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The structural, morphological, magnetic, and dielectric properties of lanthanum substituted nickel ferrite (NiLaxFe2−xO4) nanoparticles have been reported in this article. The amount of lanthanum substitution in NiLaxFe2−xO4 sample was varied from x = 0.025 to 0.125. The nanocrystalline Ni–La ferrites were synthesized using a solution combustion reaction (SCR) method. The orthorhombic crystal system of space group Pnma (62) is shown as the single-phase in all samples through structural investigation utilizing an X-ray diffraction (XRD) pattern. The observed trend indicates a positive correlation between the concentration of La and the corresponding rise in the predicted crystallite size values, which range from 60.5 nm to 65.2 nm. The nanoscale of the surface morphology has been confirmed by the utilisation of field emission scanning electron microscopy (FESEM). Energy dispersive X-ray (EDAX) mapping provides the compositional evidence for the prepared Ni–La ferrites. In addition, X-ray photoelectron spectroscopy (XPS) determines the ionic state of the individual atoms present in these samples. It reveals that there are no changes in the ionic state of the parent component atoms by substituting La. EDAX and XPS evidence the purity of prepared NiLaxFe2−xO4 samples without any other impurity elements. By regulating the composition of dopants, this research can substantiate the superparamagnetic characteristics of ferrites. The paramagnetic nature of lanthanum atoms involves in reducing the coercivity value. The dielectric measurement on NiLaxFe2−xO4 samples reveals that La3+ substitution effectively influence the electro-transport properties. [ABSTRACT FROM AUTHOR]

In this study, the characteristics of ZTO films are examined by varying the substrate temperature at an Ar ambient pressure of 3 × 10−3 Torr. The elemental content of Zn, Sn, and O in the generated Zn 2 SnO 4 films was confirmed using X-ray dispersive and X-ray photoelectron spectroscopy. The result reveals that the Zn/Sn ratio for the film formed at 300 °C reaches 2. The (222) and (311) lattice planes validated the cubic inverse spinel structure of ZTO films in the X-ray diffraction investigation. Atomic force microscopy was used to measure surface roughness, and the RMS rose in a range of 1.34–4.79 nm as the substrate temperature increased. Field-emission scanning electron microscopy revealed that the average crystal grain size grew in the region of 60–95 nm as the substrate temperature increased. The UV–vis absorption edge shift validates the Burstein-Moss shift rule, with a bandgap of ZTO-300 achieving the greatest value of 3.75 eV, corresponding to the largest carrier concentration. Electrical characteristics were investigated using Hall measurements. Film conductivity was primarily determined by the electron concentration or the presence of oxygen vacancies. The lowest resistivity measured was 5.4 × 10−3 Ω cm, which corresponded to an electron concentration of 8.57 × 1019 cm−3. The current-voltage characteristics of the ZTO/p-Si junction proved its rectifiable quality. Because of the low resistivity of the ZTO-300 sample, the ZTO-300/p-Si heterojunction has the largest photocurrent (4.72 10−3 A), making it suitable for use in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Effects of rapid thermal annealing (RTA) on the structure and photoelectric properties of Sb-doped SnO 2 (ATO) films have not been systematically reported. In this study, ATO films were prepared by RF magnetron sputtering under different O 2 flow rates (0, 15, 30 and 45 sccm), and then were subjected to RTA at different temperatures (400, 600 and 800 °C) in atmospheric environment. The results show that preferred orientations of ATO films changes from (101) to (110) crystal-plane and crystallite size increases with increasing O 2 flow rate. RTA cannot change the films' preferred orientation and crystallite size except for the film deposited in Ar atmosphere (0 sccm O 2), but it can decrease the compressive stress in the films. The as-deposited and annealed films with low transmittance in visible light range (T Vis) have obvious Raman scattering peak, and scattering peak of E g vibration mode is stronger in the appearing Raman scattering peaks. Increasing O 2 flow rate degrades electrically conductive properties of the films, increases T Vis and makes optical band-gap (E opt) first increase and then decrease. With increasing RTA temperature, the electrically conductive properties enhance and E opt increases for the films deposited with all O 2 flow rates, but T Vis basically decreases for the films deposited with O 2 flow rate of 15–45 sccm. Currently, the ATO film deposited at 15 sccm O 2 and annealed at 600 °C has the best transparent conductive properties (the resistivity, sheet resistance, T Vis and figure of merit are 2.09 × 10−3 Ω cm, 67 Ω/sq., 77.12%, and 1.11 × 10−3 Ω−1, respectively). In addition, element chemical states and point defects in the films were analyzed by XPS. Meanwhile, influence mechanisms of O 2 flow rate and RTA on structure and properties of the films were discussed. [ABSTRACT FROM AUTHOR]

Thermally stable films were obtained from a water-based polyurethane (PU) dispersion with small (0.1–1.5 wt.%) additions of graphene oxide (GO). The films were studied through elemental analysis, X-ray photoelectron spectroscopy, differential thermogravimetry, and Raman spectroscopy. It was found that the introduction of GO into a PU matrix was accompanied by a partial reduction in graphene oxide nanosheet and an increase in the concentration of defects in GO structure. It has been also established that the [C/N]at ratio in the near-surface layer of PU/GO composite films grows with an increase in the content of graphene oxide in the composite films. [ABSTRACT FROM AUTHOR]

[Display omitted] • The co-effect of perchlorate anions and hydrated protons on the electrocatalytic preparation of crystalline α-PtO 2 was experimentally observed. • A model containing non-covalent interaction between perchlorate anions, hydrated protons, and surface water molecules on the Pt(100) surface was constructed to explain this co-effect with DFT. • An alternate approach for the environmentally friendly and controllable preparation of Adams' catalyst was proposed. The structure and morphology of oxide on the metal electrodes are strongly linked with the activity and stability of the electrocatalysts. Herein, the novel co-effect of anion and hydrated proton on structure of PtO 2 formation is observed during the oxidation of water on Pt(100) preferentially oriented nanoparticles with in situ Raman spectroscopy and XPS. Higher concentrations (≥1.5 M) of non-specifically adsorbed perchlorate in 0.1 M perchloric acid solution facilitated the formation of crystalline α−PtO 2 during the electro−oxidation of Pt(100), and no crystalline α−PtO 2 was obtained without acid. Higher acidity electrolyte solution favors the formation of crystalline α–PtO 2 , indicating that proton plays a key role since specifically adsorbed sulfate without sulfuric acid did not lead to the formation of crystalline α–PtO 2. A model containing anions, protons, and water molecules co-adsorbed on the Pt surface is constructed during density functional theory (DFT) calculations, which well explains the formation of crystalline α–PtO 2 depending on anion and proton. The study findings provide an alternate approach for environmentally friendly and controllable preparation of Adams' catalyst and an atomic–level understanding of oxide formation on Pt electrodes, which is essential for developing the next–generation electro-catalyst with exceptional performance and stability. [ABSTRACT FROM AUTHOR]

Objectives. The XPS spectra of the adsorption layers of nitrated oil used as antirust inhibitor on the surface of armco-iron were studied. The interatomic interaction between the components of the nitrated oil and the armco-iron surface is revealed in the temperature range of room temperature – 500 °C. Purpose. The objective of the work is the interatomic interaction in the protective layers of nitrated oils on the armco-iron surface. Methods and methodology. The X-ray photoelectron spectroscopy studies were performed on an X-ray electron magnetic spectrometer with resolution of 10–4 and luminosity – 0.085 % at the excitation with AlKa line 1486.5 eV. In contrast to an electrostatic spectrometer, a magnetic spectrometer has a number of advantages due to the constructive possibilities of X-ray electron magnetic spectrometers which are the constancy of luminosity and resolution regardless of the energy of electrons, the high contrast of spectra, and the possibility of external actions on a sample (in the considered case, heating) during spectra taking. Results. The comparison of the results of the investigation of the nitrated oil sample with those obtained for the reference sample shows that: 1. In the protective surface layer between atoms of iron and nitrogen are formed the donoracceptor bond Fe–N. 2. At heating to the temperatures above 200 °C the content of nitrogen, which is not strongly bound to the substrate, decreases, i.e. nitrogen is partially evaporated; however the donoracceptor bond Fe–N remains at heating to 500 °C. Conclusions. The results should increase the effectiveness of the use of known inhibitors and the technology for producing preservation compositions based on nitrated oils.

New selenates La2O2SeO4 and Pr2O2SeO4, as well as selenite PbSe4+O3 and selenate PbSe6+O4, have been studied by X-ray photoelectron spectroscopy (XPS). The elemental and ionic compositions of new selenates containing Se6+, La3+, and Pr3+ ions have been confirmed on the basis of XPS parameters of the core and valence electrons. The reduction of Se6+ ions on the surface of selenite samples to Se4+ ions under X-ray radiation in the spectrometer chamber has been studied. It has been demonstrated that, unlike the PbSe6+O4 selenate, the PbSe4+O3 selenite is stable to X-ray radiation. It has been shown that La2O2SeO4 is more stable in air than Pr2O2SeO4. [ABSTRACT FROM AUTHOR]

The experimental results obtained in the study on the possibility of sensitizing titanium dioxide (polymorphic anatase phase) to the visible region of the spectrum by doping and co-doping with impurities of non-metals in order to create effective photocatalysts for the decomposition of organic compounds have been analyzed. The presence of impurity atoms appears to result in a change in the electronic structure of the titanium dioxide matrix, in the appearance of “impurity bands” and in the narrowing of the energy gap of titanium dioxide. Such a modification is accompanied by an extension of the spectral range of sensitivity of photoactive solids to the longwavelength region of the spectrum and, therefore, can be used to improve the catalytic properties of these materials. Spectral manifestations of carbon impurities in titanium dioxide in the form of carbide and carbonate, as well as sulfur in the forms of sulfite, sulfide, and sulfate, have been studied by the density functional theory method. A Ti14H22O39 cluster model was chosen for the titanium dioxide matrix. The calculations were carried out in the framework of the cluster approximation, using functional B3LYP and basis set 6-31G (d, p). Comparison of the results of quantum chemical calculations with the available experimental data shows that the impurity sulfur and carbon atoms in titanium dioxide, which are in different coordination states and different oxidation states, appear in different spectral ranges. This circumstance makes it possible to elucidate the structure of the samples based on the experimental spectra. A change in the coordination and oxidation states of impurity atoms leads to spectral shifts and splitting of peaks, which can reach 1.5 eV (XPS). The presence of admixtures of non-metals leads to a change in color (deepening in the case of sulfide or carbide) of the samples, appearing in the corresponding UV spectra. [ABSTRACT FROM AUTHOR]

The preparation of soluble conducting polymers proceeds by the chemical oxidation method in the presence of water‐soluble polyelectrolytes. Among conducting polymers, polyethylene‐(3,4‐dioxythiophene) (PEDOT) is the most investigated due to its intrinsic properties. In this work, for the first time a simple method of ethylene‐(3,4‐dioxythiophne) self‐polymerization without applying any oxidant and with the formation of PEDOT solution at room temperature with a yield of 100% is presented. This PEDOT solution could be deposited on many desirable surfaces (by simple evaporation of the solvent) for various applications from photovoltaic cell to pseudocapacitors. Moreover, it is discovered that the self‐polymerization method does not produce byproducts, which makes the method environmentally friendly. The effect of light and different acids is explored. Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy (XPS), and Raman spectroscopy confirm the formation of PEDOT by the self‐polymerization method. Moreover, this method provides a way to obtain and study individual PEDOT chains. The self‐polymerization method may be applied for the preparation of other conducting polymers. [ABSTRACT FROM AUTHOR]

The interatomic Auger transitions in compounds containing atomic components with core levels close in energy are studied theoretically and experimentally. The Coulomb transitions of holes between such levels lead to resonant enhancement of the Auger spectra (with respect to the energy difference between the levels). Interatomic Auger transitions involving higher levels are formed by shaking up electrons due to the dynamic field of photo-holes produced in the process of absorbing X-ray radiation and during the transition. These effects are observed experimentally in the XPS and Auger spectra of CuInSe2-type materials. [ABSTRACT FROM AUTHOR]

The spatial structure and electronic structure of oxygen defect and nitrogen impurity centers of anatase and their manifestation in water adsorption, O1s XPS spectra were analyzed. The role of various forms of adsorbed water on anatase surface is considered. The results of experimental studies are compared with the properties of molecular models for the bulk and surface of titanium dioxide studied by the quantum chemical density functional theory method. [ABSTRACT FROM AUTHOR]

Theoretical studies of the interactions of an oxygen molecule with the surface of a solid phase are of great importance for understanding the mechanisms of reactions involving oxygen on a solid surface. In this work, the spatial and electronic structure of oxygen defects and nitrogen impurity centers of the anatase surface and their manifestation in water adsorption are investigated. The anatase surface was simulated for by clusters of the composition Ti14H22O39 (defect-free face (001)), Ti14H22O38 (surface with oxygen vacancy), and Ti14H22N2O36 (surface with both oxygen vacancy and incorporated nitrogen), terminated with boundary hydrogen atoms. Calculations on the total energy of the optimized geometric structures of the model TiO2 clusters and on the corresponding theoretical XPS spectra were performed using the density functional theory (DFT) method and the B3LYP hybrid functional with an extended valence-split basis set 6-31G (d, p). In the XPS spectra of O1s, each peak can be attributed to a specific type of oxygen atoms in the initial structure, dependent on their coordination environment. The substitution of nitrogen atoms for oxygen ones leads to a complication of the spectrum. Simultaneous replacement of nitrogen atoms for oxygen ones and presence of an oxygen vacancy leads to further complication of the XPS spectrum. The different structure of the adsorption complexes of water molecules on the anatase surface formed due to the HOH···O hydrogen bond (this displaces by 0.05 eV all the peaks in the XPS spectrum) or the coordination bond Ti···OH2 has been also considered. Based on the analysis of theoretical results, the role of various forms of defects in the adsorption of water on the anatase surface is considered. The results of quantum chemical studies of molecular models simulated for the bulk and surface of titanium dioxide are compared with the literature data available. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • 0.6 mol% of Nd3+-doped CBP phosphor is promising for near infrared emission applications at 1.06 μm. • The emission band at 1.53 μm is useful in optical communication systems and IR laser applications. • 0.6 mol% of Er3+ doped CBP phosphor useful for green emission applications. Abstract Different concentrations of neodymium (Nd3+) and erbium (Er3+) doped calcium borophosphate (CBP) phosphors were prepared by solid state reaction method. These phosphors were characterized by XPS, photoluminescence (PL) and decay profiles. XPS spectra were recorded and discussed about various anionic groups. NIR photoluminescence spectra were measured and studied for Nd3+ and Er3+ doped CBP phosphors of different concentrations. The PL measurements showed that the intensity of luminescence increased with increasing doping concentrations upto 0.6 mol % and then decreased at higher concentrations due to the concentration quenching effect for both the ions. Decay curves were obtained for the energy levels, 4F 3/2 of Nd3+ and 4I 13/2 of Er3+ in these CBP phosphors and lifetimes were measured. In the case of Er3+ ion, visible emission and decay profiles were also measured in these phosphors. CIE color chromaticity diagrams are drawn for Er3+ ions in calcium borophosphate phosphors. The above results showed that Nd3+ and Er3+ doped CBP phosphors might be useful for NIR and green emission applications. [ABSTRACT FROM AUTHOR]

The suppression of Ti 3+ generation in Ba 3.75 Nd 9.5 Ti 18 O 54 (BNT) ceramic sintered at high temperature is investigated by substituting four metal ions M (M = Cu 2+ , Cr 3+ , Al 3+ , Mn 4+ ) for Ti 4+ at B-site. The XRD results show BNT ceramics substituted by M are formed as single tungsten-bronze type structured phase. All M substitutions have significant impact on the suppression of oxygen vacancies (V O •• ) and Ti 3+ generation in BNT ceramic, which is confirmed by XPS results. BNTM ceramics have noticeable increase of Q×f values and decrease of positive τ f values, but tiny decline in ε r values. The SEM images of BNTM ceramics show a promotion of grain size by substituting M for Ti, which may be conducive to improvement on Q×f values. [ABSTRACT FROM AUTHOR]

Poly o-phenetidine (POPT) and POPT/TiO2 nanocomposite with different types (Anatase, Rutile, and Mixture of them) and different ratios (0.05, 0.15, 0.20 g) of TiO2 NPs was successfully electropolymerized on 304 stainless steel material by cyclic voltammetry, and Galvanostatic and Potentiostatic technique. The obtained polymers were characterized by FT-IR, UV-vis, TEM, SEM-EDX, and XPS spectra. The anticorrosion properties examined by both of potentiodynamic Tafel polarization and electrochemical spectroscopy. The POPT/TiO2 mixture type with 0.15 g TiO2 NPs showed considerable protection against corrosion in 0.5 M HCl solution compared with the other type and ratio of POPT/TiO2 nanocomposite. [ABSTRACT FROM AUTHOR]

Under in situ UV illumination, some materials present evolution of their opto-electronic properties that can be monitored by spectroscopy. We present here a mathematical method which can be applied to spectroscopic measurements when an evolving set of data is recorded: the vectorial method. The investigations and quantifications are performed by Infrared spectroscopy and XPS on organic-inorganic thin films prepared by sol-gel. The inorganic part of these hybrid thin films contains Ti oxide-network based whereas the organic part is composed of N,N-dimethylformamide and its hydrolysis products. Under UV illumination, those films exhibit intermediate bandgap behavior due to the photoreduction of Ti(IV) in Ti(III). The role of the solvent in the thin film is underlined during the process of photoreduction together with an understanding of the condensation of the Ti oxide-based network, as these evolutions are critical for the opto-electronic properties of those thin films. [ABSTRACT FROM AUTHOR]

TiO2-SiO2 mixed oxides have been prepared by the sol-gel technique from tetrabutyl orthotitanate and tetraethyl orthosilicate. The prepared materials were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, nitrogen physisorption, Fourier-transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectroscopy (XPS). The results indicate that the TiO2-SiO2 mixed oxides have a large surface area and a nanoscale size. FT-IR spectra show that Ti atoms are bonded to silica by oxygen bridging atoms in Ti-O-Si bonds. The titanium valence states in TiO2-SiO2 mixed oxides were investigated by XPS, and their spectra report the presence of Ti2+ and Ti3+ cations for high silica concentration, suggesting the formation of oxygen vacancies. The photocatalytic activity of the prepared materials has been evaluated for the photodegradation of methylene blue (MB). The mixed oxides were activated by means of a UV light source, and the concentration of MB was monitored by UV-Vis spectroscopy. The synthesized TiO2-SiO2 shows significantly higher MB removal efficiency in comparison with that of the commercial TiO2 Degussa, P25. [ABSTRACT FROM AUTHOR]

We report the modifications of lattice structure, optical and electrical properties of α-Al 2 O 3 by 100 MeV Ag9+ ion beam irradiation with fluences in the range of 1 × 1011 -1 × 1013 ions/cm2. X-ray diffraction patterns have confirmed the polycrystalline form of rhombohedral structure (space group R-3c) for both pristine and irradiated samples. The Raman active phonon-modes of the pristine sample gradually disappeared with the increase of fluence. The Field Emission Scanning Electron Microscopic images indicated a transformation of the surface morphology from a distinct and layered-type grain structure in pristine sample to a soft layered-type grain structure in the irradiated sample of highest infuence. The Energy Dispersive X-Ray Analysis confirmed elemental composition of the irradiated samples close to nominal value of pristine sample. The X-ray Photoelectron spectroscopy confirmed chemical state modification at the surface of irradiated samples, where a fraction of the Al–O bonds has reduced into metallic Al state. The electrical conductivity in irradiated samples has been enhanced and showed thermal irreversibility where the conductivity in the cooling mode is smaller than that in the warming mode. The optical band gap and activation energy for the electronic transition from valence band to conduction band of α-Al 2 O 3 have been affected by Ag9+ ion beam irradiation. • Demonstrate the effects of Ag ion beam interactions with the lattice structure of α-Al 2 O 3. • The effects of low and high fluence levels on reversibility and irreversibility of properties. • Modification of surface chemical state by ion beam irradiation on α-Al 2 O 3. • The broken Al–O bonds at the surface and its effects on metal like conductivity behaviour. • The materials have been characterized by XRD, Raman spectra, FE-SEM and XPS. [ABSTRACT FROM AUTHOR]

In this paper, the electrochemical microcorrosion behavior of High-nitrogen steel hybrid weld joints with different wires addition were investigated. Polarization curves measurement was conducted to evaluate the corrosion feature in 3.5% NaCl solution. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to analyze the specific corrosion behavior and pitting deepening mechanism induced by precipitated ferrite-dendrites. The experimental results showed that the addition of nitrogen-containing welding wire improved the corrosion resistance of whole weld joint. As a transitional region, the HAZ exhibited relative weak pitting resistance and severe shedding behavior. The coherent dendrites and similar complex geometries led to the accumulation of continuous corrosion channels. The XPS spectra results indicated that the additional nitrogen in the welding wire optimized oxide composition of the surface passive film.

As-synthesized Fe 2+ Cr x Fe (2− x ) O 4 nanoferrites, 0.0 ≤ x ≤ 1, were prepared by the wet-chemical co-precipitation route and characterized by the X-ray diffraction, Brunauer-Emmett-Teller and transmission electron microscopy, IR spectra, thermographometry and vibrating sample magnetometry (VSM) techniques. This study proved that these samples have single phase of cubic spinel structure in nano-metric scale and are ferrimagnetic materials. VSM measurements revealed that these nanoferrites are soft ferrimagnetic materials. The crystallite size R, porosity P, strain ε, Debye temperature, nanoparticle specific surface area, B-site force constant, elastic parameters and sheer and longitudinal velocities were increased with increasing the Cr 3+ ion content x , whereas the lattice constant, density, grain specific surface area and A-site force constant were decreased. The strain ε proved dependence on P and R. Six absorption bands were observed in IR spectra and assigned to their corresponding sites and bonds. Thermal analysis of the samples displayed three steps of combustion process where the net loss of weight ranged 19%–33%. The saturation magnetization M S of the samples was decreased against x, whereas the coercivity H C was increased. Two peaks at 710 and 723 eV appeared in XPS spectra and attributed to Fe 2p 3/2 and Fe 2p 1/2 . They reveal that the ratio of Fe 2+ to Fe 3+ ions increases with Cr ion increment. [ABSTRACT FROM AUTHOR]

A novel 5,10,15,20-tetra[4-(3,5-dioctoxybenzamide)phenyl]porphyrin and its transition metal complexes are reported in this paper. Their molecular structures were characterized by elemental analysis, IR spectra, 1HNMR spectra and UV-Vis spectra. Their spectroscopic properties were studied by Raman spectra, fluorescence spectra and X-ray photoelectron spectra (XPS). The fluorescence quantum yields have been measured at room temperature. The fluorescence intensity of porphyrin ligand was stronger than that of the complexes. In Raman spectra, there was much difference between porphyrin ligand and its metal complexes due to changes of the symmetry of porphyrin plane. In the XPS spectra, the replacement of the free-base protons by a metal ion to form the metalloporphyrin increases the symmetry of the molecule also introduces an electron with-drawing group into the center of the porphyrin ligand which increases the N1s binding energy.

This study investigates a variation of the N 2 content in the mixed sputtering gas effects on the optical, electrical, and structural properties of p-type Zn-N-doped SnO 2 films. The incorporation of N into the tin oxide lattice of the synthesized films was confirmed by energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD) analysis, ultraviolet–visible (UV–vis) spectroscopy, and Hall measurements. Further, atomic force microscopy, field-emission scanning electron microscopy, and current-voltage characteristics confirmed the substitution of O by N in the SnO 2 lattice. The sufficiently large N3−–O2− substitution in the SnO 2 lattice was confirmed by a (200) cubic plane in the XRD pattern. N3−–O2− substitution was also ascertained by the redshift of the UV–vis absorption edge. The crystallinity increased significantly with an increase in N3−–O2− substitution in the SnO 2 lattice, including an increase in the crystal grain size and a decrease in surface roughness. The optimum N3−–O2− substitution for the film synthesized using 80% N 2 in the mixed sputtering gas resulted in the best crystal quality. This film showed the highest hole mobility and the greatest increase in the photocurrent of the film/n-Si heterojunction. The excess N-substituted O content in the tin oxide lattice degraded the crystal quality. Therefore, the optimally synthesized film is more suitable for optoelectronic devices. [Display omitted] • An increase in the N3−–O2− substitution in the SnO 2 lattice was determined by (200) plane -cubic phase. • The optimum N3−–O2− substitution in the SnO 2 lattice improved the best quality and the highest hole mobility. The best quality and the highest hole mobility resulted in the highest photocurrent of film/Si junction. [ABSTRACT FROM AUTHOR]

Ba 1 − x Fe x TiO 3 ( x = 0, 0.005, 0.01) polycrystalline ceramics are prepared using solid state reaction method. Structural studies through XRD, Raman and XPS confirm single tetragonal phase for BaTiO 3 whereas a structural disorder tends to intervene with the introduction of smaller Fe ions which reduces the tolerance factor and tetragonality ratio. Grain size of the samples is estimated using SEM micrographs with ImageJ software and chemical composition is confirmed using EDX spectra. Raman spectra measured in the temperature range of 303 K to 573 K showers light on the structural phase transition exploiting a significant disappearance of the 306 cm − 1 mode. Further, structural analyses suggest the entry of Fe into the B-site upon increasing its concentration in BaTiO 3 . The dopant sensitive modes lying at around 640 cm − 1 and 650 cm − 1 are assigned to lattice strain. A reduction in ferroelectric to paraelectric transition temperature is observed with a transformation from diffused type to normal ferroelectric upon the increased Fe content. The oxidation state of Fe in the BaTiO 3 lattice has been decided using EPR Spectra precisely. Room temperature magnetic ordering is observed in Fe substituted BaTiO 3 using PPMS. The coexistence of ferroelectric and magnetic ordering is established in the present study for optimized Fe substituted BaTiO 3 . [ABSTRACT FROM AUTHOR]

The solvent reaction of five flexible unsymmetrical bis(pyridyl) ligands, N -(pyridin-2-ylmethyl)pyridin-2-amine ( L1 ), N -(pyridin-2-ylmethyl)pyridin-3-amine ( L2 ), N -(pyridin-3-ylmethyl)pyridin-2-amine ( L3 ), N -(pyridin-3-ylmethyl)pyridin-3-amine ( L4 ) and N -(pyridin-4-ylmethyl)pyridin-3-amine ( L5 ), with HgX 2 (X = Cl − , Br − and I − ) salts leads to the formation of fifteen Hg(II) complexes, namely [Hg( L1 )X 2 ] n [X = Cl ( 1 ) and Br ( 2 )], [Hg 2 I 6 ] 2− ·2 HL1 + ( 3 ), [Hg( L2 )Cl 2 ] 2 ( 4 ), [Hg( L2 )X 2 ] n [X = Br ( 5 ) and I ( 6 )], [Hg( L3 )Cl 2 ] n ( 7 ), [Hg( HL3 )X 3 ] [X = Br ( 8 ) and I ( 9 )], [Hg( L4 )Cl 2 ] n ( 10 ), [HgX 4 ] 2− ·2 HL4 + [X = Br ( 11 ) and I ( 12 )], [Hg 3 Cl 10 ] 4− ·2 H 2 L5 2+ ( 13 ) and [Hg 2 ( L5 )( HL5 )X 5 ] [X = Br ( 14 ) and I ( 15 )], which have been characterized by elemental analysis, IR, TG, PL, XPS, powder and single-crystal X-ray diffraction. Structural analyses indicate that complexes 1 , 2 , 5 – 7 and 10 exhibit linear or helical chain motifs while complex 4 shows a [2+2] metallomacrocyclic structure. Complexes 8 , 9 , 14 and 15 present simple mono- or dinuclear motifs, in which the Hg(II) cations exist in HgNX 3 or Hg 2 N 2 X 5 (X = Br and I) spheres. On the contrary, under the same conditions, complexes 3 and 11–13 are obtained as ionic salts composed of protonated bis(pyridyl) ligands and various mercury-halide clusters, [HgX 4 ] 2− (X = Br − and I − ), [Hg 2 I 6 ] 2− or [Hg 3 Cl 10 ] 4− . The structural diversities and evolutions of these architectures can be attributed to the diverse mercury-halide clusters, the ligand conformation ( cis – trans , trans – cis , trans – trans ) as well as non-covalent interactions, such as C/N–H⋯X, C–H⋯π, π⋯π and Cl⋯π. Moreover, the binding energies of the Hg 4f 7/2 level in the XPS spectra present a regular decrease from Cl-containing, Br-containing to I-containing complexes. For the N1s core level, the different binding energies in the XPS spectra can be attributed to the N atoms with different chemical environments. [ABSTRACT FROM AUTHOR]

The metal-organic frameworks of the formula Ln(bta)· nHO where n = 3, 4, 5 or 6; bta = benzene-1,3,5-triacetate ion: [CH(COO)]; Ln = La(III), Nd(III), Eu(III), Tb(III), Ho(III), Tm(III), Lu(III) were synthesized by the reaction of LnCl· xHO with ammonium salt of Hbta acid in water solution. Insoluble water compounds crystallize in the monoclinic or triclinic crystal system, and they are stable up to 30 °C. When heated, they decompose up to 160-200 °C in two stages to stable anhydrous compounds. The dehydrated compounds Ln(bta) are still crystalline and stable up to about 350 °C. When heated above 350 °C, they undergo decomposition where the intermediate products are LnOCO or TbOCO and the residues are: LnO or TbO. The interpretation of IR spectra of title compounds was made taking into consideration the experimental and theoretical wavenumbers obtained for Hbta specie. The XPS spectra of Hbta and its complexes were recorded. The way of metal-carboxylate group of ligand coordination was discussed. This work presents the results of the XPS analyses, which allowed to determine the binding energies ( E ) for the main lines of Ln3d, Ln4d, Ln5p, C1s, O1s spectra, spin-orbital splitting and full width at half maximum complexes. [ABSTRACT FROM AUTHOR]

Valence and core-level photoemission spectra of two gaseous nitrogen containing heterocycles, lumazine and alloxazine, have been studied experimentally and theoretically. Comprehensive information about the electronic structure of these aromatic molecules has been acquired. The outer-valence Green's function (OVGF) approach was used to calculate vertical ionization energies and relative intensities (pole strengths) of the valence band spectra. The C, N, and O 1s core level spectra of both compounds were measured and assigned on the basis of Δ -Kohn–Sham calculations. The relative stability of different tautomers of lumazine and alloxazine was investigated through DFT calculations. Only the single, most stable tautomer for lumazine and alloxazine was populated at the present experimental conditions and this finding is confirmed by the core-level photoemission signal, which is able to discriminate between different isomers of a molecule. Other tautomers of lumazine and alloxazine have not been clearly identified spectroscopically, however their relative free energies and Boltzmann populations were calculated and compared with previous studies. [ABSTRACT FROM AUTHOR]

The paper reviews black chromium electrodeposited from a trivalent chromium bath containing ZnO as a second main component. The chemical compositions of the top layers of the black chromium coatings were studied by the X-ray photoelectron spectroscopy method. The surface of black chromium was found to be almost entirely covered with organic substances. To gain information on the state of each element in the deposit bulk, the layer-by-layer etching of the black chromium surface with argon gas was used. Analysis of XPS spectra has shown that the top layers of black chromium without zinc are composed of various Cr(III) components, organic substances and metallic Cr, whereas metallic Cr is almost absent in black chromium containing some amount of Zn(II) compounds. The ratios of metal/oxide phases were found to be 10/27 and 2/28 for black chromium without and with zinc, respectively. It has been determined that owing to the presence of ZnO in the Cr(III) bath, the percentage of metallic chromium is substantially reduced in black chromium which is quite important for good solar selective characteristics of the coating. The results confirm some of earlier observations and provide new information on the composition of the near-surface layers. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy data are analyzed by solving the problem of the photoemission-current density function using the invariant immersion method. X-ray photoelectron spectra in a wide energy loss range are described on the basis of exact solution of the problem of elastic photoelectron scattering in solids using the discrete ordinate technique. The X-ray photoelectron spectrum is recorded in the form of a series of inelastic scattering orders. Comparison of the results of the exact solution with the data of transport and small-angle approximations reveals significant errors in the approximate solutions in X-ray photoelectron spectroscopy. The spectra calculated using different approximations are presented and compared with the experiment. The errors of the traditional background subtraction procedures are considered. [ABSTRACT FROM AUTHOR]

The electronic structure of the polycrystalline La0.67Ca0.33Mn1-xCoxO3 compounds with x = 0.5, 0.6, 0.7, 0.8, 0.9 and 1 has been investigated by X-ray photoelectron spectroscopy (XPS). The valence band and the transition metal core level spectra were analyzed. Several contributions from the Mn 3d, Co 3d and of extensively hybridized Mn3d-O2p and Co3d-O2p states were found in the spectral region between 2 eV and 5 eV. The core level spectra show the presence of Co4+ and Co2+ states. [ABSTRACT FROM AUTHOR]

Highlights: [•] 9-aminoacridine intercalation was performed in thin films of exfoliated Li2x Mn1−x PS3. [•] Li2x−y Mn1−x PS3(C13H11N2) y and C13H11N2Cl film XPS spectra were investigated. [•] XPS spectra confirm that the 9-aminoacridine molecule is protonated in both films. [•] The interaction between 9AAH+ (guest) and Li2x−y Mn1−x PS3 − (host) is electrostatic. [•] Mn2+ in Li2x−y Mn1−x PS3(C13H11N2) y films is in the high spin state as in MnPS3. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews the CrNi alloys electrodeposited from Cr(III) oxalate bath containing NiSO4. Ni-rich and Cr-rich alloy coatings were shown to have a nodular structure with smaller size of nodules for the Ni-rich alloy compared to those for the Cr-rich one which has a nanoscale cracked morphology. The chemical composition of the top layers of CrNi alloys electrodeposited from Cr(III)+Ni(II) bath was studied by the X-ray photoelectron spectroscopy method. Analysis of XPS spectra has shown that the surfaces of both Ni-rich and Cr-rich alloys are covered with the oxide films consisting mainly of Cr(OH)3, Cr(OH)O and Cr2O3 with minor amounts of both NiO and organic substances. The data obtained suggest that Cr(OH)3 and Cr(OH)O dominate outside, whereas, Cr2O3 dominates inside the film. It has been found that nickel is incorporated in bulk of the deposits as metallic Ni0, whereas, chromium is present as metallic Cr0 and chromium carbides. [Copyright &y& Elsevier]

Abstract: Na0.88Mn0.56PS3compounds have been synthesized by starting from MnPS3 polycrystalline powders by means of a two-step cation-exchange process at a higher intercalation time than the one used for producing the literature reported Na0.62Mn0.69PS3 compounds. The obtained samples have been characterized by X-ray photoelectron spectroscopy (XPS). The resulting spectra of the so-synthesized compounds have been compared with those observed in Na0.62Mn0.69PS3 in our previous paper and similar electronic properties have been noted. In particular by XPS it has been shown that greater sodium content affects neither the core-level binding energies of the host matrix elements nor the type of link between Na+ and (Mn1−x PS3)−. [Copyright &y& Elsevier]

Abstract: This research studied optical and structural properties of SrO–Nb2O5–P2O5 glasses containing 0~25mol% Nb2O5 and 35~60mol% SrO using spectra of UV–Vis, FTIR and XPS. Our aim was to work new moldable glasses which are colorless with high refractive index and transmittance, and their correlation with glass structure. Nb2O5 plays the role as an intermediate of glass formation, and transforms the role to network-former or glass-modifier depending on composition. Refractive index increases monotonically with Nb2O5 content at the expense of transmittance, and specific coloring which occurs in ternary compositions with the ratio P2O5/SrO >1. This effect arises from much increased [Nb3+ and Nb4+] fraction, as quantitatively deconvoluted in Nb3d XPS spectra, in the ligand [NbO6]octahedral which is supported by FTIR and O1s XPS spectra. As the ratio P2O5/SrO≤1, Nb2O5 is more of a network former and [NbO6]octahedral structure turns into [NbO4]tetrahedron with partial Nb–O…(Sr) bonding turns into (Nb–O–Nb)tetrahedron, coloring disappears. [Copyright &y& Elsevier]

Abstract: Solid solutions Re1−x Mn x O2 (x =0; 0.08; 0.21) with a tetragonal rutile-type structure (sp. gr. P42/mnm, z =2) have been synthesized from NH4ReO4, KReO4 and KMnO4 in argon atmosphere at 450–520°C in a quartz cell. According to XPS measurements, Mn in solid solutions Re1−x Mn x O2 is present as Mn3+ and Mn2+ cations, while the degree of oxidation of Re partly increases to penta- or hexavalent state. A transition of ReO2 presumably in the antiferromagnetic state at 41K was for the first time established by magnetic measurements. Along with the anomaly at 41K, the second magnetic transitions at 6.5K (x =0.08) and 11K (x =0.21) was registered in these solid solutions. [ABSTRACT FROM AUTHOR]

X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM) and magnetic measurements as a function of applied magnetic field and temperature for In1− xMn xSb (0.05≤ x≤0.2) system are reported. Magnetic measurements performed at high and small magnetic field in ZFC and FC indicate the coexistence of ferromagnetic In1− xMn xSb solid solution and two types of magnetic cluster: ferromagnetic MnSb and ferrimagnetic Mn2Sb. XPS valence band and Mn 2p core level spectra have confirmed the presence of MnSb and Mn2Sb phases. TEM images show some manganese antimonide phase microinclusions with dimension between (30–40) nm. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the paper is to present the surface film composition formed on AISI 316L stainless steel after electropolishing (EP) and magnetoelectropolishing (MEP) for a wide range of the process conditions. The electropolishing EP process has been performed under natural convection (in still electrolyte), and under a forced convection (moderate stirring below 0.1m/s), both at the polarization plateaux and much above it. Another series of experiments were carried out on AISI 316L SS samples prepared by MEP at 350mT. The samples prepared by mechanical abrasive polishing, with the grit size of 1000 served as a reference. The Cr:Fe ratio was also studied for the differently prepared samples and it was found that this ratio was significantly higher for the EP and MEP samples than the mechanically polished one. Based on the results, the selection of proper electropolishing conditions have been formulated. [Copyright &y& Elsevier]

Abstract: A nanostructured conducting copolymer poly(aniline-co-o-aminophenol) (PANOA) was electrochemically synthesized on a glassy carbon (GC) electrode and its redox and anion exchange properties for perchlorate removal were investigated by cyclic voltammetry, FTIR, and X-ray photoelectron spectroscopy (XPS). Results from cyclic voltammograms in a wide range of solution pHs showed that this conducting polymer had a good redox electrochemical stability and reversibility. FTIR spectra demonstrated that ions were immobilized in the copolymer film after its oxidation in a solution containing NaCl and NaClO4. The result of XPS spectra showed that the copolymer films oxidized in a solution containing 0.10M NaCl and 0.010M NaClO4 at pH 5.7 and 9.0 had molar ratio of 0.53 and 0.31, respectively, which were significantly higher than the ratio of 0.10 in the tested aqueous solution. The results, thus, indicated that the PANOA copolymer can be used to develop an electrically controlled anion-exchange process to remove perchlorate from the industrial wastewaters. This would be an environment-friendly green process, as it does not face the brine disposal problem, as encountered in traditional ion-exchange processes that required uses of regenerative agents. [Copyright &y& Elsevier]

Two new organic-inorganic hybrid cobalt-molybdovanadates [Co(phen)3]H2[H2V2Mo6O26] · 7H2O (1) and [Co(2,2'-bipy)3][Na(H2O)7][VMo12O40] (2) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV, XPS spectroscopy, thermogravimetric (TG) analyses, and X-ray single crystal diffraction. The molecular structure of 1 consists of a [V2Mo6(OH)2O24]4- polyoxoanion, a [Co(phen)3]2+, two H+ and seven lattice water molecules. The structure of [V2Mo6(OH)2O24]4- consists of six MoO6 octahedra and two VO4 tetrahedra; six MoO6 octahedra are linked by edge-sharing oxygens forming a {Mo6} ring, and two VO4 tetrahedra cap opposite sides of the {Mo6} ring. The molecular structural unit of 2 is constructed from a typical Keggin-type [VMo12O40]3- polyoxoanion and a [Co(2,2'-bipy)3]2+ cation and a Na+ countercation; Co2+ is coordinated by six nitrogens from three 2,2'-bipyridines forming a distorted octahedron. [ABSTRACT FROM AUTHOR]

Abstract: Poly(aniline-co-o-aminophenol) (PANOA) deposited on the glassy carbon (GC) electrode was first used to investigate the electrocatalytic reduction of arsenate in a NaCl solution. The electrocatalytic evidence came from the pronounced increase in the current of arsenate reduction at the PANOA/GC electrode compared to the bare GC electrode under the same conditions. In the latter case the reduction current was small, indicating that arsenate is electrochemically inactive at the bare GC electrode. The catalytic activity of PANOA depended on the pH in the range 5.6–7.0, which is related to the effect of pH on the redox activity of PANOA and the dissociated form of arsenate in the solution. In addition, the electrochemical activity of PANOA was found to increase in a solution containing arsenate, which was caused by the increase in both the unpaired spin density of PANOA and the pH buffer capacity of the solution due to the presence of arsenate. The XPS data indicated that PANOA can be used to remove arsenate from the solution. [Copyright &y& Elsevier]

Abstract: X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), magnetization and magnetic susceptibility of Mn1− x Al x Ni alloys are reported. A change in the crystallographic structure takes place around x=0.4 from CuAuI to CsCl (B2) structure type. For x0.5 a mixed B2+L21 state exists which incorporates antiferromagnetic (B2) and ferromagnetic (L21) parts. A direct evidence for the existence of local moments on Mn sites in Mn1- x Al x Ni alloys is given by the exchange splitting of XPS Mn 3s and Mn 2p3/2 core levels. The gradual filling of the Ni 3d band as the Al concentration increases can be explained by the hybridization of the Ni 3d band and Al 3sp states. [Copyright &y& Elsevier]

Abstract: In this paper, high quality Al-doped ZnO (AZO) thin films were prepared by direct current (DC) reactive magnetron sputtering using a Zn target (99.99%) containing Al of 1.5wt.%. The films obtained were characterized by X-ray photoelectron spectroscopy (XPS) and thermoelectric measurements. The XPS results reveal that Zn and Al exist only in oxidized state, while there are dominant crystal lattice and rare adsorbed oxygen for O in the annealed AZO thin films. The studies of thermoelectric property show a striking thermoelectric effect in the AZO thin films. On the one hand, the thermoelectromotive and magnetothermoelectromotive forces increase linearly with increasing temperature difference (ΔT). On the other hand, the thermoelectric power (TEP) decreases with the electrical resistance of the sample. But the TEP increases with the increase of temperature below 300K, and it nearly does not change around room temperature. The experimental results also demonstrate that the annealing treatment increases TEP, while the external magnetic field degrades TEP. [Copyright &y& Elsevier]

Abstract: Novel chitosan-N-inulin graft copolymers with different degree of substitution (DS) of chitosan were synthesized via water-soluble 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide mediated reaction. Chemical structure and composition of the chitosan derivatives was confirmed by chemical analysis, FT-IR, XPS, 1H and 13C NMR spectroscopy, and potentiometry. Chitosan–inulin copolymers were high-molecular-weight hydrophilic products soluble in water in a wide pH range forming extraordinary viscous solutions. Intrinsic viscosity of N-modified chitosans was sharply suppressed by added electrolyte and had tendency to decrease at higher DS of chitosan. pK α values of the chitosan–inulin copolymers determined from potentiometric titration data using Henderson–Hasselbalch equation were in the range 6–7 slightly increasing at higher DS. Novel water-soluble chitosan copolymers retained cationic properties of chitosan and could be used as surface conditioners. [Copyright &y& Elsevier]

Abstract: Different polymorphs of MRe2O6 (M i) with rutile-like structures were prepared using high-pressure high-temperature synthesis. For syntheses temperatures higher than ∼1573K, tetragonal rutile-type structures (P42/mnm) with a statistical distribution of M- and Re-atoms on the metal position in the structure were observed for all three compounds, whereas rutile-like structures with orthorhombic or monoclinic symmetry, partially ordered M- and Re-ions on different sites and metallic Re–Re-bonds within Re2O10-pairs were found for CoRe2O6 and NiRe2O6 at a synthesis temperature of 1473K. According to the XPS measurements, a mixture of Re+4/Re+6 and M 2+/M 3+ is present in both structural modifications of CoRe2O6 and NiRe2O6. The low-temperature forms contain more Re+4 and M3+ than the high-temperature forms. Tetragonal and monoclinic modifications of NiRe2O6 order with a ferromagnetic component at ∼24K, whereas tetragonal and orthorhombic CoRe2O6 show two magnetic transitions: below ∼17.5 and 27K for the tetragonal and below 18 and 67K for the orthorhombic phase. Tetragonal FeRe2O6 is antiferromagnetic below 123K. [Copyright &y& Elsevier]