Exploring the structural, optical and photoluminescent properties of (1-x)NiCo2O4/xPbS nanocomposites for optoelectronic applications

2021 ◽  
Author(s):  
Zein K. Heiba ◽  
Mohamed Bakr Mohamed ◽  
Noura M. Farag ◽  
Ali Badawi
Keyword(s):  
Refractive Index ◽  
Rietveld Analysis ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Low Frequencies ◽  
High Frequencies ◽  
Transmission Electron ◽  
Microstructure Parameters ◽  
Line Detector ◽  
Rietveld Quantitative Phase Analysis

Abstract (1-x)NiCo2O4/xPbS (0≤x≤0.2) nanocomposite samples were synthesized using the hydrothermal and thermolysis procedures. The different phases developed in the obtained nanocomposite samples were accurately determined using the x-ray diffraction technique equipped with a line-detector. The percentage of the formed phases (NiCo2O4 (NCO), PbS, PbSO4), structural and microstructure parameters were determined using Rietveld quantitative phase analysis. The transmission electron microscope (TEM) images and Rietveld analysis reveal almost isotropic particle size in the nano range with a very narrow size distribution. The obtained phase percentages of PbS and PbSO4 are smaller than nominated values (x) suggesting dissolving of some Pb and S ions in NCO which then confirmed by the analysis of Fourier-transform infrared (FTIR) spectra of nanocomposite samples. The absorption spectra are modified upon doping NCO with PbS. The optical band gaps of the nanocomposites increase as the amount of PbS is increased. The effect of alloying on extinction coefficient, refractive index, dielectric constant, optical conductivity, the intensity, and emitted color from the photoluminescence of the nanocomposite samples are also studied. The refractive index values of NCO and NCO-PbS nanocomposite samples exhibit normal dispersions. The photoluminescent measurements reveal that NCO-PbS nanocomposites could emit a violet color. The improvement in the values of the non-linear optical (NLO) parameters of pristine NCO at high frequencies or the nanocomposite samples at low frequencies, nominated them to be used in NLO photonic applications.

Conductivity Characterizationof Iron Oxide Doped 8 mol% Yttria Stabilized Zirconia

2018 ◽  
Vol 280 ◽  
pp. 58-64
Author(s):  
Tinesha Selvaraj ◽  
Johar Banjuraizah ◽  
S.F. Khor ◽  
M.N. Mohd Zainol
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Solid Electrolytes ◽  
Electrode Materials ◽  
Rietveld Method ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Solid Electrode ◽  
Short Sample ◽  
X Ray ◽  
Rietveld Quantitative Phase Analysis

A facile strategy was proposed to incorporate the dopant Fe into 8YSZ-based material, which can be potentially applied as solid electrode materials for Solid Oxide Fuel Cells (SOFC). In this study, 8YSZ powder was investigated in terms of densification, conductivity and thecrystal structure as a solid electrolytes. Therefore, varying mol% of Fe included 1, 2, and 3 were prepared for investigation. The crystalline structure of the pristine and Fe doped samples were characterized by X-ray diffraction (XRD) and the phase contents were evaluated by using the Rietveld method. Rietveld quantitative phase analysis demonstrates that the monoclinic-ZrO2phase increases (12.8 wt% to 39.7 wt%) as the concentration of Fe increases, while the amount of tetragonal-ZrO2phase drop (40.4 wt% to 11.9 wt%) dramatically. Sintering activity was applied to improve incorporation of the 8YSZ powder and the dopant Fe where the relative density increases from 77% to 92%. Sample YSZ-2Fe has been fitted with CPE equivalent circuit and achieved 6.251 x 10-6S/cm at 300 °C in air. However, it was found that conductivity levels decreased as the mol% of Fe increased. In short, sample YSZ-2Fe ceramic demonstrated good results in terms of densification (92.09%), cubic ZrO2phase (22 wt%) and conductivity 6.251 x 10-6S/cm.

Crystal structure of microwave dielectric ceramics Ba[(Mg1−xCdx)0.33Nb0.67]O3

2007 ◽  
Vol 22 (4) ◽  
pp. 295-299
Author(s):  
J. X. Deng ◽  
X. R. Xing ◽  
J. Chen ◽  
R. B. Yu ◽  
G. R. Liu ◽  
...  
Keyword(s):  
Synthesis Temperature ◽  
Partial Substitution ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Low Frequencies ◽  
X Ray ◽  
Microwave Dielectric ◽  
Trigonal Structure ◽  
Ordering Degree ◽  
Dielectric Ceramics

A series of complex perovskite solid solutions of Ba[(Mg1−xCdx)0.33Nb0.67]O3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that Ba[(Mg1−xCdx)0.33Nb0.67]O3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg. However, a decrease in the ordering degree in the Ba(Cd0.33Nb0.67)O3 sample is observed, which can be attributed to a relatively lower synthesis temperature. All the impurity phases are successfully identified by X-ray quantitative phase analysis. Dielectrics properties at low frequencies for all the Ba[(Mg1−xCdx)0.33Nb0.67]O3 compounds have been measured successfully.

CONTROLLED SYNTHESIS AND CHARACTERIZATION OF TiO2 NANOPARTICLES VIA A SOL–GEL METHOD

2004 ◽  
Vol 03 (06) ◽  
pp. 749-755 ◽  
Author(s):  
YING LI ◽  
SUO HON LIM ◽  
TIM WHITE
Keyword(s):  
Sol Gel ◽  
Critical Role ◽  
Rietveld Analysis ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
Gelation Temperature ◽  
Gel Method ◽  
Sol Gel Method ◽  
Transmission Electron

The properties influencing the photocatalytic activity of TiO 2 particles have been suggested to include the surface area, crystallinity, crystallite size and crystal structure. Therefore, manipulation of the microstructure of titania, especially of nanocrystalline powders, is very important in the preparative process. In this study, nanocrystalline TiO 2 powders with controlled particle size and phase composition were synthesized at low temperature (<80°C) by a modified sol–gel method. The effects of gelation temperature were systematically investigated. It was found that this parameter played a critical role in determining the crystallinity of single phase anatase. With increasing gelation temperature, the crystallinity of anatase improved initially and then decreased if the temperature was raised to 80°C. These nanomaterials were characterized comprehensively by powder X-ray diffraction (including Rietveld analysis), high-resolution transmission electron microscopy, DSC/TGA thermal analysis and UV–Vis spectrometry.

Microstructure of Pyrolytic Carbon Matrix in Carbon/Carbon Composites after Graphitization

2007 ◽  
Vol 336-338 ◽  
pp. 1270-1273 ◽  
Author(s):  
Wan Chang Sun ◽  
He Jun Li ◽  
Shou Yang Zhang ◽  
Yong Huang
Keyword(s):  
Polarized Light ◽  
Carbon Matrix ◽  
Pyrolytic Carbon ◽  
Interplanar Distance ◽  
Carbon Composites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After ◽  
The Matrix ◽  
Microstructure Parameters

The morphologies and textures of the pyrolytic carbon matrix in 2D-C/C composites after graphitization were investigated by means of polarized light microscope (PLM) and high resolution transmission electron microscope (HRTEM). The microstructure parameters of the pyrolytic carbon matrix before and after graphitization were characterized with X-ray diffraction (XRD) technology. It was found that the interplanar distance of (002) planes (d002) of pyrolytic carbon matrix decreases, and the microcrystalline stack height (LC) increases after graphitization. Graphitization treatment resulted in a coarsening of the surface texture and in the formation of circumferential cracks within the matrix. The lattice fringes of the pyrolytic carbon matrix are continuous and longer in each domain and the (002) peak spot is smaller and more intense after graphitization.

Enhanced optical, morphological, dielectric, and conductivity properties of gold nanoparticles doped PVA/CMC blend as an application in organoelectronic devices

2021 ◽  
Author(s):  
M. R. Atta ◽  
Qana M. Alsulami ◽  
G. M. Asnag ◽  
A . rajeh
Keyword(s):  
Gold Nanoparticles ◽  
Stevia Rebaudiana ◽  
Ultra Violet ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Low Frequencies ◽  
Bright Spots ◽  
Transmission Electron ◽  
Ft Ir ◽  
Mobile Charges

Abstract Stevia rebaudiana plant leaves were used for biosynthesis of gold nanoparticles (AuNPs). Transmission electron microscope ( TEM ) images showed various shapes and sizes of AuNPs. Various amounts of AuNPs were added to polyvinyl alcohol/carboxymethylcellulose ( PVA / CMC , 40/60) via the casting method. The X-ray diffraction (XRD) spectrum of pure blend shows the amorphous nature of the blend. FT-IR spectra showed the interaction between PVA / CMC and AuNPs. The ultra-violet and visible (UV/VIS.) spectra showed emerge new peak of surface plasmon resonance ( SPR ) of AuNPs for the filled samples. SEM images showed bright spots on the sample's surface, which was attributed to AuNPs. AC conductivity exhibited enhancement after the addition of gold nanoparticles. The ε′ and ε″ were reduced with increasing the frequency due to direction dipoles of applied electric field. Because of the mobile charges inside the polymeric backbone, higher values of ε′ and ε″ were observed at low frequencies. The tanδ showed increased with an increase in AuNPs concentration and at the decrease the frequency, as expected.

Redetermination of the crystal structure of α-copper phthalocyanine grown on KCl

2003 ◽  
Vol 59 (3) ◽  
pp. 393-403 ◽  
Author(s):  
Akitaka Hoshino ◽  
Yoshiko Takenaka ◽  
Hideki Miyaji
Keyword(s):  
Crystal Structure ◽  
Copper Phthalocyanine ◽  
Rietveld Analysis ◽  
Molecular Packing ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
Molecular Arrangement ◽  
Transmission Electron ◽  
Triclinic Unit Cell ◽  
Molecular Stacking

The crystal structure of a polymorph of copper phthalocyanine (CuPc) grown on a KCl substrate is redetermined by transmission electron diffraction. It has a triclinic unit cell containing one molecule; the crystal does not have a herringbone-type molecular arrangement, which is a common packing mode of planar phthalocyanines. The molecular packing is determined by the diffraction intensity with the aid of the calculation of molecular packing energy. One of the striking features of this polymorph is its stacking mode within a molecular column: the molecular stacking direction projected on a molecular plane is different by an angle of about 45° from that of the α-modifications of platinum phthalocyanine (PtPc) and metal-free phthalocyanine (H2Pc). A powder X-ray diffraction profile calculated for the polymorph agrees well with that of so-called α-CuPc and Rietveld analysis for α-CuPc indicates that the CuPc crystals grown on KCl are actually α-CuPc; hence, α-CuPc is not isostructural with either α-PtPc or α-H2Pc. On the basis of the present results and the reported crystal structures of the planar phthalocyanines that form molecular columns, the polymorphs of the phthalocyanines can be classified into four types distinguished by the molecular stacking mode within the column: α(×)-, α(+)-, β(×)- and β(+)-types.

scholarly journals Crystal structures of perovskite halide compounds used for solar cells

2020 ◽  
Vol 59 (1) ◽  
pp. 264-305 ◽  
Author(s):  
Takeo Oku
Keyword(s):  
Crystal Structures ◽  
Double Perovskite ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Structures And Properties ◽  
Low Dimensional ◽  
Atomic Coordinates

AbstractThe crystal structures of various types of perovskite halide compounds were summarized and described. Atomic arrangements of these perovskite compounds can be investigated by X-ray diffraction and transmission electron microscopy. Based on the structural models of basic perovskite halides, X-ray and electron diffractions were calculated and discussed to compare with the experimental data. Other halides such as elemental substituted or cation ordered double perovskite compounds were also described. In addition to the ordinary 3-dimensional perovskites, low dimensional perovskites with 2-, 1-, or 0-dimensionalities were summarized. The structural stabilities of the perovskite halides could be investigated computing the tolerance and octahedral factors, which can be useful for the guideline of elemental substitution to improve the structures and properties, and several low toxic halides were proposed. For the device conformation, highly crystalline-orientated grains and dendritic structures can be formed and affected the photo-voltaic properties. The actual crystal structures of perovskite halides in the thin film configuration were studied by Rietveld analysis optimizing the atomic coordinates and occupancies with low residual factors. These results are useful for structure analysis of perovskite halide crystals, which are expected to be next-generation solar cell materials.

On-line X-ray diffraction for quantitative phase analysis: Application in the Portland cement industry

2001 ◽  
Vol 16 (2) ◽  
pp. 71-80 ◽  
Author(s):  
Nicola V. Y. Scarlett ◽  
Ian C. Madsen ◽  
Con Manias ◽  
David Retallack
Keyword(s):  
Portland Cement ◽  
Rietveld Analysis ◽  
Cement Industry ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Joint Project ◽  
X Ray ◽  
Central Computer ◽  
Wide Range ◽  
On Line

The aim of this work was to design, construct, install, and commission an on-line, X-ray diffraction (XRD) analyzer capable of continuously monitoring phase abundances for use in process plant control. This has been achieved through a joint project between CSIRO Minerals and Fuel & Combustion Technology Pty. Ltd. with an instrument designed for use in a Portland cement manufacturing plant. Key factors in tailoring such an instrument to the cement industry were (i) the handling and presentation of a dry sample and (ii) the development of an analytical method suitable for the complex suite of phases contained within Portland cement. The instrument incorporates continuous flow of sample through the diffractometer using a purpose-built sample presentation stage. The XRD data are collected simultaneously using a wide range (120° 2θ) position sensitive detector, thus enabling rapid collection of the full diffraction pattern. The data are then analyzed using a Rietveld analysis method to obtain a quantitative estimate of each of the phases present. The instrument is controlled by a PC linked to the diffractometer through a purpose built interface. The phase abundance information is then transmitted to the central computer in the cement plant where it can be used for the control of mill parameters such as temperature and retention times as well as gypsum feed rate.

scholarly journals Electrical Breakdown Properties of Clay-Based LDPE Blends and Nanocomposites

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Mostafa Eesaee ◽  
Eric David ◽  
Nicole R. Demarquette ◽  
Davide Fabiani
Keyword(s):  
Breakdown Strength ◽  
Electrical Breakdown ◽  
Domain Size ◽  
X Ray Diffraction ◽  
Low Frequencies ◽  
Melt Compounding ◽  
Breakdown Time ◽  
Transmission Electron ◽  
Measurement Results ◽  
High Degree

Microstructure and electrical breakdown properties of blends and nanocomposites based on low-density polyethylene (LDPE) have been discussed. A series of LDPE nanocomposites containing different amount of organomodified montmorillonite (clay) with and without compatibilizer have been prepared by means of melt compounding. Two sets of blends of LDPE with two grades of Styrene-Ethylene-Butylene-Styrene block copolymers have been prepared to form cocontinuous structure and host the nanoreinforcement. A high degree of dispersion of oriented clay was observed through X-ray diffraction, scanning, and transmission electron microscopy. This was confirmed by the solid-like behavior of storage modulus in low frequencies in rheological measurement results. An alteration in the morphology of blends was witnessed upon addition of clay where the transportation phenomenon to the copolymer phase resulted in a downsizing on the domain size of the constituents of the immiscible blends. The AC breakdown strength of nanocomposites significantly increased when clay was incorporated. The partially exfoliated and intercalated clay platelets are believed to distribute the electric stress and prolong the breakdown time by creating a tortuous path for charge carriers. However, the incorporation of clay has been shown to diminish the DC breakdown strength of nanocomposites, mostly due to the thermal instability brought by clay.

scholarly journals Fundamental material property trends in the La0.8-xNdxCa0.2FeO3-δ series: crystal structure and thermal expansion

2021 ◽  
Author(s):  
Christian Berger ◽  
Edith Bucher ◽  
Judith Lammer ◽  
Christina Nader ◽  
Werner Sitte
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Rietveld Analysis ◽  
Homogeneous Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
A Site

AbstractCompounds from the series La0.8-xNdxCa0.2FeO3-δ (0.1 ≤ x ≤ 0.7) were synthesised by a sol–gel route. X-ray diffraction and Rietveld analysis showed that materials with 0 ≤ x ≤ 0.6 crystallize as single-phase orthorhombic perovskites. The smaller ionic radius of Nd3+ compared to La3+ leads to a decrease in unit cell volume with increasing x. Elemental mapping by high-resolution scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy confirms the homogeneous distribution of the A-site elements (La, Nd and Ca) in the perovskite (ABO3) lattice. The thermal expansion behaviour of La0.8-xNdxCa0.2FeO3-δ (0 ≤ x ≤ 0.6) was characterized by dilatometry at 30 ≤ T/°C ≤ 1000 and 1 × 10–3 ≤ pO2/bar ≤ 1. The thermal expansion coefficients of La0.8-xNdxCa0.2FeO3-δ, which were determined in regions I (40–530 °C) and II (530–990 °C), respectively, are almost independent of the Nd concentration in the range of (0 ≤ x ≤ 0.6) and increase slightly with decreasing pO2. The transition from orthorhombic to trigonal modification, which is observed for La0.8Ca0.2FeO3-δ at approx. 740 °C, is suppressed for all Nd-substituted compounds with x ≥ 0.1.

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