Annealing effect on the optical and photoelectrochemical properties of lead oxide

2018 ◽  
Vol 84 (3) ◽  
pp. 30301 ◽  
Author(s):  
Wided Zerguine ◽  
Djamila Abdi ◽  
Farid Habelhames ◽  
Meriem Lakhdari ◽  
Hassina Derbal-Habak ◽  
...  
Keyword(s):  
Lead Oxide ◽  
Orthorhombic Phase ◽  
Heat Treatments ◽  
Photoelectrochemical Properties ◽  
X Ray Diffraction ◽  
Vis Spectroscopy ◽  
Size And Morphology ◽  
Two Phases ◽  
P Type ◽  
The Relationship

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.

X-ray Diffraction and Modelling Studies of Multilayer SnO2 Thin Film Gas Sensors

1995 ◽  
Vol 403 ◽  
Author(s):  
L. E. Depero ◽  
C. Perego ◽  
L. Sangaletti ◽  
G. Sberveglieri
Keyword(s):  
Thin Film ◽  
Orthorhombic Phase ◽  
Sno2 Thin Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modelling Studies ◽  
Cation Coordination ◽  
Diffraction Patterns ◽  
Two Phases ◽  
The Relationship

AbstractStructural studies have been carried out on SnO2 multilayer thin film grown by the Rheotaxial Growth and Thermal Oxidation method on A120 3 substrates. A preliminary analysis of the X-ray diffraction patterns shows that, in addition to the Sn0 2 cassiterite phase, a strong contribution from an orthorhombic Sn02 phase is present.In the case of the 3-layer film, the orthorhombic phase is structurally and microstructurally stable after an annealing up to 32 h at 400 'C. The cation coordination is similar to that found in cassiterite, but the chains of edge-sharing [SnO6]8- octahedra run in a zig-zag fashion along the [100] direction, each straight unit containing four octahedra. The relationship between the two phases is discussed on the basis of structural simulations including twinning planes in the crystal structure.

Crystalline and microstructure study of the AlN–Al2O3section in the Al–N–O system. II. φ′- and δ-AlON spinel phases

1999 ◽  
Vol 32 (2) ◽  
pp. 253-272 ◽  
Author(s):  
P. Tabary ◽  
C. Servant
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Model ◽  
Spinel Phase ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Spinel Phases ◽  
Two Phases ◽  
Microscopy Techniques ◽  
The Relationship

Results from the crystalline and microstructure study of the φ′- and δ-AlON spinel phases by X-ray diffraction, neutron diffraction and standard-resolution transmission electron microscopy techniques are reported. Several samples having different compositions in mol % AlN were considered. A structural model is proposed to account for the double modulation of composition and displacement of the cations and anions, which has been determined for these two phases and for the relationship with the γ-AlON spinel phase. Some high-resolution transmission electron microscopy experiments have confirmed the present structural model. A discussion with reference to previous data is presented.

scholarly journals Graphene Synthesis by Ultrasound Energy Assisted Exfoliation of Graphite in Various Solvents

2020 ◽  
Author(s):  
Betül Gürünlü ◽  
Çiğdem Taşdelen-Yücedağ ◽  
Mahmut Bayramoğlu
Keyword(s):  
Low Cost ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Graphene Synthesis ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ultrasound Energy ◽  
Size And Morphology

Liquid Phase Exfoliation (LPE) method has been gaining increasing interest by academic and industrial researchers due to its simplicity, low-cost, and scalability. High intensity ultrasound energy was exploited to transform graphite to graphene in the solvents of dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF), and perchloric acid (PA) without any surfactants or ionic liquids. The crystal structure, number of layers, particle size, and morphology of the synthesized graphene samples were characterized by X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Ultraviolet visible (UV–vis) spectroscopy, Dynamic Light Scattering (DLS), and Transmission Electron Microscopy (TEM). XRD and AFM analyses indicated that G-DMSO and G-DMF have few layers and G-PA has multilayers. The layer numbers of G-DMSO, G-DMF, and G-PA were determined as 9, 10, and 21, respectively. By DLS analysis, the particle sizes of graphene samples were estimated in a few micrometers. TEM analyses showed that G-DMSO and G-DMF possess sheet-like fewer layers and also, G-PA has wrinkled and unordered multilayers.

scholarly journals Electrodeposition of ternary compounds for novel PV application and optimisation of electrodeposited CdMnTe thin-films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. E. Alam ◽  
O. I. Olusola ◽  
D. A. L. Loch ◽  
K. Shukla ◽  
W. M. Cranton ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Surface ◽  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
Cathodic Electrodeposition ◽  
Ternary Compounds ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Vis Spectroscopy ◽  
P Type

AbstractGrowth of polycrystalline CdMnTe ternary compound thin films has been carried out using cathodic electrodeposition technique at different cathodic potentials. The range of the cathodic potentials used in this work has been chosen according to the cyclic voltammogram results. The CdMnTe thin films were electroplated from electrolyte containing CdSO4, TeO2 and MnSO4 in an acidic aqueous medium. Glass/fluorine-doped tin oxide (FTO) substrates have been used to electrodeposit the semiconductor layers. The structural, compositional, morphological, optical and electrical properties of the CdMnTe thin films were studied using X-ray diffraction (XRD), Sputtered neutral-mass spectroscopy (SNMS), Scanning electron microscopy (SEM), UV–Vis spectroscopy and Photo-electro-chemical (PEC) cell measurements respectively. The primarily grown as-deposited (AD) layers went through two different post-growth surface treatment conditions- heat-treated in air in the presence of CdCl2 (CCT) and heat-treated in air in the presence of GaCl3 (GCT). Results from the XRD indicated the polycrystalline nature of the electrodeposited films. The electroplated films have cubic crystal structures and the preferred orientation was found to be along the (111) plane of CdMnTe. Inclusion of Mn has been qualitatively observed using SNMS measurement. The optical energy bandgaps of the thin films were found to be varying between ~ 1.90 and ~ 2.20 eV. Though all the layers after post-treatment showed p-type electrical conduction, both p and n-type conductivity were obtained at different cathodic potentials for as-deposited materials. Comparison of the deposited layers to other electrodeposited ternary compounds has also been discussed.

In situ synchrotron radiation measurements of orthorhombic phase formation in an advanced TiAl alloy with modulated microstructure

2015 ◽  
Vol 1760 ◽  
Author(s):  
M. Rackel ◽  
A. Stark ◽  
H. Gabrisch ◽  
F.-P. Schimansky ◽  
N. Schell ◽  
...  
Keyword(s):  
Orthorhombic Phase ◽  
High Energy ◽  
X Ray Diffraction ◽  
Tial Alloys ◽  
Temperature Range ◽  
Atomic Displacements ◽  
Two Phases ◽  
O Phase ◽  
Thermal Stability Of

ABSTRACTNew low aluminium high niobium TiAl alloys exhibit a nano scale modulated microstructure consisting of lamellae with a tweed substructure. These tweed like appearing lamellae are a modulated arrangement of at least two phases. One constituent of the crystallographic modulation in the lamellae is an orthorhombic phase, which is closely related to both the hexagonal α2-Ti3Al phase and the cubic B2 ordered βo-TiAl phase.In this study the nature and formation of this orthorhombic phase has been investigated by high-energy X-ray diffraction.Measurements have shown that the newly formed orthorhombic phase is structurally comparable to the O phase (Ti2AlNb). It forms in the temperature range of 550 °C to 670 °C from the α2 phase by small atomic displacements and chemical reordering. The in situ experiments yielded information about the thermal stability of the orthorhombic phase. After dissolving at temperatures above 700 °C the phase can be re-precipitated by annealing within the temperature range of formation.

Francolite in a concretion from argillaceous sediments in the Westphalian of Yorkshire

1977 ◽  
Vol 41 (318) ◽  
pp. 287-287 ◽  
Author(s):  
Mike J. Pearson
Keyword(s):  
Electron Microprobe ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Dimensions ◽  
Carbonate Fluorapatite ◽  
Phosphate Phase ◽  
Two Phases ◽  
Relationship Of ◽  
The Relationship

SynopsisA phosphate-rich carbonate nodule from carboniferous mudstones has been studied by wet chemistry, X-ray diffraction, and electron microprobe. Partial heavy-liquid separation has enabled characterization of the phosphate phase as francolite (carbonate fluorapatite) with a composition Ca10(PO4)5·59(CO3)1·00((OH)1·49F2·10). Diffractometer data for this mineral is presented and cell dimensions are calculated as a = 9·349 Å, c = 6·887 Å. with c/a = 0·737. The problem of the structural positioning of carbon in francolite is discussed.The francolite is seen in thin section as a structureless groundmass enclosing siderite spheru-lites. Electron microprobe X-ray distribution photographs for P, Al, Si, Mg, and Fe show the relationship of these two phases to quartz, pyrite, and at least two clay minerals. One of the latter is intimately mixed with francolite.Possible origins of phosphatic nodules are discussed. Textural evidence in the present case strongly suggests that the francolite is concretionary and formed during early diagenesis possibly by replacement of earlier calcite. Phosphate was probably derived from protein degradation, which also maintained the alkaline pH necessary for francolite formation.

scholarly journals Spray Pyrolysis Technique for the deposition of Lead Oxide (PbO) Thin Films; its Electrochemical behaviour and Structural and optical Properties

2018 ◽  
Vol 15 (2) ◽  
pp. 134-140
Author(s):  
Anil B Gite ◽  
G. E. Patil ◽  
G. H. Jain
Keyword(s):  
Spray Pyrolysis ◽  
Lead Oxide ◽  
Spray Pyrolysis Technique ◽  
Electrochemical Behaviour ◽  
Reference Electrode ◽  
X Ray Diffraction ◽  
Oxidation Reduction ◽  
Cyclic Voltammetry Measurement ◽  
Vis Spectroscopy

Thin film of Lead oxide (PbO) was prepared by spray pyrolysis technique on glass substrate at 250°C. The cyclic voltammetry measurement was carried out to study the oxidation reduction reactions of non-aqueous lead ions at various molar concentrations which is from 0.01M to 0.09M. Elecrochemical studies were carried out with Ag/AgCl as a reference electrode , Pt as working electrode while platinum mesh as counter electrode.Lead oxide appears to be poisonous yellow or reddish yellow solid. Structural characterization of films was analyze with X- ray diffraction (XRD) and optical band gap was determined by UV-Vis Spectroscopy.

scholarly journals Effect of the thermal annealing on the phase transitions of biogenic CaCO3 nanostructures

2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Candelario Ramón de los Santos ◽  
Angélica Silvestre López Rodríguez ◽  
Pio Sifuentes Gallardo ◽  
Miguel Angel Hernández Rivera ◽  
German Pérez-Hernández ◽  
...  
Keyword(s):  
Calcium Hydroxide ◽  
Thermal Annealing ◽  
Annealing Treatment ◽  
Orthorhombic Phase ◽  
Natural State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Air Atmosphere ◽  
Thermal Annealing Treatment ◽  
Two Phases

The issue of the present research lays its foundation on the proposal of the Crassostrea virginica waste oyster shells (WOS) reuse to obtain calcium carbonate powder (CaCO3) and calcium hydroxide (Ca(OH)2) nanostructured, using thermal annealing treatments. The oysters shells were subjected to a previous physical grinding process to decrease their size (smaller sizes 0.074 mm). The parameter studied was the effect of annealing temperature (500, 700 and 900 °C in air atmosphere) on the structural properties and morphology of the powders by FTIR, XRD, SEM and HRTEM. The X-ray diffraction results indicate that the WOS in their natural state and thermally annealed at 500 °C  have two phases of CaCO3 the rhombohedral form for calcite with crystallite size around 24 nm and aragonite traces in orthorhombic phase. At 700 °C, the WOS powder is transformed into calcium hydroxide, also known as portlandite (Ca(OH)2), attributed to the absorption of water released during the thermal decomposition of CaCO3. This crystalline phase does not change when the temperature increases to 900 °C. The SEM and HRTEM analysis of WOS powders reveals that with a thermal annealing treatment it is possible to obtain   nanostructured CaCO3. FTIR analysis demonstrates the biogenic origin of CaCO3, due to amide groups. The nanostructured CaCO3 obtained by grinding and thermal annealing of WOS, can be used as drying agent, or as additive in ceramic and glass. The issue of the present research lays its foundation on the proposal of the Crassostrea virginica waste oyster shells (WOS) reuse to obtain calcium carbonate powder (CaCO3) and calcium hydroxide (Ca(OH)2) nanostructured, using thermal annealing treatments. The oysters shells were subjected to a previous physical grinding process to decrease their size (smaller sizes 0.074 mm). The parameter studied was the effect of annealing temperature (500, 700 and 900 °C in air atmosphere) on the structural properties and morphology of the powders by FTIR, XRD, SEM and HRTEM. The X-ray diffraction results indicate that the WOS in their natural state and thermally annealed at 500 °C  have two phases of CaCO3 the rhombohedral form for calcite with crystallite size around 24 nm and aragonite traces in orthorhombic phase. At 700 °C, the WOS powder is transformed into calcium hydroxide, also known as portlandite (Ca(OH)2), attributed to the absorption of water released during the thermal decomposition of CaCO3. This crystalline phase does not change when the temperature increases to 900 °C. The SEM and HRTEM analysis of WOS powders reveals that with a thermal annealing treatment it is possible to obtain   nanostructured CaCO3. FTIR analysis demonstrates the biogenic origin of CaCO3, due to amide groups. The nanostructured CaCO3 obtained by grinding and thermal annealing of WOS, can be used as drying agent, or as additive in ceramic and glass.

SOME PHYSICAL PROPERTIES OFBaTiO3–CoFe2O4COMPOSITE

2011 ◽  
Vol 25 (20) ◽  
pp. 2751-2767 ◽  
Author(s):  
D. M. HEMEDA ◽  
A. TAWFIK ◽  
M. M. EL-SHAHAWY
Keyword(s):  
Charge Carrier ◽  
Charge Carrier Mobility ◽  
Initial Permeability ◽  
Charge Carrier Concentration ◽  
X Ray Diffraction ◽  
Polaron Hopping ◽  
Diffraction Patterns ◽  
Two Phases ◽  
Increasing Temperature ◽  
P Type

[X]% BaTiO3[100-x]% CoFe2O4composites (x = 0, 20, 40, 60, 80, and 100) were prepared by the general ceramic method. X-ray diffraction patterns and IR spectra confirmed the presence of two phases beside identified phase in the composites with (x% = 40-80% BaTiO3).The temperature variation of conductivity was mainly attributed to change of the drift mobility rather than to the variation of charge carrier concentration. All the composites showed p-type behaviors in the range of temperature 300–400 K. For T > 400 K all composites showed n-type behavior. At this high temperature, the conduction is mainly due to Fe3+→ Fe2+. Hence, there is a p–n transition.The variation of dielectric constant as a function of temperature showed a peak value at the Curie temperature (around 390 K) of ferroelectric phase in composites. It is also noted that the phase transition temperature Tcvaried for different composites.The relation between charge carrier mobility log (μd) versus (1/T) is nearly linear supporting the polaron hopping model for the conduction. The activation energies calculated from resistivity and that from mobility are in close agreement indicating localized model of charge carrier.The initial permeability increased with increasing temperature which is due to the activation of hopping electrons between Fe3+and Fe2+giving rise to the magnetic moment of the composites.

Ferroelectric and proton conducting behavior of a new elpasolite-related vanadium oxyfluoride (NH4,K)3VO2F4

2010 ◽  
Vol 25 (7) ◽  
pp. 1251-1263 ◽  
Author(s):  
Sadequa J. Patwe ◽  
S. Nagabhusan Achary ◽  
Kalpathy Ganapathy Girija ◽  
C.G. Sivan Pillai ◽  
Avesh K. Tyagi
Keyword(s):  
Orthorhombic Phase ◽  
Impedance Analysis ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
First Order ◽  
Two Phases ◽  
Ferroelectric Hysteresis

A new elpasolite-type (NH4,K)3VO2F4 compound was prepared and characterized by x-ray diffraction, differential scanning calorimeter (DSC), impedance analysis, and electrical polarization measurements. It crystallizes in an orthorhombic lattice with unit-cell parameters: a = 8.9584(4), b = 18.6910(14), c = 6.2174(4) Å, V = 1041.04(11) Å3, Z = 6. NH4+, and K+ ions are distributed statistically over crystallographically four equivalent sites. There are two distinguishable vanadium atoms forming cis- and trans-VO2F4 octahedra present in the unit cell. High-temperature studies by DSC and in situ x-ray diffraction revealed a first-order structural transformation from orthorhombic to cubic lattice around 343 K. Impedance measurements show two different kinds of conductivity behaviors for the two phases. In orthorhombic phase a significant conductivity resulting from involvement of protonic species is observed. In the orthorhombic phase, a clear ferroelectric hysteresis loop is observed.

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