Structural and spectroscopic characterization of prepared Ag2S nanoparticles with a novel sulfuring agent

Article abstract of DOI:10.1016/j.saa.2014.05.060

Ag₂S nanoparticles were prepared by a solvothermal process via reaction of Ag(NO₃) and a new sulfuring agent from class of thio Schiff-base (2-(benzylidene amino) benzenethiol (C₁₃H ₁₁NS)) in presence of various solvents. Spectra such as X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SEAD), ultraviolet-visible (UV-Vis) spectroscopy, thermo gravimetric-differential thermal analysis (TG-DTA), and Fourier transform Infrared (FT-IR) employed to characterize the synthesized products. Results of this paper indicate that shape and size of the silver sulfide can be controlled by means of setting certain reaction parameters such as the reaction temperature, presence of surfactant, and type of solvent. Silver sulfide nanoparticles with different morphology and size successfully prepared. In addition, the growth mechanisms of the Ag₂S nanoparticles discussed preliminarily.

Full text of DOI:10.1016/j.saa.2014.05.060

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Structural and spectroscopic characterization of prepared Ag2S
nanoparticles with a novel sulfuring agent
Maryam Shakouri-Arani a, Masoud Salavati-Niasari b,
⇑
a Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran
b Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
ꢀ
ꢀ
ꢀ
Silver sulfide nanostructures were
synthesized by solvothermal method.
Shape of obtained sample was
controlled by reaction conditions.
2-(Benzylidene amino) benzenethiol
was chosen as a the newest sulfuring
agent.
ꢀ
Effects of different parameters on
purity, size and morphology were
investigated.
a r t i c l e i n f o
a b s t r a c t
Article history:
Ag2S nanoparticles were prepared by a solvothermal process via reaction of Ag(NO3) and a new sulfuring
agent from class of thio Schiff-base (2-(benzylidene amino) benzenethiol (C13H11NS)) in presence of var-
ious solvents. Spectra such as X-ray diffraction (XRD), transmission electron microscopy (TEM), selected
area electron diffraction (SEAD), ultraviolet–visible (UV–Vis) spectroscopy, thermo gravimetric–differen-
tial thermal analysis (TG–DTA), and Fourier transform Infrared (FT-IR) employed to characterize the
synthesized products. Results of this paper indicate that shape and size of the silver sulfide can be
controlled by means of setting certain reaction parameters such as the reaction temperature, presence
of surfactant, and type of solvent. Silver sulfide nanoparticles with different morphology and size success-
fully prepared. In addition, the growth mechanisms of the Ag2S nanoparticles discussed preliminarily.
Ó 2014 Elsevier B.V. All rights reserved.
Received 12 February 2014
Received in revised form 18 April 2014
Accepted 5 May 2014
Available online 12 June 2014
Keywords:
Nanoparticles
Chalcogenides
Solvothermal
Electron microscopy
Introduction
cations in various fields of science and technology such as, photo
conducting cells, photovoltaic cells, IR detectors [4] and electro-
Transition metal chalcogenides such as sulfides, selenides and
tellurides are usually found in minerals. They have attracted
world-wide attention owing to the interesting properties, in recent
decades [1]. They have commercial applications in pigments, semi-
conductors, fluorescence devices and even superconductors [2,3].
Silver sulfide is an important chalcogenide due to its photoelectric
and thermoelectric properties, which has been world-wide appli-
chemical storage cells [5,6]. It is also well recognized as a mixed
ionic and electronic conductor at high temperatures above
200 °C. Various techniques has been suggested for synthesis and
properties characterization of silver sulfide such as chemical bath
deposition (CBD) [8,9], spray pyrolysis deposition (SPD) [10], suc-
cessive ionic layer adsorption and reaction (SILAR) [11], molecular
beam epitaxy (MBE) [12], gamma irradiation [13], thermal
evaporation [14] and sol–gel and ion implantation techniques
[15], Among different methods of preparation, liquid-based tech-
niques as well as gas phase-based techniques, are aiming highly
⇑
Corresponding author. Tel.: +98 361 591 2383; fax: +98 361 555 29 30.
E-mail address: Salavati@kashanu.ac.ir (M. Salavati-Niasari).
http://dx.doi.org/10.1016/j.saa.2014.05.060
1386-1425/Ó 2014 Elsevier B.V. All rights reserved.

464
M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
crystalline particles with almost monodisperse size distribution
and regular morphology [16–20]. The polyol route applied herein
provides a promising preparative approach to such sulfide parti-
cles. The polyol method was early part used for the preparation
of elemental metals and alloys [21–24], because alcohols (e.g. glyc-
erol, glycol) with high boiling provide a suitable metal precursor
for preparation metal sulfide, alloys and elemental metals.
Recently metal oxide particles have been prepared with this route
[25,26]. Generally, reaction of the formation of binary chalcoge-
nides is relatively slow in polyol methode; till now, the synthetic
strategies based on the polyol route to binary chalcogenides are
used under microwave irradiation [27]. Yang’s group also devel-
oped solvothermal route in polyol solvent to sulfides using auto-
clave as pressure equipment [28]. In our present investigations,
the polyol method was found to be suitable for the synthesis of a
host of binary metal sulfides under moderate conditions.
work and systematic reaction conditions such as reaction temper-
ature, using of surfactant and solvent type on the morphology and
size of the products has been investigated.
The crystal structure and composition of the as-prepared
products were determined by XRD. The XRD patterns of the
Ag(NO3) and thio Schiff-base (2-(benzylidene amino) benzenethiol
(C13H11NS)) obtained in absence of surfactant, presence of surfac-
tants (sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium
bromide (CTAB) and PEG 20,000), in H2O and 1-butanol solvents
have been shown in Fig. 1a–f, respectively. Peak in Fig. 1a; corre-
spond to the reflections of Ag2S. These patterns are indexed as
cubic phase and orthorhombic phase which are very close to the
literature values (JCPDS No. 02-0998 and 03-0844 respectively).
The crystallite size measurements were also carried out using the
Scherrer equation, Dc = K k/bcosh. Where, K is about 0.9, b is the
breadth of the observed diffraction line at its half intensity maxi-
mum and k is the wavelength of X-ray source used in XRD. The
estimated crystallite size of sample is 47.04 nm. The purity of the
nanoparticles was also reckoned up by energy-dispersive X-ray
spectroscopy. When surfactants are used in the reaction, mercuric
has been synthesized instead of mercuric sulfide. Indeed, surfac-
tants acted as reducer. Fig. 1b–d patterns are indexed as cubic
phase which are very close to the literature values (JCPDS No.
87-0597). The X-ray diffraction (XRD) patterns of the prepared
Ag2S nanoparticles in H2O and 1-butanol solvents are shown in
Fig. 1e and f, all the characteristic peaks can be well-indexed as
monoclinic phase which are very close to the literature values
(JCPDS No. 65-2356).
Experimental
Reagent
All reagents and solvents were of analytical grade and were
used as received without further purification.
Synthesis of Ag2S nanocrystals
In
a typical experiment, two solutions were prepared,
respectively. (A) The 0.63 ml benzaldehyde was dissolved in
propylene glycol (10 ml) under stirring. In a separate beaker,
0.63 ml (5.88 Â 10À3 mol) 2-aminothiophenol was dissolved in
10 ml absolute propyleneglycol and added drop wise to previous
solution under 30 min stirring at room temperature (the molar
ratio of 2-ATP and benzaldehyde is 1:1). (B) 0.5 g (2.9 Â 10À3 mol)
of Ag(NO3) was dissolved in 50 ml propylene glycol under magnetic
stirring(the molar ratio of Ag(NO3) and ligand is 1:2); solution A
was added into solution B slowly under magnetic stirring for
2 h finally the color of mixture becomes yellow. The final solution
was transferred to a 70 ml Teflon-line stainless steel autoclave
and filled with propylene glycol up to 80% of the total volume.
The autoclave was sealed and maintained at 160 °C for 12 h. After
thermal treatment, the autoclave was cooled to room temperature
and the resulting black precipitate was collected, filtered, and
washed with distilled water and absolute ethanol for several times
to remove the unreacted chemicals, and finally dried in vacuum
oven at 70 °C for 6 h.
Novelty of this study compared to other research carried out this
is which for synthesize of silver sulfide was used from a new sulfur-
ing agent from class of thio Schiff-base, without any surfactant and
reduce agent in diverse solvents. Experimental results in this paper
Characterization
X-ray diffraction (XRD) patterns were recorded by a Rigaku
D-max C III, X-ray diffractometer using Ni-filtered Cu Ka radiation.
The compositional analysis was done by energy dispersive X-ray
(EDX, Kevex, Delta Class I), scanning electron microscopy (SEM)
images were obtained on LEO. Transmission electron microscopy
(TEM) images were obtained on a Philips EM208 transmission elec-
tron microscope with an accelerating voltage ao 100 kV Fourier
transform infrared (FT-IR) spectra were recorded on a Shimadzu
Varian 4300 spectrophotometer in KBr pellets. The electronic
spectra of samples were taken on a JASCO, (190–2700 nm), UV–
Visible scanning spectrometer (Model V-670). Thermogravimet-
ric–differential thermal analysis (TG–DTA) were carried out using
a thermal gravimetric analysis instrument (Shimadzu TGA-50H)
with a flow rate of 20.0 mL minÀ1 and a heating rate of 10 °C minÀ1
.
Results and discussion
Fig. 1. XRD patterns (a) Ag2S spherical nanoparticles in absence of surfactant, (b) in
presence of SDS, (c) CTAB, (d) PEG 20,000, (e) H2O as solvent and (f) 1-butanol as
solvent.
Synthesis of Ag2S at temperature of 160 °C for 12 h with propyl-
ene glycol as solvent has been selected as a basic reaction in this

M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
465
indicate that presence of surfactant and type of solvent are effective
on the size regularity of particles. thio Schiff-base ligand playing
both complexing agent role and sulfuring agent role. Herein, the
possible process could be explained in the following step: First, thio
Schiff-base (2-(benzylidene-amino)-benzenthiol) was prepared
with benzaldehyde and 2-aminothiophenol, in the second step,
metal salt was dissolved in propylene glycol and interaction occurs
between solvent OH groups and Ag+. when the former solution was
dropped into the latter solution under stirring, interaction occurs
between ligand N and S groups with Ag+ and upon heating a reac-
tion medium up to a sufficiently high temperature, the precursors
chemically transform into active atomic or molecular species, form-
ing nanocrystals whose subsequent growth is greatly affected by
the presence of ligand and solvent molecules, which can prevent
particle further growth and aggregation. Given this probable mech-
anism, thio Schiff-base ligand in hydrothermal system completely
has been destructed and finally was produced Ag2S without any
possible impurity phases such as remaining of thio Schiff-base
and S because The strong and sharp reflection peaks in the XRD pat-
tern confirms pure Ag2S nanocrystals. In addition, in the next sec-
tions we will see energy-dispersive X-ray analysis (EDX) and
Fourier transform infrared FT-IR spectrums imprinted seal of
approval on the purity produced Ag2S nanoparticles.
EDAX analysis of Ag2S nanoparticles is illustrated in Fig. 2. The
lines of Ag and S are obviously observed. In addition, neither N
nor C signals were detected in the EDAX spectrum, which means
there exist no possible impurity phases such as organic sulfur
source or propylene glycol in spherical Ag2S nanoparticles. FT-IR
of the complex of Ag(NO3) with ligand synthesized and Ag2S nano-
particles prepared at temperature of 160 °C for 12 h in hydrother-
mal method with solvent of propylene glycol are shown in
Fig. 3(a) and (b) respectively. Absorptions of 3442, 1569, 739, 611
and 477 cmÀ1 in Fig 3(a) related to OAH, C@N, CAS, AgAN and AgAS
bands respectively and weak absorption appeared in 1631.78 cmÀ1
in spectrum of Ag2S attributed to the presence of a small amount of
sulfur-containing ligands adsorbed on the surface of Ag2S, an
absorption at 3441.32 cmÀ1 is related to stretching vibrations of
OAH bond.
20,000) which they are illustrated in Fig. 5a–c, respectively. SEM
images of as product Ag in presence of SDS are shown in Fig. 5a;
sodium dodecyl sulfate (SDS) as an anionic surfactant can self
aggregate into cubic, hexagonal and lamellar structures [29,30]. In
this paper, we used this unique SDS cubic structure. For anionic sur-
factants it seems SDS capped Ag2+ and with this approach limited
the formation of Ag2S and it will lead to reduction of Ag2S to Ag. Also
SDS, as an anionic surfactant, has different influence on the
morphology. Due to its amphiphilic nature, it forms stable micelles
in solvent in which spherical nanostructures form easily [31].
CTAB as a cationic surfactant was occupied to investigate the
influence of cationic active groups on morphology of the products.
Due to its cationic head group, CTAB easily interact with free sulfur
groups on the surface of nanoparticles and covered them, with this
approach limited the formation of Ag2S and it will lead to reduction
of Ag2S to Ag.
Fig. 5b shows SEM image of the Ag sample prepared in presence
of CTAB. It can be clearly observed that CTAB has changed the
morphology The SEM image (Fig. 5c) shows that nanospheres are
also formed in presence of PEG 20,000 because this polymer
attaches to the particle surface through its active oxygen groups.
This interaction can be result to the reduction of silver ions. Due
to PEG 20,000 special structure, it covers Ag naoparticles in which
separate and small spherical nanoparticles form easily. Scheme 1.
shows probably the mechanism for the preparation of different
morphologies of Ag in different surfactants schematically.
SEM images of Ag2S nanoparticles that synthesized in H2O,
1-butanol, propylene glycol and ethylenediamine as solvent are
illustrated in Fig. 6(a–d), respectively. Results shows in H2O solvent
bulk products are obtained and in 1-butanol solvent nanostructure
products with size of lesser 100 nm are observed. We speculate
that polyols and alcohols with diverse position and number of
OH group play an important role in determining the geometric
structures and morphologies of the final products. Propylene glycol
has hydroxyl groups with more than 1-butanol and H2O, it can
SEM images of Ag2S obtained at different temperatures of
140 °C, 160 °C, 180 °C and 200 °C are illustrated in Fig. 4a–d
respectively. At temperatures of 140 °C with mole ratio Ag/sulfur
sources 1:2, mixture of spherical and cubic nanoparticles are
synthesized. With increasing temperature to 160 °C smaller spher-
ical nanoparticles are achieved. While at temperature of 180 °C and
200 °C, smaller nanoparticles with respect to the previous one are
noticeable. But particles are more disciplined in temperature
160 °C. The results confirm that in four different circumstances,
nanoparticles with average size of less than 100 nm were obtained.
For investigating the effect of surfactant on the morphology and
size of the products, the reaction carried out in presence common
surfactants such as anionic (sodium dodecyl sulfate (SDS)), cationic
(cetyltrimethyl ammonium bromide (CTAB)) and polymeric (PEG
Fig. 3. FT-IR spectra (a) the complex of Ag(NO3) with ligand synthesized and (b)
Fig. 2. EDAX spectra of Ag2S spherical nanoparticles.
Ag2S spherical nanoparticles.

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M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
Fig. 4. SEM images of the Ag2S nanostructure prepared in propylene glycol solvent for 12 h at (a) 140 °C, (b) 160 °C, (c) 180 °C and (d) 200 °C.
provide spherical nanoparticles with a more uniform and regular
than alcohol solvent. It has been reported that the hydroxyl groups
of polyol can coordinate with Ag2+ to form complexes [32] and pro-
vide affect selective growth for Ag2S but in H2O solvent due to the
lack of interaction between water and cations, amorphous and
large nanoparticles are formed. Plus, in hydrothermal system the
dielectric constant and viscosity are also important [33,34].
Fig. 6d shows as-synthesized Ag2S nanoparticles in ethylenediamin
as solvent. Ethylenediamin is a strong bidenate ligand, which it
might act as a coordinating alkali solution. So, products are formed
with morphologies of nanorod and nanoparticles. That is why,
ethylenediamin is considered as a vital factor in the growth of
nanoparticles in such as solvothermal process [35–37]. In addition,
the dielectric constant, viscosity of solvent and the increased tem-
perature within a hydrothermal medium have a significant effect
on the speciation, solubility, and transport of solids. When dielec-
tric constant is a low in a solvent, the ions saturation easily forms
to result in high Ag2S monomer concentration, which is a crucial
precondition for non-equilibrium crystal growth and provided
formless silver sulfide nanoparticles. Also, water by having high
ꢀ
Fig. 5. SEM images of the Ag2S nanostructure at 160C for 12 h in propylene glycol solvent with (a) SDS, (b) CTAB, (c) PEG 20,000.

M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
467
Scheme 1. Schematic the effect of surfactants on the morphology of Ag.
Fig. 6. SEM images of the Ag2S nanostructure prepared at 160 °C for 12 h in (a) H2O, (b) 1-butanol (c) propylene glycol and (d) ethylenediamin.

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M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
the dielectric constants provided spherical which are separate from
each other as compared to propylen glycol solvent. At room
temperature, the dielectric constants of the four solvents can
be compared as follows: H2O (80.1) > propylen glycol (32.1) >
1-butanol (17.51) > en (14.2) [38]. Obviously, propylene glycol is
the best solvent of them for selective anisotropic growth of silver
sulfide, because its most balance dielectric property makes it
possible to prepare an appropriate Ag2S monomer concentration
for preferential growth. Scheme 2 is illustrating the formation of
Ag2S samples at various conditions.
steric hindrance is a suitable capping agent for preparation of nano-
particles. Schiff-base group causes nucleation to be occurred rather
than the growth.
The optical absorption spectrum of Ag2S nanoparticles is repre-
sented in Fig. 7a it demonstrates absorption peaks at 320 nm,
which according Fig. 7b the band gap energy of Ag2S synthesized
are 3.1 eV. (The band gap energy of bulk Ag2S is 1.1 eV) which this
blue shift is attributed to decrease in the particle size which cause
to change in particle energy levels and finely increase the band gap
and blue shift occurrence.
As previously mentioned privilege of this work is application of a
new thio Schiff-base as sulfur and capping agent for synthesizing of
silver sulfide nanoparticles. Thio Schiff-base synthesized with high
The size and morphology of as-synthesized silver sulfide nano-
particles were assessed with transmission electron microscopy
(TEM) and selected area diffraction (SAED) pattern measurements.
Scheme 2. Schematic diagram illustrating the formation of Ag2S samples at various conditions.
Fig. 7. (a) UV–vis absorption spectra of the prepared Ag2S at 160 °C for 12 h in PG and (b) plot to determine the direct band gap of Ag2S.

M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
469
The typical TEM (Fig. 8a–c) and SAED images (Fig. 8e) of the Ag2S
nanoparticles are shown. The TEM image of the Ag2S shows that
the particles have cubic crystalline phase but strongly overlapped
together and also the particles with an average diameter of
42 nm are shown. SAED pattern of sample is shown in Fig. 8e.
Which indicates several sharp rings from (101), (111), (120),
(200) plans of Ag2S nanoparticles and this pattern confirms that
silver sulfide nanoparticles are of polycrystalline with high crystal-
linity. For further approval the structural aspects, the nanoparticles
were examined by HR-TEM. As can be seen from a representative
HRTEM image, recorded from edge one of Ag2S particle in Fig. 8d.
The good lattice fringes show that these nanoparticles are single
crystalline and illustrate the correspondence between the
crystallite morphology and the crystal orientation [39]. The HRTEM
image shows sharp lattice margins with 0.26 nm spacing, corre-
sponding to the (121) planes. Therefore, the HRTEM image further
verifies cubic phase nature of the as-synthesized Ag2S nanoparti-
cles and finely there are several cubic silver sulfides overlapped
together and created spherical nanoparticles that shows SEM
image them.
Thermogravimetry (TG) of Ag2S nanoparticles has been
represented in Fig. 9. The TG curve illustrates that Ag2S undergoes
two weight loss steps. When the temperature was lower than
200 °C, the step mainly corresponded desorption of water. The
Fig. 8. (a)–(c) TEM, (d) HR-TEM image and (e) SAED images of the as-synthesized Ag2S nanoparticles using the thio Schiff-base at 160 °C for 12 h.

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M. Shakouri-Arani, M. Salavati-Niasari / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 133 (2014) 463–471
Conclusions
Ag2S nanoparticles have been prepared using hydrothermal
method in a new solvent with a novel sulfur source. For the first
time in this study has been used from thio Schiff-base as organic
sulfur source and capping agent for prepare of Ag2S. In work, the
influence of different surfactants such as CTAB (cationic), SDS
(anionic), PEG 20,000 (polymeric), reaction temperature and
solvent type on the morphology of silver sulfide has been
investigated. Results show that by using surfactant of PEG 20,000
at presence propylene glycol solvent particles size were be very
smaller than basic reaction because OH groups play an important
role in determining the geometric structures, particles size and
morphologies of the final products. It may be due to the specific
interaction between OH groups and Ag+ ions, which affect selective
growth of various directions of silver sulfide nanocrystals.
Acknowledgement
Fig. 9. TGA of silver sulfide nanoparticles obtained after removal of the liquid
crystal phase by washing with ethanol.
Authors are grateful to the council of Iran National Science
Foundation and University of Kashan for supporting this work by
Grant No (159271/140).
decomposition of the organic template occurred at the tempera-
ture range 425–540 °C. After the sample was heated over 540 °C,
the sample weight did not change anymore. This samples that only
a small amount of the thio Schiff-base molecules was bound to the
Ag2S nanoparticles after they were washed. Combining the results
of the FT-IR spectra, it was obvious that thio Schiff-base ligand
molecule still existed in the as-prepared product.
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The reported researches have been mostly focused on the inor-
ganic sulfides as sulfur sources. To the best of our knowledge, there
is no report on the fabrication of silver sulfide only with presence
thio Schiff-base ligand containing 2-aminothiophenol (2-ATP) and
benzaldehyde. In comparison to other similar works that illus-
trated in Table 1, our method is more simple and profitable. In this
work, we developed a solvothermal method to synthesize silver
sulfide in propylene glycol solvent at 160 °C for only 12 h with dif-
ference size. Also the advantage use of this solvent can be
expressed such that, polyols with diverse position and number of
OH group play an important role in determining the geometric
structures and morphologies of the final products. It may be due
to the specific interaction between OH groups and Ag+ ions, which
affect selective growth of various layers of lead sulfide. We used
surfactant to improve the stability of the suspension against floc-
culation. Surfactant makes important roles in growth of nanocrys-
tals to different shapes during the solvothermal process. We
applied various surfactants, solvent, reaction temperature and
compared them with each other.
Therefore, privilege of this work is application of a thio Schiff-
base as both complexing and sulfuring agent in an environmentally
friendly solvent for synthesizing of silver sulfide nanoparticles.
Also can be said which thio Schiff-base and propylene glycol have
played a unique role in determination of morphology and size of
nanoparticles.
Table 1
Characterization comparison of Ag2S nanoparticles with other similar works.
Method
Precursors
Size
Morphology
Ref.
Synthesize at ambient temperature
Sonochemical
Synthesize at ambient temperature
Synthesize at ambient temperature
Emulsion
Solvothermal
Hydrothermal
Synthesize at ambient temperature
AgNO3, S powder, en, PVP
AgNO3, TGA
AgNO3, Na2S
AgNO3, Tu, CTAB
AgNO3, TAA
AgNO3, S powder
AgNO3, Tu
100–120 nm
100–200 nm
12 nm, 120 nm
80 nm 150 nm
50 nm
>20 nm
>100 nm
364 nm
Hexagonal
Nanowire
Nanochain nanoparticle
Nanoparticle nanocube
nanorod
nanowire
Nanoparticle
Nanoparticle
[40]
[41]
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