Cadmium Zinc Sulfide Research Articles

Influence of Zinc Content in Ternary ZnCdS Films Deposited by Chemical Bath Deposition for Photovoltaic Applications

Cadmium Zinc Sulfide thin films with different Zn concentration were synthesized in aqueous solution by chemical bath deposition (CBD) method using CdSO4, ZnSO4, CH4N2S for Cd+2, Zn+2, and S−2 ions source, respectively. The as-deposited films are well homogeneous, adherent and free from pinholes. The incorporation of Zn in CdS was found to be dependent on the annealing temperature. Structure, morphology, elemental analysis, optical and photoelectrochemical (PEC) properties of ZnCdS were characterized using X-ray diffraction, atomic force microscopy, energy dispersive spectroscopy, transmission electron microscopy and UV-Vis absorption measurements, respectively. According to EDS analysis the films are non-stoichiometric due to a deficit of sulfur, which becomes more important as the Zn content increases. The absorption edge shifts toward the lower wavelength region and hence the bandgap of the films increases as the Zn content increases. The values of optical absorption edge are found to change from 2.42 eV for CdS and 2.90 eV for ZnS thin films. The PEC and linear sweep voltammetry performance of the Zn doped CdS films were examined by chronoamperometry technique which provided a significant high potential current due to increase of the electrical conductivity as compared to CdS film.

The deposition of thin films of cadmium zinc sulfide Cd1\u2212xZnxS at 250\xa0\xb0C from spin-coated xanthato complexes: a potential route to window layers for photovoltaic cells

Thin films of Cd1−xZnxS (CZS) were prepared by a novel spin coating/melt method from cadmium ethylxanthato [Cd(C2H5OCS2)2] and zinc ethylxanthato [Zn(C2H5OCS2)2] in x ratios of 0–0.15 and of 1. A solution of the precursor(s) in THF was spin coated onto a glass substrate and then heated at 250 °C for 1 h under N2. The thickness of the film formed can be controlled by varying the solution composition and/or the spin rate of the coating. A total metal precursor solution concentration of 50 mM was used in all cases. The films were characterized by p-XRD, SEM, EDX, ICP-AES, XPS, UV–Vis absorption spectroscopy, Raman spectroscopy and resistivity measurements. The band gaps of the films were between 2.35–2.58 and 3.75 eV (0 ≤ x ≤ 0.15 and at x = 1). The resistivity of Cd1−xZnxS films was found to vary linearly with zinc contents, and the properties of the films suggest potential application to photovoltaics as window layers. This work is the first study to demonstrate Cd1−xZnxS thin films by a spin coating/melt method from xanthato precursors.

Reduced Graphene Oxide–Cadmium Zinc Sulfide Nanocomposite with Controlled Band Gap for Large-Area Thin-Film Optoelectronic Device Application

Herein, we report the one pot single step solvothermal synthesis of reduced grapheme oxide–cadmium zinc sulfide (RGO–Cd0.5Zn0.5S) composite. The reduction in graphene oxide (GO), synthesis of Cd0.5Zn0.5S (mentioned as CdZnS in the text) nanorod and decoration of CdZnS nanorods onto RGO sheet were done simultaneously. The structural, morphological and optical properties were studied thoroughly by different techniques, such as XRD, TEM, UV–Vis and PL. The PL intensity of CdZnS nanorods quenches significantly after the attachment of RGO, which confirms photoinduced charge transformation from CdZnS nanorods to RGO sheet through the interface of RGO–CdZnS. An excellent photocurrent generation in RGO–CdZnS thin-film device has been observed under simulated solar light irradiation. The photocurrent as well as photosensitivity increases linearly with the solar light intensity for all the composites. Our study establishes that the synergistic effect of RGO and CdZnS in the composite is capable of getting promising applications in the field of optoelectronic devising.

Photocatalytic degradation of methylene blue with Co alloyed CdZnS nanoparticles

In our present study, firstly; cadmium zinc sulfide (CdZnS) nanoparticles (NPs) with 1, 2, 5, 10% of Zn concentration were synthesized in aqueous solution by simple chemical co-precipitation method and their photocatalytic activity was investigated using the degradation of methylene blue under visible light in air at room temperature. It was found that CdZnS NPs with 2% of Zn concentration indicates the highest degradation efficiency compare to other Zn concentrations. CdZnS NPs with 2% of Zn concentration was symbolized as CdZnS_1. Later; 0.1, 0.2, 0.5, 1, 5, 10% of cobalt (Co) concentration was separately alloyed on the CdZnS_1 NPs. It was oberved that Co(5%):CdZnS NPs has the highest degradation efficiency. Structure, surface morphology, elemental analysis and optical properties of CdZnS_1 and Co (5%): CdZnS NPs 0were analyzed using X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and UV–Vis absorption measurements, respectively. The results showed that Co doped CdZnS NPs can be employed as capable materials to ehance the photocatalytic activity.

Structural, optical and magnetic properties of CdZnS and Ni:CdZnS nanoparticles

In this study, Cadmium Zinc Sulfide (CdZnS) and Ni-alloyed CdZnS (Ni:CdZnS) nanoparticles (NPs) prepared at room temperature by co-precipitation method using mercaptoethanol as a capping agent for the first time. The structural, optical and magnetic properties of NPs were characterized by using X-ray diffraction (XRD), ultraviolet–visible (UV–Vis) spectroscopy and physical property measurement system (PPMS). The average crystalline size of cubic phase of Ni:CdZnS NPs estimated from the XRD and optical absorption measurements was found smaller than that of cubic phase of CdZnS NPs. The optical measurements showed that the absorption edge of Ni:CdZnS NPs slightly shifts towards the lower wavelengths compare to un-doped CdZnS NPs. The band gap of CdZnS NPs (3.79 eV) increases with Ni dopant (4.02 eV) into the CdZnS structure. The temperature (M (T)) and field (M (H)) dependence magnetization data collected from PPMS indicated that a ferromagnetic behavior is observed in Ni:CdZnS NPs whereas CdZnS NPs show diamagnetic behavior.

Enhancement in the efficiency of crystalline Cu2ZnSnS4 thin film solar cell by using various buffer layers

The incorporation of different types of buffer layers has demonstrated to improve the efficiency of Cu2ZnSnS4 (CZTS) thin film solar cells. The materials tested as buffer layers were Cadmium Sulphide (CdS), Zinc Sulphide (ZnS) and Cadmium Zinc Sulphide (Cd7.23Zn2.77S10). The effect of the buffer layer and the absorber layers on the structural, morphological and optical properties of the films was studied. As grown CZTS thin films made with SILAR method were annealed at 550 °C in the sulfur atmosphere for 60 min to improve the crystallinity of the material. X-ray diffraction (XRD) and Raman studies confirm the formation of kesterite structure in CZTS thin film. CdS, ZnS and Cd7.23Zn2.77S10 thin films also confirm crystalline nature with crystallite sizes being 9 nm, 13 nm and 14 nm respectively. Leaf, flower and petal−like morphologies of CdS, ZnS and Cd7.23Zn2.77S10 thin films respectively have been confirmed by Field Emission Scanning Electron Microscopy (FESEM). The electrical properties of the completed CZTS solar cells were also examined. From the obtained J-V characteristic curves upon illumination of the heterojunction solar cells, we calculated the power conversion efficiency to be 0.76%, 1.00% and 1.24% for the FTO/ZnO/ZnS/CZTS/Ag, FTO/ZnO/CdS/CZTS/Ag and FTO/ZnO/Cd7.23Zn2.77S10/CZTS/Ag respectively.

Preparation and characterization of urchine-like cadmium zinc sulfide nanostructured powder

The cadmium zinc sulfide (CdZnS) nanostructured powders with different morphologies such as nanorods, urchin like, microsphere were synthesized by co-precipitation method. In this approach, zinc nitrate (Zn(NO3)2), cadmium nitrate dihydrate (Cd(NO3)2·2H2O) and mercaptoacetic acid (MAA) were used as a Zn, Cd, and S source, respectively. The products were characterized by XRD, SEM, TEM, EDS and TG/DTG analysis. The result show that urchin like CdZnS spheres self-assembled from sword-like nanorods with diameter of 40–50nm. Then, the optimized sample was calcined at 300°C and morphology stability and FTIR of cadmium zinc sulfide nanostructured powder was evaluated.

Band offsets engineering at CdxZn1−xS/Cu2ZnSnS4 heterointerface**Project supported by the Special Funds of the National Natural Science Foundation of China (Grant Nos. 11547226 and 11547180).

Cd1−xZnxS/Cu2ZnSnS4 (CZTS)-based thin film solar cells usually use CdS as a buffer layer, but due to its smaller band gap (2.4 eV), CdS film has been replaced with higher band gap materials. The cadmium zinc sulfide (CdZnS) ternary compound has a higher band gap than other compounds, which leads to a decrease in window absorption loss. In this paper, the band offsets at Cd1−xZnxS/Cu2ZnSnS4 (CZTS) heterointerface are calculated by the first-principles, density-functional and pseudopotential method. The band offsets at Cd1−xZnxS/CZTS heterointerface are tuned by controlling the composition of Zn in Cd1−xZnxS alloy, the calculated valence band offsets are small, which is consistent with the common-anion rule. The favorable heterointerface of type-I with a moderate barrier height (< 0.3 eV) can be obtained by controlling the composition of Zn in Cd1−xZnxS alloy between 0.25 and 0.375.

Size dependent photoluminescence properties of CdZnS nanostructures

Photoluminescence response of cadmium zinc sulfide (CdZnS) nanostructures has been studied through low-temperature and time-resolved photoluminescence measurements. The as synthesize nanostructures are single crystalline having growth along [102] direction. The CdZnS nanostructures exhibited near band edge and deep level emission bands at 2.485eV and 2.09eV, displaying bi-exponential excitonic decay with an average lifetime of 2.56ns and 4.11ns, respectively. Furthermore, single CdZnS nanostructures have been investigated for their size dependent photoluminescence properties. For isolated nanostructures, emission band systematically shifted towards the higher-energy, and defect-related low energy emission peak disappeared with a decrease in nanostructure width. Results revealed that emission originated from the radiative recombination process of the donor and acceptor bound excitons. Detrimental effect of low temperature Photoluminescence measurements have been observed in individual nanostructures.

Cadmium sulfide photoluminescence in poly(methyl methacrylate)-matrix composites

Poly(methyl methacrylate)-matrix composites containing cadmium, lead, and zinc sulfides and also mixed (cadmium lead and cadmium zinc) sulfides were prepared by reacting metal salts with thioacetamide. The transmission of the composites in the range λ > 500 nm is 92% at absorbing layer thicknesses of ≤5 mm. The photoluminescence (PL) of the composites in the wavelength range 500–820 nm is due to the cadmium sulfide, and that in the wavelength range 300–550 nm arises from the zinc sulfide. It results from radiative recombination at levels of extrinsic structural defects in CdS and ZnS, respectively. The PL excitation spectra contain excitonic absorption bands of cadmium sulfide and zinc sulfide quantum dots. The PL of the cadmium sulfide in the composites is influenced by the presence of lead(II) and zinc(II) ions and the complexation of cations on the surface of the particles.

Investigation of Light Induced Carrier Transport Phenomena Through ZnCdS Nanocomposite Based Schottky Diode

Here, we have discussed the electron transport phenomena through the interface formed by aluminium and hydrothermally synthesized Zinc-Cadmium-Sulphide (ZnCdS) nanocomposite. In this background, the structural, optical, and electrical characterization of the synthesized material were studied. The estimated optical band gap energy (=3.14 eV) and the room temperature conductivity (1.6 × 10−6 S cm−1) of the synthesized nanomaterial motivated us to explore the metal/inorganic-semiconductor interface. The carrier transport mechanism under dark and light-illuminated conditions was analyzed by the thermionic emission theory of the metal–semiconductor junction. Significant changes in rectification ratio, barrier potential, and the ideality factor were observed under light irradiance. The effect of incident radiation on mobility-lifetime (μτ) product and the diffusion length (L D) was demonstrated for the device.

Photocatalytic and photo electrochemical properties of cadmium zinc sulfide solid solution in the presence of Pt and RuS2 dual co-catalysts

A new combination of co-catalysts and photocatalyst, Pt-RuS2-Cd0.5Zn0.5S, is found to exhibit enhanced photocatalytic activity for hydrogen generation from water. The presence of dual co-catalysts not only improves the photocatalytic activity but also increases the stability of the CdZnS photocatalyst. Increased visible light absorption and a decrease in bandgap occur for Cd0.5Zn0.5S in the presence of the co-catalysts. All samples exist as nanocrystalline materials with a particle size in the range of 20–50nm. In this system, Ru is in 4+ oxidation state and Pt is in metallic state. Photoluminescence studies suggest the presence of a number of defect levels/surface states in these catalysts, whose energy vary with the composition of the catalyst. The enhanced photocatalytic activity of Pt-RuS2-Cd0.5Zn0.5S is attributed to the better separation of photogenerated charge carriers assisted by the dual co-catalysts. Another remarkable property exhibited by this system is the increased stability for repeated use, which can be attributed to the effective transfer of photogenerated holes from Cd0.5Zn0.5S to RuS2, which minimizes the photo corrosion of the catalyst. Photoelectrochemical results show a significant increase in the photocurrent with applied voltage and excellent switching characteristics for both Pt-RuS2-Cd0.5Zn0.5S and Cd0.5Zn0.5S. No discernible improvement in photocurrent is seen for Pt-RuS2-Cd0.5Zn0.5S compared to Cd0.5Zn0.5S. The difference in the photocatalytic and photo electrochemical property is explained based on the inherent differences of the two phenomena.

Synthesis and optical properties of glass with cadmium sulfide nanoparticles

A new approach to the synthesis of silicate glass with cadmium sulfide (CdS) nanoparticles has been developed. It has been demonstrated that replacement of cadmium sulfide with cadmium oxide and zinc sulfide used as sources of cadmium and sulfur allows a substantial reduction of sulfur volatilization during the melting. The produced samples have been investigated by the methods of spectrophotometry in the ultraviolet and visible ranges of the optical range. Thermal treatment of the samples at temperatures exceeding the glass formation point initiates the growth of CdS nanoparticles, which results in the increase of their average size from 3 to 5.2 nm and a significant shift of the fundamental absorption edge to the longer wavelength range from 380 to 480 nm.

INVESTIGATIONS ON STRUCTURAL AND ELECTRICAL PROPERTIES OF CADMIUM ZINC SULFIDE THIN FILMS

Nowadays, II – IV group semiconductor thin films have attracted considerable attention from the research community because of their wide range of application in the fabrication of solar cells and other opto-electronic devices. Cadmium zinc sulfide (Zn-CdS) thin films were grown by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) is used to analyze the structure and crystallite size and scanning electron microscopy is used to study the morphology of Zn-CdS thin film. Optical studies have been carried out using UV-Visible-NIR transmission spectrum. The dielectric properties of Zn-CdS thin films have been studied in the different frequency at different temperatures. The AC conductivity study shows a normal dielectric behavior with frequency which reveals that the dispersion is due to the interfacial polarization.

Synthesis and characterization of Sn-doped CdZnS nanoparticles

Tin (Sn)-doped cadmium zinc sulphide nanoparticles (CdZnS: Sn) were synthesized by the chemical bath deposition method with two different concentrations of Sn (2 and 4 mol%). X-ray diffraction (XRD) pattern reveals the formation of CdZnS nanoparticles with cubic and hexagonal structure. It was observed that the presence of Sn does not alter the structure of CdZnS. Average crystallite size was measured from XRD data by using Scherrer’s formula. From the study of absorption spectra, band-to-band absorption was obtained at 460 and 490 nm, respectively, for the Sn-doped (2 and 4 mol%) CdZnS nanoparticles. Energy bandgap for undoped and Sn-doped CdZnS varies from 3.5 to 2.9 eV with error ±0.05 eV. The presence of Sn was confirmed by energy-dispersive X-ray analysis. The effect of dopant concentration on the photoluminescence (PL) intensity has also been studied. The PL emission peak has been observed at 540, 550 and 560 nm for the Sn-doped (CdZnS, CdZnS 2 mol% and CdZnS 4 mol%), respectively, nanoparticles. XRD and PL analyses demonstrate that the Sn2+ ions uniformly substitute Cd2+ sites or interstitial sites in CdZnS lattice, which influence the optical properties. Increase in the concentration of Sn shifts the UV–vis absorption spectra and PL emission spectra towards higher wavelength side. Particle size and the crystallinity of CdZnS : Sn nanoparticles were confirmed through atomic force microscopy.

UV–Vis-NIR and micro Raman spectroscopies for the non destructive identification of Cd1 − xZnxS solid solutions in cadmium yellow pigments

Commercially available since the 1840s, cadmium zinc sulfides were extensively employed by the nineteenth and twentieth century artists. The term cadmium sulfide refers to a number of yellow–orange–red compounds sharing a common structure based on CdS where various elements including Zn, Hg, Se, may substitute for Cd or S, producing a variety of hues. In fact, their chromatic properties are linked to the fact that CdS is a semiconductor with a direct band gap of 2.42eV that can be modulated by the progressive substitution of Cd e.g. with Zn to give pale yellow cadmium zinc sulfide pigments. The aim of this paper was to develop an analytical methodology based on the combination of electronic and vibrational spectroscopies for the non destructive identification of different forms of yellow Cd1−xZnxS solid solutions. The methodology was optimized on six commercial CdS-based pigments and then applied and tested on four historical pigments from the early twentieth century. The complete set of commercial and historical samples has been investigated through X-ray fluorescence, microRaman, UV–Vis-NIR reflection, Vis-NIR emission spectroscopies and X-ray diffraction. The optical properties were investigated exploring i) the reflection behavior in the visible range and ii) the emission profiles in the visible and near infrared ranges correlating the results with the pigment composition. On the other hand, microRaman spectroscopy proved to be a sensitive probe of the short range disorder generated by Zn substitution. The availability of different Raman laser excitations (488, 514, 633 and 785nm) permitted, depending on the optical band gap value of each pigment, to record both on- and off-resonance Raman spectra giving information on the stoichiometry of the solid solutions and on their local structure in fairly good agreement with XRD analysis.

Intrinsic Kinetic Modeling of Hydrogen Production by Photocatalytic Water Splitting Using Cadmium Zinc Sulfide Catalyst

Intrinsic Kinetic Modeling of Hydrogen Production by Photocatalytic Water Splitting Using Cadmium Zinc Sulfide Catalyst

Structural characterization and photoluminescence properties of pure and Ag(1–5%)-doped (Cd0.95Zn0.5)S phosphors synthesized by solid-state reaction methods

Pure and silver-doped cadmium zinc sulphide phosphors have been synthesized by high-temperature solid-state reaction methods under a nitrogen atmosphere. The influence of silver concentration on the crystal structure and the luminescence of solid-state synthesized (Cd0.95Zn0.5)S crystals were investigated by X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDX) and photoluminescence (PL) emission spectroscopy. The powder X-ray diffraction (PXRD) pattern of silver-doped (Cd0.95Zn0.5)S revealed a hexagonal crystalline phase. The morphology of the samples was studied by scanning electron microscopy (SEM), which confirmed the microcrystalline behaviour and good connectivity with grain. The photoluminescence spectra were obtained by irradiating the samples with 345-nm UV light. The effects of silver concentration on the photoluminescence spectra of the prepared phosphors were investigated in detail.

Study of structural and optical properties of chemically synthesized nanostructured cadmium zinc sulphide films for band gap tunability

Nanostructured cadmium zinc sulphide films have been deposited onto cleaned glass substrates by chemical bath deposition method at room temperature using polyvinyl alcohol as capping agent. X-ray diffraction analysis confirms the formation of cubic-phase cadmium zinc sulphide films. Crystallite size obtained from the calculation of Scherrer’s formula and Williamson–Hall plot as well as size–strain plot is found to decrease with the increase in zinc concentration. The films have very high dislocation density of the order of 1016 m−2, whereas the strain is of the order of 10−3. Scanning electron microscopic image reveals that the particles are agglomerated to form nanoclusters and energy-dispersive X-ray analysis confirms that films are composed of cadmium, zinc and sulphur. High-resolution transmission electron microscopic image reveals that the shape of the particles is nearly spherical, uniformly distributed. Selected-area electron diffraction pattern supports the formation of cubic phase of the film. Optical absorption peaks of the films shift towards lower wavelength side and their optical band gap increases with the increase in zinc concentration. The increase in zinc concentration enhances the photoluminescence emission intensity, whose emission is in the green region of visible spectrum.

Synthesis and characterization of cerium-doped CdZnS nanoparticles

Cerium-doped cadmium zinc sulfide nanoparticles (CdZnS:Ce) were synthesized by chemical bath deposition method with three different concentrations of cerium (1.2, 2.5 and 3.84 mol%). X-ray diffraction pattern revealed the formation of cadmium zinc sulfide nanoparticles with cubic and hexagonal structure. It was observed that the presence of ceria did not alter the structure of CdZnS. Average crystallite size was measured from X-ray diffraction data by using Scherrer’s formula. From the study of absorption spectra, band-to-band absorption was obtained at 455 and 470 nm, respectively, for the Ce-doped (2.5 and 3.84 mol%) CdZnS nanoparticles. Energy band gap for undoped and Ce-doped CdZnS varied from 3.45 to 3.15 eV with error ±0.05 eV. The presence of cerium was confirmed by energy-dispersive analysis of X-rays. The effect of dopant concentration on the photoluminescence intensity was also studied. The photoluminescence emission peak was observed at 520, 540 and 560 nm, respectively, for the Ce-doped (1.2, 2.5 and 3.84 mol%) CdZnS nanoparticles. X-ray diffraction and photoluminescence analysis demonstrated that the Ce3+ ions uniformly substituted Cd2+ sites or interstitial sites in CdZnS lattice, which influenced the optical properties. An increase in the concentration of cerium shifted the UV–Vis absorption spectra and photoluminescence emission spectra toward the higher wavelength side. Particle size and the crystallinity of CdZnS:Ce nanoparticles were confirmed through transmission electron microscopy and selected area electron diffraction patterns.