Synthesis and characterization of CuInS2 nanostructure by ultrasonic-assisted method and different precursors

Accepted Manuscript

Title: Synthesis and characterization of CuInS2 nanostructureby Ultrasonic-assisted method and different precursors

Authors: Mehdi Mousavi-Kamazani, MasoudSalavati-Niasari, Hamid Emadi

PII: S0025-5408(12)00615-0DOI: doi:10.1016/j.materresbull.2012.08.044Reference: MRB 6044

To appear in: MRB

Received date: 5-3-2012Revised date: 14-8-2012Accepted date: 17-8-2012

Please cite this article as: M. Mousavi-Kamazani, M. Salavati-Niasari, H.Emadi, Synthesis and characterization of CuInS2 nanostructure by Ultrasonic-assisted method and different precursors, Materials Research Bulletin (2010),doi:10.1016/j.materresbull.2012.08.044

This is a PDF file of an unedited manuscript that has been accepted for publication.As a service to our customers we are providing this early version of the manuscript.The manuscript will undergo copyediting, typesetting, and review of the resulting proofbefore it is published in its final form. Please note that during the production processerrors may be discovered which could affect the content, and all legal disclaimers thatapply to the journal pertain.

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Synthesis and characterization of CuInS2 nanostructure by Ultrasonic-assisted

method and different precursors

Mehdi Mousavi-Kamazani a, Masoud Salavati-Niasari *

, a, b

, Hamid Emadi c

a Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P. O. Box. 87317-51167,

I. R. Iran.

b Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P. O. Box.

87317-51167, I. R. Iran

c School of Chemistry, University College of Science, University of Tehran, Tehran,

I. R. Iran

*Corresponding author: Tel.: +98 361 5555 333, Fax: +98 361 555 29 30.

E-mail address: [email protected] (Masoud Salavati-Niasari).

Abstract

This paper reports on the synthesis of CuInS2 nanostructure via an ultrasonic assisted method by

employing different sulfur source Morphology, structure and composition of the obtained products were

characterized by X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), scanning electron

microscope (SEM), infrared (IR) spectrum, and photoluminescence (PL) spectroscopy. The effects of

ultrasonic irradiation, power and time of irradiation, surfactant, and type of copper source were

investigated.

Keywords: CuInS2; nanostructure; Ultrasonic; Electron microscopy.

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1. Introduction:

A solar cell is an electronic device designed for converting the irradiated sunlight into electricity The

simplest way to reach this goal is constructing a p-n homo junction and other structures such as

metal/semiconductor (MS) and hetero junction complex that are still used as solar cells [1]. Chalcopyrite

I-II-VI compounds are the ternary analogs of the binary II-VI compounds and have received much

attention, as they can be used as both n- and p- type [2]. Cu-chalcopyrite semiconductor materials are used

as absorber layers in hetero junction solar cell devices [3]. The chalcopyrite semiconductor CuInS2 (CIS)

is particularly promising, for photovoltaic applications because it has a layer absorption coefficient of

about 10-5

cm-1

and a direct band gap energy of approximately 1.54 eV which is in the optimum range for

solar-energy conversion [4–8]. Hence, various studies have focused on providing a simple and suitable

method for synthesis of CuInS2 nanostructures and so various methods have been applied to synthesize

CuInS2 thin film and powders including molecular single-source precursors [9], solvothermal reactions

[10–16], microemulsion method [17], microwave irradiation [18], surfactant-assisted chemical reactions

[19,20], chemical vapor deposition(CVD) [21], sputtering [22], spray pyrolysis [23], molecular beam

deposition [24], and electrodeposition [25]. These methods produced nanocrystals with different

morphologies such as nanoparticles [26–28], hollow nanospheres [19], nanowires [12], nanorods [10, 11],

pyramidal nanocrystales [13], and porous microspheres [14,15]. Chen et al. have prepared color tunable

CuInS2 nanocrystals which its optical properties is greatly affected by the Cu/In molar ratio [29].

Transparent, flexible and luminescent composite films were prepared by dispersing CuInS2 based quantum

dots into a cyanoethyl cellulose matrix which their color could be regulated over green, yellow, orange,

pink, and red by changing quantum dots content [30]. Pyramidal CuInS2 nanocrystals were synthesized in

gram scale and their size dependent optical properties were investigated [31].

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In current study we report new method for synthesis of CuInS2 nanostructure. Nano sized CuInS2 were

prepared via an ultrasonic-assisted method. This method was developed to study and control the

morphology of CuInS2 nanostructure by employing different sulfur and copper source. Recently,

sonochmical method has been used since this method is simple, fast, economical, manageable,

environmentally benign and convenient [32–34]. Also influences of different parameters were

investigated.

2. Experimental

2.1. Materials and physical measurements

All chemical reagents in this experiment were of analytical grade and used without further purification.

The precursor complex, [bis(2-hydoxyacetophenato)copper(II)], was prepared as mentioned in literature

[35]. A multiwave ultrasonic generator (Sonicator 3000; Bandeline, MS 72,Germany), equipped with a

converter/transducer and titanium oscillator (horn), 12.5 mm in diameter, operating at 20 kHz with a

maximum power output of 80 W, was used for the ultrasonic irradiation. The ultrasonic generator

automatically adjusted the power level. X-ray diffraction (XRD) patterns were recorded by a Philips-

X’pertpro, X-ray diffractometer using Ni-filtered Cu Kα radiation. Fourier transform infrared (FT-IR)

spectra were recorded on Nicolet Magna-550 spectrometer in KBr pellets. The electronic spectrum of the

sample was taken on Perkin-Elmer LS-55 luminescence spectrometer. Scanning electron microscopy

(SEM) images were obtained on LEO-1455VP equipped with an energy dispersive X-ray spectroscopy.

2.2. Preparation of CIS nanocrystals

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In a typical synthesis procedure [bis(2-hydoxyacetophenato)copper(II)], InCl3, sulfide precursor, and

sodium dodecyl sulfate (SDS) were dissolved in 40 ml of propylene glycol (PG) with the molar ratio of

1:1:2: 1/5. The obtained mixture was stirred and and refluxed (188 °C) for 15 min. Afterward, the solution

was exposed by ultrasonic irradiation with different power at room temperature for appropriate time. The

black precipitates were centrifuged, washed several times with absolute alcohol and distilled water, dried

at 50 °C at vacuum oven for 10 h. The final black products were annealed for 1 h at 350 °C in argon

atmosphere to produce crystalline products [7, 36]. The annealing temperature was selected considering

the thermal stability of the compound [36]. Some parameters including ultrasonic power, reaction time,

sulfide precursor, and etc. were changed for reaching the optimized condition. Also similar experiments

were performed by CuSO4 as copper source and the results were compared with those of obtained by

[bis(2-hydoxyacetophenato)copper(II)]. Reaction conditions are listed in Table 1.

3. Results and discussion:

The crystal structure and phase composition of the annealed and unannealed products were characterized

by powder X-ray diffraction pattern, as shown in Fig.1. Fig.1a shows that before annealing no crystalline

phase was obtained. By annealing at 350 °C for 1 h CuInS2 obtained but samples were composed of In2O3

as impurity (Fig.1b). To remove this impurity samples were annealed again at 350 °C for 1 h but under

Argon atmosphere. It was revealed that under this condition crystalline CuInS2 obtained and no

characteristic peaks of impurities such as CuS, Cu2S, In2S3, and In2O3 were detected (Fig. 1c). All of the

diffraction peaks in Fig.1c can be indexed to the tetragonal structure of CuInS2 (space group I-42d) which

is very close to the values in the literature (JCPDS No. 75-0106 with lattice parameters a = b = 5.5170 A°

c = 11.0600 A°). Acceptable matches are observed for compound indicating the presence of only one

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crystalline phase in the samples. From broaden peaks in XRD it can be concluded that the particle size of

the product is small. The average crystallite diameter of the obtained product was estimated from Debeys-

Scherrer equation: ; Where β is the breadth of the observed diffraction line at its half-intensity

maximum, K is the so-called shape factor, and λ is the wavelength of X-ray source used in XRD. The

average crystallite diameter of the obtained products was about 16 nm (Sample no. 1). Also it was

revealed by XRD analysis that by using other sulfur source the same products obtained while their

crystallinity and average crystallite diameter were different. These differences can be attributed to the

release rate of sulfide in the reaction medium which affects growth parameters of the crystals. Carful

observation to Fig. 2 clearly shows that when TU and L-cystein were used as sulfide source the

crystallinity of products was lower in comparison with those which obtained with other source of sulfide.

Also the smallest crystalline diameter was observed when TAA was applied as sulfide precursors.

However in all cases CuInS2 was obtained after annealing at 350 °C.

A typical EDX spectrum is shown in Fig.3, which indicates the presence of Cu, In, and S in the

products. Based on the calculation of the peak areas, the ratio of copper to indium, and sulfide was found

to be approximately 1:1:2 as expected. Therefore, both XRD and EDX analyses revealed that pure CuInS2

was successfully synthesized via the current synthetic route.

When chemical composition is concerned, exact determination of the product content has remained

problematic. The accuracy of energy- and wavelength-dispersive X-ray analysis frequently used for this

application is relied on appropriate standards, that has unidentified minor phases and impurities. This

technique shows excellent element selectivity, quantitative character and high surface sensitivity which

can be used without standards to analyze all types of materials. In addition, XP spectra reflect atomic scale

chemical interactions, i.e. the bonds between neighboring atoms, and thus XPS also provides reliable

structural characteristics for nano-crystalline or amorphous composition, for which the application of

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diffraction techniques is not straightforward. Herein, XPS analysis was applied for further characterization

of quality and composition of the as prepared sample. It can be seen in Fig.4 that binding energy of Cu

2p3, In 3d5/2, S 2p are 931.22, 443.58, and 161.16 respectively and there is no impurity in the final

product. The ratio of Cu/In/S was calculated by quantification of the peaks which were 0.96:1:2.02 that

are in good agreement with stoichiometry of CuInS2.

The morphology of the samples was revealed by scanning electron microscopy (SEM). Fig. 5 shows

SEM images of the samples 1-6 obtained by different sulfur source. Based on modern complex theory,

some of them which dissociated and release S-2

also behave as potential ligands. Since the reactivity of

different sulfide source is not the same in the coordination reactions, the CuInS2 nanostructure synthesized

using different sulfide source led to different motphology of the nanostructure [7]. It can be seen that

when TAA and thiosemicarbazid were used as sulfide source, CuInS2 nanoparticles obtained and when TU

was used these particles agglomerated. This difference in size may be due to difference in release rate of

S-2

, when S-2

was released faster, more nucleus of sample were produced at the beginning of the reaction

which had small size that due their high surface energy, they have agglomerated. When sodium thiosulfate

was used, rice shape nanostructures obtained (Fig. 5b). Thioglycolic acid as complexing agent has

significant effect in formation of nanorods (Fig. 5c). It can prevent CuS nanocrystal aggregation and at

appropriate condition can form complex with Cu2+

which turns to CuS clusters [37] and finally changes to

CuInS2 after annealing. L-cysteine has several functional groups such as –NH2, –COOH, and –SH. When

excess concentration of L-cysteine was used, it absorbed on the surface of CuS nanoparticles and

hydrogen bonds and S-S bonds formed between L-cysteine molecules. The CuS nanoparticles cross-link

via hydrogen bonds and S-S bond interactions and agglomerated which finally turned to CuIS2 after

annealing (Fig. 5f).

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Fig. 6 relates to the SEM images of samples 7, 8, and 9 that were prepared in different times including

20, 50, and 65 min respectively. At 20 min, particles were not separated well and obtained particles were

bigger than those which obtained at higher sonication times (Fig. 6a). With increasing of time to 35 and 55

min small particles obtained (Fig. 5a and 6b respectievly). When reaction time increased to 65 min

agglomeration occurred (Fig. 6c). At this condition small nucleus obtained but when particles become

small consumedly, they are unstable and for more fixity stick together. Thus there is an optimize time

which was 35 min for current experiment.

Fig. 7 shows the SEM images of samples 10-12 obtained at different power. In the powers of fewer than

45 W microparticle are observed because they are not separated well and this power is not enough for

them to be separated (Fig. 7a). When power increased to 55 W nanoparticles obtained but samples were

not homogenous well while at power 65 W these samples were separated well and homogenous (Fig. 7b

and Fig. 7c respectively). When power reached to 80 W, effects of agglomeration observed (Fig. 5a).

There is an optimum power for these experiments which is 65 W because in this power nanoparticles

showed better uniformity. XRD pattern (Fig. 8) of samples obtained without ultrasonic irradiation (sample

no. 15) revealed the presence of some impurity such as CuS and In(OH)3 in the final products which

confirm this fact that ultrasonic irradiation is necessary for obtaining CuInS2 nanostructures.

Fig. 9 shows the SEM images of the samples 13-16 that are related to the effect of surfactant and

ultrasonic irradiation. Careful observation to Fig. 7c and Fig. 9a which are related to samples 12 and 13

respectively suggests that the SDS may has role in controlling the size distribution of CuInS2 particle.

With no surfactant CuInS2 nanoparticles can be obtained and this may be due to [bis(2-

hydoxyacetophenato)copper(II)], which inhibit aggregation by steric hindrance mechanism. These

samples were not homogenous and were aggregated in some places (Fig. 9a) but when SDS was used, this

aggregation was not observed and samples were homogenous (Fig. 7c). SDS monomers act as excess

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electrolyte which in turn lowers the electrostatic repulsion barrier for coalescence to occur and can prevent

particles from aggregation. To investigate difference between surfactant and complex effect on sample

size some experiments (sample no. 20 and 21) was performed which will be discussed later. Two different

experiments have been performed to investigate ultrasonic irradiation effect. In the first one no surfactant

has been used and there was no ultrasonic irradiation (sample no. 14, Fig. 9b) and in the second one SDS

as surfactant was used while there was no ultrasonic irradiation in medium (sample no. 15, Fig. 9c). It can

be seen in both conditions big and micro structures obtained and they were not homogenous and fused to

each other. Also, the particle size was larger than those obtained by ultrasonic irradiation. To reduce a

materials particle size, large particles or lumps must be fractured into smaller ones. To initiate fractures,

external forces are applied to the particles. Advantage of using ultrasound radiation is that it yields smaller

particles and result shows an increase in the size of particles prepared without ultrasonic irradiation. In

addition to, when ultrasonic irradiation was applied deposition rate was faster while in the absence of

ultrasonic irradiation this rate decreased. Carful observation to these images (Fig. 9b and Fig. 9c) also

revealed that when SDS was used (Fig. 9b) the obtained samples were bigger in comparison with those

which prepared at the same condition but with no SDS (Fig. 9c). It is believed that SDS has significant

effect in increasing of particle size during the annealing process. To confirm this fact a blank reaction was

performed with SDS while there was no ultrasonic irradiation and annealing process (sample no.16). SEM

image of this process (Fig. 9d) shows that nanoparticles were obtained while in the same condition

(sample no.14) after annealing micro structures were observed (Fig. 9b). Although different products

obtained in samples 14 and 16 but the difference in size is due to SDS and annealing process. In sample

14, SDS is present in final products. During the annealing process presence of SDS produce a localized

heat which accelerates size increasing. In general it can be said that appropriate amount of SDS is

necessary and its concentration should be controlled to limit agglomeration during annealing process. It

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can be said for the reaction mechanism that at the first step of reaction heating of reaction component

leads to formation of CuS nanopartilces and [bis(2-hydoxyacetophenato)copper(II)] inhibit aggregation by

steric hindrance mechanism. Then during ultrasonic irradiation these nanoparticles transform to Cu2S by

PG as a reducing agent and solvent. The as prepared In2S3 and Cu2S produce CuInS2 after annealing at

350 °C [38]. It can be concluded that ultrasonic irradiation is necessary to synthesis of CuInS2

nanoparticles. Also the results of XRD and SEM confirmed that annealing of samples can change both

sample phase and size distribution. XRD pattern of the samples obtained by CuSO4 as cupper precursor

(Fig. 10) confirmed that these samples are in the same crystalline phase with those which obtained by

bis(2-hydoxyacetophenato)copper(II) but by variation in sulfide precursors the crystallinity of samples and

average crystal diameter changed and the smallest crystal diameter was observed for those obtained by

TAA as sulfide precursor.

To investigate copper precursor effect on reaction and sample morphology, some experiments have been

repeated with CuSO4. Fig. 11 shows the SEM images of the samples 17-19 obtained by reaction between

CuSO4 and different sulfur source. Similarly with those experiments which have been done by [bis(2-

hydoxyacetophenato)copper(II)], the CuInS2 nanostructures synthesized using different sulfide source

differ in the structure and morphology In the case of TAA and TU nanoparticles obtained which differ in

size (Fig. 11a, c respectively) and when thiosemicarbazid was used, flower shaped structure observed

(Fig. 11b). Fig. 12 shows the SEM images of the samples 20 and 21 related to the effect of surfactant.

When TU was used at 65 W (sample no. 20, Fig. 12a) the samples were homogenous and narrow

distribution was seen while those obtained at 80 W were fused to each other (sample no. 19, Fig. 11c).

Fig. 12b shows the SEM images of the samples 21 that obtained with no surfactant. It is clear that larger

and non-uniform particles obtained in comparison with sample 20 which obtained by the use of surfactant.

In general, From comparison between results of experiments prepared by [bis(2-

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hydoxyacetophenato)copper(II)] and CuSO4 it can be concluded that; when CuSO4 is used, surfactant plays

a significant role in controlling the size and morphology of CuInS2 nanostructure while in the case of

[bis(2-hydoxyacetophenato)copper(II)] SDS has not important role on size but can improve size

distribution of product. In the most cases, the surface passivation reagents, including surfactant molecules,

are needed to prevent the nanoparticles from aggregation [39].

To investigate that the surface of particle is capped with organic material or not Fourier transformed

infrared (FT-IR) of the as-synthesized samples was performed (Fig. 13). It is obvious that there is no

significant impurity but there may be less organic impurity capped nanoparticles which may arise from

[bis(2-hydoxyacetophenato)copper(II)] as a weak peak at 1629 cm-1

that can be corresponded to C=O

symmetry stretching vibration. A weak peak at 3442 cm-1

can be attributed to stretching vibration of the

O-H band that is absorbed on the surface of the particle [7].

The size of the semiconductor nanocrystals can directly determine their optical properties. Optical

properties of samples were investigated using a Perkin-Elmer LS-55 luminescence spectrometer with an

excitation slit width of 5 nm and an emission slit width of 5 nm. A sharp and strong peak centered at a

wavelength of 421 nm (excitation at 352 nm) is observed (Fig. 14). As compared to the band gap of bulk

CuInS2 which is 1.54 eV [4–6] the absorption spectrum of as-prepared samples exhibits a blue-shift (2.94

eV, 421 nm).

However, as presented above, by an ultrasonic route, CuInS2 nanostructures were synthesized with use

of different precursors. In comparison with other chemical methods which have been used for preparation

of CuInS2 nanocrystals [10–20] current method is very fast and also using ultrasound radiation will lead to

high yields and smaller particles [40].

4. Conclusions:

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In summary, we reported a chemical method for preparation and controlling the morphologies of

nanosized CuInS2. CuInS2 nanostructures were successfully prepared via ultrasonic-assisted method. This

method is simple and can be easily controlled. In this work different sulfur sources were used, also effects

of different parameters including ultrasonic power, time, surfactant and copper source were investigated.

The morphology, structure and composition of the yielded nanostructures were confirmed by XRD, EDX,

SEM, FT-IR and PL. It was found that the product was pure CuInS2 which obtained after annealing at 350

°C. Optical studies confirmed quantum confinement effects for nanoparticles. It was revealed that when

[bis(2-hydoxyacetophenato)copper(II)] was used SDS did not show significant effect on size but in the

case of CuSO4 it regulates sample size and is necessary for preparation of nanosized CuInS2.

Acknowledgement:

Authors are grateful to the council of Iran National Science Foundation and University of Kashan for

supporting this work by Grant No (159271/20).

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Figure caption

Fig. 1. XRD pattern of as synthesized sample (a) not annealed, (b) annealed at 350oC for 1h (c) annealed

at 350oC for 1h under Argon atmosphere.

Fig. 2. XRD pattern of as synthesized (a) sample no. 2 (average crystal diameter 25 nm), (b) sample no. 3

(average crystal diameter 27 nm), (c) sample no. 4 (average crystal diameter 35 nm), (d) sample no. 5

(average crystal diameter 20 nm), and (e) sample no. 6 (average crystal diameter 30 nm).

Fig. 3. EDX spectrum of the as synthesized CuInS2 nanostructures (sample no. 1).

Fig. 4. XPS spectra of as-synthesized product (sample no. 1): (a) survey spectrum; (b) Cu2p; (c) In3d; and

(d) S2p.

Fig. 5. SEM images of samples obtained with different sulfide source, sample no.1 (a), sample no.2 (b),

sample no.3 (c), sample no.4 (d), sample no.5 (e), and sample no.6 (f).

Fig. 6. SEM images of samples obtained at different times, sample no.7 (a), sample no.8 (b), sample no.9

(c).

Fig. 7 SEM images of samples obtained at different powers, sample no.10 (a), sample no.11 (b), sample

no.12 (c).

Fig. 8. XRD pattern of sample no. 15.

Fig. 9. SEM images of surfactant and ultrasonic effect, sample no.13 (a), sample no.14 (b), sample no.15

(c), sample no.16 (d) which obtained without annealing.

Fig. 10. XRD pattern of as synthesized (a) sample no. 17 (average crystal diameter 13 nm), (b) sample no.

18 (average crystal diameter 23 nm), and (c) sample no. 20 (average crystal diameter 21 nm).

Fig. 11. SEM images of the effect of Cu precursor, sample no.17 (a), sample no.18 (b), sample no.19 (c).

Fig. 12. SEM images of power and surfactant effect for CuSO4, sample no.20 (a), sample no.21 (b).

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Fig. 13. FT-IR spectra of the as synthesized CuInS2 nanostructures (sample no. 1).

Fig. 14. PL spectrum of the as synthesized CuInS2 nanostructures (sample no. 1).

Table 1. Reaction conditions for preparation of CuIS2 nanopstructure.

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Fig. 1.

XRD pattern of as synthesized sample (a) not annealed, (b) annealed at 350 oC for 1 h (c) annealed at 350

oC for 1 h under Argon atmosphere.

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Fig. 2. XRD pattern of as synthesized (a) sample no. 2 (average crystal diameter 25 nm), (b) sample no. 3

(average crystal diameter 27 nm), (c) sample no. 4 (average crystal diameter 35 nm), (d) sample no. 5

(average crystal diameter 20 nm), and (e) sample no. 6 (average crystal diameter 30 nm).

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Fig. 3. EDX spectrum of the as synthesized CuInS2 nanostructures (sample no. 1).

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Fig. 4. XPS spectra of as-synthesized product (sample no. 1): (a) survey spectrum; (b) Cu2p; (c) In3d; and

(d) S2p.

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Fig. 5. SEM images of samples obtained with different sulfide source, sample no.1 (a), sample no.2 (b),

sample no.3 (c), sample no.4 (d), sample no.5 (e), and sample no.6 (f).

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Fig. 6. SEM images of samples obtained at different times, sample no.7 (a), sample no.8 (b), sample no.9

(c).

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Fig. 7. SEM images of samples obtained at different powers, sample no.10 (a), sample no.11 (b), sample

no.12 (c).

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Fig. 8. XRD pattern of sample no. 15.

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Fig. 9. SEM images of surfactant and ultrasonic effect, sample no.13 (a), sample no.14 (b), sample no.15

(c), sample no.16 (d) which obtained without annealing.

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Fig. 10. XRD pattern of as synthesized (a) sample no. 17 (average crystal diameter 13 nm), (b) sample no.

18 (average crystal diameter 23 nm), and (c) sample no. 20 (average crystal diameter 21 nm).

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Fig. 11. SEM images of the effect of Cu precursor, sample no.17 (a), sample no.18 (b), sample no.19 (c).

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Fig. 12. SEM images of the effect of power and surfactant for CuSO4, sample no.20 (a), sample no.21 (b).

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Fig. 13. FT-IR spectra of the as synthesized CuInS2 nanostructures (sample no. 1).

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Fig. 14. PL spectrum of the as synthesized CuInS2 nanostructures (sample no. 1).

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Table1. Reaction conditions for preparation of CuIS2 nanopstructure.

Sample

No. Copper source Sulfur source

Power

(W)

Time

(Min) Surfactant

Temperature of

annealing

1 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 80 35 SDS 350

2 bis(2-hydoxyacetophenato)copper(II) Sodium Thiosulfate 80 35 SDS 350

3 bis(2-hydoxyacetophenato)copper(II) Thioglycolic acid (TGA) 80 35 SDS 350

4 bis(2-hydoxyacetophenato)copper(II) Thiourea (TU) 80 35 SDS 350

5 bis(2-hydoxyacetophenato)copper(II) Thiosemicarbazid 80 35 SDS 350

6 bis(2-hydoxyacetophenato)copper(II) L-cysteine 80 35 SDS 350

7 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 80 20 SDS 350

8 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 80 50 SDS 350

9 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 80 65 SDS 350

10 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 45 35 SDS 350

11 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 55 35 SDS 350

12 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 65 35 SDS 350

13 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) 65 35 — 350

14 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) — — SDS 350

15 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) — — — 350

16 bis(2-hydoxyacetophenato)copper(II) Thioacetamide (TAA) — — SDS —

17 CuSO4 Thioacetamide (TAA) 80 35 SDS 350

18 CuSO4 Thiosemicarbazid 80 35 SDS 350

19 CuSO4 Thiourea (TU) 80 35 SDS 350

20 CuSO4 Thiourea (TU) 65 35 SDS 350

21 CuSO4 Thiourea (TU) 65 35 — 350

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*Graphical Abstract

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Research highlights

CuInS2 nanoparticles were synthesized by ultrasonic assisted method.

CuInS2 nanoparticles obtained after annealing at 350 °C for 1h.

The effect of some parameters including ultrasonic was investigated.

*Highlights