SYNTHESIS AND STRUCTURE OF PURE AND Mn-DOPED ZINC OXIDE NANOPOWDERS

2010 ◽  
Vol 09 (01n02) ◽  
pp. 19-28 ◽  
Author(s):  
M. EBRAHIMIZADEH ABRISHAMI ◽  
S. M. HOSSEINI ◽  
E. ATTARAN KAKHKI ◽  
A. KOMPANY ◽  
M. GHASEMIFARD
Keyword(s):  
Optical Constants ◽  
Magnetic Impurity ◽  
Sol Gel ◽  
Optical Characterization ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Size And Morphology ◽  
Mn Doped

Zn 1-x Mn x O (x = 0, 0.02, 0.06, 0.10, 0.15) nanopowders were synthesized by the sol–gel technique calcinated at low temperatures. By decreasing the grain size in ZnO , the solubility of magnetic impurity has been increased and no detectable secondary phases were observed even in the high Mn -doping samples. The phase formation, size and morphology of nanoparticles were investigated using X-ray diffraction and SEM observations. The samples were ferromagnetic and the Curie point was found in the range 150–170 K for Zn0.94Mn0.06O and 135–150 K for Zn0.98Mn0.02O . Optical characterization and the effect of doping were carried out by means of Fourier transform infrared (FTIR) spectroscopy. Kramers–Kronig analysis was employed to evaluate the optical constants of pure ZnO and ZnO:Mn nanopowders.

SYNTHESIS AND OPTICAL CHARACTERIZATION OF PYROELECTRIC NANOPOWDERS BASED ON PZT (95/5)

2010 ◽  
Vol 09 (03) ◽  
pp. 193-199 ◽  
Author(s):  
E. PAKIZEH ◽  
S. M. HOSSEINI ◽  
A. KOMPANY ◽  
M. GHASEMIFARD
Keyword(s):  
Low Temperatures ◽  
Optical Constants ◽  
Sol Gel ◽  
Normal Incidence ◽  
Optical Characterization ◽  
Analysis Program ◽  
Secondary Phases ◽  
Ir Reflectance ◽  
Gel Technique

Pb(Zr1-x, Tix)O3 (x = 0.05) with pyroelectric properties have been synthesized by sol–gel technique at low temperatures. XRD results indicate that the powder has perovskite structure without secondary phases and the average of particle size was estimated to be about 40 nm in diameters. The optical constants such as refractive index, n, extinction coefficient, k, and the dielectric function of PZT nanopowders have been investigated by Fourier transmittance infrared (FTIR) spectrum and Kramers–Kronig (KK) analysis program. The use of the KK method to analyze the normal incidence infrared (IR) reflectance spectra with a single resonance has also been described. The results indicated that the optical constant increases slowly as temperature of calcinations increases.

CHARACTERIZATION OF ZINC OXIDE NANOPOWDERS DOPED WITH MnO

2010 ◽  
Vol 24 (08) ◽  
pp. 749-760 ◽  
Author(s):  
M. EBRAHIMIZADEH ABRISHAMI ◽  
E. ATTARAN KAKHKI ◽  
S. M. HOSSEINI ◽  
A. KOMPANY
Keyword(s):  
Optical Constants ◽  
Optical Band Gap ◽  
Sol Gel ◽  
Secondary Phase ◽  
Band Gap Energy ◽  
Gel Technique ◽  
Size And Morphology ◽  
Mn Doped ◽  
Compositional Characterization

Pure ZnO and Zn 1-x Mn x O (x=0.02 and 0.06) nanopowders have been synthesized by sol–gel technique at low temperatures. XRD results indicated that the crystal structure is hexagonal and there is no secondary phase. The compositional characterization of Mn -doped samples was investigated by EDX spectra. The size and morphology of nanoparticles were obtained by SEM and TEM images. Optical constants such as refractive index and extinction coefficient were evaluated from transmittance spectrum in UV region. The optical band gap energy showed a red-shift from 3.22 eV to 3.14 eV for pure and Zn 0.94 Mn 0.06 O , respectively. The Curie temperature of Mn -doped ZnO samples were determined and at room temperature no ferromagnetism state was observed.

Temperature Effects on Fluorescence Intensity of Mn-Doped ZnO Quantum Dots Derived from a Sol–Gel Method

2015 ◽  
Vol 15 (10) ◽  
pp. 8023-8027
Author(s):  
Younghoon Kwon ◽  
Jongsung Kim
Keyword(s):  
Quantum Dots ◽  
Sol Gel ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Technique ◽  
Doped Zno ◽  
Zno Qds ◽  
Mn Doped

Recently, various quantum dots (QDs) have been prepared and studied extensively due to their unique electrical and optical properties. Among them, ZnO has attracted much attention because it contains no heavy metals, is biocompatible, and can be easily prepared. In addition, doping QDs with transition metals such as Mn allows for their photo-physical properties to be modified. In this study, Mn-doped ZnO QDs were synthesized by a sol–gel technique, after which the effect of temperature on their fluorescence properties was investigated. The prepared QDs were characterized by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. In addition, their photoluminescence (PL) intensities decreased linearly with temperature between 30 and 70 °C. Intensity also decreased as the amount of Mn increased. Finally, the slope of the PL temperature dependence decreased as the amount of Mn present increased.

scholarly journals Calcination Effect on Structural Trasformation of Barium Titanite Ferroelectric Ceramic by Sol-Gel Method

2019 ◽  
Vol 9 (1) ◽  
pp. 5893-5896
Keyword(s):  
Glacial Acetic Acid ◽  
Sol Gel ◽  
Ferroelectric Ceramic ◽  
Tetrabutyl Titanate ◽  
Chemical Modifier ◽  
Barium Acetate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Scanning Electron

High purity barium titanate BaTiO3 was successfully synthesized by using the sol-gel technique. Barium acetate Ba(CH3COO)2 and tetrabutyl titanate, Ti(C4H9O)4 was dissolved moderately in the solvent of glacial acetic acid and ethanol was added as the chemical modifier. The synthesized BaTiO3 nanoparticle was calcined at the temperature range of 700 ºC to 1100 ºC. The powders were further characterized by X-ray diffraction and scanning electron microscopy (SEM). Fined BaTiO3 powders result indicates the phase of tetragonal structures and high crystallites of BaTiO3. It was observed that the crystallinity and particle size of BaTiO3 is greatly influenced by the calcination temperature.

scholarly journals Synthesis Photocatalytic and Antibacterial Activities of Nickle Doped Tio2 Nanoparticles

2018 ◽  
Vol 34 (6) ◽  
pp. 3140-3144
Author(s):  
Ritu Vershney ◽  
Komal Chelaramani ◽  
Arpan Bhardwaj ◽  
Nayma Siddiqui ◽  
Suresh Kumar Verma
Keyword(s):  
Photocatalytic Degradation ◽  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Antibacterial Activities ◽  
X Ray Diffraction ◽  
Zone Of Inhibition ◽  
Time Duration ◽  
X Ray ◽  
Gel Technique ◽  
Doped Titania

The synthesis of Ni doped titania (TiO2) nanoparticles were achieved via simple novel sol gel technique, in which Titanium-n-butoxide and NiCl2 were taken as precursors. Effect of different wt% of dopant in TiO2 was studied on photocatalytic degradation of Aniline blue and Toluidine Blue. The study suggested the increased photocatalytic degradation with increased time duration. The synthesized samples were analyzed by surface electron microscopy (SEM) and X-ray diffraction studies. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus bacteriae. Studies revealed that on increasing the dopant concentration, the diameter of zone of inhibition also increased upto 1.5 wt%.

Fabrication of Porous LSCF-SDC Carbonates Composite Cathode for Solid Oxide Fuel Cell (SOFC) Applications

2011 ◽  
Vol 471-472 ◽  
pp. 179-184 ◽  
Author(s):  
Raharjo Jarot ◽  
Andanastuti Muchtar ◽  
Wan Ramli Wan Daud ◽  
Norhamidi Muhamad ◽  
Edy Herianto Majlan
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Composite Cathode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Composite Cathodes ◽  
Gel Technique ◽  
Optimum Porosity ◽  
Cold Pressed

Composite cathodes made of perovskite La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and SDC carbonates (SDC-(Li/Na)2CO3) were investigated in relation to their structure, morphology, thermal expansion coefficient and porosity. As a first step, the LSCF powder was prepared by sol-gel technique. This was followed by the preparation of the LSCF-SDC carbonates composite cathode by mixing the LSCF with SDC-(Li/Na)2CO3 electrolyte via solid state reaction in various compositions, i.e. 30, 40 and 50 wt.%, namely 70LSCF-30SDC7030, 60LSCF-40SDC7030 and 50LSCF-50SDC7030, respectively. The powder mixtures were then calcined at 680oC. The resultant powder was fine with surface area of about 3.39-7.42 m2/g and particle size of 0.56-0.66µm. The powder consists of two distinct phases, i.e. LSCF and SDC-(Li/Na)2CO3 as confirmed with x-ray diffraction. The microstructures were observed under scanning electron microscopy (SEM). Increasing the amount of the SDC-(Li/Na)2CO3 electrolyte in the composite cathode was found to bring the thermal expansion of the cathode closer to that of the electrolyte. The cathode pellets were later compacted at different pressures (27, 32 and 37 MPa) and sintered at 600oC. The optimum porosity (20.99-24.98%) was achieved for samples with SDC-(Li/Na)2CO3 content of 30-50% sintered at 600oC and cold pressed at 37 MPa.

Thick PLZT Films Grown by Sol-gel for Optical Device Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
M. Linnik ◽  
O. Wilson ◽  
A. Christou
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Phase Modulator ◽  
X Ray Diffraction ◽  
X Ray ◽  
Device Applications ◽  
Gel Technique ◽  
Scanning Electron

AbstractThe preparation and characterization of thick PLZT films for spatial phase modulator applications are reported. Films were fabricated on LSCO/LAO substrates by a sol-gel technique using multiple heat-treatment parameters. The crystal quality of PLZT 9/65/35 films was investigated by X-ray diffraction and scanning electron microscopy.

scholarly journals A novel sol–gel route to synthesize (Sr0.5Ba0.5)Nb2O6 ceramics with enhanced electrocaloric effect

2017 ◽  
Vol 07 (02) ◽  
pp. 1750012 ◽  
Author(s):  
Ting Chen ◽  
Shu Ya Wu ◽  
Xiao Qiang Liu ◽  
Xiang Ming Chen
Keyword(s):  
Sol Gel ◽  
Synthesis Temperature ◽  
Ultrafine Powders ◽  
X Ray Diffraction ◽  
Electrocaloric Effect ◽  
X Ray ◽  
Fine Powders ◽  
Sol Gel Process ◽  
Size And Morphology ◽  
Mechanism Of The Reaction

(Sr[Formula: see text]Ba[Formula: see text])Nb2O6 ultra-fine powders were synthesized by a novel sol–gel route, and the mechanism of the reaction was discussed. SrCO3, BaCO3, oxalate niobium and citric acid were used to initiate the sol–gel process, and ethylene glycol (EG) was added to further polymerize the cross-linking structure. The evolution of the (Sr[Formula: see text]Ba[Formula: see text])Nb2O6 phase, the reaction process and the microstructures were investigated by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy, DSC-TG and scanning electron microscopy. The synthesis temperature of the (Sr[Formula: see text]Ba[Formula: see text])Nb2O6 powders reached as low as 1200[Formula: see text]C, and the size and morphology of the powders were controlled by temperature. By adjusting the calcination temperature, we obtained (Sr[Formula: see text]Ba[Formula: see text])Nb2O6 powders with uniform sizes of 20[Formula: see text]nm to 500[Formula: see text]nm. Then, dense (Sr[Formula: see text]Ba[Formula: see text])Nb2O6 ceramics were successfully prepared using these ultrafine powders. Finally, an enhanced electrocaloric effect (ECE) value of 0.35[Formula: see text]C was obtained at 100[Formula: see text]kV/cm.

Synthesis and Characterization of CeO2 Doped ZrO2 Ceramics by a Simple Sol-Gel Route

2017 ◽  
Vol 907 ◽  
pp. 56-60
Author(s):  
Ummuhanı Hilal Özer ◽  
Kerim Emre Öksüz ◽  
Ali Özer
Keyword(s):  
Tetragonal Phase ◽  
Sol Gel ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Zirconia Ceramics ◽  
Simple Method ◽  
X Ray ◽  
Gel Technique

It is well known that sol-gel technique is a simple method to produce nano sized ceramic powders. In this study, cerium oxide doped zirconia samples, with 10 mol%-12mol% and14mol% CeO2, were synthesized by sol-gel technique and characterized. The surface morphology, elemental composition, microstructure, and phase analysis, of the sintered CeO2 doped ZrO2 ceramics were characterized by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDS) analysis, and X-ray diffraction (XRD) respectively. X-ray diffraction for samples sintered at 1550 °C for 4h revealed that the zirconia ceramics have a tetragonal phase structure. The addition of CeO2 can raise the content of the tetragonal phase, but the minor monoclinic phase exists even at the CeO2 content of 10 mol%. The effect of dopant concentration on the lattice parameter, average primary crystallite size and micro-strain was studied. Relative densities for CeO2 doped ZrO2 bulk ceramics varied between 95% and 99 %, depending on the CeO2 addition.

scholarly journals Impact of alumina particles on the morphology and mechanics of hybrid wood plastic composite materials

2019 ◽  
Vol 51 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Srdjan Perisic ◽  
Marija Vuksanovic ◽  
Milos Petrovic ◽  
Andjela Radisavljevic ◽  
Aleksandar Grujic ◽  
...  
Keyword(s):  
Hybrid Composite ◽  
Moisture Absorption ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Pressing Method ◽  
X Ray ◽  
Plastic Composite ◽  
Alumina Particles ◽  
Gel Technique ◽  
The Impact

Hybrid composite panels of Wood-Plastic Composites (WPC) consisting of wood and poly (methyl methacrylate) (PMMA) were reinforced with alumina particles and made by ?hot pressing? method. Alumina-based particles were made by sol-gel technique. The particles were characterized by the X-ray diffraction (XRD). The resulting alumina particles were modified with (3mercaptopropyl) trimethoxysilane (MPTMS), in order to obtain better mechanical properties of the composite relative to the composite with unmodified alumina particles. The aim of this work was to study the influence of composite structure and the moisture absorption on bending and the impact properties of the hybrid composite. The bending and impact tests revealed that modulus of elasticity and absorbed energy of deformation increased with modification of alumina and slightly decrease after moisture absorption.

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