Synthesis and Characterization of ZnS: Fe/ZnS Core-Shell Nanocrystals

2011 ◽  
Vol 148-149 ◽  
pp. 900-903
Author(s):  
Li Hua Li ◽  
Yong Jun Gu ◽  
Rui Shi Xie ◽  
Jian Guo Zhu
Keyword(s):  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Pl Spectra ◽  
Zinc Blende ◽  
Diffraction Peaks ◽  
Zns Nanocrystals ◽  
Zinc Blende Structure

ZnS:Fe and ZnS:Fe/ZnS core-shell nanocrystals were synthesized by chemical precipitation method. It was found that the ZnS: Fe based nanocrystals possess zinc blende structure. Compared to ZnS: Fe nanocrystals, the intensity of the X-ray diffraction peaks of ZnS: Fe/ZnS nanocrystals reduced and these peaks moved to lower angles. TEM images show that ZnS: Fe based nanocrystals are spheroidal and the average particles size is about 3~4 nm. PL spectra of ZnS: Fe nanocrystals revealed several mission bands, ~406nm, ~444nm, ~416nm, However, PL spectra of ZnS: Fe/ZnS nanocrystals showed several mission bands, ~420nm, ~432nm, ~449nm.

Fluorescence Enhancement of ZnS Nanocrystals via Ultraviolet Irradiation

2014 ◽  
Vol 556-562 ◽  
pp. 27-31
Author(s):  
Ling Ling Peng ◽  
Bi Tao Liu ◽  
Tao Han
Keyword(s):  
Ultraviolet Irradiation ◽  
Surface Defects ◽  
Irradiation Time ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Zns Nanocrystals

ZnS nanocrystals were prepared via chemical precipitation method and characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) and photoluminescence (PL) spectra. The results indicated that the ZnS nanocrystals have cubic zinc blende structure and diameter is 3.68 nm as demonstrated by XRD. The morphology of nanocrystals is spherical measured by TEM which shows the similar particle size. The photoluminescence spectrum peaking at about 424 nm was due mostly to the trap-state emission, and a satellite peak at 480nm ascribed to the dangling bond of S in the surface of ZnS nanocrystals. The emission intensity of ZnS was enhanced after ultraviolet irradiation, the enhancement of the Photoluminescence intensity was due to the elimination of the surface defects after ultraviolet irradiation, for the growth of the coated shell on ZnS nonacrystals, the Photoluminescence intensity was increased as ultraviolet irradiation time growth, finally tends to be stable for the surface state of nanocrystals steady.

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

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. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O 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.

Preparation of Amorphous Calcium Phosphate/Triclcium Silicate Composite Powders

2009 ◽  
Vol 79-82 ◽  
pp. 1643-1646 ◽  
Author(s):  
Qing Lin ◽  
Yan Bao Li ◽  
Xiang Hui Lan ◽  
Chun Hua Lu ◽  
Zhong Zi Xu
Keyword(s):  
Calcium Phosphate ◽  
Shell Structure ◽  
Amorphous Calcium Phosphate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
X Ray ◽  
Core Shell Structure

The amorphous calcium phosphate (ACP)/tricalcium silicate (Ca3SiO5, C3S) composite powders were synthesized in this paper. The exothermal behavior of C3S determined by isothermal conduction calorimetry indicated that the ACP could be synthesis by chemical precipitation method during the induction period (stage II) of C3S. The composite powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results indicated that nanosized ACP particles deposited on the surface of C3S particles to form core-shell structure at pH=10.5, and the nCa/nP of ACP could be controlled between 1.0 and 1.5. The core-shell structure is stable after sintered at 500 oC for 3 h to remove the β-cyclodextrin (β-CD). As compared with the irregular C3S particles (1~5 μm), the composite powders particles are spherical with a diameter of 40~150 μm. Therefore, to obtain the smaller size of composite powders, it is expected to avoid the aggregate of C3S particles in the aqueous solution by addition of dispersant. As compared with C3S, the composite powders may contribute better injectability, strength and biocompatibility.

Size Controllable Synthesis and Characterization of CuO Nanostructure

2018 ◽  
Vol 915 ◽  
pp. 98-103 ◽  
Author(s):  
Duygu Candemir ◽  
Filiz Boran
Keyword(s):  
Freeze Drying ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peg 4000 ◽  
Structure Morphology ◽  
Cuo Nanostructure

In this study, copper oxide (CuO) nanostructures were successfully prepared by adding EG (ethylene glycol) and PEG (4000, 8000) (polyethylene glycol) via an in-situ chemical precipitation method. EG and PEG (4000, 8000) were effective for changing the particular size of CuO and we examined the effects of drying type such as freeze drying, muffle and horizontal furnace on the size of CuO nanostructure. The structure, morphology and elemental analysis of CuO nanostructure were analyzed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Also, the CuO nanostructures showed excellent electrical conductivity by the changing of PEG’s molecular weight and drying processes.

Synthesis and Characterization of Modified Diatomite-Leaf-Like CuO Nanosheet Composites

2018 ◽  
Vol 915 ◽  
pp. 93-97
Author(s):  
Filiz Boran
Keyword(s):  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Cuo Nanosheets ◽  
20 Nm ◽  
Modified Diatomite

In this work, firstly we described the effect of freeze drying on modification of raw diatomite. And then, modified diatomite-leaf-like copper oxide (CuO) nanosheet composite was successfully prepared by surfactant-free in-situ chemical precipitation method. The structure, morphology and elemental analysis of CuO nanosheets and its composite were analyzed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDAX). Dimensions of leaf-like CuO nanosheets were approximately determined as 160 nm in width, 320 nm in length and 20 nm in thickness. According to the EDAX spectrum, leaf-like CuO nanosheets composed of Cu and O atoms without any impurity and also uniformly covered the entire surface of modified diatomite.

Synthesis and Luminescent Behavior of Mn(1-X)S:AX/ZnS Core/Shell Nanocrystals

2011 ◽  
Vol 335-336 ◽  
pp. 669-673
Author(s):  
Li Hua Li ◽  
Yong Jun Gu ◽  
Rui Shi Xie ◽  
Jian Guo Zhu
Keyword(s):  
Surface Passivation ◽  
Spherical Shape ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Nonradiative Recombination ◽  
X Ray Diffraction ◽  
Enhanced Photoluminescence ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Zns Nanocrystals

Mn(1-X)S:AX/ZnS (A: Er, Dy) nanocrystals were synthesized by chemical precipitation method. X-ray diffraction analysis show that Mn(1-X)S:AX/ZnS nanocrystals were zincblende structure. The high-resolution transmission electron microscope images indicated that Mn(1-X)S:AX/ZnS nanocrystals show a spherical shape, and their average grain size is about 4 nm. Photoluminescence spectra of Mn(1-X)S:AX/ZnS nanocrystals revealed that there existed several major emission bands, ～417 nm, ~509 nm, ~580 nm, ~617nm and ~680 nm. Mn(1-X)S:AX/ZnS nanocrystals exhibited enhanced luminescence properties compared with the pure Mn(1-X)S:AX nanocrystals. The enhanced photoluminescence properties of Mn(1-X)S:AX/ZnS nanocrystals should be attributed to the effective suppression of nonradiative recombination by the surface-passivation layer.

scholarly journals Synthesis and characterization of non-stoichiometric hydroxyapatite nanoparticles using unmodified and modified starches

2020 ◽  
Vol 9 (12) ◽  
pp. e30791210996
Author(s):  
Geraldine Nancy Rodriguez Perea ◽  
Mariana Bianchini Silva ◽  
Bruno Xavier Freitas ◽  
Ésoly Madeleine Bento dos Santos ◽  
Luiz Carlos Rolim Lopes ◽  
...  
Keyword(s):  
Chemical Precipitation ◽  
Soluble Starch ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Cationic Starch ◽  
Rietveld Refinements ◽  
Modified Starches ◽  
Natural Additive ◽  
Additional Phase

Non-stoichiometric hydroxyapatite (HAp) presents an additional phase in its structure due to calcium or phosphorus excess, which can influence the material’s mechanical properties, as well as its bioactivity and biodegradability. While stoichiometric HAp, with calcium to phosphorus ratio (Ca/P) of 1.67, has been widely investigated, only a few studies have reported the synthesis of HAp with higher Ca/P ratio. In this work, non-stoichiometric HAp nanoparticles were synthesized using chemical precipitation method followed by a calcination protocol. In order to achieve better process control with chemical precipitation, starch, a natural additive, was applied. Three types of starch were selected for comparison: nonionic starch (NS), soluble starch (SS), and cationic starch (CS). Infrared spectroscopy and chemical analysis results confirmed the non-stoichiometric profile of the synthesized HAp, with a 1.98 Ca/P ratio. X-ray diffraction (XRD) results showed that HAp and calcium oxide (CaO) crystalline phases were obtained and no residual starch was detected. Rietveld refinements confirmed that, for all three types of starch, the content of crystalline HAp was greater than 96.5% and the unit cell volume was not affected. Scanning electron microscopy (SEM) showed agglomeration of particles. Nanoparticle tracking analysis (NTA) results demonstrated that the use of SS produced the smallest particles (approximately 60nm).

Synthesize and Characterization of Hollow Hydroxyapatite Nanopowders with Different Morphologies: Role of Cationic and Non-Ionic Surfactants

2013 ◽  
Vol 829 ◽  
pp. 268-273 ◽  
Author(s):  
Amir Seyfoori ◽  
Hamideh Mahmoodzadeh Hosseini ◽  
Abbas Ali Imani Fooladi ◽  
Mohammad Reza Nourani
Keyword(s):  
Protein Delivery ◽  
Nitrogen Adsorption ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Live Cells ◽  
X Ray Diffraction ◽  
Hollow Structures ◽  
Average Surface Area

Today, hydroxyapatite hollow nanopowders have attracted the attention of researchers as a reliable option for drug and protein delivery systems. In this study, nanohydroxyapatite powders with different morphologies were successfully synthesized via wet chemical precipitation method. Elongated rice-shape and semi-spherical nanopowders with hollow structures were synthesized using CTAB and the mixture of cetyltrimethylammonium bromide (CTAB) and polyethylene glycol (PEG) as surfactants respectively. The properties of these nanopowders were charecterized by means of scanning electron microscopy, x-ray diffraction, fourier transform infrared spectroscopy and nitrogen adsorption experiments. The results showed that using CTAB as a surfactant not only can alter the morphology of the HAp nanopowders but also it can have a significant effect on the structure of them, so that by using CTAB and mixture of CTAB and PEG, nanoporous HAp nanopowders were acquired. Moreover, the analysis of nitrogen adsorption showed a higher average surface area for CTAB synthesized HAp in comparison to CTAB/PEG synthesized nanopowder. The amount of live cells adjacent to the HAp suspensions in PBS (50, 100, 200 mg/L) was evaluated by MTT experiment. The results of MTT assay showed the ascending cell proliferation trend for spherical nanopowders by an increment in suspension concentration, while this trend was descending for rice-shape nanopwders.

Structural and Optical Investigation of Mn-Doped ZnS Nanocrystals

2005 ◽  
Vol 475-479 ◽  
pp. 1795-1798 ◽  
Author(s):  
W.Q. Peng ◽  
S.C. Qu ◽  
G.W. Cong ◽  
Z.G. Wang
Keyword(s):  
Visible Spectrum ◽  
Optical Investigation ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Zinc Blende ◽  
Order Of Magnitude ◽  
Zns Nanocrystals ◽  
Average Size ◽  
Mn Doped ◽  
Zinc Blende Structure

Using a solution-based chemical method, we have prepared ZnS nanocrystals doped with high concentration of Mn2+. The X-ray diffraction analysis confirmed a zinc blende structure. The average size was about 3 nm. Photoluminescence spectrum showed room temperature emission in the visible spectrum, which consisted of the defect-related emission and the 4 T1-6 A1 emission of Mn2+ ions. Compared with the undoped sample, the luminescence of the ZnS:Mn sample is enhanced by more than an order of magnitude, which indicated that the Mn2+ ions can efficiently boost the luminescence of ZnS nanocrystals.

scholarly journals Role of annealing temperature on the properties of SrO nanoparticles by precipitation method

2020 ◽  
Vol 1 (1) ◽  
pp. 18-23
Author(s):  
Suresh R ◽  
◽  
Indira Priyadharshini T ◽  
Thirumal Valavan K ◽  
Justin Paul M ◽  
...  
Keyword(s):  
Single Phase ◽  
Annealing Temperature ◽  
Surface Defects ◽  
Visible Region ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Crystalline Nature ◽  
Diffraction Peaks

Strontia nanoparticles are successfully prepared by chemical precipitation method. The SrO nanoparticles are characterized by XRD, UV-DRS and I-V analysis. X-ray diffraction peaks reveal the single-phase polycrystalline tetragonal structure with preferential orientation along (2 0 2) direction. Influence of annealing temperature strongly induce the growth of peak which indicates the increased intensity of (202) peak. The heat treatment strongly distresses the growth of triplet peaks (002), (101) and (110) whereas the same augment the growth of (202) and (310). Strontium oxide nanoparticles would allow more light for absorption in UV region due to its rough surface whereas the same would allow moderate light absorption in visible region due to its high packing density. The expansion and contraction of Sr-O bonds leads to a high crystalline nature with its purity at 322 nm. It is proposed that strain and surface defects in SrO nanocrystal take place due to different absorption edge.

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