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.

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.

scholarly journals Effect of Annealing on the ZnS Nanocrystals Prepared by Chemical Precipitation Method

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nadana Shanmugam ◽  
Shanmugam Cholan ◽  
Natesan Kannadasan ◽  
Kannadasan Sathishkumar ◽  
G. Viruthagiri
Keyword(s):  
Chemical Precipitation ◽  
Chemical Precipitation Method ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Atomic Force ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Uv Visible ◽  
Dta Curves

Nanocrystals of ZnS have been synthesized through simple chemical precipitation method using thiourea as sulphur source. The synthesized products were annealed at different temperatures in the range of 200–800∘C. The as-synthesized and annealed samples were characterized by X-ray diffraction (XRD), UV-Visible absorption (UV-Vis), and room temperature photoluminescence (PL) measurements. The morphological features of ZnS annealed at 200 and 500∘C were studied by atomic force microscope (AFM) and transmission electron microscope (TEM) techniques. The phase transformation of ZnS and formation of ZnO were confirmed by thermogravimetric (TG) and differential thermal analysis (DTA) curves.

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.

Synthesis of RePO4 (Re=La, Nd, Pr, or Y) Nanowires by Chemical Precipitation in Nanochannels

2011 ◽  
Vol 181-182 ◽  
pp. 495-500 ◽  
Author(s):  
Cheng Mu ◽  
Jun Hui He
Keyword(s):  
Rare Earth ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Aao Template ◽  
Sem Images ◽  
Transmission Electron ◽  
Rare Earth Phosphate ◽  
Xrd Patterns ◽  
Uniform Diameter

Monodisperse nanowires of rare earth phosphates were synthesized by chemical precipitation method using anodic aluminum oxide (AAO) template. Scanning electron microscope (SEM) images indicated that rare earth phosphate nanowires are parallelly arranged in AAO template, all of which are in uniform diameter of about 50 nm. X-ray diffraction (XRD) patterns and high magnification transmission electron microscopy (HRTEM) images showed that the nanowires were polycrystal structure.

scholarly journals Synthesis and characterization of ZnTe nanoparticles

2016 ◽  
Vol 17 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Sujan Dhungana ◽  
Bhoj Raj Paudel ◽  
Surendra K. Gautam
Keyword(s):  
Particle Size ◽  
Field Effect Transistors ◽  
Average Particle Size ◽  
Precursor Solution ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Zinc Compounds ◽  
Transmission Electron

In this work, we report the ZnTe semiconductor nanoparticles (NPs) prepared by aqueous chemical precipitation method using the tellurium precursor solution with different zinc compounds. Three batches of ZnTe NPs were synthesized to study the effect of dilution on the size and phase purity of ZnTe. The influence of source compounds and concentrations of the size and structure of NPs were studied. ZnTe NPs have great applications as field-effect transistors and photodetectors. The existing controversy regarding the crystalline structure of ZnTe NPs, whether it is cubic or hexagonal, has been resolved using X-ray Diffraction (XRD) data. The ZnTe NPs possess cubic structure, which is also confirmed by Electron Diffraction (ED) pattern. The average particle size determined from XRD data with the help of Debye-Scherrer equation is about 6 nm. The particle size can be further verified by Transmission Electron Microscopy (TEM) studies.  

Effects of Temperature and Concentration on the Nano-Sized Hydroxyapatite Whisker Prepared by Chemical Precipitation Method

2007 ◽  
Vol 353-358 ◽  
pp. 2191-2194
Author(s):  
Yun Qiang Bai ◽  
Mu Sen Li ◽  
Yu Peng Lu ◽  
Ning Cao
Keyword(s):  
Heat Treatment ◽  
Raw Materials ◽  
Chemical Precipitation ◽  
Strength Test ◽  
Precipitation Method ◽  
Test Results ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Synthetic Temperature ◽  
Effects Of Temperature

Chemical precipitation is a popular method for the preparation of hydroxyapatite(Ca10 (PO4)6 (OH)2, HA) because of its simple operation. In this work, nano-sized HA whiskers were synthesized at various synthetic temperatures and concentration by chemical precipitation with Ca (NO3) 2·4H2O and (NH4) 2HPO4 as raw materials. Heat treatment was carried out after they were synthesized. The HA powders were analyzed by using X-ray diffraction (XRD), transmission electron microscope (TEM) and strength test in order to find the favorable growing condition for HA whiskers. The results show that the HA prepared at different synthetic temperatures show no impurity diffraction peak, indicating that they have a high purity. Prior to heat treatment, the crystallinity and length/diameter ratio of the HA whiskers become larger with the increasing of synthetic temperature. So a higher synthetic temperature can promote the growth of the HA whiskers. There is no obvious difference in crystallinity after the heat treatment. Besides, a lower reaction concentration can also promote the growth of HA whiskers. The strength test results show that the compressive strength of the HA prepared gets a maximum value at 50°C.

scholarly journals Structural, morphological, and magnetic properties of copper zinc cobalt ferrites systems nanocomposites

2020 ◽  
Vol 10 (4) ◽  
pp. 6015-6019
Keyword(s):  
Electron Microscopy ◽  
Magnetic Measurements ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Cobalt Ferrites ◽  
Ultraviolet Light Irradiation ◽  
Copper Zinc ◽  
Co Precipitation

In this study, by the method of co-precipitation with PEG as surfactant as agent nanocomposite of the Copper Zinc Cobalt ferrites systems (CuZnCoFO NCs) are prepared. The X-ray diffraction (XRD), transmission electron microscopy, and field emission scanning electron microscopy of the samples are carried out. To analyse the magnetic measurements the samples are subjected to the vibrating sample magnetometer (VSM). The results of the paramagnetic properties formed out of chemical precipitation method are effective at room temperature. These ferrite system nanoparticles with magnetic fields could have effective application. The photocatalyst activity when annealed at 600ºC at 2h NPs is also evaluated by Methylene Blue degradation when exposed to ultraviolet light irradiation.

scholarly journals Densification and Mechanical Behavior of β-Tricalcium Phosphate Bioceramics

2014 ◽  
Vol 36 ◽  
pp. 37-49 ◽  
Author(s):  
Behzad Mehdikhani ◽  
Gholam Hossein Borhani
Keyword(s):  
Tricalcium Phosphate ◽  
Calcium Nitrate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Average Grain Size ◽  
Ammonium Hydrogen ◽  
Sample Characterization ◽  
Nano Size

Nano-size β-tricalcium phosphate powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and di-ammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of sub-micrometre β-TCP powder in situ. The sinterability of the nano-size powders, and the microstructure, mechanical strength of the prepared β-TCP bioceramics were investigated. Bioceramic sample characterization was achieved by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and density measurements. Powders compacted and sintered at 800, 900, 1000 and 1100 °C showed an increase in relative density from 70 % to 93 %. The results revealed that the maximum hardness of 240 H was obtained for β-TCP sintered at 1100 °C.

Synthesis and Characterization of Fe and Fe2O3 Nanoparticles

2013 ◽  
Vol 678 ◽  
pp. 46-49 ◽  
Author(s):  
Ponnaian Peula Kumari ◽  
Rachel Oommen ◽  
Chinna Kannaiyan Senthil Kumaran ◽  
Mariyappan Thambidurai ◽  
Natarajan Muthukumarasamy ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Secondary Phase ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Synthesis And Characterization ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Fe and Fe2 O3 nanoparticle have been synthesized by chemical precipitation method. The x-ray diffraction studies indicate the formation of Fe and Fe2 O3 nanoparticles with cubic phase and no secondary phase was observed. Surface morphology of Fe and Fe2 O3 has been studied using scanning electron microscopy (SEM). Transmission electron microscopy (TEM) images reveal that Fe and Fe2 O3 nanoparticle have size ranging from 25-41 nm.

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