YVO4: RE3+(RE = Eu, Sm, Dy, Er) nanophosphors: Facile hydrothermal synthesis, microstructure, and photoluminescence

2009 ◽  
Vol 24 (10) ◽  
pp. 3050-3056 ◽  
Author(s):  
Bing Yan ◽  
Jianhua Wu
Keyword(s):  
Particle Size ◽  
Rare Earth ◽  
Electron Microscope ◽  
Hydrothermal Synthesis ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Synthesis Process ◽  
Average Particle ◽  
Sodium Vanadate ◽  
Rare Earth Nitrates

YVO4: 10%RE3+(RE = Eu, Sm, Dy, Er) nanophosphors have been synthesized by a facile modified hydrothermal technology to obtain the high purity. The key procedure for this hydrothermal process is the adding order of precursors, in which excess sodium vanadate should be added in the solution of rare earth nitrates. The microstructure (crystal phase, morphology, particle size) of these phosphors are characterized by x-ray powder diffraction, scanning electron microscope, and transmission electron microscope, which indicates that there are some cube-like crystals with tetragonal zircon structure and the average particle size is approximately 40 nm. The luminescent behaviors for the four rare earth ion-activated YVO4nanophosphors have been studied, and, for YVO4: 10%Eu3+nanophosphors in particular, it is found that a different hydrothermal process influences the phase composition, microstructure, and photoluminescence. This result suggests that the hydrothermal synthesis process (by adding sodium vanadate to the solution of rare earth nitrates) is favorable for YVO4nanophosphor to obtain pure phase, small particle size, long luminescent lifetime, and high luminescence quantum efficiency.

scholarly journals Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1548
Author(s):  
Peng Zhu ◽  
Huapeng Zhang ◽  
Hongwei Lu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Phase Separation ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Droplet Evaporation ◽  
Average Particle ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Pei Nanoparticles

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

scholarly journals Preparation of ultrafine iron phosphate micro-powder from phosphate slag

2018 ◽  
Vol 238 ◽  
pp. 02002
Author(s):  
Fangjing Sun ◽  
Yi Zhang ◽  
Jiawei Zhang ◽  
Xixi Yan ◽  
Xiaoyu Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Electron Microscope ◽  
Average Particle Size ◽  
Iron Phosphate ◽  
Average Particle ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Phosphate Slag ◽  
Scanning Electron

In this experiment, ultrafine iron phosphate micro-powder was prepared by hydrothermal method which used phosphate slag as an iron source. The effects of reaction temperature, surfactants type and amount on its particle size were explored. The samples were characterized by using Malvern Laser Particle Size Analyzer (MS2000), X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).The results showed that at 160 °C, 1 wt%CTAB, monoclinic iron phosphate micro-powder was obtained with an average particle size about 0.4 μm which also has a good dispersion in aqueous solution.

Preparation of Cr2O3 Nanoparticles via Hydrothermal Reduction of CH3OH

2012 ◽  
Vol 463-464 ◽  
pp. 760-763
Author(s):  
Zhen Zhao Pei ◽  
Hong Bin Xu ◽  
Yi Zhang
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Average Particle Size ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Cr2o3 Nanoparticles ◽  
Average Size ◽  
Hydrothermal Reduction ◽  
Scanning Electron

Nanoparticles of Cr2O3 were successfully obtained via hydrothermal reduction of CH3OH. The oxidant and chromium source was CrO3. The process needs no stirrer or surfactant and the CrO3 concentration was 0.83mol/L. The obtained products were loosely agglomerated Cr2O3 nanoparticles with the average size of 29 to 79 nm. Influences of reactant ratios and calcination temperatures on the specific surface area and average particle size were discussed. And the morphology of nanoparticles was investigated by use of field-emission scanning electron microscope.

Synthesis of Nano-Sized Barium Titanate Powder by Rotary-Hydrothermal Process

2009 ◽  
Vol 421-422 ◽  
pp. 269-272
Author(s):  
Takashi Kubo ◽  
Masayuki Hogiri ◽  
Hiroshi Kagata ◽  
Atsushi Nakahira
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Water System ◽  
Starting Material ◽  
Average Particle ◽  
Rotary Speed ◽  
Average Size ◽  
Faceted Particles

Nano-sized BaTiO3 powders with narrow size distribution and the high tetragonality were attempted to synthesize by the rotary-hydrothermal process in water system, using two kinds of commercial anatase-type TiO2 (ST21/ST01) with different particle size and Ba(OH)2. The rotary-hydrothermal syntheses were done with the rotary-speed of 20 revolutions per minute at 523 K for 24 h. Highly- and mono-dispersed BaTiO3 powders were successfully synthesized by applying the rotary-hydrothermal process. For rotary-hydrothermal synthesis, it was found that the average size, tetragonality, and quality of the BaTiO3 particle strongly depended on the particle size of the starting material. In the case of using ST01 as a starting material, BaTiO3 nano-powders mainly composed of coarse-faceted particles (average particle size = ca.100 nm) with the tetragonal phase and very little lattice defects were successfully synthesized.

Determination of Latex Particle Size Distributions by Fractional Creaming with Sodium Alginate

1961 ◽  
Vol 34 (2) ◽  
pp. 433-445 ◽  
Author(s):  
E. Schmidt ◽  
P. H. Biddison
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Sodium Alginate ◽  
Mass Distribution ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Size Distributions ◽  
Particle Size Distributions

Abstract Knowledge of mass distribution of particle sizes in latex is very important to the latex technologist. Therefore, it is desirable to have available a simple method for the determination of mass distribution of particle sizes. This paper presents a method, based on fractional creaming of latex with sodium alginate, which can be used in any laboratory without special equipment. The method is particularly advantageous for analyzing latexes of very wide particle size distributions. When analyzed with an electron microscope, these latexes require counting a very large number of particles. McGavack found that partial creaming of normal hevea latex with ammonium alginate gives concentrates of larger average particle size than the original latex. He found that the average particle size in the cream approaches that of the original latex as the amount of creaming agent is increased. In a previous paper from this laboratory, Schmidt and Kelsey demonstrated that the phenomenon of fractionation according to particle size with increasing amounts of creaming agent is applicable in a wide variety of anionic latex systems and in colloidal silica. Their results indicated also the existence of a quantitative relationship, independent of the nature of the dispersed particles, between the concentration of creaming agent and size of creamed particles. Maron confirmed fractionation with respect to particle size as a consequence of partial creaming with alginate. He showed that the mass average particle sizes of fractions, determined optically, cumulate to that of the original latex. Although the previous paper by Schmidt and Kelsey implied the basic concept of a method of determining particle size distribution by fractional creaming, it was not exploited at that time. In order to adapt the fractional creaming phenomenon to a quantitative method for particle size determination, we required a more precise knowledge of the relation between creaming agent concentration and size of particles creamed. It was proposed to establish this relationship with the aid of the electron microscope. Various factors influencing the creaming of latex, such as polymer concentration, electrolyte, soap content, and variability of the creaming agent, had to be considered in standardizing the creaming procedure.

Effect of Synthetic Technology on the Properties of Co2O3 Powder

2018 ◽  
Vol 281 ◽  
pp. 46-51
Author(s):  
Ge Xiong ◽  
Hui Min Sun ◽  
Xue Yang ◽  
Jin Shi Li ◽  
Mei Hua Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Salt Solution ◽  
Average Particle Size ◽  
Particle Aggregation ◽  
Molar Ratio ◽  
Average Particle

Ultrafine Co2O3powder was prepared via hydrothermal synthesis. The effect of technology on the performance of the superfine Co2O3powders was investigated, and the hydrothermal parameters in preparing Co2O3were gradually improved. In addition, the morphology and grain size of the Co2O3powder were analyzed by FESEM. Results show that reducing the salt–alkali molar ratio resulted in more uniform Co2O3powder and smaller particles, with average particle size of approximately 40 nm. Reaction time displayed little effect on the Co2O3powder, but the particle size decreased with the reaction time. The concentration of salt solution remarkably affected the morphology of the Co2O3powder. Lower concentration resulted in smaller particle aggregation and particle size.

scholarly journals Synthesis of rare-earth nanosized phosphors using microwave processing

2021 ◽  
Vol 2056 (1) ◽  
pp. 012049
Author(s):  
A B Vlasenko ◽  
V V Bakhmetyev
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Visible Light ◽  
Average Particle Size ◽  
Microwave Treatment ◽  
Viral Diseases ◽  
Medical Applications ◽  
Average Particle ◽  
Light Spectrum ◽  
X Ray

Abstract Nanomaterials find permanently extending applications in various areas of life. In particular, nanosized phosphors can be used as pharmaceutical carriers capable of emitting ultraviolet or visible light that activates a photosensitizer, thus significantly expanding the possibilities of photodynamic therapy in the treatment of oncological, bacterial and viral diseases. The conditions required for the use of nanosized phosphors in medicine include their fine dispersion and effective luminescence in the red region of visible light spectrum upon stimulation by X-ray radiation of the range accepted for medical applications, particularly for diagnostic and therapeutic purposes in many diseases. The aim of this work was to study the effect of microwave treatment of Y2O3:Eu phosphors prepared by hydrothermal synthesis in ethylene glycol at 230 °C for 6 hours, involving the decomposition of mixed acetate. In order to reduce the aggregation and growth of the resulting particles, Aerosil A300 with average particle size 7 nm was added to the reaction mixture in the course of hydrothermal synthesis in the ratio 1:1 relating to the obtained phosphor. The microwave treatment was carried out at 800 °C for 5 minutes. The developed method provided Y2O3:Eu phosphor samples featuring with increased luminescence intensity in the region 610…700 nm compared to similar phosphors earlier prepared using the rapid thermal annealing (RTA) procedure.

Minimum Particle Diameter of the Sulfur-Doped Nano-TiO2 Transparent Hydrosol at Room Temperature

2014 ◽  
Vol 587-589 ◽  
pp. 788-791
Author(s):  
Ling Li ◽  
Hua Yan Zhang ◽  
Xiao Wei Li ◽  
Zi Hao Xu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Raw Materials ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Synthesis Process ◽  
Average Particle ◽  
Hydrolysis Method ◽  
Particle Size Analyzer

Sulfur-doped nanoTiO2transparent hydrosol with an average particle size of 3.8 nm was synthesized by a novel complexation-controlled hydrolysis method at room temperature and atmospheric pressure by using TiCl4, thiourea, organic carboxylic acid, NH3H2O, D-sorbitol etc. as raw materials. The composition, phase structure, particle size, absorbance spectrum, and photocatalytic performance of samples were characterized by XRD, nanolaser particle size analyzer, ultraviolet-visible spectrophotometer. In addition, the influence of reaction conditions in the synthesis process was also studied. The results indicate that when nanoparticle doped with 0.5% S, and the reflux time was 15 min, the photocatalytic performance of sulfur-doped TiO2hydrosol was best.

scholarly journals Characterization, Antimicrobial and Antioxidant evaluation of biofabricated silver nanoparticles from endophytic Pantoea anthophila

2021 ◽  
Author(s):  
C. Nirmala ◽  
M Srid
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Electron Microscope ◽  
Pathogenic Bacteria ◽  
Average Particle Size ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Average Particle ◽  
X Ray ◽  
Uv Visible

Abstract Endophyte mediated nanoparticles fabrication was emerging as a new frontier in nanomedicines that produce high biocompatible and functionalized silver nanoparticles. In this study, silver nanoparticles were successfully biosynthesized from the extracellular extract of endophytic bacterium Pantoea anthophila isolated from the stem of Waltheria indica for the first time. The synthesised nanoparticles were characterized by UV-Visible and Fourier Transform Infra-Red spectroscopy. The structural analysis is done by X-ray diffraction and the stability was studied by dynamic light scattering and particle size analyser. The size and shape were observed by Transmission Electron Microscope, Scanning Electron Microscope and Energy Dispersive X-Ray spectrum. Further, the nanoparticles were evaluated for antimicrobial and antioxidant properties. Synthesized nanoparticle showed a strong absorption band in the UV-Visible range at 410 nm. The average particle size was found to be 16.8 nm with spherical shaped, crystalline nature. Good zones of inhibition at various ranges were detected against a broad range of human pathogenic bacteria and fungi. A strong free radical scavenging activity of silver nanoparticles with IC50 values 30.75, 19.47, 34.59, 41.12, 27.24, 28.16, 36.21 µg/ml was obtained that was comparable to the reference. The study suggests that the silver nanoparticles can be biosynthesised from endophytic P. anthophila metabolites with significant therapeutic potential. With proper validation, the biosynthesised silver nanoparticles can be developed as a promising antiviral and anticancer drug candidate.

SYNTHESIS, CHARACTERIZATION, AND OPTICAL PROPERTIES OF Y-DOPED ZnO NANOPARTICLES

NANO ◽  
2009 ◽  
Vol 04 (04) ◽  
pp. 225-232 ◽  
Author(s):  
TALAAT M. HAMMAD ◽  
JAMIL K. SALEM ◽  
ROGER G. HARRISON
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Zno Nanoparticles ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Doped Zno ◽  
Size And Morphology

Zinc oxide ( ZnO ) and yttrium-doped ZnO nanoparticles with particle size in the nanometer range have been successfully synthesized by the alkali precipitation method. The nanoparticle size and morphology have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). The average particle size of Y-doped ZnO nanoparticles is about 17–29 nm. The absorption and photoluminescence (PL) spectra of the undoped and doped ZnO nanoparticles were also investigated. The optical band gap of ZnO nanoparticles can be tuned from 3.27 to 3.40 eV with increasing yittrium doping levels from 0 to 5%. The nanoparticles gave two emission peaks, one at around 376 nm and the other at 500 nm.

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