One-pot microwave assisted approach for synthesis of CdSe/CdS core-shell quantum dots (QDs) and investigating optical properties

2016 ◽  
Vol 30 (07) ◽  
pp. 1650074 ◽  
Author(s):  
M. Molaei ◽  
F. Salari Bardsiri ◽  
A. R. Bahador ◽  
M. Karimipour
Keyword(s):  
Core Shell ◽  
Heat Sensitivity ◽  
X Ray Diffraction ◽  
Cdse Qds ◽  
One Pot ◽  
X Ray ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Microwave Assisted Method

In this work, CdSe QDs were synthesized using a microwave assisted method and chemical reaction between NaHSe, CdSO4 at the presence of TGA as capping molecule. Thereafter without CdSe extraction, CdS shell was grown subsequently around CdSe cores by a reaction based on the heat sensitivity of Na2S2O3 dissociation. Synthesized QDs were characterized by means of X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV–Vis and photoluminescence (PL) spectroscopy. All of these analyzes confirmed formation of CdSe QDs and successfully growth of CdS shell on surface of CdSe to forming CdSe/CdS core-shell structure.

Enhancement of durability of NIR emission of Ag2S@ZnS QDs in water

2017 ◽  
Vol 31 (32) ◽  
pp. 1750297 ◽  
Author(s):  
M. Karimipour ◽  
M. Bagheri ◽  
M. Molaei
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Xrd Analysis ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nir Emission ◽  
Core Shell Structure ◽  
Phase Transmission

Stability of Ag2S@ZnS QDs in water is a crucial concern for their application in biology. In this work, both physical sustainability and emission stability of Ag2S QDs were enhanced using parameter optimization of a pulsed microwave irradiation (MI) method up to 105 days after their preparation. UV–Vis and photoluminescence spectroscopies depicted an absorption and emission about 817 nm and 878 nm, respectively. X-ray diffraction (XRD) analysis showed a growth of Ag2S acanthite phase. Transmission Electron Microscopy (TEM) images revealed a clear formation of Ag2S@ZnS core–shell structure.

Effect of protamine on Fe3O4@CS@GFTN composite magnetic nanoparticles

2019 ◽  
Vol 13 (02) ◽  
pp. 2050001 ◽  
Author(s):  
Huiping Shao ◽  
Luhui Wang ◽  
Tao Lin ◽  
Yumeng Zhang ◽  
Zhinan Zhang
Keyword(s):  
Magnetic Nanoparticles ◽  
Shell Structure ◽  
Lung Diseases ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Average Size ◽  
Chemical Coprecipitation Method

Fe3O4@chitosan (CS)@Gefitinib (GFTN) core-shell structure composite magnetic nanoparticles (NPs) were prepared by chemical coprecipitation method in this study. In addition, protamine was doped in Fe3O4 cores to prepare Fe3O4@protamine@CS@GFTN core-shell structure composite NPs, in order to increase the loading of GFTN in composite NPs. They were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and spectrophotometer. The results show that the average size of Fe3O4@CS@GFTN and Fe3O4@protamine@CS@GFTN composite NPs is approximately 19 and 21[Formula: see text]nm, respectively. The saturation magnetizations of composite magnetic NPs and corresponding magnetic fluids are 57.20, 20.79, 59.58 and 19.75[Formula: see text]emu/g, respectively. The loading of GFTN in composite NPs was measured by a spectrophotometer to be about 13.5% and 27.6%, respectively. The addition of protamine increased the loading of GFTN two times, indicating that it will play an important role in the management of lung diseases.

Silica/Polyurea Composite: Preparation, Characterization and Study of Dielectric Constant

2016 ◽  
Vol 13 (10) ◽  
pp. 7234-7237
Author(s):  
Botong Wang ◽  
Zebo Xu ◽  
Zhiqiang Wang
Keyword(s):  
Electron Microscopy ◽  
Dielectric Constant ◽  
Hydrogen Bonds ◽  
Ultraviolet Spectroscopy ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Modified Silica ◽  
X Ray ◽  
Transmission Electron ◽  
Core Shell Structure

Silica/polyurea composite was prepared after surface modification of silica nanoparticles. Silica/polyurea composite was characterized by Fourier-transform infrared spectroscopy, ultraviolet spectroscopy, X-ray diffraction and transmission electron microscopy. The results indicate that the helical polyurea has been successfully grafted onto the surfaces of the modified silica. Silica/polyurea composite exhibits clearly core–shell structure. The ultraviolet absorption and crystallizability of silica/polyurea are changed due to the shell of helical polyurea, which possesses regular singlehanded conformation and interchain hydrogen bonds. The dielectric constant of silica/polyurea was also investigated. The result indicates that the interfacial interactions between organic shell and inorganic core increase the dielectric constant value being increased to 6.42 for silica/polyurea. The interchain hydrogen bonds of helical polyurea could also be the reason for the increasing of dielectric constant.

scholarly journals Crystallization of BaF2 from droplets of phase separated glass – evidence of a core–shell structure by ASAXS

CrystEngComm ◽  
2020 ◽  
Vol 22 (30) ◽  
pp. 5031-5039
Author(s):  
Armin Hoell ◽  
Vikram Singh Raghuwanshi ◽  
Christian Bocker ◽  
Andreas Herrmann ◽  
Christian Rüssel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Shell Structure ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Core Shell Structure

Glasses with the mol% compositions 1.88 Na2O·15.04 K2O·7.52 Al2O3·69.56 SiO2·6.00 BaF2 and 1.88 Na2O·15.03 K2O·7.52 Al2O3·69.52 SiO2·6.00 BaF2·0.05 SmF3 were studied using X-ray diffraction, transmission electron microscopy, and anomalous small-angle X-ray scattering.

CdSe/ZnS core–shell QDs: Synthesis and investigating optical properties

2016 ◽  
Vol 30 (08) ◽  
pp. 1650093 ◽  
Author(s):  
M. Molaei ◽  
F. Sarhani ◽  
F. Salari Bardsiri ◽  
M. Karmipour
Keyword(s):  
Room Temperature ◽  
Thioglycolic Acid ◽  
Cdse Quantum Dots ◽  
Temperature Reaction ◽  
X Ray Diffraction ◽  
Cdse Qds ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible

In this work, CdSe quantum dots (QDs) were synthesized using a microwave activated reaction between NaHSe and CdSO4 in the presence of thioglycolic acid (TGA) as capping molecule and then using a one-pot method, ZnS shell was grown subsequently around CdSe cores by a room temperature reaction based on the photo-sensitivity of Na2S2O3 dissociation. Synthesized QDs were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV-visible (UV-Vis) and photoluminescence (PL) spectroscopy. All these analyses confirmed the formation of CdSe QDs and successful growth of ZnS shell around CdSe cores.

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.

An expeditious one-pot synthesis of pyrido[2,3-d]pyrimidines using Fe3O4–ZnO–NH2–PW12O40 nanocatalyst

2019 ◽  
Vol 43 (3-4) ◽  
pp. 135-139
Author(s):  
Pegah Farokhian ◽  
Manouchehr Mamaghani ◽  
Nosrat Ollah Mahmoodi ◽  
Khalil Tabatabaeian ◽  
Abdollah Fallah Shojaie
Keyword(s):  
Electron Microscopy ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
Pyrimidine Derivatives ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Novel Method ◽  
Operational Simplicity

An efficient protocol for the facile synthesis of a series of pyrido[2,3- d]pyrimidine derivatives has been developed applying Fe3O4–ZnO–NH2–PW12O40 nanocatalyst in water. This novel method has the benefits of operational simplicity, green aspects by avoiding toxic solvents and high to excellent yields of products. Fe3O4–ZnO–NH2–PW12O40 was synthesized and characterized by Fourier transform infrared, X-ray diffraction, vibrating sample magnetometer, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy analyses. The nanocatalyst is readily isolated and recovered from the reaction mixture by an external magnet.

scholarly journals Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 999
Author(s):  
Yi-An Chen ◽  
Kuo-Hsien Chou ◽  
Yi-Yang Kuo ◽  
Cheng-Ye Wu ◽  
Po-Wen Hsiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Particle Size ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Alloy Quantum Dots ◽  
First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

scholarly journals Novel Graphene/In2O3 Nanocubes Preparation and Selective Electrochemical Detection for L-Lysine of Camellia nitidissima Chi

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1999
Author(s):  
Jinsheng Cheng ◽  
Sheng Zhong ◽  
Weihong Wan ◽  
Xiaoyuan Chen ◽  
Ali Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Sensor ◽  
Chiral Recognition ◽  
Graphene Nanosheets ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Camellia Nitidissima

In this work, novel graphene/In2O3 (GR/In2O3) nanocubes were prepared via one-pot solvothermal treatment, reduction reaction, and successive annealing technology at 600 °C step by step. Interestingly, In2O3 with featured cubic morphology was observed to grow on multi-layered graphene nanosheets, forming novel GR/In2O3 nanocubes. The resulting nanocomposites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), etc. Further investigations demonstrated that a selective electrochemical sensor based on the prepared GR/In2O3 nanocubes can be achieved. By using the prepared GR/In2O3-based electrochemical sensor, the enantioselective and chem-selective performance, as well as the optimal conditions for L-Lysine detection in Camellia nitidissima Chi, were evaluated. The experimental results revealed that the GR/In2O3 nanocube-based electrochemical sensor showed good chiral recognition features for L-lysine in Camellia nitidissima Chi with a linear range of 0.23–30 μmol·L−1, together with selectivity and anti-interference properties for other different amino acids in Camellia nitidissima Chi.

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