Cadmium Sulfide Nanostructures Research Articles

Cr-doped CdS and ZnS nano/microstructures with ferromagnetic properties

Transition-metal-doped cadmium sulfide (CdS) and zinc sulfide (ZnS) dilute magnetic semiconductors have attracted widespread research interests due to their potential spin electron applications. Most theoretical and experimental analyses have focused on studying their optical properties. In response to the widespread application of dilute magnetic semiconductor nanomaterials in electronic components, semiconductor chips, integrated circuits and other fields, dilute magnetic semiconductors with room-temperature ferromagnetic chromium (Cr)-doped cadmium sulfide and zinc sulfide nanostructures were synthesized using the solvothermal method. According to X-ray diffraction analysis, the products of chromium-doped cadmium sulfide and zinc sulfide were clearly determined to be a hexagonal phase. Scanning electron microscopy images showed that the morphologies of cadmium sulfide and zinc sulfide with different contents of chromium were mainly composed of nanorods and a micro-floral shape. Energy-dispersive X-ray spectroscopy measurements indicated that the synthesized products were composed of chromium, cadmium (Cd), zinc (Zn) and sulfur (S). Vibrating-sample magnetometry showed that undoped cadmium sulfide exhibited weak ferromagnetism at room temperature, and undoped zinc sulfide exhibited diamagnetism, while chromium-doped cadmium sulfide and zinc sulfide had strong ferromagnetism. The saturation magnetization M s of chromium-doped cadmium sulfide (chromium = 4.21%) was about 9.524 × 10−3 emu/g; the coercivity H c was about 98.327 Oe. The saturation magnetization M s of chromium-doped zinc sulfide (chromium = 7.67%) was about 8.502 × 10−3 emu/g; the coercivity H c was about 96.237 Oe. The ferromagnetism of chromium-doped cadmium sulfide and zinc sulfide was attributed to the double-exchange mechanism.

Hetero-integration of cadmium sulfide nanorod arrays on graphite substrates to guide electron pathways for effective photocatalytic and photoelectrochemical activities

One-dimensional (1D) cadmium sulfide (CdS) nanostructures in photosynthetic systems have attracted attention because of their effective transport pathways for charge extraction which are essential for efficient photocatalytic and photoelectrochemical systems. Despite the numerous benefits of aligned 1D CdS nanostructures in photosynthetic systems, limited attention has been paid to hetero-integrating 1D CdS arrays on substrates with rapid charge extraction capabilities and practical applicability. Herein, we report the fabrication of vertically aligned CdS nanorod arrays on graphite substrates, in which electron transport pathways are rationally designed for effective photocatalysts and photoanodes. Specifically, CdS nanorod arrays integrated on graphite substrates exhibited photocatalytic reactions with excellent reusability and photostability owing to their superior bifacial properties compared to the control free-standing nanostructures. The proposed system also demonstrated excellent photoelectrochemical performance relative to control CdS nanorod arrays integrated on fluorine-doped tin oxide substrates because of the enhanced separation and extraction of photogenerated electrons combined with curvilinear surfaces.

Synthesis and characterization of CuxCd1‐xS nanocrystals into functionalized nitrile butadiene rubber matrix

AbstractIntroductionPolymetallic sulfides and heterostructures like CdIn2S4, CdZnS2, CuxS‐NiySz, Cu2CoSnS4, CoNi2S4, Zn0.76Co0.24S have been fabricated with various shapes and forms for new applications. Ternary copper cadmium sulfides (CuCdS2) are a p‐type semiconductor with a direct band gap of about 2.4 eV forms very good nanocrystals like copper sulfide could be potentially applied to optical and electronic applications. Knowing that the SILAR synthesis, optical, paramagnetic, dielectric properties, and annealing of copper cadmium sulfides have not been sufficiently investigated, they are extensively analyzed and studied in the present work.ObjectivesCuxCd1−xS (x = 0, 0.5, and 1) nanoparticles have been synthesized on the base of functionalized nitrile butadiene rubber by SILAR method and characterized using scanning electron microscopy, x‐ray diffractometer, UV–visible spectroscopy, Fourier‐transform infrared spectroscopy, electron paramagnetic resonance spectroscopy, and Raman spectroscopy. Effects of cycles, reaction time, and precursor concentration on the particle size, crystal growth and structure, bandgap energy, dielectric and paramagnetic properties, elemental composition, and morphology were investigated.MethodsThe synthesis of CuxCd1−xS nanocrystals was carried out into the obtained functional polymer matrix by SİLAR method. The functional polymer (FNBR) is a dark brown powder which contains ‐PO(OH)2 and ‐OPO(OH)2 functional groups and does not dissolve in organic and inorganic solvents, can be used as a very good stabilizer of nanostructures. The synthesis of CuxCd1−xS/FNBR nanocompsite was carried out in 3, 5, and 15 cycles.Results and discussionIn the process of ternary sulfide formation, the nucleation rate of CdS was high at the beginning of the reaction, while the growth rate and stability of CuS were high in the later course of the reaction. The average crystallite size of the nancrystallites has been increased from 1.13 nm to 7.39 nm by the increasing of the number of cycles from 5 to 15, respectively. It is explained by the inclusion of copper in the composition and getting more stable material. Copper cadmium sulfide nanostructures demonstrate wide band gap energy (~3.7 eV) in this work which is explained by the formation of nanosized particles in a limited volume of FNBR matrix.ConclusionsThe synthesis of CuxCd1‐xS nanocrystals was carried out into the obtained functional polymer matrix by SİLAR method. Strong diffraction peaks corresponding to cubic CdS are found with low SILAR cycles. SEM images of CuxCd1−xS/FNBR nanocomposite show that the atomic percentage of Cu and Cd into the ternary sulfide is 20.19% and 0.61%, respectively. It is explained by the inclusion of copper in the composition and getting more stable material with low solubility products (Ksp) which is in good agreement with XRD results. The calculated band gaps are higher than that of bulk CdS, CuS, and CuCdS2. Larger band gap is usually reported for defects or structural disorders, which is in good agreement with XRD and Raman results.

Elaboration and Characterization of CdS Nanostructures Using Pulse‐Assisted Electrodeposition: Effect of Time‐Off Duration

The presence of metallic cadmium in the electrodeposited cadmium sulfide (CdS) films is a persistent problem that leads to low photoactivity. Changing the deposition mode is a way to address this problem and thus increase the photoelectrochemical performance. Herein, the effect of the deposition mode on the composition of the CdS films prepared under the same deposition parameters is investigated for the first time. In addition, the influence of the time‐off duration on the properties of the electrodeposited thin films is studied. The results of the X‐Ray diffraction, UV–vis spectroscopy, atomic force microscopy, and photoelectrochemical characterizations reveal that the pulse‐deposited CdS films show enhanced microstructural, optical, and morphological properties as compared to that of the film deposited under direct mode. The CdS thin film deposited at time‐off duration of 0.5 s is composed of a pure CdS phase following a mixture of cubic and hexagonal lattice structure. This sample shows a smooth surface, high absorption in UV and visible light and an intense photoresponse of 90 μA under visible light.

Improving the Performance of Polydimethylsiloxane-Based Triboelectric Nanogenerators by Introducing CdS Particles into the Polydimethylsiloxane Layer.

Energy harvesting and power generation technologies hold significant potential for meeting future energy demands and improving environmental sustainability. A triboelectric nanogenerator (TENG), which harnesses energy from the surrounding environment, has garnered significant attention as a promising and sustainable power source applicable in various fields. In this study, we present a technique to improve the triboelectric performance of a PDMS-based TENG by incorporating nanostructured cadmium sulfide (N-CdS). This study investigates the utilization of CdS nanomaterials in TENG production, where mechanical energy is converted into electrical energy. We conducted a comparative analysis of TENGs utilizing N-CdS/PDMS, commercial CdS/PDMS (C-CdS/PDMS), and pure PDMS substrates. The N-CdS/PDMS substrates demonstrated superior triboelectric performance compared to TENG devices based on pure PDMS and C-CdS/PDMS. The triboelectric open-circuit voltage (Voc) and short-circuit current (Isc) of the N-CdS/PDMS-based TENG device were approximately 236 V and 17.4 µA, respectively, when operated at a 2 Hz frequency. These values were approximately 3 times and 2.5 times higher, respectively, compared to the pure PDMS-based TENGs. They were further studied in detail to understand the effect of different parameters such as contact-separation frequency and contact force on the TENGs' operation. The stability of the TENG devices was studied, and their potential to be integrated into self-powered smart textiles as power sources was demonstrated.

Growth-control of hexagonal CdS-decorated ZnO nanorod arrays with low-temperature preheating treatment for improved properties and efficient photoelectrochemical applications.

The limitations of oxide semiconductor-based solar cells in achieving high energy conversion efficiencies have prompted incessant research efforts towards the creation of efficient heterostructures. Despite its toxicity, no other semiconducting material can fully replace CdS as a versatile visible light-absorbing sensitizer. Herein, we explore the aptness of preheating treatment in the successive ionic layer adsorption and reaction (SILAR) deposition technique and improve the understanding of the principle and the effects of a controlled growth environment on thus-formed CdS thin films. Single hexagonal phases of nanostructured cadmium sulfide (CdS)-sensitized zinc oxide nanorods arrays (ZnO NRs) have been developed without the support of any complexing agent. The influences of film thickness, cationic solution pH and post-thermal treatment temperature on the characteristics of binary photoelectrodes have been investigated experimentally. Interestingly, the preheating-assisted deposition of CdS, which is rarely applied for the SILAR technique, resulted in improved photoelectrochemical performance similar to the post-annealing effect. The X-ray diffraction pattern revealed that optimized ZnO/CdS thin films were polycrystalline with high crystallinity. Examination of the morphology of the fabricated films via field emission scanning electron microscopy showed that film thickness and medium pH altered the growth mechanism of nanoparticles, thereby changing their particle sizes, which had a significant influence on the film's optical behavior. The effectiveness of CdS as a photosensitizer and the band edge alignment for ZnO/CdS heterostructures were evaluated using ultra-violet visible spectroscopy. Facile electron transfer in the binary system as evidenced in electrochemical impedance spectroscopy Nyquist plots, therefore, promotes higher photoelectrochemical efficiencies from 0.40% to 4.30% under visible light illumination as compared with the pristine ZnO NRs photoanode.

Nanophotonics and optical fibers: New avenues for sensing and active devices

Rapid development in electronic and optical devices has unequivocally eased human life to an appreciable extent, which, however, involved lots of hard work in the miniaturization of technology. The continual fabrication and characterization of devices in the field of spectroscopy, security/imaging, information technology, nanophotonics, opticalfiber-based devices, photodetectors, etc. is going on in full swing. By citing exemplary instances, this article comprehensively shows various applications based on nanophotonics and optical fiber technologies. This article focuses on the recent advancements in the field of nanophotonics and optical fiber to use them in sensing and active devices. Initiating with an overview of the recent areas of research, design, and implementation of nanophotonics and optical fiber, the paper discusses the instrumentation used for fabricating and characterization of surface plasmon resonance (SPR) based fiber optic refractive index sensor and visible photodetector furnished by cadmium sulfide (CdS) nanostructures. The fabricated CdS nanostructures were characterized using XRD, Raman, SEM, UV–vis and photoluminescence spectroscopic techniques so as to obtain the required/favourable properties for the realization of fiber-optic refractive index sensing device employing SPR technique and for visible photodetection applications. The performance parameters of both the fabricated devices were also evaluated and explained in detail. Lastly, the paper outlines the limitations, challenges as well as available opportunities in this avenue.

Highly induced photosensing behavior of Erbium (Er), Yttrium (Y) and Terbium (Tb) doped nanostructured Cadmium Sulphide (CdS) thin films prepared by nebulizer spray pyrolysis method

Using nebulizer spray pyrolysis method, we investigate the optoelectronic properties of Erbium (Er:2 %), Yttrium (Y:2 %) and Terbium (Tb:2 %) doped CdS thin films. The pure CdS film belongs to the II-IV semiconductor chalcogenide family, and it has good optical properties, making it appropriate for photo-detector applications. In addition, rare earth (RE) elements such as Erbium (Er), Yttrium (Y) and Terbium (Tb) doped CdS thin film is more suitable for photo sensing applications due to their good physical and optical properties. The polycrystalline structure of pure and doped CdS films with the structure of hexagonal and preferential orientation (002) was shown by structural analysis (XRD). In addition, the phase purity of RE doped CdS thin films was confirmed using Raman spectra. The direct bandgap values fell (2.52–2.47 eV) for the RE dopant, reaching a minimum for the film formed with RE of high ionic radius Tb. Three emission peaks were discovered in photoluminescence (PL) spectra: a strong dominant peak at 525 nm due to interband transitions and a peak with minimum intensity at 475 and 640 nm. With the exception of two RE materials, Er and Y, the CdS film coated with Tb had improved photo-sensitivity characteristics. Responsivity (3.32 AW−1), detectivity (2.82 × 1011 Jones), and external quantum efficiency (883 %) are the photo sensing values of Tb doped CdS film. The Tb coated films were found to exhibit good optical properties, making them suitable for photodetector applications.

Efficient visible light photocatalytic organic colorants elimination performance induced by biosynthesized titanium dioxide coupled cadmium sulfide nanostructures

Efficient visible light photocatalytic organic colorants elimination performance induced by biosynthesized titanium dioxide coupled cadmium sulfide nanostructures

Enhanced photocatalytic degradation of Acid Blue dye using CdS/TiO2 nanocomposite

Photocatalytic degradation is essential for the successful removal of organic contaminants from wastewater, which is important for ecological and environmental safety. The advanced oxidation process of photocatalysis has become a hot topic in recent years for the remediation of water. Cadmium sulphide (CdS) nanostructures doped with Titanium oxide (CdS/TiO2) nanocomposites has manufactured under ambient conditions using a simple and modified Chemical Precipitation technique. The nanocomposites crystal structure, thermal stability, recombination of photo-generated charge carriers, bandgap, surface morphology, particle size, molar ratio, and charge transfer properties are determined. The production of nanocomposites (CdS-TiO2) and their efficient photocatalytic capabilities are observed. The goal of the experiment is to improve the photocatalytic efficiency of TiO2 in the visible region by doping CdS nanocomposites. The results showed that as-prepared CdS-TiO2 nanocomposites has exhibited the highest photocatalytic activity in the process of photocatalytic degradation of AB-29 dye, and its degradation efficiency is 84%. After 1 h 30 min of visible light irradiation, while CdS and TiO2 showed only 68% and 09%, respectively. The observed decolorization rate of AB-29 is also higher in the case of CdS-TiO2 photocatalyst ~ 5.8 × 10−4mol L−1 min−1) as compared to the reported decolorization rate of CdS ~ 4.5 × 10−4mol L−1 min−1 and TiO2 ~ 0.67 × 10−4mol L−1 min−1. This increased photocatalytic effectiveness of CdS-TiO2 has been accomplished by reduced charge carrier recombination as a result of improved charge separation and extension of TiO2 in response to visible light.

Decoration of X2C nanoparticles on CdS nanostructures for highly efficient photocatalytic wastewater treatment under visible light

It is necessary to design and fabricate effective and stable heterostructures to enhance the photocatalyst performance. In this research, we developed stable metal carbide (Mo2C and W2C) embedded cadmium sulfide (CdS) hybrid nanostructure photocatalysts to increase the light adsorption capacity and effectively enhance the photocatalytic activity.A simple hydrothermal technique was employed to effectively fabricate the CdS and CdS:X2C (X = Mo or W) hybrid photocatalyst. Microscopy studies demonstrated the surface modification of the hybrid structure due to the X2C incorporation with CdS. X-ray photoelectron spectroscopy, X-ray diffraction, and energy dispersive analysis measurements were performed to characterize the hybrid structure materialization. The photocatalytic properties of CdS and CdS:X2C hybrid structures were evaluated by degrading Rhodamine B (RhB) under visible light. The polygonal shaped CdS:X2Cexhibited excellent photocatalytic activities. The highly porous structure of CdS:X2C indicated that manyexposed active facets were available due to the embedding of petal-shaped X2C, which enabled the effective adsorption and transference of RhB organic molecules to the active edges. Moreover, the hierarchical structure of CdS:X2Ccorresponded to a high light-absorption efficiency due to the increased length of light trails and enhanced interfacial shifting of the valence state electrons, which reduced the optical band-gap.

Preparation and Characterization of Nickel Doped Cadmium Sulfide Nanostructure Thin Films via Spray Pyrolysis Method

Pure and nickel-doped cadmium sulphide (NixCd1-xS where x= 2.5%, 5%, 7.5%) nanostructure thin films were successfully prepared by spray pyrolysis method on glass substrate at 350 °C. The films characterized using X-ray crystallography diffractmeter, Scanning Electron Microscope, Atomic Force Microscope and Uv-visible analysis in order to explore the properties of thin film. Structural studies revealed that the deposited films exhibit hexagonal structure with strong intensity at (002) plane. Structural parameters such as crystallite size, strain and dislocation density were calculated for films with different doping concentration. AFM measurements showed that the average diameter increased with increasing Ni doping, where surface roughness and root mean sequre decreased with increasing Ni doping, SEM images show that thin film have been grown and converted into nanowire with increasing of Ni content.Finally, Uv-visible analysis show that the optical band gap of CdS decreased from 2.44 to 2.38 eV with increasing of Ni doping concentrations.

Green synthesis of Cadmium Sulphide nanoparticles for the photodegradation of Malachite green dye, Sulfisoxazole and removal of bacteria

The development in nanoscience has led to cleaner and safer semiconductor materials that can be used for degrading toxic and resistant pollutants in water. Ecological and environmentally friendliness’s are added features that the semiconductor photocatalyst should possess and these are incorporated via green synthetic approaches. Hence, in this study, Sutherlandia frutescence (S. frutescens), leaf extract was used during the synthesis of Cadmium Sulphide (CdS) nanostructures, as a reducing and stabilising agent. Their morphological analysis revealed the presence of spherical particles. Structural analysis by XRD confirmed the presence of hexagonal S. frutescens CdS nanostructures. Furthermore, through FTIR, the deposition of the phytochemicals on the S. frutescens CdS was confirmed. The S. frutescens CdS nanostructures exhibited a bandgap of 3.55 eV. Thus, they were further investigated for their degradation of Malachite Green dye and Sulfisoxazole (SIZ) under UV light irradiation. Approximately, 91% photocatalytic efficiency was achieved for MG (dye:10 mg/L, catalyst: 50 mg, pH: 2) and the materials could be recycled up to 3 times without using stability. The photogenerated electrons were the major contributors to the photodegradation. The pharmaceutical pollutant, sulfisoxazole, had a 68% degradation after 120 min. In addition, the antibacterial activity of the S. frutescens CdS gave excellent removal against all the bacterial strains for both the model and real water pollutants. This study has shown that various pollutants can be degraded (MG and SIZ) and removed (bacteria) using the S. frutescens CdS.

Green synthesis of sunlight responsive zinc oxide coupled cadmium sulfide nanostructures for efficient photodegradation of pesticides

Structural design of semiconductor nanomaterials via facile and green methodology is noteworthy to advance their photocatalytic activity for resolving the problem of energy and environment. Herein, sunlight active zinc oxide coupled with cadmium sulfide (ZnO@CdS) was synthesized by employing the leaf extract of Azadirachta indica. Subsequently, it was used for removal of chlorpyrifos (CP) and atrazine (Atz) pesticides that have shown high persistence, bioaccumulation, and toxicity in the environment. Synthesized ZnO@CdS nanocomposite was characterized by spectroscopic and microscopic techniques. The unique morphology of nanocomposite (particle size ≤ 50 nm) and appearance of stretching vibrations at 600 cm−1 for Zn-S and 679 cm−1 for Cd-O has confirmed the coupling of ZnO with CdS. The degradation conditions were optimized by varying the pesticide amounts, catalyst dose, and pH under the sunlight irradiation. At moderate dosage and neutral pH, the nanocomposite was found highly efficient for the quantitative removal of pesticides (89–91%) due to improved surface area (111 m2g−1), low band energy (1.67 eV), and semiconducting nature resulted from synergism. The degradation followed Langmuir adsorption and first order kinetics. The Effect of ionic strength was helpful to understand the interaction mechanism involved in the removal of contaminants. Being more effective than natives, ZnO@CdS has substantially suppressed the half-life of pesticides as revealed from generation of smaller and less toxic metabolites in GC–MS analysis. The charge separation was supported by photoluminescence and UV-reflectance studies. A scavenger analysis has indicated the presence of active radicals in photocatalysis. The Applicability of green or alternative photocatalyst for multiple times (n = 10) confirmed its sustainability and high efficiency for environmental and industrial purposes.

An Inclusive Review on Recent Advancements of Cadmium Sulfide Nanostructures and its Hybrids for Photocatalytic and Electrocatalytic Applications

Abstract A comprehensive report has been presented on the recent developments of CdS and its hybrid with focus on photo and electrocatalytic applications. CdS as semiconductor possess remarkable chemical stability for redox reactions, high absorption capacity, negative conduction bandedge, and offers diverse morphologies. Photo and electrocatalytic applications of CdS and its hybrids include low cost and green water-splitting for H2 generation, wastewater treatment by degradation of organics toxins e.g., Cr (VI), Rhodamine B, Methylene blue (MB), Methyl orange etc., and fuel production such as CH4, Ethylene, Methanol, Ethanol, HCOOH, and CO via photocatalytic and electrocatalytic CO2 reduction. Starting from the fundamentals, design,synthesis process and catalytic activity factors of CdS-based catalysts for various applications are summarized.

Ag2S/CdS/Ni ternary nanostructures: long-range electric field to enhanced photocatalytic hydrogen production activity

Silver sulfide, cadmium sulfide and nickel (Ag2S/CdS/Ni) ternary nanostructures were fabricated by a two step process and characterized by x-ray powder diffraction, transmission electron microscopy, and UV–vis diffuse reflection spectroscopy. The photocatalytic hydrogen production activity of ternary nanostructures and reference samples were evaluated using triethanolamine (TEOA) as sacrificial reagent in water under visible-light illumination (λ ≥ 420 nm). The result shows Ag2S/CdS/Ni nanostructures exhibited a high visible light photocatalytic H2 evolution rate of 1.54 mmolh−1 g−1, which was 4.6 times and 1.4 times higher than that of 1.2% mol Ag2S/CdS and Ni/CdS. The degree of photocorrosion of CdS were employed to study the photogenerated carriers transfer route by measuring and comparing the concentration of Cd2+ in the solution of the photocorrosion experiments in a nonsacrificial system. A long-range electric field, which is similar to the p-i-n electric field structure, was proposed to be constructed by Ni nanoparticles and Ag2S nanoparticles in CdS. Most of the photogenerated electrons and holes in CdS drift to the electron donor and electron acceptor respectively under the action of long-range electric field, which greatly improves the separation efficiency of photogenerated carriers and the photocatalytic H2 production activity.

Induced conducting energy-levels in a boron nitride nano-framework for asymmetric supercapacitors in high charge-mobility ionic electrolytes

Boron nitride's (BN) large band gap does not permit carrier transport at ambient conditions. We show that BN sheets can be exfoliated by functionalization with oxy-groups to introduce additional acceptor and donor energy levels appropriate for energy storage devices. Further, the incorporation of heteroatoms into transition metal sulfides enhances capacitance via Faradic redox reactions and their cyclic stability. The functionalized boron nitride (mK-BN) and Carbon Nanotubes (CNTs) are intertwined with a Zn-doped Cadmium-Sulfide (Zn–CdS) nanostructure to increase the surface area-charge storage. In a supercapacitor application, Zn–CdS/mK-BN/CNT exhibits a 787 F/g specific capacitance (SC) in an aqueous (aq.) electrolyte. Further, the Zn–CdS/mK-BN/CNT was deployed as a cathode material in an asymmetric supercapacitor device (ASC) coupled with an ionic electrolyte (IE), (NHEt3)+(NO3)−, offered a SC of 173 F/g with an approximate 99% stability due to the enhanced charge mobility. The reported functionalization of BN induces additional energy levels making the material ideal for energy storage devices and will directly impact the next-generation of advanced supercapacitor electrode materials.

Structural and optical modifications of CdS properties in CdS-Au thin films prepared by CBD

In this work highlights the modifications of the crystalline structure and properties of the nanostructured cadmium sulphide (CdS) thin films, including gold quantum dots grown to form a hybrid metal-semiconductor system. By means of chemical bath deposition (CBD) good quality thin films are obtained, with the advantage of doping in-synthesis with no required additional steps. Film thicknesses around 100 nm were determined by ellipsometry. The binding energies of elements in the CdS and CdS-Au samples were measured by X-ray photoelectronic spectroscopy (XPS). The materials crystalline structure was studied by X-ray diffraction (XRD). A change from disperse like-single-crystalline (highly oriented) CdS NP’s films to monodisperse CdS NP’s–Au QD’s like-single-crystalline samples was observed. This behaviour was confirmed by TEM micrographs. The samples properties pass from an intermediate quantum confinement regime (IQCR) in CdS to a strong one (SQCR) in CdS-Au. The Raman vibrational spectra allowed the analysis of the phonon emissions in CdS, where the Raman shift gives structural information and confirms the effects of IQCR in CdS and the SQCR in CdS-Au. The optical UV–Vis characterization describes the effect of the structural modifications, with an optical band gap shift at higher energy in the CdS-Au sample related to the SQCR. Photoluminescence (PL) measured at room-temperature shows a decrease of PL intensity in CdS-Au film due to via defects-recombination, with respect to that in CdS. This fact is interpreted as an effect of a decreasing of surface defects due to passivation by the Au presence.

Preparation and magnetic properties of chromium doped zinc sulfide and cadmium sulfide nanostructures by solvothermal method

With the continuous development of nanotechnology, people have higher and higher requirements for the performances of nanomaterials. In the past few decades, researchers have used various methods to prepare nanomaterials with different dopants, and studied their optical and electrical properties. Nanomaterials with ferromagnetic properties have a wide range of applications, and there have been many reports about the ferromagnetic properties of doped magnetic elements. However, there have been few reports about Cr-doped ZnS and CdS. In order to obtain Cr-doped ZnS and CdS nanosheets with room temperature ferromagnetism, in this paper, using ethanolamine (EA) and ethylenediamine (EN) as mixed solvents, ZnS and CdS semiconductor nanostructures doped with different amounts of chromium are successfully prepared in S, ZnO and CdO sources by simple solvent thermal method. The X-ray diffraction (XRD) measurements show that the ZnS and CdS nanostructure have a wurtzite structure. Scanning electron microscopy (SEM) images show the morphologies of ZnS and CdS with different chromium content. When the content of Cr is 4.31 at% or 7.25 at%, the thickness of Cr-doped ZnS nanosheets is about 210–290 nm, and the morphology of undoped ZnS is composed of sub-morphologies of relatively thick nanosheets. The morphologies of CdS doped with different amounts of Cr are composed of sub-morphologies of snowflake like nanosheets with thickness of about 120–190 nm. Energy dispersive spectrometer (EDS) is used to observe the product composed of Cr, Zn, Cd, and S. The EDS measurement and calculation of the Cr content in Cr-doped ZnS nanosheets are 4.31 at% and 7.25 at% respectively, and those of the Cr content in Cr-doped CdS nanosheets are 1.84 at% and 2.12 at%. The vibration sample magnetometer(VSM) measurements show that ZnS doped with chromium exhibits ferromagnetism at room temperature, while the undoped ZnS exhibits diamagnetism at room temperature. The values of saturation magnetization <i>M</i><sub>s</sub><italic/> of Cr-doped ZnS nanosheets with Cr = 4.31 at% and 7.25 at% are 2.314 and 5.683 (10<sup>–3</sup> emu/g), and the coercivity values of <i>H</i><sub>c</sub><italic/> are 54.721 and 88.441 Oe, respectively. The ferromagnetism of pure CdS is weak, while that of Cr-doped CdS is enhanced at room temperature. The saturation magnetization <i>M</i><sub>s</sub><italic/> values of Cr-doped CdS nanosheets with Cr = 0, 1.84 at% and 2.12 at% are 0.854, 2.351 and 7.525(10<sup>–3</sup> emu/g), respectively, and the coercivity values of <i>H</i><sub>c</sub><italic/> are 74.631, 114.372 and 64.349 Oe, respectively. The values of saturation magnetization of ZnS and CdS increases with the Cr doping increasing. The ferromagnetism of Cr-doped ZnS at room temperature is confirmed by the experimental result, which is consistent with the ferromagnetism of Cr-doped ZnS calculated by the first principle. The origin of ferromagnetism of Cr-doped CdS is related to the doping of Cr in CdS lattice.

Preparation of CdS semiconductor nanomaterials with different morphologies

Cadmium sulfide (CdS) nanocrystals were successfully prepared by hydrothermal method, and chromium nitrate [Cd(NO3)2] was used as the source of cadmium, thiourea as the source of sulfur, and hexamethylenetetramine [(CH2)6N4, HMT] as a capping agent. In this paper, the shape and size of nanocrystals were regulated by adjusting the preparation process, such as the proportion of raw materials and the amount of capping agent. The X-ray diffraction (XRD) was used to identify structure of CdS nanostructures, and morphologies were examined by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM).