Nanoparticles of antimony sulfide by pulsed laser ablation in liquid media

In the present article, antimony sulfide nanoparticles have been synthesized by pulsed laser ablation of an antimony sulfide pellet in distilled water and isopropyl alcohol. The target was irradiated by 1064 and 532 nm from a pulsed Nd:YAG laser operated at 10 Hz and pulse width of 10 ns at room temperature. Analysis of the morphology, crystalline phase and elemental composition were done using transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The optical band gap energies of these colloidal nanoparticles were evaluated from UV–Visible absorption spectra. It was observed that the morphology, size, and optical properties of the antimony sulfide nanoparticles depend on the wavelength of the laser and the liquid media.     

One step synthesis of rutile TiO2 nanoparticles at low temperature

Sphere-like rutile TiO2 nanocrystals have been synthesized by sol-gel method followed by hydrolysis of titanium tetrachloride in deionized water in the presence of ammonium hydroxide as hydrolysis catalyst. The as-prepared TiO2 nanoparticles have single rutile phase with average diameter approximately 26.4 nm. The results show that the temperature has a great influence on the particle size distribution and also crystalline phase (rutile) of TiO2 nanoparticles is consistent with the temperature. Characterization of the as-prepared nanocrystalline powder was carried out by different techniques such as powder X-ray diffraction (XRD), field emission transmission electron microscopy (FE-TEM) and Raman spectroscopy.     

Structure and properties of lead and lead sulfide nanoparticles in natural zeolite

We have synthesized lead and lead sulfide nanoparticles embedded in a natural zeolite (clinoptilolite) matrix by a simple hydrothermal process. The process steps involve the partial removing of the natural cations in clinoptilolite, the ion-exchange process to enclose Pb ions and nanoparticles and finally a sulfuration process at different temperatures to obtain lead sulfide phases in the zeolite matrix. The samples were studied by X-ray diffraction, diffuse reflectance spectroscopy, energy dispersive X-ray spectroscopy, X-ray photon spectroscopy and transmission electron microscopy. The experimental results show the inclusion of three Pb species with different valence states after the Pb ion-exchange step, namely Pb²⁺, Pb⁴⁺, and Pb⁰. At the end of the process, two simultaneous lead sulfide crystalline phases, PbS (Galena) and PbS₂ (tetragonal) were synthesized in the clinoptilolite matrix. The optical absorption spectra of the samples show the exciton absorption peaks typical of colloidal PbS nanoparticles. The average size of the PbS nanoparticles was about 10 nm and their crystalline structure was determined from diffraction electron patterns. The high-pressure phase PbS₂ was also identified and its formation was attributed to the influence of the special conditions of clinoptilolite matrix as crystallization media to induce some selective nucleation process of this crystalline phase.     

Thin film deposition on plastic substrates using silicon nanoparticles and laser nanoforming

Reduced melting temperature of nanoparticles is utilized to deposit thin polycrystalline silicon (c-Si) films on plastic substrates by using a laser beam without damaging the substrate. An aqueous dispersion of 5 nm silicon nanoparticles was used as precursor. A Nd:YAG (1064 nm wavelength) laser operating in continuous wave (CW) mode was used for thin film formation. Polycrystalline Si films were deposited on flexible as well as rigid plastic substrates in both air and argon ambients. The films were analyzed by optical microscopy for film formation, scanning electron microscopy (SEM) for microstructural features, energy dispersive spectroscopy (EDS) for impurities, X-ray photoelectron spectroscopy (XPS) for composition and bond information of the recrystallized film and Raman spectroscopy for estimating shift from amorphous to more crystalline phase. Raman spectroscopy showed a shift from amorphous to more crystalline phases with increasing both the laser power and irradiation time during laser recrystallization step.     

Ag_2S纳米粒子的合成与表征

以油酸钠为表面活性剂、硝酸银和硫脲为反应物,在甲苯-水两相界面处合成了Ag_2S纳米粒子。采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)和广角X射线衍射(WAXD)等方法对Ag_2S纳米粒子的光学性质、形貌及晶体结构进行了表征。结果表明,通过改变甲苯-水两相界面反应体系的条件,可以得到粒子尺寸窄分布的Ag_2S纳米粒子;WAXD测定表明所合成的Ag_2S纳米粒子具有单斜结构。     

Synthesis and characterization of PbSe nanoparticles obtained by a colloidal route using Extran as a surfactant at low temperature

Lead selenide nanoparticles (PbSe NPs) have been obtained through an easy and low cost route using colloidal synthesis in aqueous solution. The synthesis was carried out at room temperature using Extran (Na?P?O??, NaOH and H?O) as surfactant. Hydrochloric acid (HCl) was used to eliminate the generated by-products. The size of PbSe NPs was varied by changing the Pb:Se molar concentration. The PbSe NPs were characterized by powder x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDAX), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The XRD measurements showed that the PbSe NPs have the face-centered cubic phase structure. The crystal size was found to be between 14 and 20 nm as calculated from the XRD patterns and these values were corroborated with SEM and TEM. Additionally, HRTEM micrographs showed crystalline planes at (200), (220) and (111) of the PbSe NPs, in agreement with the XRD results.     

Synthesis and characterization of ZnO/MgO solids prepared by deposition of preformed colloidal ZnO nanoparticles

The ZnO/MgO solids were prepared by colloidal technique which involves the deposition of preformed colloidal ZnO nanoparticles on magnesia. The morphology of ZnO nanoparticles was investigated by transmission electron microscopy and UV-Vis absorption and diffuse reflectance spectroscopy. We found a good agreement between the average radius and the particle size distribution of the ZnO nanoparticles obtained by both methods. It was shown the ability to control the size of the supported ZnO nanoparticles (3.8-4.4nm) by varying pH of the colloidal solution.     

Optical and structural characteristics of silicon nanoparticles thin film prepared by laser ablation

In this paper thin film of silicon nanoparticles on glass substrates have been prepared by dip-coating method using colloidal silicon nanoparticles generated by nanosecond laser ablation of silicon wafer in ethanol. The resulting nanoparticles and structural properties and morphology of thin film were characterized by UV-Visible absorption spectrometry, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction pattern and atomic force microscopy image. Nanoparticles with diameters ~ 9 nm were observed to be formed in the colloidal solution. The atomic force microscopy image of Si nanoparticles thin film shows that the overall average width is about 80 nm.     

Antibacterial activity of hybrid chitosan–cupric oxide nanoparticles on cotton fabric

In this study, cupric oxide (CuO) nanoparticles were prepared using sonochemical method. The prepared nanoparticles were studied using X‐ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. The colloidal chitosan (CS) solution was prepared using ultrasound irradiation method and simultaneously mixed with CuO nanoparticles. The coatings of colloidal solution with and without CuO nanoparticles were studied through TEM images. The cotton fabrics were separately soaked in the prepared nanoparticle‐containing (hybrid) solutions by sonication method followed by pad‐dry‐cure method. The structural, functional, and morphological analyses of the coated and uncoated fabrics were performed using XRD, FTIR‐attenuated total reflectance, and SEM analyses, respectively. The hybrid‐coated cotton fabrics showed better antibacterial activity against Staphylococcus aureus and Escherichia coli. The bioactivity performance of the coated fabrics was in the order of CuO‐coated fabric > CS‐coated fabric.Inspec keywords: cotton fabrics, nanoparticles, antibacterial activity, transmission electron microscopy, Fourier transform spectroscopy, infrared spectroscopy, scanning electron microscopy, copper compoundsOther keywords: antibacterial activity, hybrid chitosan‐cupric oxide nanoparticles, cotton fabric, cupric oxide nanoparticles, sonochemical method, X‐ray diffraction, XRD pattern, Fourier transform infrared spectroscopy, FTIR spectroscopy, scanning electron microscopy, SEM, transmission electron microscopy, TEM methods, colloidal chitosan solution, ultrasound irradiation method, colloidal solution, TEM images, cotton fabrics, nanoparticle‐containing solutions, sonication method, pad‐dry‐cure method, morphological analyses, structural analyses, functional analyses, FTIR‐attenuated total reflectance, SEM analyses, hybrid‐coated cotton fabrics, Staphylococcus aureus, Escherichia coli, bioactivity performance, CuO     

Necklace-shaped Au-Ag nanoalloys: laser-assisted synthesis and nonlinear optical properties

Here in this paper, necklace-shaped Au-Ag nanoalloys (NAs) have been synthesized by a laser-based approach. A chain of Ag nanoparticles (NPs), which were joined together with Au junctions, was formed upon copper vapor laser (CVL) irradiation of a colloidal mixture of Ag and Au NPs; while the corresponding NPs were separately provided by laser ablation of gold and silver targets in deionized water by a 1064 nm Q-switched Nd:YAG laser. Dependence of the NAs development process on the CVL irradiation time in three distinct stages of as-mixed, nucleation and complete formation has been systematically studied by UV-vis optical absorption spectroscopy analysis as well as by transmission electron microscopy (TEM), which was exploited to visually confirm the NAs evolution through the process. Furthermore, the x-ray photoelectron spectroscopy (XPS) technique was accurately employed to determine the synthesized alloy content. On the other hand, using the open-and closed-aperture Z-scan technique, the nonlinear absorption (NLA) as well as nonlinear refraction (NLR) changes in Au-Ag NAs were investigated through their formation. The deduced results from the nonlinear optical properties of the colloidal NAs in the mentioned stages were interpreted considering the spectroscopic and microscopic observations. The total change of individual Au and Ag NPs saturable absorption (SA) into the reverse saturable absorption (RSA) behavior was concluded through the evolution into Au-Ag NAs.     

Stoichiometry of alloy nanoparticles from laser ablation of PtIr in acetone and their electrophoretic deposition on PtIr electrodes

Charged Pt-Ir alloy nanoparticles are generated through femtosecond laser ablation of a Pt?Ir target in acetone without using chemical precursors or stabilizing agents. Preservation of the target's stoichiometry in the colloidal nanoparticles is confirmed by transmission electron microscopy (TEM)-energy-dispersive x-ray spectroscopy (EDX), high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM)-EDX elemental maps, high resolution TEM and selected area electron diffraction (SAED) measurements. Results are discussed with reference to thermophysical properties and the phase diagram. The nanoparticles show a lognormal size distribution with a mean Feret particle size of 26 nm. The zeta potential of -45 mV indicates high stability of the colloid with a hydrodynamic diameter of 63 nm. The charge of the particles enables electrophoretic deposition of nanoparticles, creating nanoscale roughness on three-dimensional PtIr neural electrodes within a minute. In contrast to coating with Pt or Ir oxides, this method allows modification of the surface roughness without changing the chemical composition of PtIr.     

Green Synthesis of Silver Nanoparticles Using Salacia chinensis: Characterization and its Antibacterial Activity

The aim of the present research work was to synthesize silver nanoparticles (AgNPs) using Salacia chinensis plant extract and to evaluate its antibacterial activity. AgNPs were successfully synthesized and formation of AgNPs was confirmed by visual color change and UV (ultraviolet) spectroscopy. Prepared AgNPs were purified and characterized by using dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDAX), and transmission electron microscopy (TEM). UV peak at 434 nm confirmed the formation of AgNPs. DLS studies showed that AgNPs size prepared in all conditions were in the range of 100–200 nm. XRD studies revealed crystalline nature of AgNPs. EDAX studies confirmed the presence of silver in colloidal dispersion and images were recorded by using SEM and TEM. Synthesized AgNPs were found to be effective against Staphylococcus aureus and Pseudomonas aeruginosa. In conclusion, AgNPs could serve as a good alternative in treatment of bacterial infections in this era of multidrug resistance.     

Self-assembly directed synthesis of poly(ortho-toluidine)-metal(gold and palladium) composite nanospheres

Poly(ortho-toluidine) (POT)-gold (Au) and palladium (Pd) composite nanospheres were successfully synthesized by the reaction of o-toluidine with the corresponding metal (Au or Pd) colloidal solution through self-assembly process in the presence of dodecylbenzenesulfonic acid (DBSA), which acts as both a dopant and surfactant, and ammonium peroxydisulfate as an oxidizing agent. The composites (POT-DBSA/Au or Pd) were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, UV-Visible (UV-Vis) spectroscopy, and electrical conductivity measurements. TEM images of the nanocomposites reveal that metal (Au or Pd) nanoparticles were well dispersed on POT spheres. TGA and XRD results show that the composites exhibit high thermal stability and are more crystalline compared with pristine POT. It was found that the electrical conductivity of the POT-DBSA/Au or Pd composites is 2 orders of magnitude higher than that of pristine polymer. Also, the POT-DBSA/Pd composite exhibits magnetic property. The formation mechanism of the POT-DBSA/Au or Pd composite nanosphere is discussed.     

Plants used in folkloric medicine of Iran are exquisite bio‐resources in production of silver nanoparticles

This study reports screening of 102 Iranian medicinal plant species belonging to 49 families for the biosynthesis of colloidal silver nanoparticles (AgNPs). Among tested plants, 37 species in 19 plant families are new bio‐resources in this regard. Water extracts of macerated plant parts are used in this survey. Six of the bioactive plants are selected for further analysis. They produced amorphous spherical 40–70 nm AgNPs. Biosynthesised colloidal AgNPs are characterised by UV–visible spectroscopy, transmission electron microscopy and scanning electron microscopy. Families of Lamiaceae (8 out of 12), Leguminosae (7 out of 9), Liliaceae (4 out of 7) contained most bio active species. No correlation noticed between bioactivity and pH of plant water‐extracts. The simple procedure used in this study may form a platform for mass production of environmentally safe and eco‐friendly green production of these multipurpose AgNPs in future; however, optimisation protocols need to be well documented.Inspec keywords: silver, nanoparticles, drugs, ultraviolet spectroscopy, visible spectroscopy, scanning electron microscopy, pH, agriculture, nanobiotechnologyOther keywords: folkloric medicine, screening, Iranian medicinal plant species, biosynthesis, colloidal silver nanoparticles production, bioresources, plant water extracts, macerated plant parts, bioactive plants, amorphous spherical AgNP, UV–visible spectroscopy, transmission electron microscopy, scanning electron microscopy, Lamiaceae, Leguminosae, Liliaceae, pH, mass production, environmentally safe green production, eco‐friendly green production     

A versatile approach for the fabrication of Au hollow nanoparticles based on poly(styrene-co-2-aminoethyl methacrylate) template

The hollow Au nanospheres were successfully prepared by the template method. The poly(styrene-co-2-aminoethyl methacrylate hydrochloride) (P(St-co-AEMH)) nanoparticles synthesized by the emulsion polymerization were used as the templates. After coating by Au colloidal nanoparticles and the formation of Au shells, the interior templates were etched out by sulfuric acid, leading to the formation of Au hollow nanospheres. The structure and morphology of the nanoparticles and hollow nanospheres were carefully investigated by the fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), wide-angle X-ray diffractometer (WAXD), and thermal gravimetric analysis (TGA) techniques.     

Deposition of metallic nanoparticles on carbon nanotubes via a fast evaporation process

A new technique was developed for the deposition of colloidal metal nanoparticles on carbon nanotubes. It involves fast evaporation of a suspension containing sonochemically functionalized carbon nanotubes and colloidal nanoparticles. It was demonstrated that metallic nanoparticles with different sizes and concentrations can be deposited on the carbon nanotubes with only a few agglomerates. The technique does not seem to be limited by what the nanoparticles are, and therefore would be applicable to the deposition of other nanoparticles on carbon nanotubes. PtPd and CoPt(3) alloy nanoparticles were used to demonstrate the deposition process. It was found that the surfactants used to disperse the nanoparticles can hinder the nanoparticle deposition. When the nanoparticles were washed with ethanol, they could be well deposited on the carbon nanotubes. The obtained carbon nanotube supported metal nanoparticles were characterized by transmission electron microscopy, energy dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and cyclic voltammetry.     

Synthesis of noble metal/carbon nanotube composites in supercritical methanol

A simple and efficient route has been employed to deposit noble metal nanoparticles (Pt, Ru, Pt-Ru, Rh, Ru-Sn) onto carbon nanotubes (CNTs) in supercritical methanol solution. In this method, the inorganic metallic salts acted as metal precursors, and methanol as solvent as well as reductant for the precursors. The as-prepared nanocomposites were structurally and morphologically characterized by X-ray diffraction spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy, and X-ray photoelectron spectroscopy analyses. It was demonstrated that the CNTs were decorated by crystalline metal nanoparticles with uniform sizes and a narrow particle size distribution. The size and loading content of the nanoparticles on CNTs could be tuned by manipulating reaction parameters. Furthermore, the formation mechanism of the composites was also discussed.     

形貌可控的TiO2纳米晶的溶胶凝胶-水热法组合制备

以四烷基氢氧化铵为结构导向剂,正丁醇为结构导向助剂,采用溶胶凝胶-水热法组合制备了不同形貌的二氧化钛纳米晶.通过TG/DTA、TEM、XRD、DLS等手段对产物进行了结构和形貌表征.研究表明,通过选择结构导向剂的烷基种类可分别得到四方型和纺锤型纳米晶,在一定范围内改变其浓度则可以控制晶体的晶化度、分散性和颗粒尺寸.     

Analysis and optimization of silver nanoparticles laser synthesis with emission spectroscopy of induced plasma

Emission spectroscopy of the laser induced plasma is used to characterize the laser synthesis of silver nanoparticles in water via attributing the thermodynamic parameters of the plasma plume to qualitative features of the synthesized nanoparticles. In this approach, effects of the pulse energy and frequency of a pulsedNd:YAGlaser on nanoparticles synthesis yield and size distribution is studied by an analysis on the behavior of electron temperature and total density of the plasma dominant species (neutral Ag atoms; AgI). Variation of these thermodynamic parameters obtained from the time-integrated emission spectroscopy of the induced plasma was found to be in a closed correlation with the mentioned characteristics of the synthesized nanoparticles. Assessment of the qualitative features of nanoparticles was performed by evaluating the particles concentration in liquid, optical absorption spectroscopy and transmission electron microscopy. Finally, the optimum operating conditions for the synthesis of silver nanoparticles in pure water is determined by summarizing the results of emission spectroscopy observations attributed to the mentioned characteristics of synthesized nanoparticles.     

Facile synthesis and catalytic properties of silver colloidal nanoparticles stabilized by SDBS

A facile method was explored to prepare stable silver colloidal nanoparticles (AgCNPs) in water. Sodium dodecyl benzene sulfonate (SDBS) was used as the stabilizing agent, without addition of any co-surfactant. The reaction was rapid and the product prepared at different conditions was measured by transmission electron microscopy (TEM) and UV-Vis spectroscopy. The results showed that AgCNPs stabilized by SDBS was stable in water with narrow size distribution (1–5 nm). The amount of surfactant has great influence on the products. When the molar ratio of Ag⁺ to SDBS increased to 1: 4, AgCNPs can be obtained with high dispersion (2–3 nm), which has high catalytic activity on reduction of 4-nitrobenzoic acid to 4-aminobenzoic acid.