Synthesis of Volcano‐Like CdS/Organic Nanocomposite

Cadmium sulfide/organic nanocomposites, which were based on long nanowires, were synthesized by a simple reaction between cadmium nitrate and thioglycolic acid (TGA) at room temperature. The products were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected‐area electron diffraction (SAED), Fourier transform infrared (FTIR) spectra, and thermogravimetric analysis (TG). The CdS/organic nanocomposites was decomposed into pure wurtzite CdS nanorods through hydrothermal treatment at 190°C. Photoluminescence (PL) spectra were used to study the optical properties of CdS/organic composite and pure CdS. It is found that the emission maximum of the CdS/TGA nanocomposite is significantly blue‐shifted, and the intensity is highly enhanced as compared to the luminescence spectrum of the bare CdS nanorods.     

Morphological variations in cadmium sulfide nanocrystals without phase transformation

A very novel phenomenon of morphological variations of cadmium sulfide (CdS) nanorods under the transmission electron microscopy (TEM) beam was observed without structural phase transformation. Environmentally stable and highly crystalline CdS nanorods have been obtained via a chemical bath method. The energy of the TEM beam is believed to have a significant influence on CdS nanorods and may melt and transform them into smaller nanowires. Morphological variations without structural phase transformation are confirmed by recording selected area electron diffraction at various stages. The prepared CdS nanorods have been characterized by X-ray powder diffraction, TEM, UV-Vis spectroscopy, and photoluminescence spectroscopy. The importance of this phenomenon is vital for the potential application for CdS such as smart materials.     

Synthesis and Characterization of Cadmium Selenide (CdSe) Nanoparticles Using Trigonal Selenium (t-Se) Nanorods as Selenium Source

Cadmium selenide (CdSe) nanoparticles were synthesized through colloidal method in aqueous medium using the reaction intermediates selenium nanorods as selenium source. Trigonal selenium nanorods (t-Se) were synthesized in water by the reduction method in the presence of sodium borohydride at 60?°C using sodium selenite (Na₂SeO₃) as selenium source. These selenium nanorods were further utilized to synthesis cadmium selenide nanoparticles at 100?°C in water. The synthesized nanorods and nanoparticles were characterized using XRD, SEM, TEM and XPS analysis. X-ray diffraction (XRD) analysis shown that the nanorods possess trigonal phase while the nanoparticles possess a cubic zinc blende structure. Scanning electron microscope (SEM) analysis of the prepared hexagonal shaped nanorods reveals the diameter of the nanorods are about 150 nm. Transmission electron microscopy (TEM) analysis shows the size of the synthesized CdSe nanoparticles are about 4–8 nm. X-ray photoelectron spectroscopy (XPS) analysis illustrates the presence of respective elements Cd, Se with its corresponding oxidation states. The activity of nano selenium rods in aqueous solution during the conversion of cadmium selenide nanoparticles was discussed.     

A Novel Method for Preparing Vertically Aligned CdS Nanorod Arrays and Its Application in Photovoltaic Cells with P3HT Fibers

Vertically aligned cadmium sulfide (CdS) nanorod arrays were prepared through a novel thermal annealing route. By embedding the as-prepared CdS nanorod arrays into the poly(3-hexylthiophene) (P3HT) nanofiber (NF) matrix, the photovoltaic devices were fabricated with the structure of ITO/PEDOT:PSS/CdS arrays/P3HT NF/Au. The device performance was highly dependent on the P3HT NF layer thickness in this structure, and a power conversion efficiency (PCE) of 0.23 % was obtained for optimal P3HT NF layer thickness of 150 nm. In addition, much higher PCE of 0.84 % was achieved after post-annealing. The significantly improved photovoltaic performance may be caused by the increased interfacial areas between P3HT NFs and CdS nanorods for efficient charge separation, as well as the decreased inter-nanocrystal distance caused by insulating organic ligands after the annealing treatment. The results demonstrate a promising inorganic–organic hybrid photovoltaic structure with vertically aligned CdS nanorods arrays.     

超声诱导乳液介质中花状CdS纳米结构的制备

为考察超声作用和无表面活性剂乳液对合成纳米材料的影响作用,在超声诱导形成的油包水乳液介质中,制备出菊花状CdS纳米结构微球。用SEM,TEM和XRD等对产物进行了表征,考察了反应温度的影响作用,并初步探讨了产物的形成机理。结果表明:CdS纳米结构微球的平均直径为7μm,属于立方晶系,由纳米级的结构单元——直径为140 nm的CdS纳米棒组成;随着反应温度的升高,所合成的CdS纳米结构微球的直径变小。油包水乳液的分散相液滴对CdS纳米结构微球的形成起到空间限定和模板作用。文中报道的方法可望用于其他组成的球状纳米结构的合成。     

Colloidal Synthesis of ZnS,CdS and Zn x Cd1−x S Nanoparticles from Zinc and Cadmium Thiobiuret Complexes

ZnS, CdS and Zn _x Cd_1?x S nanoparticles were synthesised from the thermolysis of 1,1,5,5-tetra-iso-propyl-4-thiobiuret complexes of Zn and/or Cd in oleylamine. The influence of the different reaction parameters (precursor concentration, growth temperature, reaction time and injection solvent/capping agent combination) on the size, morphology and optical properties of the produced nanoparticles were studied. ZnS nanoparticles with size smaller than 4.3 nm had the cubic phase whereas the particles with size larger than 4.3 nm had a hexagonal crystal structure as suggested by the selected area electron diffraction. Transmission electron microscopy showed the formation of spherical ZnS nanoparticles in addition to few ZnS nanorods only at growth temperature of 280 °C. Powder X-Ray diffraction (p-XRD) showed that the obtained CdS nanoparticles were cubic under all reaction conditions except when dodecanethiol was used as an injection solvent which produced hexagonal CdS. The change in the crystal structure of the CdS nanoparticles was accompanied with a change in morphology from spherical to triangular. Cubic Zn _x Cd_1?x S nanoparticles were obtained under all reaction conditions. Lattice spacing of the Zn _x Cd_1?x S nanoparticles showed a very good agreement with Vegard’s law. The optical properties of the Zn _x Cd_1?x S nanoparticles were highly dependent on the ZnS to CdS precursor ratio and the solvents/capping agent combinations. This in detail study on the relationship of solvent systems (capping agents), thermolysis temperatures, time of reactions and precursors will help in understanding to control the morphology, size of the crystallites and phase of the materials.     

Polymer-assisted solvothermal growth of CdS nanowires

Summary  Large quantities of CdS nanowires were successfully synthesized through a one-step poly (ethylene glycol)-assisted solvothermal route. The nanowires obtained were characterized by XRD, SEM, TEM, HRTEM, UV-vis and PL. The single crystalline nanowire is uniform in morphology with a [001] growth direction. Optical properties measurement reveals the quantum confinement effect of the CdS nanowires. Based on the comparative experimental results, a possible growth mechanism of CdS nanowires was proposed that the formation of CdS nanowires was controlled by the number of CdS nucleus at the initial reaction stage. The applicability of the growth mechanism for CdS nanowires was further verified by substituting poly (vinyl alcohol) for poly (ethylene glycol).     

Nanorod-like Fe2O3/graphene composite as a high-performance anode material for lithium ion batteries

In this study, a nanorod-like Fe₂O₃/graphene nanocomposite is synthesized by a facile template-free hydrothermal method and a following calcination in air at 300 °C for 2 h. The Fe₂O₃ nanorods with diameter of 15–30 nm and length of 120–300 nm are homogenous distributed on both sides of graphene. The morphologies of intermediates at different hydrothermal reaction times are investigated by transmission electron microscopy (TEM) characterization, and a possible growth mechanism of this one-dimensional structure is proposed. It is shown that the α-FeOOH rodlike precursors are formed through a rolling-broken-growth (RBG) model, then the α-FeOOH is transformed into α-Fe₂O₃ nanorods during calcinations, preserving the same rodlike morphology. Electrochemical characterizations demonstrate that the Fe₂O₃ nanorod/graphene composites exhibit a very large reversible capacity of 1063.2 mAh/g at the charge/discharge rate of 0.1 C.     

Preparation and photoelectrochemical properties of CdS quantum dot-sensitized ZnO nanotube arrays

CdS/ZnO nanotubes (NTs) arrays were synthesized on a transparent conductive glass (FTO) substrate by hydrothermal method, chemical bath etching and successive ionic layer adsorption and reaction (SILAR) method, which were used in semiconductor-sensitized photoelectrochemical cells (PECs). The crystal structure, morphology and photoelectrochemical conversion properties of different photoanodes were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM), and electrochemical workstation. The results show a heterojunction has been formed between ZnO and CdS QDs. The ZnO NTs and CdS QDs played a remarkable controllability for PEC performances. The photoelectrochemical conversion efficiency of ZnO NTs photoanodes was 3 times that of ZnO nanorods (NRs) arrays photoanodes. After sensitization of CdS quantum dots, the photoelectrochemical conversion efficiency of CdS/ZnO NRs was improved by 7 times and the CdS/ZnO NTs was increased by 4 times. These results demonstrate that the CdS/ZnO core-shell structure can provide a facile and compatible frame for the potential applications in nanotube-based solar cells.     

Polyhydrosilane Mediated Synthesis of One-Dimensional Gold Nanostructures

This work presents a solution-phase approach for the “one pot” synthesis of polysilane-gold nanorods. The process starts by the reduction of HAuCl₄ to Au^o with a solution of poly[diphenylsilane-co-methyl(H)silane] cooled to 4 °C. The formed small Au nanoparticles (5–15 nm diameter) serve further as seeds for the heterogeneous nucleation and anisotropic growth that takes place at 25 °C and yields crystalline needle-like polymer–gold nanostructures. The evolution of the small spherical nanoparticles to nanorods with length/width aspect ratios up to 10³ has been proved by UV–Vis spectroscopy, polarized light microscopy and AFM. Further insights on the growth mechanism were obtained by SEM, DLS and TEM.     

Facile Hydrogen Evolution Reaction on WO3 Nanorods

Tungsten trioxide nanorods have been generated by the thermal decomposition (450 °C) of tetrabutylammonium decatungstate. The synthesized tungsten trioxide (WO₃) nanorods have been characterized by XRD, Raman, SEM, TEM, HRTEM and cyclic voltammetry. High resolution transmission electron microscopy and X-ray diffraction analysis showed that the synthesized WO₃ nanorods are crystalline in nature with monoclinic structure. The electrochemical experiments showed that they constitute a better electrocatalytic system for hydrogen evolution reaction in acid medium compared to their bulk counterpart.     

Synthesis, characterization and morphology of polyanthranilic acid micro- and nanostructures

Polyanthranilic acid (PANA) nanofibres, nanorods, nanospheres and microspheres were synthesized by polymerization of anthranilic acid using ammonium peroxydisulfate (APS) as oxidant without hard or soft templates. Polymerization of anthranilic acid was carried out in aqueous solutions of strong (hydrochloric) and weak (acetic) acids. The influence of synthetic parameters such as oxidant, initiator, dopant acid and its concentration, redox initiator, and reaction medium on the morphology and particle size of PANA have been investigated. PANA nanofibres and nanorods were obtained via redox polymerization of anthranilic acid initiated by FeSO₄ as redox initiator. PANA nanospheres and nanofibres were also obtained when used aromatic amines as initiators. When polymerization carried out in the solution of weak (acetic) acid the microsphere morphology obtained and the particle size increase with increasing the concentration of weak acid. PANA nanorods were obtained also by polymerization of anthranilic in ethanol-water mixture unlike interfacial polymerization of anthranilic acid (in chloroform-water) that give PANA microspheres. The morphology and particle size of PANA was studied by scanning electron microscope (SEM) and transmission electron microscope (TEM). The average diameter of nanostructures obtained ≤100 nm. The optical bandgap of microspheres and nanofibers polymeric products were determined using UV-vis spectroscopic technique and found to be 2.0 eV and 1.6 eV, respectively. The bandgap decreased with decreasing the particle size. IR spectrum confirmed the structure of PANA nanofibres (synthesized with FeSO₄ as redox initiator) in emeraldine form. The thermal stability of polymer obtained was determined by thermal gravimetric analysis (TGA). The molecular weight was determined also by gel permeation chromatography (GPC).     

Surfactant-assisted growth and characterization of CdS nanorods

Well-defined CdS nanorods were synthesized using hydrothermal process with ethylenediamine as a bidentate ligand to form Cd²⁺ complexes and polyoxyethylene 20 cetyl ether providing an effective control over the crystal uniformity of CdS nanorods. The photoluminescence (PL) spectrum of the nanorods indicated that they have potential applications in light-emission devices.     

合成CdS纳米材料的新方法

以硫代碳酸钠为原料 ,用室温液相反应合成出前驱物 Cd CS3 和 [Cd(en) 3 ]CS3 分别置于高压釜中 ,在适当温度和压力下分解 ,即得纳米 Cd S。用 X-射线粉末衍射 ,透射电镜对产物的组成、大小、形貌进行表征。结果表明 ,产物纳米 Cd S为粒度分布均匀的六方晶形 ,晶粒大小约为 2 0 nm。其光催化活性翠蓝 KNL实验表明具有良好的光催化活性。     

A simple additive-free approach for the synthesis of uniform manganese monoxide nanorods with large specific surface area

A simple additive-free approach is developed to synthesize uniform manganese monoxide (MnO) one-dimensional nanorods, in which only manganese acetate and ethanol were used as reactants. The as-synthesized MnO nanorods were characterized in detail by X-ray diffraction, scanning and transmission electron microscopy (TEM) including high-resolution TEM and selected-area electron diffraction, Fourier transform infrared spectrum, and nitrogen adsorption isotherm measurements. The results indicate that the as-synthesized MnO nanorods present a mesoporous characteristic with large specific surface area (153 m² g⁻¹), indicating promising applications in catalysis, energy storage, and biomedical image. On the basis of experimental results, the formation mechanism of MnO one-dimensional nanorods in the absence of polymer additives was also discussed.     

Synthesis, Optical Properties, and Photocatalytic Activity of One-Dimensional CdS@ZnS Core-Shell Nanocomposites

One-dimensional (1D) CdS@ZnS core-shell nanocomposites were successfully synthesized via a two-step solvothermal method. Preformed CdS nanowires with a diameter of ca. 45 nm and a length up to several tens of micrometers were coated with a layer of ZnS shell by the reaction of zinc acetate and thiourea at 180 °C for 10 h. It was found that uniform ZnS shell was composed of ZnS nanoparticles with a diameter of ca. 4 nm, which anchored on the nanowires without any surface pretreatment. The 1D CdS@ZnS core-shell nanocomposites were confirmed by XRD, SEM, TEM, HR-TEM, ED, and EDS techniques. The optical properties and photocatalytic activities of the 1D CdS@ZnS core-shell nanocomposites towards methylene blue (MB) and 4-chlorophenol (4CP) under visible light (λ > 420 nm) were separately investigated. The results show that the ZnS shell can effectively passivate the surface electronic states of the CdS cores, which accounts for the enhanced photocatalytic activities of the 1D CdS@ZnS core-shell nanocomposites compared to that of the uncoated CdS nanowires.     

Effect of Annealing Temperature on TiO2 Nanorod Films Prepared by dc Reactive Magnetron Sputtering for Dye-Sensitized Solar Cells

Anatase TiO₂ nanorod films have been prepared on ITO coated glass substrates at room temperature by dc reactive magnetron sputtering technique. The nanorods are highly ordered and are perpendicular to the substrate. XRD measurements show that the anatase nanorods have a preferred orientation along the [110] direction. The prepared nanorods were annealed at different temperatures (200?C500 °C) in air for 1 h. The dye-sensitized solar cells (DSSC) have been made using the as-deposited and annealed TiO₂ nanorods as working electrodes. It has been found that annealing improves the efficiency of the DSSC. An optimum conversion efficiency of 2.13%, at 100 mW/cm² light intensity has been achieved with TiO₂ nanorods annealed at 300 °C.     

Novel Colloidal Nanothermite Particles (MnO<Subscript>2</Subscript>/Al) for Advanced Highly Energetic Systems

Nanothermites (metal oxide/metal) are tremendously exothermic and run with self sustaining oxygen content. Manganese oxide is one of the most effective oxidizers for nanothermite applications. This paper reports on the sustainable fabrication of different nanoscopic forms of colloidal manganese oxides including: MnO₂ nanoparticles of 20 nm average particle size and Mn₂O₃ nanorods of 50 nm diameter and 1 µm length. TEM micrographs demonstrated mono-dispersed particles and rods. XRD diffractograms revealed highly crystalline materials. MnO₂ nanoparticles (oxygen content 37 wt%) can offer high oxidizing ability compared with Mn₂O₃ nanorods (oxygen content 30 wt%). The integration of colloidal particles into energetic matrix can offer enhanced dispersion characteristics; consequently stoichiometric binary mixture of MnO₂ and Al nanoparticles were re-dispersed in organic solvent. The integration of developed colloidal nanothermite particles into tri-nitro toluene offered enhanced shock wave strength by 35% using ballistic mortar test. Thanks to nanotechnology which offered sustainable manufacture and subsequent integration of one of the most effective nanothermite particles into highly energetic system.     

Transitions of domain ordering and domain size in a spherical-forming polystyrene-block-poly(ethylene oxide) copolymer and its composites with colloidal cadmium sulfide quantum dots

With specific annealing schemes applied to a neat polystyrene-block-poly(ethylene oxide) (SE) and its composites with cadmium sulfide quantum dots (CdS QD), we have observed microdomain structures and phase transitions in the system using temperature-resolved small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Both TEM images and SAXS results show clearly that incorporation of surfactant-tethered CdS QD preferentially into PEO blocks leads to increases in thermal stabilities of both bcc-packed lattice (referred as long-range order) and microdomains themselves in the sphere-forming SE/CdS composites. The bcc-packed lattice in the SE/CdS composites sustains better than that in the neat SE, during a temperature elevation to ∼160 °C, at which the bcc-packed SE/CdS spheres start to transform into micelles with a short-range liquid-like order. Quantitative model analysis shows that the PEO/CdS micelles can retain their size in the SE/CdS composites up to 200 °C, whereas the PEO micelles shrink after the softening of the PS matrix around 100 °C, and disassociate largely into the PS matrix of the neat SE at 160 °C.     

Construction of NiPx/MoS2/NiS/CdS composite to promote photocatalytic H2 production from glucose solution

Constructing multi-component photocatalyst is an efficient method to achieve high photocatalytic efficiency. In this work, CdS nanorods modified with NiS nanoparticles are first prepared to improve the photocatalytic performance, as no H₂ generates on single NiS or CdS catalyst from glucose solution. MoS₂ and NiP_x, as the cocatalysts for H₂ production, are loaded on the surface of NiS/CdS composite. With step-by-step solvothermal synthesis, four components (CdS, NiS, Mo₂S, and NiP_x) are fully combined in the NiP_x/MoS₂/NiS/CdS nanorods, generating many intimate contact interfaces. Moreover the optimized NiP_x/MoS₂/NiS/CdS performs a significantly increased photocatalytic activity, with H₂ production rate at 297 µmol h^–1 g^–1. The synergistic effects of heterostructure (NiS/CdS) and cocatalysts (MoS₂ and NiP_x) are the main reasons in enhancing photocatalytic performance, which facilitate the separation of charge carriers and prolong their lifetimes. This work provides an effective strategy to design photocatalysts with multiple components and fast charge separation for highly efficient H₂ production.