scholarly journals Reducing the Crystallite Size of Spherulites in PEO-Based Polymer Nanocomposites Mediated by Carbon Nanodots and Ag Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 874 ◽  
Author(s):  
Ranjdar Abdullah ◽  
Shujahadeen Aziz ◽  
Soran Mamand ◽  
Aso Hassan ◽  
Sarkawt Hussein ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Polymer Nanocomposites ◽  
Electron Transition ◽  
Peak Position ◽  
Carbon Nanodots ◽  
Ag Nps ◽  
Peak Broadening ◽  
Vis Spectroscopy ◽  
Solution Cast ◽  
Significant Change

The PEO-based polymer nanocomposites were prepared by solution cast method. Green approaches were used for synthesis of carbon nanodots (CNDs) and silver nanoparticles (Ag NPs). It was found that the crystallite size of spherulites of PEO was greatly scarified upon incorporation of CNDs and Ag NPs. In the present work, in opposition to other studies, broadening of surface plasmon resonance (SPR) peak of metallic Ag NPs in PEO-based polymer composites was observed rather than peak tuning. Various techniques, such as powder X-ray diffraction (XRD), SEM, UV–Vis spectroscopy, and photoluminescence (PL), were used to characterize the structural, morphological, and optical properties of the samples. Increase of amorphous phase for the PEO doped with CND particles was shown from the results of XRD analyses. Upon the addition of suspended Ag NPs to the PEO:CNDs composites, significant change of XRD peak position was seen. A field-emission scanning electron microscope (FESEM) was used to investigate the surface morphology of the samples. In the SEM, a significant change in the crystalline structure was seen. The size of PEO spherulites in the PEO nanocomposite samples became smaller and the percentage of amorphous portion became larger, owing to the distribution of CNDs and Ag NPs. The UV–Vis absorption spectra of the PEO-based polymer were found to improve and shift to higher wavelengths upon incorporation of CNDs and Ag NPs into the PEO matrix. The SPR peak broadening in the UV–Vis spectra was observed in the PEO:CNDs composites due to the Ag NPs. The absorption edge value of PEO was found to shift toward lower photon energy as the CNDs and Ag NPs are introduced. The photoluminescence (PL) spectra were also observed for the PEO:CNDs and PEO:CNDs:Ag samples and found to be more intense in the PEO:CNDs system than in the PEO:CNDs:Ag system. Lastly, the optical band gap of the samples was further studied in detail using of Tauc’s model and optical dielectric loss parameter. The types of electron transition were specified.

A comparative study on characterizations and synthesis of pure lead sulfide (PbS) and Ag-doped PbS for photovoltaic applications

2021 ◽  
Vol 10 (1) ◽  
pp. 1484-1492
Author(s):  
Muhammad Hasnain Jameel ◽  
Shahroz Saleem ◽  
Muhammad Hashim ◽  
Muhammad Sufi Roslan ◽  
Hamoud Hassan Naji Somaily ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Lead Sulfide ◽  
Average Crystallite Size ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Pure Lead ◽  
Vis Spectroscopy ◽  
Small Lattice ◽  
Device Applications

Abstract In this study, a hydrothermal technique was used to synthesize lead sulfide (PbS) and silver (Ag)-doped PbS nanoparticles (NPs) at different concentrations of 20, 40, and 60% of Ag. The small lattice phase changes appeared due to the shifting of diffraction angle peaks toward higher 2θ for samples doped with PbS with increasing Ag content. The analysis of average crystallite size, phase structure, and lattice constant was observed under X-ray diffraction. The value of crystallite size, volume of the unit cell, and porosity (%) were found to increase with the increasing concentration of Ag NPs in PbS. The pure PbS crystallite size is small compared to Ag-doped PbS. The optical characteristics including absorption spectra of the prepared samples were investigated and confirmed by using scanning electron microscope and UV-Vis spectroscopy. The observation of the composition showed that higher doping concentrations of Ag lead to an increase in particle size. Absorption peaks in the UV-Vis spectra corresponding to pure and 20, 40, and 60% of Ag/PbS were observed at different wavelengths of 368, 369, 371, and 372 nm, respectively. Fourier transformation infrared spectroscopy peaks were found in the vibration mode of the ions due to the increment in Ag doping concentrations. These results indicate the possibility of tuning the optical structural properties of Ag-doped PbS through doping various concentrations of Ag NPs. Ag-doped PbS is considered promising future semiconductor nanomaterial, which will enhance the efficiency of photovoltaic device applications.

scholarly journals Green synthesis of silver nanoparticles: Characterization and its potential biomedical applications

2021 ◽  
Vol 10 (1) ◽  
pp. 412-420
Author(s):  
Mona S. Alwhibi ◽  
Dina A. Soliman ◽  
Manal A. Awad ◽  
Asma B. Alangery ◽  
Horiah Al Dehaish ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Aloe Vera ◽  
Inhibition Zone ◽  
Biologically Active ◽  
Noble Metal Nanoparticles ◽  
Biological Synthesis ◽  
Ag Nps ◽  
Mouse Melanoma ◽  
Therapeutic Benefits ◽  
Vis Spectroscopy

Abstract In recent times, research on the synthesis of noble metal nanoparticles (NPs) has developed rapidly and attracted considerable attention. The use of plant extracts is the preferred mode for the biological synthesis of NPs due to the presence of biologically active constituents. Aloe vera is a plant endowed with therapeutic benefits especially in skincare due to its unique curative properties. The present study focused on an environmental friendly and rapid method of phytosynthesis of silver nanoparticles (Ag-NPs) using A. vera gel extract as a reductant. The synthesized Ag-NPs were characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier transform infrared (FTIR), and dynamic light scattering (DLS). TEM micrographs showed spherical-shaped synthesized Ag-NPs with a diameter of 50–100 nm. The UV-Vis spectrum displayed a broad absorption peak of surface plasmon resonance (SPR) at 450 nm. The mean size and size distribution of the formed Ag-NPs were investigated using the DLS technique. Antibacterial studies revealed zones of inhibition by Ag-NPs of A. vera (9 and 7 mm) against Pseudomonas aeruginosa and Escherichia coli, respectively. Furthermore, the antifungal activity was screened, based on the diameter of the growth inhibition zone using the synthesized Ag-NPs for different fungal strains. Anticancer activity of the synthesized Ag-NPs against the mouse melanoma F10B16 cell line revealed 100% inhibition with Ag-NPs at a concentration of 100 µg mL−1. The phytosynthesized Ag-NPs demonstrated a marked antimicrobial activity and also exhibited a potent cytotoxic effect against mouse melanoma F10B16 cells. The key findings of this study indicate that synthesized Ag-NPs exhibit profound therapeutic activity and could be potentially ideal alternatives in medicinal applications.

scholarly journals Nanocatalytic Activity of Silver Nanoparticles (Ag-Nps) Fabricated using Camellia sinensis (Linn) Tender Leaf Extract and their Characterization

2020 ◽  
Vol 2 (1) ◽  
pp. 24
Keyword(s):  
Silver Nanoparticles ◽  
Zeta Potential ◽  
Pancreatic Enzyme ◽  
Alpha Amylase ◽  
Assay Method ◽  
Ag Nps ◽  
Visible Absorption ◽  
Biological Reduction ◽  
Vis Spectroscopy ◽  
Uv Visible

Silver nanoparticles (Ag-NPs) were prepared by the biological reduction method. Green tea extract was taken as a reducing and stabilizing agent and silver nitrate as the metal precursor for nanoparticle synthesis. The formation of the silver nanoparticles was monitored visually and using UV-Visible absorption spectroscopy. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, FTIR, Zeta sizer, Zeta potential, and antimicrobial studies. Silver nanoparticles were also subjected to investigate nanocatalytic activity with standard pancreatic alpha-amylase and bacterial amylase enzyme by the DNS assay method. UV-Vis spectroscopy revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption maxima at 430 nm. Four major functional groups of bio-molecules such as phenol, carboxylic acid, protein, and alkyl group were recorded in FTIR spectra. The size of the nanoparticles ranges between 5nm and 150nm. The average size and size distribution of silver nanoparticles is 59.66nm. The zeta potential of the silver nanoparticle is negatively charged and rendered as a sharp peak at -31.7mV. Antimicrobial activity of silver nanoparticles exhibited the highest inhibition against Gram-negative bacteria than Gram-positive bacteria and yeast pathogens. Starch hydrolysis of Ag-NPs was studied with pancreatic alpha-amylase (tailor made), crude and purified bacterial amylase enzyme. The formation of reducing sugar was increased about 40-fold for a purified enzyme, 11-fold for the pancreatic enzyme, and 6-fold for crude bacterial enzyme incorporated with Ag-NPs over control. The present studies recommended that Ag-NPs have a significant role in the degradation of starch into reducing sugars by acting as a nanocatalyst.

Structural, Optical, and Electrical Properties of ZnO/Nb/ZnO Multilayer Thin Films

2014 ◽  
Vol 975 ◽  
pp. 238-242 ◽  
Author(s):  
Adolfo Henrique Nunes Melo ◽  
Petrucio Barrozo Silva ◽  
Marcelo Andrade Macedo
Keyword(s):  
Thin Films ◽  
Peak Position ◽  
Multilayer Thin Films ◽  
Optical And Electrical Properties ◽  
Zno Thin Film ◽  
Energy Band Gap ◽  
X Ray ◽  
Unit Cell Size ◽  
Vis Spectroscopy ◽  
Sputtering System

ZnO multilayers and pure ZnO thin films were deposited onto glass using a sputtering system, and were subsequently characterized by X-ray diffractometry and UV-Vis spectroscopy. The resistivity of the samples was measured by the four-probe method. All films exhibited preferential orientation along the c-axis and the peak position (002) shifted to a lower position, indicating a reduction in the unit cell size. The pure ZnO thin film exhibited a maximum transmittance of approximately 98%, which decreased as the Nb layer increased, thus increasing the absorbance of the multilayer thin films. The energy band gap decreased as the thickness of the metal increased which higher value was 3.18 eV. The resistivity had a minimum of 0.1 × 10-4 Ω m.

scholarly journals Fabrication and Characterization of a Highly-Sensitive Surface-Enhanced Raman Scattering Nanosensor for Detecting Glucose in Urine

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 629 ◽  
Author(s):  
Yudong Lu ◽  
Ting Zhou ◽  
Ruiyun You ◽  
Yang Wu ◽  
Huiying Shen ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Internal Standard ◽  
Surface Enhanced Raman Scattering ◽  
Quantitative Detection ◽  
Core Shell ◽  
Ag Nps ◽  
Vis Spectroscopy ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Herein we utilized coordination interactions to prepare a novel core-shell plasmonic nanosensor for the detection of glucose. Specifically, Au nanoparticles (NPs) were strongly linked with Ag+ ions to form a sacrificial Ag shell by using 4-aminothiophenol (4-PATP) as a mediator, which served as an internal standard to decrease the influence of the surrounding on the detection. The resultant Au-PATP-Ag core-shell systems were characterized by UV-vis spectroscopy, transmission electron microscopy, and surface-enhanced Raman scattering (SERS) techniques. Experiments performed with R6G (rhodamine 6G) and CV (crystal violet) as Raman reporters demonstrated that the Au@Ag nanostructure amplified SERS signals obviously. Subsequently, the Au@Ag NPs were decorated with 4-mercaptophenylboronic acid (4-MPBA) to specifically recognize glucose by esterification, and a detection limit as low as 10−4 M was achieved. Notably, an enhanced linearity for the quantitative detection of glucose (R2 = 0.995) was obtained after the normalization of the spectral peaks using 4-PATP as the internal standard. Finally, the practical applicability of the developed sensing platform was demonstrated by the detection of glucose in urine with acceptable specificity.

scholarly journals Microwave-Assisted Green Synthesis of Silver Nanoparticles Using Juglans regia Leaf Extract and Evaluation of Their Physico-Chemical and Antibacterial Properties

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 68 ◽  
Author(s):  
Mahsa Eshghi ◽  
Hamideh Vaghari ◽  
Yahya Najian ◽  
Mohammad Najian ◽  
Hoda Jafarizadeh-Malmiri ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Juglans Regia ◽  
Antibacterial Properties ◽  
Infrared Analysis ◽  
Ag Nps ◽  
Stabilizing Agents ◽  
Agno3 Solution ◽  
Transmission Electron ◽  
Vis Spectroscopy

Silver nanoparticles (Ag NPs) were synthesized using Juglans regia (J. regia) leaf extract, as both reducing and stabilizing agents through microwave irradiation method. The effects of a 1% (w/v) amount of leaf extract (0.1–0.9 mL) and an amount of 1 mM AgNO3 solution (15–25 mL) on the broad emission peak (λmax) and concentration of the synthesized Ag NPs solution were investigated using response surface methodology (RSM). Fourier transform infrared analysis indicated the main functional groups existing in the J. regia leaf extract. Dynamic light scattering, UV-Vis spectroscopy and transmission electron microscopy were used to characterize the synthesized Ag NPs. Fabricated Ag NPs with the mean particle size and polydispersity index and maximum concentration and zeta potential of 168 nm, 0.419, 135.16 ppm and −15.6 mV, respectively, were obtained using 0.1 mL of J. regia leaf extract and 15 mL of AgNO3. The antibacterial activity of the fabricated Ag NPs was assessed against both Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria and was found to possess high bactericidal effects.

Crystallite size and lattice strain of lithiated spinel material for rechargeable battery by X-ray diffraction peak-broadening analysis

2019 ◽  
Vol 43 (5) ◽  
pp. 1903-1911 ◽  
Author(s):  
Ahmed A. Al-Tabbakh ◽  
Nilgun Karatepe ◽  
Aseel B. Al-Zubaidi ◽  
Aida Benchaabane ◽  
Natheer B. Mahmood
Keyword(s):  
Crystallite Size ◽  
Lattice Strain ◽  
Diffraction Peak ◽  
Rechargeable Battery ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Broadening

scholarly journals Three-Dimensional Printed Polylactic Acid (PLA) Surgical Retractors with Sonochemically Immobilized Silver Nanoparticles: The Next Generation of Low-Cost Antimicrobial Surgery Equipment

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 985 ◽  
Author(s):  
Lazaros Tzounis ◽  
Petros I. Bangeas ◽  
Aristomenis Exadaktylos ◽  
Markos Petousis ◽  
Nectarios Vidakis
Keyword(s):  
Electron Microscopy ◽  
3D Printing ◽  
Polylactic Acid ◽  
Low Cost ◽  
Three Dimensional ◽  
Film Deposition ◽  
Average Particle ◽  
Ag Nps ◽  
Fused Deposition ◽  
Vis Spectroscopy

A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer of silver (Ag) nanoparticles (NPs) was developed via a simple and scalable sonochemical deposition method. The PLA retractor covered with Ag NPs (PLA@Ag) exhibited vigorous AM properties examined by a reduction in Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) bacteria viability (%) experiments at 30, 60 and 120 min duration of contact (p < 0.05). Scanning electron microscopy (SEM) showed the surface morphology of bare PLA and PLA@Ag retractor, revealing a homogeneous and full surface coverage of Ag NPs. X-Ray diffraction (XRD) analysis indicated the crystallinity of Ag nanocoating. Ultraviolent-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM) highlighted the AgNP plasmonic optical responses and average particle size of 31.08 ± 6.68 nm. TEM images of the PLA@Ag crossection demonstrated the thickness of the deposited Ag nanolayer, as well as an observed tendency of AgNPs to penetrate though the outer surface of PLA. The combination of 3D printing and sonochemistry technology could open new avenues in the manufacturing of low-cost and on-demand antimicrobial surgery equipment.

Plasmonic Effects, Size and Biological Activity Relationship of Au-Ag Alloy Nanoparticles

2018 ◽  
Vol 54 ◽  
pp. 98-111 ◽  
Author(s):  
Ahson Jabbar Shaikh ◽  
Maria Batool ◽  
Muhammad Arfat Yameen ◽  
Amir Waseem
Keyword(s):  
Biological Activity ◽  
Gradual Increase ◽  
Reducing Agent ◽  
Alloy Nanoparticles ◽  
Ag Nps ◽  
Uniform Size ◽  
Vis Spectroscopy ◽  
Plasmonic Effects ◽  
Lower Temperature ◽  
Relationship Of

The plasmonic effects of Au-Ag alloy nanoparticles, gold nanoparticles (AuNPs), and silver nanoparticles (AgNPs) are studied and compared to their size. Various factors that affect the size of alloy nanoparticles are varied such as concentration and ratio of gold and silver salt, time of addition of reducing agent, temperature and pH. Addition of reducing agent at different time intervals for the synthesis of pure and alloy Au-Ag NPs shows a gradual increase in size, as well as increase in heterogeneity of nanoparticles with delayed addition of reducing agent. Temperature dependent alloy nanoparticles also shows a gradual increase in size with increase in temperature. pH dependent alloy nanoparticles show decrease in size with increase in pH from 4 to 8. Their size is characterized by SEM and corelated with UV-Vis spectroscopy. Furthermore, alloy nanoparticles synthesized by varying temperature are also characterized for their antibacterial studies against Escherichia coli and Staphylococcus aureus strains. Nanoparticles synthesized at high temperature (100°C) have shown higher bioactivity against both organisms due to small and uniform size nanoparticles, while nanoparticles synthesized at lower temperature (50°C) have lower biological activity. Alloy nanoparticles synthesized at 60°C and 70°C are more active against E. coli while those of 80°C and 90°C are more active against S. aureus.

scholarly journals Biogenic silver nanoparticles from Trichodesma indicum aqueous leaf extract against Mythimna separata and evaluation of its larvicidal efficacy

2017 ◽  
Vol 57 (2) ◽  
pp. 194-200 ◽  
Author(s):  
Abdul A. Buhroo ◽  
Gousul Nisa ◽  
Syed Asrafuzzaman ◽  
Ram Prasad ◽  
Razia Rasheed ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Average Particle ◽  
Particle Sizes ◽  
Mythimna Separata ◽  
Ag Nps ◽  
Leaf Extracts ◽  
Tem Analysis ◽  
Vis Spectroscopy ◽  
Aqueous Leaf Extract

AbstractThe present exploration is focused on the bio-fabrication of silver nanoparticles (Ag NPs) usingTrichodesma indicumaqueous leaf extract as a reducing agent. The synthesized Ag NPs were productively characterized by UV-vis spectroscopy, XRD, and TEM studies. The photosynthesis of Ag NPs was done at room temperature for 24 h and at 60°C. The green synthesis of spherical-shaped Ag NPs bio-fabricated fromT. indicumwith a face centred cubic structure showed average particle sizes of 20–50 nm, which is inconsistent with the particle size calculated by the XRD Scherer equation and TEM analysis. We further explored the larvicidal efficacy of biosynthesized Ag NPs with leaf extracts ofT. indicumagainstMythimna separata. The results showed that Ag NPs (20–50 nm) ofT. indicumpossess good larvicidal activity againstM. separatawith an LC50of 500 ppm. Thus, we can advocate that Ag NPs of 20–50 nm size extracted fromT. indicummay be considered in the pest management programme ofM. separatain future.

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