PREPARATION AND INVESTIGATION OF OPTICAL, THERMAL, AND ELECTROCHEMICAL PROPERTIES OF Ag/Co NANOPARTICLES

NANO ◽  
2012 ◽  
Vol 07 (02) ◽  
pp. 1250006 ◽  
Author(s):  
Z. PARANG ◽  
A. KESHAVARZ ◽  
S. FARAHI ◽  
S. M. ELAHI ◽  
M. GHORANNEVISS ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electrochemical Techniques ◽  
Mie Theory ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Step Method ◽  
Ag Nps ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Co Nanoparticles

Ag/Co nanoparticles (NPs) were prepared by a two-step method. First, Ag NPs were synthesized by "Controlled Current Coulometry" (CCC) electrochemical method using a Pt rotating electrode. Then, Ag/Co core-shell NPs were prepared through the reduction method using Ag NPs as a core. Both steps were accomplished at room temperature. Techniques such as patterned X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed for the characterization of Ag/Co NPs. Optical properties of synthesized NPs were also investigated by UV-Vis spectroscopy. The absorption peak of Ag NPs was observed at ~400 nm wavelength and the peaks that were detected at 425 nm and 415 nm wavelengths reveal the formation of Ag/Co NPs. The core-shell structure of Ag/Co NPs was confirmed by thermal and electrochemical techniques. We also applied "Mie" theory to calculate the absorption cross-section band of synthesized Ag/Co NPs. Comparison between the results of optical properties and also those obtained from "Mie" theory showed good agreements.

scholarly journals A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe3O4 magnetic and fluorescent nanocrystals

2015 ◽  
Vol 6 ◽  
pp. 1743-1751 ◽  
Author(s):  
Houcine Labiadh ◽  
Tahar Ben Chaabane ◽  
Romain Sibille ◽  
Lavinia Balan ◽  
Raphaël Schneider
Keyword(s):  
Core Shell ◽  
Remnant Magnetization ◽  
Biological Applications ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Magnetite Layer ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Magnetic Shell

Bifunctional magnetic and fluorescent core/shell/shell Mn:ZnS/ZnS/Fe3O4 nanocrystals were synthesized in a basic aqueous solution using 3-mercaptopropionic acid (MPA) as a capping ligand. The structural and optical properties of the heterostructures were characterized by X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence (PL) spectroscopy. The PL spectra of Mn:ZnS/ZnS/Fe3O4 quantum dots (QDs) showed marked visible emission around 584 nm related to the 4T1 → 6A1 Mn2+ transition. The PL quantum yield (QY) and the remnant magnetization can be regulated by varying the thickness of the magnetic shell. The results showed that an increase in the thickness of the Fe3O4 magnetite layer around the Mn:ZnS/ZnS core reduced the PL QY but improved the magnetic properties of the composites. Nevertheless, a good compromise was achieved in order to maintain the dual modality of the nanocrystals, which may be promising candidates for various biological applications.

Synthesis of Fe2+ Ion Doped ZnS Nanoparticles

2014 ◽  
Vol 879 ◽  
pp. 155-163 ◽  
Author(s):  
Rahizana Mohd Ibrahim ◽  
Markom Masturah ◽  
Huda Abdullah
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Quantum Confinement Effect ◽  
Band Gap Energy ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Co Precipitation

Nanoparticles of Zn1-xFexS ( x=0.0,0.1,0.2 and 0.3) were prepared by chemical co-precipitation method from homogenous solution of zinc and ferum salt at room temperature with controlled parameter. These nanoparticles were sterically stabilized using Sodium Hexamethaphospate (SHMP). Here, a study of the effect of Fe doping on structure, morphological and optical properties of nanoparticles was undertaken. Elemental analysis, morphological and optical properties have been investigated by Fourier-Transform-Infrared spectroscopy (FT-IR), X-Ray Fluorescence (XRF), Field Emmision Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and UV-Visible Spectroscopy. FTIR measurement confirmed the presence of SHMP in the nanoparticles structure with the FESEM images depicting considerable less agglomeration of particles with the presence of SHMP. While XRF results confirm the presence of Fe2+ ion as prepared in the experiment. The particles sizes of the nanoparticles lay in the range of 2-10 nm obtained from the TEM image were in agreement with the XRD results. The absorption edge shifted to lower wavelengths with an increase in Fe concentration shown in the UV-Vis spectroscopy. The band gap energy value was in the range of 4.95 5.15 eV. The blueshift is attributed to the quantum confinement effect.

scholarly journals Synthesis and characterization of Fe3O4@SiO2 sub-nano core/shell with SiO2 derived from rice husk ash

2020 ◽  
pp. 52-56
Author(s):  
Luong Huynh Vu Thanh, Tran Nguyen Phuong Lan Luong
Keyword(s):  
Spherical Shape ◽  
Xrd Analysis ◽  
Research Process ◽  
Infrared Spectrometry ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ft Ir

This study aims to synthesize and characterize Fe3O4@SiO2 sub-nanoparticles (SNPs) with high saturation magnetization (SM). The research process was conducted in simple and environmentally friendly conditions. The results of ultraviolet-visible (UV-Vis) spectroscopy and X-ray diffraction (XRD) analysis presented that the Fe3O4@SiO2 SNPs were well formed and the phase change of Fe3O4 NPs did not happen in Fe3O4@SiO2 SNPs. Transmission electron microscope (TEM) analysis showed that the Fe3O4@SiO2 SNPs are in a fairly spherical shape with a core/shell structure and a diameter in a range of 100 nm to 500 nm. Fourier transform infrared spectrometry (FT-IR) spectra of Fe3O4@SiO2 SNPs presented some absorption peaks indicating the existence of Si-O-Si, O-Si-O, Fe-O and Fe-O-Si. The SM of Fe3O4 particles and Fe3O4@SiO2 SNPs determined via vibrating sample magnetometer (VSM) were 50.9 emu.g−1 and 19.5 emu.g−1, respectively. All the above results provide clear evidence that the Fe3O4 particles were coated by SiO2 to form sub-nano core/shell with great SM.

Structural and optical properties of KNN nanocubes synthesized by a green route using gelatin

2015 ◽  
Vol 08 (02) ◽  
pp. 1550030 ◽  
Author(s):  
Gh. H. Khorrami ◽  
A. Kompany ◽  
A. Khorsand Zak
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Structural Deformation ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Transmission Electron ◽  
Green Route ◽  
Vis Spectroscopy ◽  
Xrd Patterns ◽  
Average Size

Sodium potassium niobate nanoparticles [( K 0.5 Na 0.5) NbO 3, KNN ], KNN-NPs, were synthesized using a modified sol–gel method. Structural and optical properties of the prepared samples were investigated by thermogravometric analyzer (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman and UV–Vis spectroscopy. The XRD patterns showed that the formation of the orthorhombic KNN-NPs starts at 500°C calcination temperature. Raman spectroscopy was used to investigate the crystalline symmetry and the structural deformation of the prepared KNN-NPs. TEM images showed that the morphology of the prepared particles is cubic, with the average size of about 50 nm. From diffused reflectance spectroscopy along with using Kubelka–Munk method, the energy bandgaps were determined to be indirect with the values of 3.13 eV and 3.19 eV for the samples calcined at 500°C and 600°C, respectively.

Synthesis of Fe-Co Nanobars Using Sodium Sulfite Assisted Polyol Process and their Structural and Magnetic Studies

2011 ◽  
Vol 15 ◽  
pp. 21-28 ◽  
Author(s):  
G. Suresh ◽  
P. Saravanan ◽  
D. Rajan Babu
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Sodium Sulfite ◽  
Polyol Process ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Magnetic Studies ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Co Nanoparticles

We report the synthesis of soft magnetic Fe-Co nanobars by an improved polyol process using cetyltrimethylammonium bromide (CTAB) as stabilizer. The synthesized samples were studied by using Transmission Electron Microscopy. The Fe-Co nanoparticles were characterized by X-ray diffraction, UV-Vis spectroscopy, Fourier transform infrared spectroscopy and Vibrating Sample Magnetometer. The Fe-Co nanobars showed prominent UV-VIS absorption at 371 nm. This report discusses the effect of sodium sulfite and CTAB on the synthesis of Fe-Co nanoparticles.

Photocatalytic Degradation of Methyl Orange Dye with Synthesized Chitosan/Fe2O3Nanocomposite and its Isotherm Studies.

2020 ◽  
Vol 16 ◽  
Author(s):  
Nimisha Jadon ◽  
Gulzar Ahmad Bhat ◽  
Manoharmayum Vishwanath Sharma ◽  
Harendra Kumar Sharma
Keyword(s):  
Methyl Orange ◽  
Dye Degradation ◽  
Dose Effect ◽  
X Ray Diffraction ◽  
Methyl Orange Degradation ◽  
Transmission Electron ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Vis Spectroscopy ◽  
Methyl Orange Dye ◽  
Degradation Of Methyl Orange

Background: The study focuses on the synthesis of chitosan/ Fe2O3 nanocomposite, its characterization and application in methyl orange dye degradation. Methods: The synthesized chitosan/ Fe2O3 nanocomposite was characterized with Powder X-Ray Diffraction, Fourier Transformation Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and UV-Vis Spectroscopy. Results: The characterization showed that the Fe2O3nanoparticles were embedded in the polymer matrix of chitosan. The size of the Fe2O3nanoparticles were less than 10nm and the crystallite size was 1.22 nm.The synthesized chitosan/ Fe2O3nanocomposite was tested for methyl orange degradation using different parameters such as effect of contact time, effect of dose, effect of concentration and effect of pH for the degradation of methyl orange dye in aqueous solution.The Fruendlich, Langmuir and Temkin isotherm studies were also conducted for adsoption of methyl orange on Chitosan/ Fe2O3nanocomposite. Conclusion: The study indicated that the synthesized chitosan/Fe2O3 nanocomposite had the potential of degrading methyl orange dye up to 75.04% under the set condition in this experiment which indicate that Chitosan/ Fe2O3 nanocomposite is a viable option that can be used for the degradation of methyl orange dye.

scholarly journals Temperature Dependence of Stress and Optical Properties in AlN Films Grown by MOCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 698
Author(s):  
Wenwang Wei ◽  
Yi Peng ◽  
Jiabin Wang ◽  
Muhammad Farooq Saleem ◽  
Wen Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Compressive Stress ◽  
Sapphire Substrate ◽  
Light Transmission ◽  
Chemical Vapor ◽  
Biaxial Stress ◽  
X Ray Diffraction ◽  
Patterned Sapphire Substrate ◽  
Transmission Electron ◽  
Nano Patterning

AlN epilayers were grown on a 2-inch [0001] conventional flat sapphire substrate (CSS) and a nano-patterned sapphire substrate (NPSS) by metalorganic chemical vapor deposition. In this work, the effect of the substrate template and temperature on stress and optical properties of AlN films has been studied by using Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectrophotometer and spectroscopic ellipsometry (SE). The AlN on NPSS exhibits lower compressive stress and strain values. The biaxial stress decreases from 1.59 to 0.60 GPa for AlN on CSS and from 0.90 to 0.38 GPa for AlN on NPSS sample in the temperature range 80–300 K, which shows compressive stress. According to the TEM data, the stress varies from tensile on the interface to compressive on the surface. It can be deduced that the nano-holes provide more channels for stress relaxation. Nano-patterning leads to a lower degree of disorder and stress/strain relaxes by the formation of the nano-hole structure between the interface of AlN epilayers and the substrate. The low crystal disorder and defects in the AlN on NPSS is confirmed by the small Urbach energy values. The variation in bandgap (Eg) and optical constants (n, k) with temperature are discussed in detail. Nano-patterning leads to poor light transmission due to light scattering, coupling, and trapping in nano-holes.

scholarly journals Size Control of Synthesized Silver Nanoparticles by Simultaneous Chemical Reduction and Laser Fragmentation in Origanum majorana Extract: Antibacterial Application

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2326
Author(s):  
Entesar Ali Ganash ◽  
Reem Mohammad Altuwirqi
Keyword(s):  
Silver Nanoparticles ◽  
Irradiation Time ◽  
Chemical Reduction ◽  
Size Control ◽  
Reduction Process ◽  
Laser Wavelength ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Transmission Electron ◽  
Origanum Majorana

In this work, silver nanoparticles (Ag NPs) were synthesized using a chemical reduction approach and a pulsed laser fragmentation in liquid (PLFL) technique, simultaneously. A laser wavelength of 532 nm was focused on the as produced Ag NPs, suspended in an Origanum majorana extract solution, with the aim of controlling their size. The effect of liquid medium concentration and irradiation time on the properties of the fabricated NPs was studied. While the X-ray diffraction (XRD) pattern confirmed the existence of Ag NPs, the UV–Vis spectrophotometry showed a significant absorption peak at about 420 nm, which is attributed to the characteristic surface plasmon resonance (SPR) peak of the obtained Ag NPs. By increasing the irradiation time and the Origanum majora extract concentration, the SPR peak shifted toward a shorter wavelength. This shift indicates a reduction in the NPs’ size. The effect of PLFL on size reduction was clearly revealed from the transmission electron microscopy images. The PLFL technique, depending on experimental parameters, reduced the size of the obtained Ag NPs to less than 10 nm. The mean zeta potential of the fabricated Ag NPs was found to be greater than −30 mV, signifying their stability. The Ag NPs were also found to effectively inhibit bacterial activity. The PLFL technique has proved to be a powerful method for controlling the size of NPs when it is simultaneously associated with a chemical reduction process.

Synthesis of CaWO4:(Eu3+,Tb3+) Thin Films by a Two-Step Method at Room Temperature

2013 ◽  
Vol 710 ◽  
pp. 170-173
Author(s):  
Lian Ping Chen ◽  
Yuan Hong Gao
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Composition ◽  
Room Temperature ◽  
Electrochemical Techniques ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Rare Earth Doped

It is hardly possible to obtain rare earth doped CaWO4thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize CaWO4:(Eu3+,Tb3+) thin films at room temperature. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that (Eu3+,Tb3+)-doped CaWO4films have a tetragonal phase. When the ratio of n (Eu)/n (Tb) in the solution is up to 3:1, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Tb element; on the contrary, when the ratio in the solution is lower than 1:4, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Eu element. Under the excitation of 242 nm, sharp emission peaks at 612, 543, 489 and 589 nm have been observed for CaWO4:(Eu3+,Tb3+) thin films.

The effect of silver concentration and calcination temperature on structural and optical properties of ZnO:Ag nanoparticles

2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Visible Emission ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Zno Nps ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.

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