Microemulsion-mediated solvothermal synthesis of ZnS nanowires

doi:10.1016/j.matlet.2007.03.001

Materials Letters

Volume 61, Issues 23–24, September 2007, Pages 4651-4654

https://doi.org/10.1016/j.matlet.2007.03.001 Get rights and content

Abstract

Uniform and high-aspect-ratio ZnS nanowires with length up to several micrometers and diameter of 30–50 nm are synthesized by a facile and low-cost microemulsion-mediated solvothermal method. Moreover, ZnS nanorods and bamboo-leaf-like ZnS nanostructures were also obtained by modulating the reaction parameters. Especially, hollow bamboo-leaf-like ZnS nanostructures formed by radiating those bamboo leaves with electron beam. A reasonable mechanism to the formation of the as-prepared one-dimension zinc blend ZnS nanocrystals is also discussed.

Introduction

Nanometer scale one-dimensional structures have attracted considerable attention due to their unique electronic, optical and mechanical properties [1], [2]. In recent years, synthesis of one-dimensional semiconductor materials such as nanowires, nanorods or nanotubes has been the focus of research work [3], [4], [5], [6]. In which semiconductor nanowires may one day be employed in high-performance field-effect transistors [7], [8], logic circuits [9], nonvolatile memories [10], and biosensors [11]. They are considered promising candidates to augment or even replace silicon planar technology, which is approaching fundamental scaling limits [12]. As one of the most important semiconductors, ZnS has been known for a long time as a versatile and excellent phosphor host material and it has a wide band-gap of 3.8 eV and a small Bohr radius (2.4 nm), which make it an excellent candidate for exploring the intrinsic recombination processes in dense excitonic systems. Therefore, the synthesis and physical properties of ZnS nanocrystals have been widely investigated. Up to date, ZnS nanocrystals with various morphologies, such as nanowires [13], nanobelts [14], hollow nanospheres [15], hollow nanovessels [16] and nanotubes [17], have been prepared successfully. However, most ZnS nanowires were obtained by chemical vapor deposition (CVD) method [13], [18], [19], [20], the wet chemical route, which is simple, inexpensive and typically scalable for industrial production, has seldom been reported, [21], [22] and that uniform, straight and high-aspect-ratio ZnS nanowires with large scale production have not been reported so far to our best knowledge. So it is still a challenge for chemists and materialists to explore facile and low-cost methods to synthesize uniform and high-aspect-ratio ZnS nanowires.

In the recent past, surfactant-assisted reverse micelles or microemulsions have been widely and successfully used as an ideal media to prepare inorganic nanoparticles. A reverse micelle or microemulsion is a transparent and isotropic liquid medium with nanosized water pools dispersed in a continuous phase and stabilized by surfactant and cosurfactant molecules at the water/oil interface. Accordingly, reverse micelles or microemulsions are thermodynamically stable systems and isotropic on a molecular scale and have the ability to solubilize proper solution. As the nanosized water pools, they have been widely used as spatially constrained microreactors for controlled synthesis of nanoparticles with desired narrow size distribution. In addition, the solvothermal method has been widely used to synthesize nanomaterials because of its unique reaction environment. It has been proven that the use of solvothermal method for the synthesis of nanomaterials cannot only decrease reaction temperature of systems but also improve the crystallinity of the products. Whereas the microemulsion-mediated solvothermal method, as a combination of the two methods mentioned above, possesses all the merits of both and has already been approved as an effective tool to fabricate inorganic nanocrystals with uniform morphology, narrow size distribution and good crystallinity [23], [24], [25], [26]. Therefore, in this paper, the microemulsion-mediated solvothermal method is reported to synthesize uniform and long ZnS nanowires with a diameter of 30–50 nm. Moreover, nanorods and bamboo-leaf-like ZnS nanostructures were also obtained by modulating the reaction parameters.

Section snippets

Experimental section

The reaction to form ZnS in present case can be formulated as the following equation:ZnSO₄ + 3Na₂S₂O₄ → ZnS↓ + Na₂SO₄ + NaS₂O₅ + SO₂

This reaction cannot take place till the solution is boiling, so it was chosen to synthesize ZnS nanocrystals under solvothermal condition. A quaternary microemulsion, cetyltrimethylammonium bromide (CTAB)/water/cyclohexane/n-hexanol, was selected for this study. As a typical synthesis, two identical solutions were prepared by dissolving CTAB (0.5 g) in 15 mL of cyclohexane

Results and discussion

Fig. 1 shows the XRD pattern of ZnS nanowires as-synthesized at 160 °C for 12 h with the w₀ = 20. The data is in good agreement with that of pure cubic phase zinc blende ZnS (JCPDS No.: 01-0792). The three strong peaks with 2θ values of 28.62, 47.84, and 56.63° correspond to the three crystal plane of (111), (220), and (311) of zinc blende ZnS, respectively. The broadening of the diffraction peaks is due to the small diameter (30–50 nm) of the nanowires.

Fig. 2a shows the typical TEM image of the

Acknowledgments

This work was supported by the Natural Science Fund of China (No. 20573017) and Analysis and Testing Foundation of Northeast Normal University.

References (28)

Q.S. Wu et al.
Inorg. Chem. Commun.
(2002)
R. Lv et al.
Mater. Res. Bull.
(2004)
Y. Liu et al.
Mater. Chem. Phys.
(2005)
J. Hu et al.
Acc. Chem. Res.
(1999)
C. Dekler
Phys. Today
(1999)
Y. Li et al.
Chem. Mater.
(1998)
S. Yu et al.
Chem. Mater.
(1998)
K. Cho et al.
J. Am. Chem. Soc.
(2005)
C. Yang et al.
Chem. Mater.
(2002)
Y. Cui et al.
Nano Lett.
(2003)

X. Duan et al.

Nature

(2003)

Y. Huang et al.

Science

(2001)

X. Duan et al.

Nano Lett.

(2002)

F. Patolsky et al.

Proc. Natl. Acad. Sci. U. S. A.

(2004)

Cited by (31)

Suppression of ferromagnetism due to N co-doping in Cr(II)-doped ZnS nanowires and their optical properties: Insights from density-functional calculations
2023, Journal of Magnetism and Magnetic Materials
Spin-related optical properties will be the main basis for future information technology, but they require microscopic ferromagnetic and anti-ferromagnetic couplings between the d-states of the transition metal ions or magnetic interaction between excitons and magnetic ions, all of which remain unclear in these diluted magnetic semiconductors. In this work, we studied the influence of Cr doping and co-doping of Cr with N on the electronic, optical, and magnetic properties of ZnS nanowires using spin-polarized density functional theory. According to our findings, Cr(II) doping induces a half-metallic state with a magnetic moment of 4 $μ_{B}$ per Cr(II) ion. The ferromagnetic behaviors and high Curie temperature in undoped Cr(II)-doped ZnS nanowires were suppressed due to the hole-carriers introduced by N co-doping. The band-coupling model was used to explain ferromagnetic (FM) stability in Cr(II)-doped nanowires with and without N co-doping. The optical properties of undoped ZnS nanowire, doped, and co-doped wires have been computed, and it is found that the bandgap (3.49 eV) exhibits a red shift upon Cr(II) doping, with the energy bandgap falling from 3.49 to 3.20 eV, and the bandgap being further decreased to 3.05 eV upon N co-doping. Compared with pure ZnS nanowires, mono- and co-doped nanowires have a higher electron-hole pair formation rate and better optical properties. The d-state to d-state transitions of the Cr(II) ion in the wire occur in the mid-infrared and near-infrared red regions and are shifted to the high energy side by N co-doping. Furthermore, we correlated the optical band gap of ZnS nanowire and the d-d transition peak of Cr ions under different modes of magnetic coupling, and we found that the optical band gap and d-state to d-state transition peaks of Cr(II) ions shift to lower and higher energies in FM and AFM configurations, respectively. Such a shift in bandgap and d-d transition peaks of Cr(II) ions in the FM and AFM states of the far configuration was not observed.
The effects of Ag-ions on the physiochemical characteristics and visible-light catalytic activity of ZnS nanoparticles
2023, Inorganic Chemistry Communications
In this case of study, the pure and different weight percentages of Ag ions doped ZnS Nanoparticles were synthesized by beneficial solid-state reaction method. Further, the synthesized nanoparticle’s physiochemical properties were thoroughly examined by the appropriate characterization tools. The structural examination demonstrates that the synthesis of crystalline nanoparticles with an average crystallite size of 2.41 nm was reduced from 3.68 nm to 2.41 nm and increased further due to the influence of Ag-ions on ZnS matrix. The FT-IR investigation validated the Zn-S functional molecule presence. A considerable quantity of spherical-shaped nanoparticles with uniform distribution enhances the possibility of aggregation due to heterogeneous particle interactions. The optical research demonstrates that the bandgap wideness is decreasing due to Ag-ion interstitial secondary energy levels. Due to the limitations in charge carrier recombination caused by Ag-influences, the catalytic capability of ZnS nanoparticles under renewable sunlight irradiation is enhanced. As a result, the Ag-doped ZnS nano-catalyst degraded 95 % of the detrimental MO dyes within a short sun light irradiation period.
Influence of transition metals dopant type on the structural, optical, magnetic, and dielectric properties of ZnS nanoparticles prepared by ultrasonication process
2021, Materials Science and Engineering: B
Citation Excerpt :
Wide band gap semiconductor quantum dots (QDs) with a nanoparticle size comparable with the characteristic exciton Bohr radius [1] have gained much attention because they exhibit various size-dependent features such as tuning the optical band gap and wavelength of their emission bands, the improvement of room-temperature ferromagnetism (RTFM), as well as the tailoring of the interfacial space charge polarization of the QDs that is preferable for barrier layer capacitor in power-related applications [2–4]. N-type ZnS QDs have various advantages such as a wide band gap of 3.54 eV for the bulk cubic phase [5], high thermal and chemical stability, high electronic mobility, large exciton binding energy of 40 meV, and excellent transport properties (i.e., reduction of the carriers scattering and recombination processes) [6–9]. Doping ZnS NPs with a functionalized dopant element can tune the physical properties of the host lattice to be utilized for specific applications.
Undoped and (Ni, Co, and Mn)-doped ZnS nanoparticles (NPs) are successfully synthesized by a sonochemical-assisted co-precipitation technique. XRD patterns reveals the incorporation of dopant ions by substitution of Zn ions. Ni ions induce growth rate enhancement and the increase of crystallite size, whereas Co and Mn ions slow down the growth rate and caused the decrease of the corresponding crystallite size. The UV–visible absorption spectra exhibit a decrease in the optical band gap for all doped samples. The photoluminescence spectra of Co- and Mn-doped ZnS NPs show an improvement in the visible-light, whereas Ni-doping results in a slight decrease in the emission intensity allover spectral range. The room-temperature ferromagnetism of ZnS NPs is strongly improved by Ni- and Co-doping and slightly enhanced by Mn-doping. The AC conductivity of ZnS NPS is enhanced by Ni- and Co-doping and decreased by Mn-doping in the frequency range from 2 kHz to 1 MHz.
Influence of doping with Sb3+, In3+, and Bi3+ ions on the structural, optical and dielectric properties of ZnS nanoparticles synthesized by ultrasonication process
2021, Physica B: Condensed Matter
Citation Excerpt :
Besides, they are characterized by large binding energy of 40 meV, high thermal and chemical stability, and high electronic mobility. These features make the ZnS nanomaterials feasible for various technological applications [9–12]. The interfacial surface state defects at the nanoparticles (NPs) grains have a profound effect on many physical properties related to the optical excitation of charge carriers to higher energy levels within the material or charge carriers transport between the NPs grains due to electrical field excitation.
Doped-ZnS nanoparticles (NPs) with various trivalent elements ions (Sb³⁺, In³⁺, and Bi³⁺) were synthesized using the sonochemical method. X-ray diffraction patterns proved the formation of the ZnS cubic phase without any phase separation with the doping process. The dependence of the crystallite size and the internal micro-strain on the dopant type was demonstrated. Optical absorption spectra of doped ZnS NPs revealed a decrease in the optical band gap due to the formation of extended defect states below the conduction band. Photoluminescence spectra of the doped samples revealed the enhancement of visible light emission intensity compared with the as-prepared ZnS NPs. The AC electrical properties of the trivalent elements doped ZnS NPs were studied at room temperature in the frequency range from 2 kHz to 1 MHz, where In-doped ZnS NPs had the lowest dielectric constant and largest conductivity compared with the other samples.
Green synthesis of inorganic nanoparticles using microemulsion methods
2020, Green Sustainable Process for Chemical and Environmental Engineering and Science: Green Inorganic Synthesis
Microemulsion-assisted chemical synthesis of nanostructured materials has been proved to be a potential eco-friendly approach to achieve superior results over conventional synthesis approaches. This method provides very unique nano/micro reactors such as micelles, reverse micelles of various shapes and sizes. Further, through surfactant and reactant concentration, one can control the reaction rate and also the product shape, size, and yield are the noteworthy attractions of this synthesis method. In this chapter, the parameters associated with the formation of the microemulsion such as types of surfactants, cosurfactants, solvents, water-to-oil ratio and the importance of microemulsion as a nanoreactor for nanomaterials synthesis are detailed with experimental evidences. A sincere effort has been made to provide comprehensive information about the synthesis of inorganic nanostructured materials such as metals, metal oxides, metal chalcogenides, and quantum dots via a microemulsion-assisted protocol. This chapter also explores the various nanostructured materials with important morphological structures synthesized by various research groups in the past two decades using this method.
Synthesis and enhanced photocatalytic property of Ni doped ZnS nanoparticles
2018, Solar Energy
Pure and Ni (0.5–2.0%) doped ZnS nanoparticles were prepared by an inexpensive solid state reaction method. The structural, functional, optical, morphological and chemical compositions of the products were characterized by XRD, FT-IR, UV–Vis, PL, SEM with EDX and TEM analyses. The X-ray diffraction results confirmed that the polycrystalline nature with cubic crystal structure of the nanoparticles. Also, using these data, crystallite size, dislocation density, micro-strain, stacking fault and lattice constant were calculated. The functional group associated with the vibration of a molecule was investigated by FTIR spectroscopy. The optical band gap was increased from 3.58 to 3.97 eV with increasing Ni dopant concentrations. The SEM and TEM images depict the nanosized particles with spherical shape morphology. The elemental composition of Ni-ZnS nanoparticles was examined by EDX analysis. The PL emission spectra show an intensity quenching upon Ni doping and exhibit green emission in the visible region. The photocatalytic activity results indicated that the Ni doping enhanced the photocatalytic activity of ZnS. Thus, Ni-ZnS could be effectively used as photocatalyst for degradation of environmental pollutant Methylene Blue dye.

View all citing articles on Scopus

View full text

Article preview

Materials Letters

Abstract

Introduction

Section snippets

Experimental section

Results and discussion

Acknowledgments

References (28)

Inorg. Chem. Commun.

Mater. Res. Bull.

Mater. Chem. Phys.

Acc. Chem. Res.

Phys. Today

Chem. Mater.

Chem. Mater.

J. Am. Chem. Soc.

Chem. Mater.

Nano Lett.

Nature

Science

Nano Lett.

Proc. Natl. Acad. Sci. U. S. A.

Cited by (31)

Suppression of ferromagnetism due to N co-doping in Cr(II)-doped ZnS nanowires and their optical properties: Insights from density-functional calculations

The effects of Ag-ions on the physiochemical characteristics and visible-light catalytic activity of ZnS nanoparticles

Influence of transition metals dopant type on the structural, optical, magnetic, and dielectric properties of ZnS nanoparticles prepared by ultrasonication process

Influence of doping with Sb<sup>3+</sup>, In<sup>3+</sup>, and Bi<sup>3+</sup> ions on the structural, optical and dielectric properties of ZnS nanoparticles synthesized by ultrasonication process

Green synthesis of inorganic nanoparticles using microemulsion methods

Synthesis and enhanced photocatalytic property of Ni doped ZnS nanoparticles