scholarly journals Comparative Study of Bulk and Nanoengineered Doped ZnSe

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 71
Author(s):  
Brett Setera ◽  
Ching-Hua Su ◽  
Bradley Arnold ◽  
Fow-Sen Choa ◽  
Lisa Kelly ◽  
...  
Keyword(s):  
Zinc Selenide ◽  
Average Particle Size ◽  
Average Particle ◽  
Bulk Crystals ◽  
Cobalt Doping ◽  
Nanoparticle Growth ◽  
Chromium Doping ◽  
Growth Method ◽  
Order Of Magnitude

Chromium- and cobalt-doped zinc selenide nanoparticles were synthesized using a low-temperature reactive solution growth method. The morphological and optical characteristics were compared to those of doped zinc selenide (ZnSe) bulk crystals grown by the physical vapor transport (PVT) method. We observed agglomeration of particles; however, the thioglycerol capping agent has been shown to limit particle grain growth and agglomeration. This process enables doping by addition of chromium and cobalt salts in the solution. A slightly longer refluxing time was required to achieve cobalt doping as compared with chromium doping due to lower refluxing temperature. The nanoparticle growth process showed an average particle size of approximately 300 nm for both Cr- and Co-doped zinc selenide. The optical characterization of Co:ZnSe is ongoing; however, preliminary results showed a very high bandgap compared to that of pure ZnSe bulk crystal. Additionally, Co:ZnSe has an order of magnitude higher fluorescence intensity compared to bulk Cr:ZnSe samples.

CHARACTERIZATION OF PHOTOCHEMICALLY INITIATED GOLD NANOPARTICLES SYNTHESIZED VIA INCOHERENT ULTRAVIOLET RADIATION

2016 ◽  
Vol 78 (3-2) ◽  
Author(s):  
Jia-Cherng Chong ◽  
Siew-Ling Lee ◽  
Noriah Bidin
Keyword(s):  
Gold Nanoparticles ◽  
Ultraviolet Radiation ◽  
Average Particle Size ◽  
Correlation Spectroscopy ◽  
Average Particle ◽  
Nanoparticle Growth ◽  
Particle Stability ◽  
Ultraviolet Wavelength ◽  
Post Synthesis

A modified Turkevich pathway of synthesizing water suspended gold nanoparticles using incoherent ultraviolet radiation as photochemical reaction initiator produced broader absorbance band corresponding to localised surface plasmonresonsnce around 530 nm with average particle size separated into two distinct distributions from 5 nm to 100 nm depending on ultraviolet wavelength. Presence and dynamics of nanoparticle growth was observed with photon correlation spectroscopy where aged colloids produced submicron sized agglomerated particles. Post-synthesis colloidal pH shows gradual degradation of particle stability.  

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

scholarly journals Preparation and characterization of domperidone nanoparticles for dissolution improvement

2018 ◽  
Vol 27 (1) ◽  
pp. 39-52
Author(s):  
Mohammed Sabar Al-lami ◽  
Malath H. Oudah ◽  
Firas A. Rahi
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Methyl Cellulose ◽  
Precipitation Method ◽  
Average Particle ◽  
Antisolvent Precipitation ◽  
Stirring Time

This study was carried out to prepare and characterize domperidone nanoparticles to enhance solubility and the release rate. Domperidone is practically insoluble in water and has low and an erratic bioavailability range from 13%-17%. The domperidone nanoparticles were prepared by solvent/antisolvent precipitation method at different polymer:drug ratios of 1:1 and 2:1 using different polymers and grades of poly vinyl pyrolidone, hydroxy propyl methyl cellulose and sodium carboxymethyl cellulose as stabilizers. The effect of polymer type, ratio of polymer:drug, solvent:antisolvent ratio, stirring rate and stirring time on the particle size, were investigated and found to have a significant (p? 0.05) effect on particle size. The best formula was obtained with lowest average particle size of 84.05. This formula was studied for compatibility by FTIR and DSC, surface morphology by FESEM and crystalline state by XRPD. Then domperidone nanoparticles were formulated into a simple capsule dosage form in order to study of the in vitro release of drug from nanoparticles in comparison raw drug and mixture of polymer:drug ratios of 2:1. The release of domperidone from best formula was highly improved with a significant (p? 0.05) increase.

Synthesis of nanoscale particles of Ta and Nb3Al by homogeneous reduction in liquid ammonia

2001 ◽  
Vol 16 (9) ◽  
pp. 2544-2549 ◽  
Author(s):  
Hongmin Zhu ◽  
Donald R. Sadoway
Keyword(s):  
Particle Size ◽  
Liquid Ammonia ◽  
Average Particle Size ◽  
Multicomponent System ◽  
Mixed Conductor ◽  
Average Particle ◽  
Metallothermic Reduction ◽  
Solid Product ◽  
Order Of Magnitude ◽  
Co Reduction

The analysis of metallothermic reduction as an electronically mediated reaction predicted that the particle size of solid product could be reduced if the reaction were conducted in a medium that is a mixed conductor (ionic and electronic). This prediction was confirmed by reacting TaCl5 with sodium, each dissolved in liquid ammonia, to produce tantalum powder having an average particle size over an order of magnitude finer than the micron-sized powders produced commercially today. Metallothermic reduction in a mixed conducting medium has been extended to a multicomponent system in order to synthesize nanosized powder of Nb3Al by co-reduction of NbCl5 and AlCl3 both dissolved in liquid ammonia.

CONTROLLED SYNTHESIS AND CHARACTERIZATION OF CERIUM-DOPED ZnS NANOPARTICLES IN HMTA MATRIX

2011 ◽  
Vol 10 (03) ◽  
pp. 487-493 ◽  
Author(s):  
K. VIJAI ANAND ◽  
R. MOHAN ◽  
R. MOHAN KUMAR ◽  
M. KARL CHINNU ◽  
R. JAYAVEL
Keyword(s):  
Quantum Confinement Effect ◽  
Average Particle Size ◽  
Surface States ◽  
Deep Trap ◽  
Average Particle ◽  
Zns Nanoparticles ◽  
Selected Area Electron Diffraction ◽  
Luminescence Process ◽  
Photoluminescence Studies

Cerium-doped ZnS nanoparticles have been synthesized through hydrothermal method. The nanoparticles were stabilized using hexamethylenetetramine (HMTA) as surfactant in aqueous solution. The average particle size of the prepared samples is about 2 nm. The structure of the as-prepared ZnS nanoparticles is cubic (zinc blende) as demonstrated by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEM results showed that the synthesized nanoparticles were uniformly dispersed in the HMTA matrix without aggregation. The UV–Vis absorption spectra of the prepared ZnS nanoparticles show a considerable blueshift in the absorption band edge compared to bulk ZnS indicating a strong quantum confinement effect. Formation of HMTA-capped ZnS nanoparticles was confirmed by FTIR studies. Photoluminescence studies showed that the relative emission intensity of Ce3+ -doped ZnS nanoparticles is higher than that of undoped ZnS nanoparticles, which is due to the enhancement of radiative recombination in the luminescence process. The PL spectra showed two emission peaks at around 420 nm and 442 nm, which may be attributed to deep-trap emission or defect-related emission of ZnS and presence of various surface states.

The Aggregation Study and Characterization of Silver Nanoparticles

2017 ◽  
Vol 263 ◽  
pp. 165-169
Author(s):  
Silvia Chowdhury ◽  
Faridah Yusof ◽  
Nadzril Sulaiman ◽  
Mohammad Omer Faruck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Average Particle Size ◽  
Average Particle ◽  
Transmission Electron ◽  
Vis Spectroscopy

In this article, we have studied the process of silver nanoparticles (AgNPs) aggregation and to stop aggregation 0.3% Polyvinylpyrrolidone (PVP) was used. Aggregation study carried out via UV-vis spectroscopy and it is reported that the absorption spectrum of spherical silver nanoparticles were found a maximum peak at 420 nm wavelength. Furthermore, Transmission Electron Microscopy (TEM) were used to characterized the size and shape of AgNPs, where the average particle size is around 10 to 25 nm in diameter and the AgNPs shape is spherical. Next, Dynamic Light Scattering (DLS) were used, owing to observed size distribution and self-correlation of AgNPs.

scholarly journals Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method

2016 ◽  
Vol 18 (2) ◽  
pp. 131-139
Author(s):  
Kinga Łuczka ◽  
Barbara Grzmil ◽  
Bogumił Kic ◽  
Krzysztof Kowalczyk
Keyword(s):  
Particle Size ◽  
Physicochemical Parameters ◽  
Average Particle Size ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Influence Of Process Parameters ◽  
Molar Ratios ◽  
Aluminum Phosphates ◽  
The Individual

Abstract Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios) in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.

Preparation and Characterization of Folate-Decorated Chitosan Microspheres as a Sustained-Release Drugs Carrier

2013 ◽  
Vol 684 ◽  
pp. 57-62 ◽  
Author(s):  
Zhi Hua Xing
Keyword(s):  
Encapsulation Efficiency ◽  
Average Particle Size ◽  
Morphological Characteristics ◽  
Average Particle ◽  
Loading Capacity ◽  
Chitosan Microspheres ◽  
Ionic Crosslinking ◽  
Artificial Gastric Juice

Folic acid-chitosan (FA-CTS) and 10-hydroxycamptothecin (HCPT)-loaded folate-conjugated chitosan (FA-CTS/HCPT) microspheres were prepared by the ionic crosslinking method.The morphological characteristics of microspheres were examined using a scanning electron microscope (SEM). The average particle size and size distribution were determined by dynamic light scattering. The drug encapsulation efficiency (EE) , loading capacity (LC)and release characteristics in vitro were determined using ultraviolet spectrophotometer.The results shown that the microspheres are uniform spherical and regular with a size between 19.79 and81.40μm.Optimized preparation parameters lead to the successful preparation of hydroxycamptothecin-loaded folate-conjugated chitosan microspheres characterized with encapsulation efficiency and loading capacity up to (86.8±0.1)% and 20.6±0.3 % respectively. More then 90% of 10-hydroxycamptothecin was released from microspheres in 4 h at artificial gastric juice, 8h at artificial small intestinal fluid with a good delayed release effect.

Rheological, Structural and Mechanical Characterization of Monolithic Zircon-Alumina Bodies

2014 ◽  
Vol 793 ◽  
pp. 151-158 ◽  
Author(s):  
M. León-Carriedo ◽  
C.A. Gutiérrez Chavarría ◽  
J.L. Rodríguez Galicia ◽  
Jorge López-Cuevas ◽  
M.I. Pech Canul
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Mechanical Test ◽  
Average Particle Size ◽  
Young Modulus ◽  
Particle Morphology ◽  
Ceramic Materials ◽  
Transgranular Fracture ◽  
Average Particle

In the present work, the characterization of monolithic materials formulated at different weight concentrations was conducted; employing two of the ceramic materials most used in the refractory industry, zircon and alumina. These monolithic materials were fabricated using colloidal techniques, specifically plaster casting mold, in order to obtain pieces with a higher particle consolidation and density, reducing porosity to lower values than the obtained using traditional shaping process of these materials. The monoliths were obtained employing two ceramic powders with different average particle size and morphology to achieve better packing in the green body. This characterization was carried out, firstly, determining the particle size of the raw materials by laser diffraction and the evaluation of particle morphology by scanning electron microscopy. Aqueous suspensions were formulated by containing both ceramic materials, which were dispersed with Tamol 963, and analyzed by rheometric techniques. Subsequently, bars were manufactured having the following dimensions; 4 mm wide, 3 mm thick and 45 mm in length, according to ASTM C1161-02cc, to be characterized microstructural and mechanically, also was observed the fracture habit after the mechanical test. As a final result, the materials formulated at higher alumina content showed higher density values, reaching 94.95% of the theoretical density, also showed a higher thermal expansion coefficient and high rupture modulus, reaching up to 600 MPa and Young modulus of 230 GPa. From the microstructure characterization it was observed that alumina matrix shows a transgranular fracture across the grains and zircon particles exhibited intergranular fracture among the grain boundaries.

Synthesis and Characterization of the ZnO-TiO2 Nanoparticles by a Hydrothermal Processing

2006 ◽  
Vol 324-325 ◽  
pp. 1297-1300 ◽  
Author(s):  
J.W. Kim ◽  
S.W. Kim ◽  
K.S. Park ◽  
J.K Lee ◽  
Byung Ik Kim ◽  
...  
Keyword(s):  
Average Particle Size ◽  
Ammonium Hydroxide ◽  
Average Particle ◽  
Hydrothermal Processing ◽  
Zinc Titanate ◽  
High Temperature And Pressure ◽  
Metal Precursors ◽  
Temperature And Pressure ◽  
Zinc Titanates

Zinc titanate nanoparticles were prepared under high temperature and pressure conditions by precipitation from metal precursors with aqueous ammonium hydroxide. Zinc titanates powders were obtained in the temperature range of 180-230 for 4 h. The phase of synthesized particle with calcined at 800 for 2h. ZnTiO3, Zn2TiO4, Zn2Ti3O8, TiO2, ZnO. The average particle size and distribution of the synthesized zinc titanate nanoparticles were below 100 nm and narrow, respectively.

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