chen., J. Mater. Chem. 19 (2009) 489–496.
[28] X.G. Peng, Adv. Mater. 15 (2003) 459–463.
[29] Q. Tang, W. Zhou, W. Zhang, S. Ou, K. Jiang, W. Yu, Y.T. Qian, Cryst. Growth Des.
5 (2005) 147–150.
[30] J. Yang, C.X. Li, Z.W. Quan, D.Y. Kong, X.M. Zhang, P.P. Yang, J. Lin, Cryst. Growth
Des. 8 (2009) 695–699.
[31] C.X. Li, J. Yang, Z.W. Quan, P.P. Yang, D.Y. Kong, J. Lin, Chem. Mater. 19 (2007)
4933–4942.
[32] R. Qin, H. Song, G. Pan, X. Bai, B. Dong, S. Xie, L. Liu, Q. Dai, X. Qu, X. Ren, H. Zhao,
Cryst. Growth Des. 9 (2009) 1750–1756.
[33] C. Li, C. Zhang, Z. Hou, L. Wang, Z.Q.H. Lian, J. Lin, J. Phys. Chem. C 113 (2009)
2332–2339.
Acknowledgments
[34] X. Peng, L. Manna, W. Yang, J. Wickham, E. Scher, A. Kadavanich, A.P. Alivisatos,
Nature 404 (2000) 59–61.
[35] G. Blasse, A. Bril, J. Chem. Phys. 51 (1969) 3252–3254.
[36] L. Yu, H. Song, Z. Liu, L. Yang, S. Lu, Z. Zheng, J. Phys. Chem. B 109 (2005)
11450–11455.
[37] M. Yu, J. Lin, J. Fu, H.J. Zhang, Y.C. Han, J. Mater. Chem. 13 (2003) 1413–1419.
[38] H. Lai, A. Bao, Y. Yang, Y. Tao, H. Yang, Y. Zhang, L. Han, J. Phys. Chem. C 112
(2008) 282–286.
This research was supported by Basic Science Research Program
through the NRF funded by the Ministry of Education, Science and
Technology (2009-0073255) and also this research was supported
by National Core Research Center (NCRC) program through the
National Research Foundation of Korea funded by the Ministry of
Education, Science and Technology (2010-0001-226).
[39] H. Guo, Appl. Phys. B 84 (2006) 365–369.
[40] J.C. Bourcet, F.K. Fong, J. Chem. Phys. 60 (1974) 34–39.
[41] G. Blasse, B.C. Grabmaier, Luminescent Materials, Springer-Verlag, Berlin,
Heidelberg, 1994.
References
[42] T. Fujii, K. Kodaira, O. Kawauchi, N. Tanaka, H. Yamashita, M. Anpo, J. Phys.
Chem. B 101 (1997) 10631–10637.
[1] K. Kompe, H. Borchert, J. Storz, A. Lobo, S. Adam, T. Moller, M. Haase., Angew.
Chem. Int. Ed. 42 (2003) 5513–5516.
[43] X. Qu, H. Song, G. Pan, X. Bai, B. Dong, H. Zhao, Q. Dai, H. Zhang, R. Qin, S. Lu, J.
Phys. Chem. C 113 (2009) 5906–5911.
[2] G.A. Kumar, C.W. Chen, J. Ballato, R.E. Riman., Chem. Mater. 19 (2007)
1523–1528.