Ag Crystalline Research Articles

Effects of AgO incorporation with 2D rGO nanocomposite characteristics and its beneficial electrochemical detection of acetaminophen

In this study, the AgO/rGO nanocomposite was facile synthesized via green molecules controllable route using Ocimum tenuiflorum leaf extract. And, we delve into the electrochemical sensing capacity of nanocomposite for the detection of both acetaminophen and 4-nitrophenols. XRD study revealed that the wider (002) rGO diffraction plane integrates with the Ag crystalline characteristic, with a nanocomposite crystallite size of 10.3 nm. Ocimum tenuiflorum biomolecules effectively reduced the metal ions as well as graphene oxide to the expected elemental compound. The incorporation of various leaf biomolecules such as poly-phenolic and alkaloids was bonded with rGO sheet position in the form of C-OH, C–H, N–H, with C = C molecular presence. The efficient interfacial contact between Ag, O and C (rGO) were investigated using XPS, which claimed that the biomolecular group phenol (O–H) with metallic compound as C-O-Ag around 533.9 eV, which has a significant witness for biomolecules incorporations. An identifiable count of elongated spherical-shaped Ag nanoparticles was stacked as well as incorporated between the thin rGO layers with 31.5 nm of particle size was confirmed by HR-TEM analysis. The electrochemical sensing parameters for acetaminophen the proposed sensor exhibits the lowest limit of detection of 0.25 mM for the linear range of concentrations 0.005 to 0.3 mM and 4-aminophenol exhibits the lowest limit of detection of 0.012 mM for the linear range of concentrations 0.001 to 0.3 mM. Overall, this research underscores the potential of AgO/rGO as a robust and efficient platform for achieving enhanced sensitivity in electrochemical sensing applications.

High-Performance Ag 2 Se/Methyl Cellulose Thermoelectric Composites for Flexible Power Generators

Flexible thermoelectric generators (FTEGs) offer a promising solution for powering wearable electronics, while their practical applications are mainly obstructed by the moderate properties of flexible thermoelectric (TE) materials. Here, flexible Ag 2 Se nanowire (NW)/methyl cellulose (MC) composite films were developed via facile screen-printing technology combined with cold pressing and annealing treatment, and a highest power factor of 1,641.58 μW m −1 K −2 at 360 K was achieved. The reasons for the high TE performance of the Ag 2 Se NW/MC composite films were because, after the annealing treatment, the Ag 2 Se NWs were sintered to form conductive network structures, the crystallinity of Ag 2 Se was markedly enhanced, and the content of insulating phase MC in the composite film was decreased. The Ag 2 Se NW/MC composite film held appreciable flexibility, as its room-temperature power factor (1,312.08 μW m −1 K −2 ) can retain ~93% after bending for 1,000 cycles at a radius of 4 mm. Furthermore, the assembled FTEG consisting of 4 strips can generate a maximal power density of 3.51 W m −2 at a temperature difference of 14.1 K. Our results open an effective and large-scale strategy for fabricating high-performance flexible TE materials and energy-harvesting devices.

Eco-Friendly Green Synthesis and Photocatalyst Activity of Ag-ZnO Nanocomposite

The study successfully synthesized Ag NPs, ZnO NPs, and Ag/ZnO nanocomposites using an easy, cost effect and sustainable green synthetic approach. The purpose of synthesizing Ag/ZnO nanocomposites using two different plant extracts was to study their photo-degradation activity on Methylene Blue (MB) dye. (XRD) diffraction analysis confirmed the presence of Ag crystalline size and the wurtzite hexagonal structure of ZnO. (FE-SEM) results indicated spherical, nanorods and there is Clustering of NPs with an irregular shape. The resulting metal/semiconductor oxide nanocomposites possessed unique photo degradation characteristics that were absent in the individual Ag NPs and ZnO NPs.

Rumex hastatus derived silver nanoparticles development and their potential applications as hepatic-protection agent along with antimicrobial activity

Current study aimed to develop eco-friendly and cost-effective approaches for silver nanoparticle (AgNPs) synthesis using leaf extract of Rumex hastatus and characterization using various analytical techniques. Besides, the crystallinity of Ag+, reduction/stability, functional groups and structural morphology were determined through X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR spectroscopy) and scanning electron microscopy (SEM) respectively. The biosynthesized RH-AgNPs were investigated for hepatoprotective and cytotoxic effect, antioxidative activities and antimicrobial potential. Results revealed that RH-AgNPs were effective against hepatotoxin (carbon tetrachloride) at all tested concentrations by exhibiting very valuable results; showed high antioxidant potential and cytotoxic effect against HepG2 cancer cell lines. RH-AgNPs showed very promising antibacterial results as well. Overall, these results highlighted the potential of RH-AgNPs to be used for the treatment of various diseases.

An Investigation of Physicochemical and Biological Properties of Rheum emodi-Mediated Bimetallic Ag–Cu Nanoparticles

An eco-friendly and cost-effective technique for the synthesis of R. emodi roots extract (RERE)-mediated bimetallic silver–copper nanoparticles (Ag–Cu NPs) with anticancer and antibacterial applications are reported in the present investigation. Ag–Cu NPs were characterized using different techniques such as UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy and X-ray diffraction (XRD) to reveal physicochemical properties. The XRD analysis illustrates the face-centered cubic crystallinity of Ag–Cu NPs with $$Fm\bar{3}m$$ space group and space group no. 225. FTIR analysis portrays that the phytochemicals present in the RERE play a key role in stabilizing the Ag–Cu NPs. The optical analysis was carried out through UV–Vis spectroscopy. TEM analysis shows that Ag–Cu NPs are spherical in dimension with an average particle size of range between 40 and 50 nm. SAED ring pattern of Ag–Cu NPs reveals the crystalline nature which completely complements the XRD studies. In the present study, anticancer and antibacterial activities were evaluated against breast cancer cell lines (MDA-MB-231) and bacterial strains (Escherichia coli and Staphylococcus aureus).

Optimization of Cr Seed Layer Effect for Surface Roughness of As-Deposited Silver Film using Electron Beam Deposition Method

The surface roughness is an important parameter in determining the physical properties and quality of thin films deposited by physical vapor deposition (PVD) method. The presence of an intermediate layer between metallic nanoparticles and substrate significantly promotes the adhesion and reduces the surface roughness. In this article, we have investigated the effect of Chromium (Cr) seed layer to optimize the surface roughness on the growth of as-deposited silver (Ag) film using borosilicate glass and silicon wafer substrates. For this purpose, Ag thin films were deposited with a Cr seed layer of different thickness on borosilicate glass and silicon wafer substrates using an electron beam (E-Beam) deposition method. The Cr thin film of different thickness ranging from 1 nm to 6 nm was thermally evaporated and pure Ag with the same thickness was evaporated at the same rate on previously coated substrates. The deposition of the nanostructured thin film was confirmed by UV-Vis and XRD characterizations. The difference in transmittance for uncoated and coated substrates ensured the deposition. The presence of pure Ag crystalline phase was confirmed by XRD pattern. Surface roughness was measured using Atomic Force Microscopy (AFM) and the conductance was measured using 4-probe conductivity method. The density of nanoparticles and smoothness were visualized from two dimensional (2D) and three dimensional (3D) surface height histograms of representative AFM images. The quantitative roughness was measured in terms of root mean square (RMS) roughness and mean roughness. The high dense and smoother thin films were found for ~2-4 nm Cr layer thickness in case of the glass substrate. The slight increase in roughness was observed for ~1-6 nm Cr layer thickness in case of the silicon substrate. The dependence of the conductivity of thin films on surface roughness is investigated to verify the effect of surface roughness on different applications of Ag thin film. The conductance results have been analyzed as; for a glass substrate, conductivity was maximum for thin films containing ~2 nm Cr seed layer thickness, while for silicon substrate the maximum conductivity was found for the thin film containing ~1 nm Cr seed layer.

Optimization of Cr Seed Layer Effect for Surface Roughness of As-Deposited Silver Film using Electron Beam Deposition Method

The surface roughness is an important parameter in determining the physical properties and quality of thin films deposited by physical vapor deposition (PVD) method. The presence of an intermediate layer between metallic nanoparticles and substrate significantly promotes the adhesion and reduces the surface roughness. In this article, we have investigated the effect of Chromium (Cr) seed layer to optimize the surface roughness on the growth of as-deposited silver (Ag) film using borosilicate glass and silicon wafer substrates. For this purpose, Ag thin films were deposited with a Cr seed layer of different thickness on borosilicate glass and silicon wafer substrates using an electron beam (E-Beam) deposition method. The Cr thin film of different thickness ranging from 1 nm to 6 nm was thermally evaporated and pure Ag with the same thickness was evaporated at the same rate on previously coated substrates. The deposition of the nanostructured thin film was confirmed by UV-Vis and XRD characterizations. The difference in transmittance for uncoated and coated substrates ensured the deposition. The presence of pure Ag crystalline phase was confirmed by XRD pattern. Surface roughness was measured using Atomic Force Microscopy (AFM) and the conductance was measured using 4-probe conductivity method. The density of nanoparticles and smoothness were visualized from two dimensional (2D) and three dimensional (3D) surface height histograms of representative AFM images. The quantitative roughness was measured in terms of root mean square (RMS) roughness and mean roughness. The high dense and smoother thin films were found for ~2-4 nm Cr layer thickness in case of the glass substrate. The slight increase in roughness was observed for ~1-6 nm Cr layer thickness in case of the silicon substrate. The dependence of the conductivity of thin films on surface roughness is investigated to verify the effect of surface roughness on different applications of Ag thin film. The conductance results have been analyzed as; for a glass substrate, conductivity was maximum for thin films containing ~2 nm Cr seed layer thickness, while for silicon substrate the maximum conductivity was found for the thin film containing ~1 nm Cr seed layer.

Enhancing of cotton fabric antibacterial properties by silver nanoparticles synthesized by new Egyptian strain Fusarium keratoplasticum A1-3.

Spectral analysis of biogenic silver nano-particles (AgNPs) produced by Fusarium keratoplasticum A1-3 showed absorption at 400 nm which is used as a monitor for the formation of silver nanoparticles. TEM analysis indicated the formation of spherical AgNPs in size range from 6 to 36 nm. The band at 1650.13 cm−1 in FTIR analysis refers to the binding vibrations of amide I band of protein with N–H stretching band. XRD pattern of Ag-NPs indicated silver Ag crystalline phase indexed; the particle size of the so obtained AgNPs was poly dispersed mixture with diameter average of 54.33 (92.7%) with Zeta potential (mV) -23.7. AgNPs were applied to enhance antibacterial properties of cotton fabric with 86% and 93% growth reduction of test pathogenic bacterial strains.

Effect of Substrate Temperatures on Structural and Morphological Properties of Nano-Crystalline Silver Thin Films Grown on Silicon Substrates

The silver (Ag) thin films were deposited on silicon substrates by DC magnetron sputtering method under different substrate temperatures of 100–500 °C. Then the as-deposited films were subjected to annealing treatment. The XRD results revealed that the Ag thin films have a good nanocrystalline structure and a considerable increase in the crystallinity of Ag (111) peak was observed at substrate temperature of 200 °C. The average crystalline size of Ag films varied between 18 and 44 nm which confirms the presence of nanocrystal’s in the films. The AFM and SEM images demonstrated that the grain size and surface roughness of the films are sensitive to substrate temperature during deposition of the films and annealing treatment. The SEM results is in good agreement with the results of XRD and AFM analysis.

Growth and characterization of single phase AgInS2 crystals for energy conversion application through β-In2S3 by thermal evaporation

Silver indium sulfide thin films have been successfully synthesized out from β-In2S3 buffer layers using appropriate heat treatments of evaporated β-In2S3/Ag. X-ray analysis show that the β-In2S3/Ag crystalline films with 60nm thickness of Ag, which were annealed under sulfur atmosphere at 400°C, were mainly formed by the ternary AgInS2. Raman spectra confirmed that the observed peaks were characteristics to AgInS2 chalcopyrite of thin film structure. The optical band gap of AgInS2, which was evaluated as nearly 1.80eV, was confirmed by the electrical study which yielded a value in the order of 1.78eV. The electrical conductivity, conduction mechanism, dielectric properties and relaxation model of this thin film were studied using impedance spectroscopy technique in the frequency range 5Hz–13MHz under various temperatures (370–440°C). Besides, complex impedance, AC conductivity and complex electric modulus have been investigated on the basis of frequency and temperature dependence.

Green synthesis of water-dispersible silver nanoparticles at room temperature using green carambola (star fruit) extract

Silver nanoparticles (AgNPs) dispersible in water were synthesized at room temperature in the presence of carambola fruit extract at different pH. The UV–Vis absorption revealed that with increase in pH of the solution, the intensity of the peaks became higher and narrower along with blue shift signifying decrease in particle size. Crystallinity of Ag in the synthesized product was determined by X-ray diffraction. Fourier transform infrared spectroscopy confirmed the presence of polyols, aldehydes, amines and organic acids in the fruit extract which became useful as capping and reducing agent for the synthesis of AgNPs. Transmission electron microscopy showed the average particle size of Ag as 16, 13 and 12 nm for pH 4, pH 7 and pH 10, respectively, while the corresponding sizes determined by DLS method were found to be 169, 134 and 80 nm. The high negative zeta potential values indicated dispersion stability of AgNPs. The present method is important in terms of green, energy-efficient and environmentally friendly process.

Preparation and properties of Ag/DLC nanocomposite films fabricated by unbalanced magnetron sputtering

Silver (Ag)/diamond-like carbon (DLC) nanocomposite films with different Ag concentrations ranging from 0 to 11.02at.% were prepared by medium frequency unbalanced magnetron sputtering, in which the mixed Ar/CH4 of different volume ratios were used as the source gases. The doping effects of Ag concentration on microstructure, mechanical and vacuum tribological properties of the DLC films were investigated. It is found that the Ag concentration increased with the increasing Ar/CH4 ratios, accompanied with the increasing number and size of Ag crystalline. With moderate incorporation of Ag at 3.55at.%, the film (deposited at the Ar/CH4=65/45) maintained a low internal stress without considerable decrease of hardness and thus improved the adhesion strength. Moreover, the film showed low friction coefficient and the longest sliding lifetime in vacuum. The significant improvement in tribological properties of Ag/DLC nanocomposite films with moderate Ag concentration can be attributed to the low shear strength of Ag clusters on the surface, as well as the diffusion of Ag from the bulk to the surface and wear track.

Briefly brominated Ag thin films: XRD, FESEM, and optical studies of surface modification

Nanoparticulate silver thin films have been prepared on glass substrates by thermal evaporation and their surface modification was triggered by brief (<10min) bromination carefully monitored ex situ using structural, microscopic and optical probes. X-ray diffraction reveals that this sample remains amorphous even after brief bromination which gave the crystallinity of Ag. The optical absorption of the samples manifests the surface plasmon resonance (SPR) phenomena, which is very sensitive to bromination time and also varies with Ag film thickness. The number density of Ag particles decreases even as their mean size increases upon bromination. Optimization of the bromination process of a new type of plasmonic material could lead to applications in sensor, SERS-active substrates and plasmonic technologies.

XRD, optical and AFM studies on pristine and partially iodized Ag thin film

This study has shown that thermally evaporated Ag thin films neither too thin (ultra-thin) nor too thick (foil)—50 and 130nm thick films used here—are ideal for investigating surface modification by a simple iodization procedure for less than ∼15min. XRD, optical, AFM have helped track the interesting changes such as appearance of surface plasmon absorption and initiation of Ag crystalline formation at the nanostructure level. The 50nm, Ag films show gradual development of surface Plasmon resonance and brood visible bands forward by raising absorption in contrast 130nm Ag films show flat absorbance over the wavelength 350–800nm with absorbance systemically reducing upon the increase of iodization time. The systemic trends absorbance spectra should be useful in the design of detector bases in the iodine. Nanostructures supporting localized plasmons are the subject of intense research for their applications in plasmonics including nanophotonic devices, chemical sensors, and optical filters.

Sonochemical synthesis and characterization of ZnO nanorod/Ag nanoparticle composites

AbstractA simple sonochemical route for the synthesis of Ag nanoparticles on ZnO nanorods is reported. Ultrasonic irradiation of a mixture of ZnO nanorods, Ag(NH3)2+, and formaldehyde in an aqueous medium yields ZnO nanorod/Ag nanoparticle composites. The powder X‐ray diffraction of the ZnO/Ag composites shows additional diffraction peaks corresponding to the face‐center‐cubic structured Ag crystalline, apart from the signals from the ZnO nanorods. Scanning electron microscopy and transmission electron microscopy images of the ZnO/Ag composites reveal that the ZnO nanorods are coated with Ag nanoparticles with a mean size of several tens nanometer. The absorption band of ZnO/Ag composites is distinctly broadened and red‐shifted, indicating the strong interfacial interaction between ZnO nanorods and Ag nanoparticles. This sonochemical method is simple, mild and readily scaled up, affording a simple way for synthesis of other composites. (© 2009 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Mechanical properties of AgCo nanostructured nanowires

The mechanical deformation properties of nanostructured AgCo nanowires were studied by Molecular Dynamics (MD) under uniaxial tensile and compressive stresses. The cohesion of the immiscible AgCo system was modeled by an Embedded Atom Model (EAM). Crystalline Co grains were embedded into a Ag crystalline matrix and the whole system was set to relax by MD at 300 K. The Ag crystal structure turned out to be unstable and to transform into the same layered structure as was already predicted in AgCo nanoclusters and AgCo Cluster Assembled Materials (CAM). Deformation was modeled by varying the length of the nanowire in the axial direction. Both isothermal and isoenergetic—whereby mechanical work converts into heat in the system—deformation mechanisms were considered. In contrast with the case of AgCo CAM where an elastic regime was identified, deformation of AgCo nanowires was never found fully elastic, whatever the magnitude of the deformation. In case of constant temperature deformation, Ag kept its layered structure and the Co grains kept crystalline. At constant energy, as a consequence of the rise of temperature, phase separation and melting took place whereby a coaxial structure was formed with the Co covered by Ag.