A Comparative Study of Theoretical Methods to Estimate Semiconductor Nanoparticles’ Size

In this paper, we compare four different methods to estimate nanoparticle diameters from optical absorption measurements, using transmission electron microscopy (TEM) images as a reference for the nanoparticle size. Three solutions of colloidal nanoparticles coated with thiophenol with different diameters were synthesized by thiolate decomposition. The nanoparticle sizes were controlled by the addition of a certain volume of a 1% sulphur solution in toluene. TEM measurements showed that the average diameter for each type of these nanoparticles was 2.8 nm, 3.2 nm, and 4.0 nm. The methods studied for the calculation of the nanoparticles diameter were: The Brus model, the hyperbolic band model (HBM), the Henglein model, and the Yu equation. We evaluated the importance of a good knowledge of the nanoparticle bandgap energy, and the nature of electronic transitions in the semiconductor. We studied the effects that small variations in the electron and hole effective mass values produced in the Brus equation and in the HBM model for CdS, PbS, and ZnS nanoparticles. Finally, a comparison was performed between the data provided by these models and the experimental results obtained with TEM images. In conclusion, we observed that the best approximation to the experimental results with TEM images was the Brus equation. However, when the bandgap energy was close to the bulk bandgap energy, the theoretical models did not adjust correctly to the size measured from the TEM images.

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Intentions versus Outcomes: Cooperation and Fairness in a Sequential Prisoner’s Dilemma with Nature

Games ◽

10.3390/g12030058 ◽

2021 ◽

Vol 12 (3) ◽

pp. 58

Author(s):

Garret Ridinger

Keyword(s):

Perspective Taking ◽

Prisoner's Dilemma ◽

Prisoner’S Dilemma ◽

Theoretical Models ◽

Empathic Concern ◽

Experimental Results ◽

Prisoner’S Dilemma Game ◽

Psychometric Measures ◽

Prisoner's Dilemma Game ◽

First Mover

This paper investigates the importance of concerns about intentions and outcomes in a sequential prisoner’s dilemma game with nature. In the game, there is a chance that the first mover’s choice is reversed. This allows the separation of intended actions from the resulting outcomes. Equilibrium predictions from theoretical models of fairness are tested experimentally by varying the chance the first mover’s choice is reversed and whether the second mover observes the first mover’s choice. The results show that second mover cooperation is higher when the first mover has little control over their choice and when the second mover is not told what the first mover chose. While subject behavior is consistent with concerns for both intentions and outcomes, the results indicate that these concerns work in ways not predicted by current theoretical models. In addition, I find that psychometric measures of empathic concern and perspective taking are correlated with second mover cooperation and provide potential explanations for the experimental results.

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A New Nanocomposite Packaging Based on LASiS-Generated AgNPs for the Preservation of Apple Juice

Antibiotics ◽

10.3390/antibiotics10070760 ◽

2021 ◽

Vol 10 (7) ◽

pp. 760

Author(s):

Maria Chiara Sportelli ◽

Antonio Ancona ◽

Annalisa Volpe ◽

Caterina Gaudiuso ◽

Valentina Lavicita ◽

...

Keyword(s):

Metal Ion ◽

Chemical Characterization ◽

Average Diameter ◽

Biological Action ◽

Metal Species ◽

Ion Release ◽

Bioactive Materials ◽

Transmission Electron ◽

Metal Ion Release ◽

Bulk Chemical

Designing bioactive materials, with controlled metal ion release, exerting a significant biological action and associated to low toxicity for humans, is nowadays one of the most important challenges for our community. The most looked-for nanoantimicrobials are capable of releasing metal species with defined kinetic profiles, either by slowing down or inhibiting bacterial growth and pathogenic microorganism diffusion. In this study, laser ablation synthesis in solution (LASiS) has been used to produce bioactive Ag-based nanocolloids, in isopropyl alcohol, which can be used as water-insoluble nano-reservoirs in composite materials like poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Infrared spectroscopy was used to evaluate the chemical state of pristine polymer and final composite material, thus providing useful information about synthesis processes, as well as storage and processing conditions. Transmission electron microscopy was exploited to study the morphology of nano-colloids, along with UV-Vis for bulk chemical characterization, highlighting the presence of spheroidal particles with average diameter around 12 nm. Electro-thermal atomic absorption spectroscopy was used to investigate metal ion release from Ag-modified products, showing a maximum release around 60 ppb, which ensures an efficient antimicrobial activity, being much lower than what recommended by health institutions. Analytical spectroscopy results were matched with bioactivity tests carried out on target microorganisms of food spoilage.

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Preparation and Characterization of Ultrafine Monodisperse Iron Oxide Nanoparticles by Solvothermal Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.748.93 ◽

2015 ◽

Vol 748 ◽

pp. 93-96

Author(s):

Cheng Mei Liu ◽

Yu Xia Zhao ◽

Jin Dong ◽

Lu Hai Li ◽

Yen Wei ◽

...

Keyword(s):

Iron Oxide ◽

Iron Oxide Nanoparticles ◽

Solvothermal Method ◽

Physical Property Measurement System ◽

Thermo Gravimetric Analysis ◽

Physical Property ◽

Oxide Nanoparticles ◽

Gravimetric Analysis ◽

Transmission Electron ◽

Different Diameters

Using iron-oleate complex as a precursor, oleic acid as a stabilizer and 1-octadecene as a reductant, uniform-sized and highly monodisperse iron oxide nanoparitcles with different diameters were successfully synthesized via solvothermal method by changing reaction time. Transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), physical property measurement system (PPMS) and dynamic light scattering (DLS) was used to characterize obtained iron oxide nanoparticles. These results indicated that iron oxide nanoparitcles with the diameter ranging from 4 to 8 nm can be controllably synthesized.

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Antifungal Effectiveness of Nanosilver Colloid against Rose Powdery Mildew in Greenhouses

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.135.15 ◽

2008 ◽

Vol 135 ◽

pp. 15-18 ◽

Cited By ~ 37

Author(s):

Hae Sic Kim ◽

Hyun Suk Kang ◽

Gyo Jin Chu ◽

Hong Sik Byun

Keyword(s):

Electron Microscopy ◽

Powdery Mildew ◽

Colloidal Solution ◽

Physical Method ◽

Average Diameter ◽

Optical Microscope ◽

Size Analysis ◽

Large Area ◽

Transmission Electron ◽

Antifungal Effects

The antifungal effectiveness against rose powdery mildew using antimicrobial nanosilver colloidal solution was investigated. Double-capsulized nanosilver was prepared by chemical reaction of silver ion with aid of physical method, reducing agent and stabilizers. The average diameter of nanosilver was about 1.5 nm. They were highly stable and very well dispersive in aqueous solution. The Transmission electron microscopy and UV-vis spectrometer were used for measurements of size analysis and their stability, respectively. The nanosilver colloidal solution of concentration of 5000 ppm was diluted in 10 ppm of 500 kg and sprayed at large area of 3306 m2polluted by rose powdery mildew. The white rose powdery mildew fade out above 95 % after 2 days and was not recurred for a week. The antifungal effects were observed by an optical microscope and photographs.

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Characterization of Al65.0Cu32.9Co2.1 Alloy Containing Nanofibres

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.186.212 ◽

2012 ◽

Vol 186 ◽

pp. 212-215

Author(s):

Jacek Krawczyk ◽

Włodzimierz Bogdanowicz ◽

Grzegorz Dercz ◽

Wojciech Gurdziel

Keyword(s):

Electron Microscopy ◽

Average Diameter ◽

Chemical Compositions ◽

X Ray ◽

Transmission Electron ◽

Orthogonal Set ◽

T Phase ◽

Terminal Area ◽

Scanning Electron

Microstructure of terminal area of Al65Cu32.9Co2.1ingots (numbers indicate at.%), obtained via directional solidification was studied. Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray powder diffraction were applied. Point microanalysis by Scanning Electron Microscope was used for examination of chemical compositions of alloy phases. It was found that tetragonal θ phase of Al2Cu stoichiometric formula was the dominate phase (matrix). Additionally the alloy contained orthogonal set of nanofibres of Al7Cu2Co T phase with the average diameter of 50-500 nm and oval areas of hexagonal Al3(Cu,Co)2H-phase, surrounded by monoclinic AlCu η1phase rim. Inside some areas of H-phase cores of decagonal quasicrystalline D phase were observed.

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Tribological Behavior of Carbon Nanotubes as an Additive on Lithium Grease

Journal of Tribology ◽

10.1115/1.4028225 ◽

2014 ◽

Vol 137 (1) ◽

Cited By ~ 49

Author(s):

Alaa Mohamed ◽

T. A. Osman ◽

A. Khattab ◽

M. Zaki

Keyword(s):

Carbon Nanotubes ◽

Arc Discharge ◽

Average Diameter ◽

Friction Reduction ◽

Lithium Grease ◽

X Ray ◽

Transmission Electron ◽

Boundary Film ◽

Load Carrying ◽

Worn Surface

Carbon nanotubes (CNTs) with 10 nm average diameter and 5 μm in length were synthesized by electric arc discharge. The morphology and structure of CNTs were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray powder diffraction. The tribological properties of CNTs as an additive on lithium grease were evaluated with a four ball tester. The results show that the grease with CNTs exhibit good performance in antiwear (AW) and decrease the wear scare diameter (WSD) about 63%, decrease friction reduction about 81.5%, and increase the extreme pressure (EP) properties and load carrying capacity about 52% with only 1% wt. of CNTs added to lithium grease. The action mechanism was estimated through analysis of the worn surface with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results indicate that a boundary film mainly composed of CNTs, Cr, iron oxide, and other organic compounds was formed on the worn surface during the friction process.

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Structure And Morphology Of Carbon Nanofibers Synthesized On Cu Nanopowders

Siberian Journal of Physics ◽

10.54362/1818-7919-2016-11-3-62-71 ◽

2016 ◽

Vol 11 (3) ◽

pp. 62-71

Author(s):

Gulmira Partizan ◽

Batyr Mansurov ◽

Botagoz Medyanova ◽

Аizhan Koshanova ◽

Madina Mansurova ◽

...

Keyword(s):

Carbon Nanofibers ◽

Chemical Vapor ◽

Temperature Growth ◽

Copper Clusters ◽

Transmission Electron ◽

Amorphous Nature ◽

Diffraction Patterns ◽

Stable Growth ◽

Different Diameters ◽

Copper Nanopowders

This article presents the results of experiments on the synthesis of carbon nanofibers by thermal chemical vapor deposition using copper nanopowders obtained by electric explosion of wire as catalysts. Stable growth of carbon nanofibers was carried out at temperatures significantly lower than normally used. The process parameters that are optimal for low-temperature growth of carbon nanofibers have been identified during the performed experiments. The synthesized samples have different diameters and morphology (from spiral to direct). Copper clusters are both at the ends and inside the fibers. The results of IR spectroscopy indicate that the structure of the obtained carbon nanofibers is polymeric. X-ray analysis revealed the presence of a halo on the diffraction patterns at small values of the angle 2θ, which proves that the grown structures have an amorphous nature. There are no groups that are responsible for long-range order in all Raman spectra. Studies by transmission electron microscopy showed that nanostructures do not have an internal channel and nanofibers are solid.

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FeYO3@rGO nanocomposites: Synthesis, characterization and application in photooxidative degradation of atrazine under visible light

Materials Express ◽

10.1166/mex.2021.1957 ◽

2021 ◽

Vol 11 (5) ◽

pp. 706-716

Author(s):

Nada D. Al-Khthami ◽

Tariq Altalhi ◽

Mohammed Alsawat ◽

Mohamed S. Amin ◽

Yousef G. Alghamdi ◽

...

Keyword(s):

Visible Light ◽

Photoelectron Spectroscopy ◽

Sol Gel ◽

Bandgap Energy ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Reduced Graphene ◽

Structural Surface ◽

Adsorption Desorption

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

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Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.306-307.410 ◽

2011 ◽

Vol 306-307 ◽

pp. 410-415

Author(s):

Li Sun ◽

Fu Tian Liu ◽

Qi Hui Jiang ◽

Xiu Xiu Chen ◽

Ping Yang

Keyword(s):

Average Diameter ◽

Chemical Precipitation ◽

Precipitation Method ◽

Core Shell ◽

X Ray Diffraction ◽

Shell Nanoparticles ◽

X Ray ◽

Transmission Electron ◽

Shell Particles ◽

Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO47H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO47H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

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Preparation of a monodisperse poly (N-phenylmaleimide–acrylonitrile–styrene) structural nanolatex for heat-resistant modification of PVC

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705718780976 ◽

2018 ◽

Vol 32 (3) ◽

pp. 409-423

Author(s):

Jin Wang ◽

Hua Qiu ◽

Bo Cheng ◽

Fan Zhang ◽

Shuhua Qi

Keyword(s):

Electron Microscope ◽

Elemental Analysis ◽

Hybrid Composite ◽

Average Diameter ◽

Microemulsion Polymerization ◽

Scanning Calorimetry ◽

Thermogravimetric Analyzer ◽

Melt Compounding ◽

Transmission Electron ◽

Ftir Spectrometer

A monodisperse poly ( N-phenylmaleimide–acrylonitrile–styrene) (PNAS) nanolatex was synthesized via seed microemulsion polymerization. The obtained PNAS nanolatex was then directly used as an organic nanofiller to prepare polyvinyl chloride (PVC)/PNAS hybrid composite through water blending and melt compounding. The characteristics of PNAS nanolatex were analyzed by Fourier transform infrared (FTIR) spectrometer, elemental analysis, scanning electron microscope, transmission electron microscope (TEM), dynamic laser lighting scattering (DLS), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). FTIR and elemental analysis confirmed the formation of PNAS copolymer with high monomers conversion; meanwhile, for the PNAS nanoparticles, the morphology of a well-defined core–shell spherical structure with average diameter ranging from 156 nm to 249 nm was observed. DSC analysis and TGA indicated that both polymers had excellent compatibility, and the corresponding heat resistance of PVC was greatly improved with the addition of PNAS. When PNAS loading was 50 wt%, the glass transition temperature value of PVC/PNAS hybrid composite was increased by 22.4°C, compared with that of pristine PVC. The mechanical properties of the PVC composite were also enhanced with the addition of PNAS.

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