Indium sulfide microflowers: Fabrication and optical properties

Article abstract of DOI:10.1016/j.materresbull.2009.05.023

With the assistance of urea, uniform 2D nanoflakes assembled 3D In₂S₃ microflowers were synthesized via a facile hydrothermal method at relative low temperature. The properties of the as-obtained In₂S₃ flowers were characterized by various techniques. In this work, the utilization of urea and l-cysteine, as well as the amount of them played important roles in the formation of In₂S₃ with different nanostructures. Inferred from their morphology evolution, a urea induced precursor-decomposition associated with the Ostwald-ripening mechanism was proposed to interpret these hierarchical structure formation. Furthermore, the optical properties of these In₂S₃ microflowers were investigated via UV-vis absorption and photoluminescence (PL) spectroscopies in detail.

Full text of DOI:10.1016/j.materresbull.2009.05.023

Materials Research Bulletin 44 (2009) 2033–2039
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Materials Research Bulletin
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Indium sulfide microflowers: Fabrication and optical properties
Hui Zhu a,b, Xiaolei Wang a,b, Wen Yang a,b, Fan Yang a, Xiurong Yang a,
*
a State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, Jilin, 130022, China
b Graduate School of the Chinese Academy of Sciences, Beijing, 100039, China
A R T I C L E I N F O
A B S T R A C T
Article history:
With the assistance of urea, uniform 2D nanoflakes assembled 3D In2S3 microflowers were synthesized
via a facile hydrothermal method at relative low temperature. The properties of the as-obtained In2S3
Received 1 February 2009
Received in revised form 27 April 2009
Accepted 31 May 2009
flowers were characterized by various techniques. In this work, the utilization of urea and L-cysteine, as
well as the amount of them played important roles in the formation of In2S3 with different
nanostructures. Inferred from their morphology evolution, a urea induced precursor-decomposition
associated with the Ostwald-ripening mechanism was proposed to interpret these hierarchical structure
formation. Furthermore, the optical properties of these In2S3 microflowers were investigated via UV–vis
absorption and photoluminescence (PL) spectroscopies in detail.
Available online 9 June 2009
Keywords:
A. Semiconductors
B. Chemical synthesis
C. Electron microscopy
D. Luminescence
D. Optical properties
ß 2009 Elsevier Ltd. All rights reserved.
1. Introduction
2.07 eV. Considerable attention has been focused on it because of
its defect structure and the corresponding optical, acoustic, and
Nowadays, the controllable synthesis of micro- and nano-scale
materials with unique morphology and hierarchy has stimulated
intensive interest due to their importance in basic scientific
research and technological applications [1–3]. Many efforts have
been devoted to the fabrication of two-dimensional (2D) or three-
dimensional (3D) micro-structure with 0D or 1D building blocks
[4,5]. Generally, these hierarchical structures were fabricated via
the oriented attachment mechanism, the Ostwald ripening process
or both. However, due to the difficulties in controlling the
nucleation and growth processes, the construction of well-defined
3D architectures with 2D components is still a great challenge [6–
8]. These hierarchical structures may endow them with morphol-
ogy-dependant properties and imply their potential application in
various fields. Therefore, further research is warranted to realize
the advantages of them.
electronic properties. It has motivated application researches such
as green and red phosphors for color televisions, window materials
in photovoltaic device, medical tracers for cancer diagnosis and dry
cells [10–12]. Thus, many methods such as sonochemical method,
precipitation, hydrothermal method, solvent reduction route,
microwave assisted method and MOCVD method have been
developed to fabricate In2S3 with different morphologies like
urchin-like microspheres, dendrites, nanofibers, hollow micro-
spheres, etc. [13–17]. However, there are few reports about the
In2S3 secondary nanostructure fabrication. Hence, it is desirable to
develop the controllable synthesis of In2S3 nanostructures with
exceptional properties.
As a biomolecule, L-cysteine has several functional groups such
as –NH2, –COOH and –SH, which have a strong tendency to
coordinate with inorganic cations. Inspired this, some metal sulfide
nanostructures have been prepared in the presence of cysteine,
which acted not only as a complex agent but also as a sulfur source
and structure directing molecule [18–20]. To rupture the C–S bond,
a high reaction temperature was utilized in these reports. Recently,
to reduce the reaction temperature, some bases such as NaOH and
NH3ÁH2O were selected [21,22]. In this paper, we develop a facile,
one-step hydrothermal route to fabricate In2S3 microflowers with
As a mid-band gap semiconductor indium sulfide has two kinds
of compositional forms (InS and In2S3) [9]. Furthermore, In2S3 is
known to crystallize in three polymorphic forms as a function of
temperature: e.g., a defect cubic structure called
to about 693 K), a defect spinel structure called
a
-In2S3 (stable up
b
-In2S3 (stable up
to about 1027 K) and a higher temperature layered hexagonal
structure in the -form (above 1027 K). Among these three forms,
-In2S3 is known as an n-type semiconductor with a band gap of
g
b
the assistance of urea and
L-cysteine at a low temperature. Herein,
urea served as both an inducement to the decomposition of
L-
cysteine and a structure-directing agent. Furthermore, the optical
properties of them were investigated via UV–vis absorption and
photoluminescence (PL) spectrum.
* Corresponding author. Tel.: +86 431 85682056; fax: +86 431 85689278.
E-mail address: xryang@ciac.jl.cn (X. Yang).
0025-5408/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.materresbull.2009.05.023

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H. Zhu et al. / Materials Research Bulletin 44 (2009) 2033–2039
2. Materials and methods
2.1. Materials
All chemical materials used (indium chloride tetrahydrate, L-
cysteine, urea, etc.) were purchased from Beijing Chemical
Corporation with analytical purities.
2.2. Synthesis of
b-In2S3 microflowers
In
a
typical procedure to prepare
b-In2S3 microflowers,
0.4 mmol of InCl3Á4H2O, 1.8 mmol of
L
-cysteine and 0.8 mmol of
urea were added to 24 mL distilled water. After stirring for 15 min,
a transparent solution was formed and transferred into a 30 mL
Telfon lined stainless steel autoclave. The autoclave was heated at
140 8C for 16 h, and then cooled to room temperature naturally.
The yellow precipitates were collected, washed with distilled
water for several times. In order to explore the influence of reaction
parameters on the morphologies of
ments were designed, e.g., reaction time, different quantities of
urea, -cysteine, etc.
b-In2S3, controlled experi-
L
2.3. Characterization
X-ray diffraction (XRD) patterns of the prepared samples were
recorded on a Rigaku-Dmax 2500 diffractometer equipped with
graphite monochromatized Cu Ka (l = 0.15405 nm) radiation at a
scanning speed of 48/min in the range from 208 to 708. Scanning
electron microscopy (SEM) images were taken using Philips XL 30
and a JEOL JSM-6700F microscope. Energy dispersive X-ray
analysis (EDX) was also done on the same instrument. Transmis-
sion electron microscopy (TEM) and selected area electron
diffraction (SAED) measurement were carried out with JEM-
2000 FX operating at 200 kV accelerating voltage. FT-IR spectra
were recorded on a Bruker Vertex 70 FT-IR spectrometer. UV–vis
absorption was characterized by Cary 50 UV–vis NIR spectrometer
(Varian, USA). Photoluminescence (PL) emission measurements
Fig. 1. (a) X-ray diffraction pattern (XRD) and (b) energy dispersive X-ray analysis
(EDX) of the In2S3 sample (140 8C for 16 h).
tals. These nanopetals were connected to each other to build the 3D
were performed using
(PerkinElmer).
a
LS-55 luminescence spectrometer
b
-In2S3 flower-like structures (Fig. 2d). Fig. 3a showed the TEM
image of -In2S3 which was in good agreement with the results
b
from SEM. In addition, under SEM magnification, the petal-like
building blocks exhibited smooth surfaces. But based on the
observation of TEM (Fig. 3b), the petals had rough surfaces. The
selected area electron diffraction (SAED) (the inset of Fig. 3b) of the
3. Results and discussion
3.1. Compositions and morphologies of the products
petal showed a set of diffraction rings, indicating the cubic b-In2S3
The crystal structure and phase composition of the products
were characterized by XRD and EDX analysis. As shown in Fig. 1a,
according to the diffraction peaks location, the sample could be
polycrystalline nature. These results were consistent with the XRD
data shown in Fig. 1a.
indexed to cubic
b
-In2S3 crystalline phase (JCPDS No. 65-0459)
3.2. Influence of urea on morphology
with a primitive cubic unit cell (a = 1.0774 nm). In addition, no
other impurities, e.g., In(OH)3, In2O3 or InS were detected in
this pattern. Furthermore, the chemical composition was
also investigated by EDS pattern (Fig. 1b). It was revealed that
the final product consisted of In and S elements with a molar
ratio of 2:3, confirming the formation of In2S3 nanostructure in
our synthesis. (The element of Au was from the coating layer
used for SEM imaging while Si was originated from the
substrate.)
The hierarchical architectures of the products were recorded by
the SEM and TEM. Fig. 2 showed the typical In2S3 images at
different magnifications. From Fig. 2a, it was found that the
spherical structures dominated in the full image, indicating a high
yield for our products. In addition, their diameters were in a
To investigate the influence of urea in the synthetic route,
different quantity of urea was used in their preparation. As shown
in Fig. 4, the quantity of urea played an important role in
determining the morphology of In2S3. In the urea-free control
reaction, the samples mainly showed spherical shapes with coarse
surfaces in a broad size range (0.5–2
characterization indicated their cubic phase of
m
m) (Fig. 4a). Further XRD
-In2S3 in weak
b
crystallinity (Fig. 4b). When 0.8 mmol urea was added, the uniform
flowery architectures developed and became the dominant (Fig. 2).
If we further increased the urea dose to 4 mmol, the resulting SEM
image exhibited a 2D petal like In2S3 nanostructure (Fig. 4c).
Detailed TEM image revealed that these flakes also combined
together to construct flowery structures (Fig. 4d). However, the
petals subunits are too filmy to support them on SEM substrate.
relative uniform range between 0.8 and 1.2
mm. Detailed
observations of these spherical morphologies were presented in
Fig. 2b and c. It was noticed that all these spheres had flowery
refined architectures, which were composed of dozen of nanope-
The SAED pattern (the inset in Fig. 4c) also expressed the cubic b-
In2S3 phase with polycrystalline nature. When 8 mmol urea was
induced to the synthetic system, similar petal-like structures were

H. Zhu et al. / Materials Research Bulletin 44 (2009) 2033–2039
2035
Fig. 2. FE-SEM images of the In2S3 flowers (140 8C for 16 h) at different magnification.
also recorded by SEM technology (Fig. 4e). The TEM image
elucidated the real features of these petals as well as some
3.3. Influence of
L-cysteine on morphology
integrated structures (Fig. 4f). The polycrystalline
b
-In2S3 nature
Besides the influence of urea, the effect of
L-cysteine was also
was also indicated by the SAED pattern (the inset of Fig. 4e).
Therefore, urea served as both an inducement to the decomposi-
investigated in our research. As shown in Fig. 6a, if the dosage of
cysteine was reduced to 0.8 mmol, the compacted flowery
structures were formed (Fig. 6a). When the quantity of -cysteine
L-
tion of
L
-cysteine and a structure directing agents herein [23,24].
L
Neither a very low nor a very high quantity of urea is suitable for
the construction of these flower-like nanostructures. Besides the
concentration influence, the differences between alkaline sources
were also investigated. When the alkaline source was replaced by
NaOH, NH3ÁH2O and hexamethyleneteramine (HETA) respec-
tively, the products showed different morphologies. As shown in
Fig. 5a, when NaOH acted as the alkaline source, the samples
exhibited flowery morphology, which were densely compacted
and in a broad size range. If NH3ÁH2O was chosen, flowers with
sparse petals dominated the whole image (Fig. 5b). When HETA
was selected, the samples expressed spherical morphologies with
coarse surfaces in narrow size range and connected each other
(Fig. 5c). From the data above, we can draw the conclusion that not
only the alkaline source but also the concentration of urea played
important roles in the fabrication of these flowery super-
structures.
was increased to 3.2 mmol, the obtained samples showed a broad
size distribution (Fig. 6b). If the sulfur source was substituted by
mercapto propionic acid (MPA), which possessed the similar
molecular structure except an amine group, the products exhibited
spherical morphologies accreted by some In(OH)3 microcubes
(Fig. 6c) [24]. The reason for this phenomenon may be due to the
lower coordination ability and the slower decomposition rate of
MPA. Thus it was concluded that the selection of L-cysteine as well
as its quantity played important roles in the fabrication of these 3D
flower-like structures.
3.4. Growth mechanism of In2S3 flowery structure
In order to understand the fabrication process of the 3D flower-
like In2S3 nanostructures, time-dependent evolutions of morphol-
ogy at 140 8C were elucidated by SEM and TEM (Fig. 7a–e). If the
Fig. 3. The typical TEM images of In2S3 flowers (140 8C for 16 h) at different magnification and SAED pattern of the samples.

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H. Zhu et al. / Materials Research Bulletin 44 (2009) 2033–2039
Fig. 4. FE-SEM images ans the SAED patterns of the products obtained with different urea quantity: (a) 0 mmol, (c) 4 mmol, (e) 8 mmol; (b) the XRD pattern for the sample s in
(a); (e) and (f): the TEM images for the samples in (c) and (e) respectively.
Fig. 5. FE-SEM images of the products obtained with different basic source (a) 0.8 mmol NaOH, (b) 0.8 mmol NH3ÁH2O and (c) 0.8 mmol HETA.
Fig. 6. FE-SEM images of the sample obtained with different sulfur source: (a) 0.8 mmol cysteine; (b) 3.2 mmol cysteine; (c) 1.8 mmol MPA.

H. Zhu et al. / Materials Research Bulletin 44 (2009) 2033–2039
2037
Fig. 7. FE-SEM images of the samples collected at different time period: (a) 2 h, (b) 4 h, (c) 6 h, (d) 10 h; (e): the typical TEM image for (d); (f) the XRD patterns for the samples
above (*: the cubic In(OH)3 phase).
reaction time was shortened to 2 h, the samples collected were in a
low quantity. As shown in Fig. 7a, the products obtained at this
stage consisted of spheres with smooth surfaces in a broad size
SEM, XRD and FT-IR analysis. As shown in Fig. 8a, these white
hybrid precursors exhibited irregular morphologies in nano-size
about 50 nm. In addition, the corresponding EDS pattern indicated
that five different elements (C, N, O, S and In) existed in the
complex precursors (Fig. 8b). Quantitative analysis of the peak
intensities indicated atom contents of 45.46% for C, 12.56% for N,
12.44% for O, 18.05% for S and 11.49% for In respectively. The sulfur
range between 200 nm and 1.5
mm. When the reaction was
conducted for 4 h, the yield of the precipitation increased. The
surface of these spheres became rougher in a relative narrow size
range between 700 nm and 1.2
mm (Fig. 7b). After the reaction was
performed for 6 h, those spheres were carved into flowery
hierarchies with the same size (Fig. 7c). If the reaction were kept
for 10 h, the flowers combined by several petals became the
dominative structure (Fig. 7d). Further TEM characterization
indicated the uniform size range and the detailed petal subunits
(Fig. 7e). With the extension of reaction time, the products
exhibited the flowery structures constructed by many petals in a
narrow size range (Fig. 2). Afterward XRD were used to track the
composition change of them. As shown in Fig. 7f, it was observed
that at the embryo stage (2 h), the composition of the products
element may be derived from
may originate from both -cysteine and urea. The further XRD
pattern provided amorphous nature of the hybrid complex
(Fig. 8c). In addition, The FT-IR spectra of pure -cysteine, urea
L-cysteine. The C, N and O elements
L
L
and the hybrid composites were also shown in Fig. 8d. Several
differences between these spectrum curves were detected. The
characteristic amide I (1626 cmÀ1, curve 3) band may attributed to
the C55O stretching vibration and amide II (1496 cmÀ1) band
resulted from the combination of N–H bending and C–N stretching,
different from 1677, 1604 and 1465 cmÀ1 in curve 1. The
+
were proved to be
time was prolonged to 4 h, the In(OH)3 phase began to disappear.
With the reaction time extended, the -In2S3 crystalline increased
and no other impurities were detected.
b
-In2S3 and In(OH)3 mixture. When the reaction
characteristic –NH3 band at 2016 cmÀ1 (curve 1) and
2081 cmÀ1 (curve 2) disappeared. The typical signal of –SH at
2552 and 2508 cmÀ1 (curve 2) also disappeared indicating that S
b
element of the complex originated from the –SH group of L-
It was interesting to note that at the initial stage, the yield of the
precipitation was quite low. Thus which states were in for those
dissolved precursors was put forward as a question. Hence the
upper solution was collected and a certain quantity of ethanol was
added in it. Some white precipitates were gathered and washed for
cysteine. Based on the above data, even though the precise
chemical composition and molecular structure of the hybrid
precursors cannot be deduced, it was pertinent to conclude that
In3+ can coordinate with cysteine [18–21] and urea [23,24] to form
embryo precursor complexes.

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H. Zhu et al. / Materials Research Bulletin 44 (2009) 2033–2039
Fig. 8. (a) FE-SEM image, (b) the EDS pattern, (c) the XRD pattern and (d) the FT-IR characterization of the hybrid precursors obtained.
As discussed above, the growth mechanism can be proposed as
urea induced precursor-decomposition associated with ripening
mechanism. As illustrated in Scheme 1, at the initial stage, In3+ ions
nated the reaction, and yielded unified spherical shaped particles
(Fig. 7b). The solute particles were transferred to the crystal
interface and were incorporated into the crystal by surface
kinetics. Those spheres were carved into flowery hierarchies with
combined with
L-cysteine and urea molecules in the mixed
solution as a result of coordination effects (Fig. 8). These produced
hybrid complex served as both the indium source and the sulfur
source. With the increase of reaction temperature, urea molecules
began to hydrolyze to give off ammonia, the pH value of the
solution rose uniformly [25–27]. This prevented the occurrence of
local supersaturation, favored the homogenous nucleation of tiny
the same size (Fig. 7c). Due to the lower solubility of
that of In(OH)3Á(Ksp(In2S3) < Ksp(In(OH)3), the In(OH)3 impurities
were transformed to -In2S3 phase completely. In the following
procedure, due to the excess existence of -cysteine, the flowery
structures turned into a concise form with thinner flakes (Fig. 7d).
At the final period, due to the thermodynamic stability, the Oswald
ripening process took place. The concise form compacted to a
certain degree (Fig. 2).
b-In2S3 than
b
L
single crystals and meanwhile induced the decomposition of
cysteine. However due to the unparallel decomposition rate
between urea and -cysteine, the irregular shaped nanoparticles
were formed at this stage (Fig. 7a). Both the cubic In(OH)3 phase
and the cubic -In2S3 phase was detected in the XRD pattern. As
the reaction proceeded, the decomposition of -cysteine domi-
L-
L
Based on the mechanism above, the influence of the reaction
parameters may also be interpreted. If the dosage of urea was
reduced to 0 mmol, there would be not enough OHÀ in the solution
b
L
to induce the decomposition of L-cysteine. Thus the growth of the
Scheme 1. Schematic illustration of the growth mechanism for the 3D flowery In2S3.

H. Zhu et al. / Materials Research Bulletin 44 (2009) 2033–2039
2039
Fig. 9. (a) UV–vis adsorption spectrum of the In2S3 flowers. (b) PL emission spectra of the above sample (excited by 335 nm).
flowery nanostructures was inhibited and spherical particles with
coarse surfaces came into being in a broad size range. Besides, the
poor crystalinity of them was also detected. When the urea
concentration was increased, enough OHÀ anions were supplied.
These anions may bind on the surface to direct the flowers
fabrication with thinner flakes to a certain extent. For the anions
supply, if NaOH and NH3ÁH2O were selected, due to the local
supersaturation, heterogeneous nucleation occurred and resulted
in flowers in wide size range. When HETA was chosen, uniform
spheres formed due to the homogeneous nucleation. However, due
to the different coordination ability, these spheres linked together
and failed to transform into flowery structures. Similar explanation
was also applicable for the cysteine supply.
final structure and composition control. Urea induced precursor-
decomposition associated with ripening mechanism was proposed
to interpret their shape evolutions. These In2S3 novel architectures
showed a quantum confinement effect in absorption spectra and
exhibited a strong blue emission, which allowed to be utilized as
promising materials for quantum electronic.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (No. 90713022), the National Key Basic
Research Development Project of China (No. 2007CB714500) and
the Project of Chinese Academy of Sciences (No. KJCX2. Y. W. H09).
3.5. Optical properties of the flowery In2S3
References
As a promising semiconductor, its optical properties were also
studied at room temperature. Fig. 9a represented the UV–vis
absorption spectrum of the as-prepared In2S3 microflowers.
Besides a weak broad absorption at 508 nm, a strong peak located
at 291 nm was observed, which obviously revealed their blue shift
compared with the reported data of 620.6 nm for bulk In2S3
materials [16,21]. The flower petals exhibited a thickness of about
20 nm, which was smaller than the Bohr exaction radius of In2S3
(33.8 nm). Consequently, this blue shift phenomenon of the
absorption may be interpreted by the quantum confinement
effect. In addition, we also carried out photoluminescence (PL)
studies to investigate the optical properties of the stacked In2S3
flowers. This hierarchical superstructures showed good lumines-
cence compared with the non-luminescent behavior of bulk In2S3.
Under the excitation at 335 nm, a strong emission peak at 484 nm
accompanied with several shoulders (420, 454 and 533 nm) was
observed as shown in Fig. 9b. The blue luminescence at 484, 420
and 454 nm can be attributed to the presence of several deep trap
states or defects in the structure. The weak green luminescence at
533 nm may be an emission from the indium interstitial sites,
which corresponded to the report of Chen et al. [11].
[1] Z.L. Wang, J.H. Song, Science 312 (2006) 242–246.
[2] Y.N. Xia, P.D. Yang, Y.G. Sun, Y.Y. Wu, B. Mayers, B. Gates, Y.D. Yin, F. Kim, Y.Q. Yan,
Adv. Mater. 15 (2003) 353–389.
[3] J.X. Huang, A.R. Tao, S. Connor, R.R. He, P.D. Yang, Nano Lett. 6 (2006) 524–529.
[4] H.T. Shi, L.M. Qi, J.M. Ma, H.M. Cheng, J. Am. Chem. Soc. 125 (2003) 3450–3451.
[5] C. Burda, X.B. Chen, R. Narayanan, M.A. Ei-sayed, Chem. Rev. 105 (2005) 1025–
1102.
[6] G.M. Whitesides, B. Grzybowski, Science 295 (2002) 2418–2421.
[7] S. Park, J.H. Lim, S.W. Chung, C.A. Mirkin, Science 303 (2004) 348–351.
[8] L.P. Xu, Y.S. Ding, C.H. Chen, L.L. Zhao, C. Rimkus, R. Joesten, S.L. Suib, Chem. Mater.
20 (2008) 308–316.
[9] A. Datta, S.K. Panda, D. Ganguli, P. Mishra, S. Chaudhuri, Cryst. Growth. Des. 7
(2007) 163–169.
[10] D.K. Nagesha, X. Liang, A.A. Mamedov, G. Gainer, M.A. Eastman, M. Giersig, J.J.
Song, T. Ni, N.A. Kotov, J. Phys. Chem. B 105 (2001) 7490–7498.
[11] W. Chen, J.O. Bovin, A.G. Joly, S.P. Wang, F.H. Su, G.H. Li, J. Phys. Chem. B 108 (2004)
11927–11934.
[12] M. Afzaal, P. O’Brien, J. Mater. Chem. 16 (2006) 1597–1602.
[13] S. Avivi, O. Palchik, M.A. Slifkin, A.M. Weiss, A. Gedanken, Chem. Mater. 13 (2001)
2195–2220.
[14] Y.J. Xiong, Y. Xie, G.A. Du, X.B. Tian, J. Mater. Chem. 12 (2002) 98–102.
[15] P.V. Kamat, N.M. Dimitrijevic, R.W. Fessenden, J. Phys. Chem. 92 (1988) 2324–
2329.
[16] S.D. Naik, T.C. Jagadale, S.K. Apte, R.S. Sonawane, M.V. Kulkarni, S.I. Patil, S.B.
Ogale, B.B. Kale, Chem. Phys. Lett. 452 (2008) 301–305.
[17] K.H. Park, K. Jang, S.U. Son, Angew. Chem. Int. Ed. 45 (2006) 4608–4612.
[18] C.B. Chory, C. Remenyi, H. Strohm, G. Muller, J. Phys. Chem. B 108 (2004) 7637–
7640.
4. Summary
[19] B. Zhang, X. Ye, W. Hou, Y. Zhao, Y. Xie, J. Phys. Chem. B 110 (2006) 8978–8985.
[20] S.J. Bao, C.M. Li, C.X. Guo, Y. Qiao, J. Power Sources 180 (2008) 676–681.
[21] L.Y. Chen, Z.D. Zhang, W.Z. Wang, J. Phys. Chem. C 112 (2008) 4117–4123.
[22] P.T. Zhao, T. Huang, K.X. Huang, J. Phys. Chem. C 111 (2007) 12890–12897.
[23] Q.L. Zhang, Series Books of Inorganic Chemistry, Science Press, Beijing, 1998.
[24] H. Zhu, X.L. Wang, F. Yang, X.R. Yang, Cryst. Growth. Des. 8 (2008) 950–956.
[25] L.S. Zhong, J.S. Hu, H.P. Liang, A.M. Cao, W.G. Song, L.J. Wan, Adv. Mater. 18 (2006)
2426–2431.
In summary, 2D flakes based 3D flowery In2S3 architectures
have been successfully synthesized by a simple hydrothermal
method at relatively low temperature with the assistance of urea.
In this case, urea not only acted as the alkaline source to induce the
decomposition of cysteine but also directed the superstructure
formation. In addition, it was intriguing to note that the sulfur
source selected as well as the quantity had great influence on the
[26] A.M. Cao, J.S. Hu, H.P. Liang, W.G. Song, L.J. Wan, X.L. He, X.G. Gao, S.H. Xia, J. Phys.
Chem. B 110 (2006) 15858–15863.
[27] S.Y. Zeng, K.B. Tang, T.W. Li, Z.H. Liang, J. Colloid Interface Sci. 316 (2007) 921–929.