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To evaluate the impact of speed sintering on the microstructure and optical properties of 3 and 5 mol% yttria-partially stabilized monolithic zirconias. 120 plate-shaped zirconia specimens (10x10x 0.4 mm) were prepared from three commercial 5 mol% yttria-partially stabilized zirconia blocks (5Y-PSZs); Katana UTML (Kuraray Noritake), Cercon xtML (Dentsply Sirona), and Zolid FX white (Amann Girrbach), and two commercial 3 mol% yttria-partially stabilized zirconia blocks (3Y-PSZs); Lava Plus (3 M ESPE) and InCoris (Sirona, GmbH). Specimens were either conventional sintered (CS) using a 7-hour program or speed sintered (SS) using a quick 90-minute program. The microstructure was inspected with a scanning electron microscope (SEM), and phase fractions were detected using x-ray diffraction analysis (XRD). Translucency (TP 00), and contrast ratio (CR) were obtained using a spectrophotometer (VITA Easyshade V). Color difference (ΔE 00) between both sintering processes was calculated with the CIEDE2000 formula. ΔE 00 up to 1.8 was set as the acceptability threshold. Data were analyzed using two-way ANOVA, Krusakll-Wallis, and Mann-Whitney U tests. (n = 12, α =.05). Grain size was significantly decreased after SS for all tested materials (P <.0001). The average grain sizes of 5Y-PSZs were significantly larger than those of 3Y-PSZs. The atomic structure, microstructure, and transparency of CS and SS were all affected by the amount of yttria, the size of the crystals, and tetragonality. SS significantly reduced TP 00 (F = 7135.95, P < 0.0001) and increased CR (F = 453.21, P < 0.0001). The CS Katana presented the highest TP 00 and lowest CR value. ΔE 00 between the CS and SS groups were clinically acceptable except for Lava, which had values above the set threshold (1.89). SS altered the grain size and internal structure of the tested materials, which was reflected in translucency. • Variations in yttria concentration, crystal size, and tetragonality between CS and SS within each material which affected the atomic structure, microstructure, and translucency. • The lightness decreased and chroma increased after speed sintering in 3 and 5 mol% yttria-partially stabilized monolithic zirconia. • The final color of monolithic zirconia restorations may be adversely affected by zirconia manufacturers. [ABSTRACT FROM AUTHOR]

Co-precipitation, a minimal technique, was used successfully to create a novel (Cr, Cu) dual-doped ZnO nanoparticles (NPs). X-ray diffraction (XRD), energy dispersion X-ray (EDX) analysis, scanning electron microscopes (SEM), and UV–visible absorption spectra had been used to characterize the produced nanoparticle. According to the XRD pattern, the produced NPs have a hexagonal wurtzite structure with a high phase purity. The substitution of Cr increased optical absorption and induced new absorption peaks in the visible regions that correspond to the transitions from 4A2(4F) to CB and 4A2(4F) to 4T1(4F). Absorption of photons in the visible region led to an increase in the photo-generated electron–hole pairs and hence RO-species which are responsible for photocatalytic activity. Therefore, the (Cu, Cr) dual doped ZnO NPs had unique photocatalytic activity under sunlight irradiation. MTT assay was employed to analyse the in-vitro cytotoxicity of Cr-doped Zn0.98Cu0.02O NPs on human normal PBMC. In which, the toxicity is enhanced by a proliferation in Cr concentration and has very small amounts at low concentrations and significantly at high concentrations. The antibacterial characteristics of the synthesized NPs were examined against the bacterial strains P. putida and B. subtilis. [ABSTRACT FROM AUTHOR]

In the present study, composite samples of BaTiO 3 /(Co 0.8 Ni 0.1 Mn 0.1 Fe 1.9 Ce 0.1 O 4) x (noted as BTO/(CNMFCO) x) were prepared and their structural, morphological, optical, magnetic, and magnetoelectric coupling properties were investigated. Firstly, the BaTiO 3 and spinel ferrite CNMFCO phases were prepared separately through the sol-gel auto-combustion route, then, the composite samples BTO/(CNMFCO) x were made via the solid-state reaction method. The structural, morphological, optical, magnetic, and magnetoelectric coupling properties were examined using X-rays diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), scanning electron microscope (SEM) coupled with EDX spectrometer, UV–visible diffuse reflectance spectrophotometer (UV–vis DRS), vibrating sample magnetometer (VSM) techniques, and lock-in amplifier, respectively. The successful preparation of biphasic samples was confirmed by XRD and SEM studies. From SEM images, a compact structure with good density was observed. The mean size of BTO grains decreases with increasing the concentration of the magnetic phase. The optical properties have been explored in the UV–visible light range. The extracted band gap energy (E g) values showed a reduction with the rising of the magnetic phase content. The analysis of magnetization measurements revealed the magnetic character of different composites. It is found that the saturation (M s) and remanent (M r) magnetizations are increasing with the rise in the concentration of the magnetic CNMFCO phase (x %). High magnetoelectric voltage coefficients (α M E ) were attained for different composites with the highest α M E value of about 22.8 mV/cm.Oe reached in composite with x content of 20%. The high ME coupling in these composites makes these composites promising candidates to be used in multifunctional devices. [ABSTRACT FROM AUTHOR]

MgMoO 4 with hexagonal particles were prepared by combining high energy ball milling with heat treatment technique. The influence of the mechanochemical activation/heat-treatment on the phase, structural and morphology transformation were investigated by X-ray powder diffraction analysis (XRD), infrared spectroscopy (IR), differential scanning calorimetry (DSC), particle size distribution (PSD) and scanning electron microscope (SEM). Optical properties of the final product were studied by UV–Vis and photoluminescence (PL) measurements. Mechanochemical activation of the initial oxides for 10 h ball milling leads to a full amorphization of MoO 3, only. The heat-treatment at different temperatures after 10 h milling time results to the phase formation of MgMoO 4. The reaction started at 400 °C for 5 h and completed at 800 °C for 5 h. The calculated energy band gap value as prepared MgMoO 4 is 2.03 eV and exhibits photoluminescence emission above 600 nm. The CIE chromaticity coordinates (x = 0.53 and y = 0.43) were found to lie in the orange region. [ABSTRACT FROM AUTHOR]

The Nebulizer spray pyrolysis technique is used to make tin disulphide thin films at various substrate temperatures. SnS2 thin films structural, electrical and optical properties are investigated. The polycrystalline nature was confirmed by Xray diffraction (XRD) analysis, which revealed a hexagonal structure with a preferred orientation along the (0 0 2) plane. The full width half maximum value of the Bragg peak is used to calculate the size of SnS2 crystallization. Scanning Electron Microscope (SEM) is used to examine the composition and surface morphology of SnS2 thin films. The wavelength range of 400-1110 nm is used to determine the transmittance and absorption spectra of these films. With increasing substrate temperature, the optical band gap of tin disulphide thin films decreases from 3.17 eV to 2.61 eV. With regard to substrate temperature, the absorption coefficient and activation energy were reduced with SnS2 deposition. [ABSTRACT FROM AUTHOR]

CaxBa1-xNb2O6 (CBN) ceramics with tetragonal tungsten bronze (TTB) structures are very attractive from academic and technological fronts due to their stupendous ferroelectric properties. Polycrystalline samples of CaxBa1-xNb2O5 were prepared by a high temperature solid state reaction technique. The phase formation, microstructure and optical properties of the prepared samples were investigated by X-ray diffraction, scanning electron microscope and Raman spectrometer, respectively. X-ray analysis confirms the partially filled tetragonal tungsten bronze (TTB) structure. Scanning electron micrographs provide information related to the morphology and grain size distribution of the samples. Detailed analysis of the structural and optical properties suggests that these samples have undergone a phase transition well above the room temperature. [ABSTRACT FROM AUTHOR]

Cr-doped Fe3O4 nanoparticles have been efficiently synthesized by microwave combustion approach to evaluate structural, magnetic, and optical properties. The as-synthesized Fe3O4 nanopowders structural, optical, morphological, and magnetic properties assessment was carried out by employing X-ray diffraction analysis, optical spectroscopic technique, scanning electron microscope, and vibrating-sample magnetometer. The X-ray diffraction (XRD) analysis studied the structural properties of the nanoparticles and confirms structure of the Fe3O4 and Cr-doped Fe3O4 crystal structure. The magnetic hysteresis loops of the samples indicated that the samples are ferromagnetism in nature. The ferromagnetism behavior of the samples is also discussed. [ABSTRACT FROM AUTHOR]

Abstract In this study, synthesis of pure and Cu doped lead sulfide (PbS) nanoparticles was facilely achieved. The good crystalline nature of the nanoparticles was confirmed via X-ray diffraction (XRD) analysis. Specifically, XRD data was also used to estimate the diffraction planes, lattice constants, size of crystallites, density of dislocations, and strain produced in the lattice. The XRD pattern was indexed after identifying the diffraction planes. The crystallite size was estimated to be in the range of 18–23 nm. The absence of any additional vibrational mode in Raman spectra was observed, and this confirmed the purity of PbS even at a higher Cu doping level. However, the vibrational modes exhibited some shift towards lower wavenumbers. Low dimension nanoparticles morphology and presence of Cu were investigated via scanning electron microscope/ Energy Dispersive X-Ray (SEM/EDX) analysis. Additionally, homogeneous Cu doping in final product was observed in an EDX elemental mapping image. Optical measurements were performed by recording diffused reflectance. Both direct energy gap values were estimated in the range of 1.15–1.50 eV, and this significantly exceeded that of the bulk (i.e., 0.41 eV). Dielectric and J-V electrical measurements were performed. The dc conductivity and mobility values were observed extremely high for 2.5% Cu doped PbS NPs [which correspond to 2.48 × 10−5 S/cm and 1.3 × 104 cm2/(V s)] when compared to those of pure and other doped PbS NPs. Graphical abstract fx1 Highlights • Facile synthesis of pure and Cu doped PbS nanoparticles is attained via the chemical route. • XRD, Raman, EDX and SEM mapping confirm single phase of PbS and Cu doping. • SEM shows homogeneous low dimension NPs synthesis of pure and Cu doped PbS. • Energy gap is observed in range of 1.15–1.50 eV, which exceeds that of bulk. • High dc conductivity (2.48 × 10−5 S/cm) and mobility (1.3 × 104 cm2/V s) are observed for 2.5% Cu doped PbS NPs. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The speed of the preparation of SiO 2 -Fe 2 O 3 heterogeneous metamaterials was successfully improved by the one-step method. • Ordered SiO 2 -Fe 2 O 3 heterogeneous metamaterials can be prepared via the one-step method without applying a voltage. • There is a photonic band gap in the infrared range. Abstract SiO 2 -Fe 2 O 3 heterogeneous metamaterial was fabricated by one-step self-assembly process. The micro-morphology and optical properties of the SiO 2 -Fe 2 O 3 heterogeneous metamaterials were characterized by scanning electron microscope (SEM) and UV/Vis/NIR spectrophotometer respectively. The crystal phase of the calcined Fe 2 O 3 powders was characterized by X-ray diffraction (XRD). The influences of the concentration of SiO 2 suspension and voltage on heterogeneous metamaterials are discussed. The model of SiO 2 -Fe 2 O 3 heterogeneous photonic crystal was established, and the wavelength of the bandgap center was simulated and analyzed. The results show that the ordered SiO 2 -Fe 2 O 3 heterogeneous metamaterial can be successfully obtained by a one-step self-assembly process with no voltage when the concentration of SiO 2 suspension is 3% (in a short time). In the suspension system, the voltage is not beneficial to the self-assembly process, and even destroys the electrode cathode. As can be seen from transmission spectra, the as-prepared samples have three bandgaps, and the absorption peaks are obvious in the near infrared range (1235˜1419 nm). In this paper, we show that the application of this composite system can avoid dependence on the ITO electrode material. [ABSTRACT FROM AUTHOR]

Potassium chloride (KCl) nanoparticles were synthesized by ball milling technique with different milling time. The effect of milling time on structural and optical properties was investigated. The structural properties of the purchased samples are characterized by Raman spectroscopy, scanning electron microscope and X-ray diffraction techniques. The Raman spectroscopy of the KCl hints at an excellent alloying behavior of those compounds and a preferred crystal structure for certain composition. The optical band is calculated by analyzing the spectral behavior of the absorption coefficient in the absorption region which revealed direct transitions. The value optical band increases (4.02–5.11 eV) with increasing milling time (0–15 h) due to quantum confinement after the ball milling process. The refractive and absorption indices were calculated for all samples. The model of Wemple–DiDomenico was used to calculate the dispersion parameters. The nonlinear susceptibility of the third order and the nonlinear refractive index were calculated by linear optical parameters using the generalized Miller rule. Mechanical milling for different milling times (0, 5, 10 and 15 h) by a planetary ball mill with zirconium oxide balls has been carried out for milling KCl. The images of as-purchased KCl have regular uniformly grains distributed like cubic particles with size of around 10 μm. By increasing the milling time to 15 h, these individual regular shapes form a smaller reasonably dense having a size less than 500 nm. [ABSTRACT FROM AUTHOR]

Abstract In this study, the production, microstructural characterization and optical properties evaluation of heterostructured NiO-TiO 2 films were performed. The film is intended to be used in solar cell applications. Ni-P electroless film was made on an AA7050 aluminum alloy. The film was black nickel electrodeposited by diluted nitric acid and then a thin TiO 2 layer coating was deposited by Sol-gel process. The microstructure of the film was analyzed by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS) detector. X-ray diffraction (XRD) technique was used to determine the phases formed in the heterostructured film. Optical properties of the heterostructured film were measured by UV–visible spectroscopy and photoluminescence (PL) Test. Results showed that the heterostructured NiO-TiO 2 films had a cauliflower characteristic and was amorphous crystallographically. The heterostructured films also increased the absorption coefficient of the solar absorber plates up to more than 98% in the visible-ultraviolet range. Finally, it was shown that, in the infrared region, the absorption coefficient for dispersion was down to 2%. [ABSTRACT FROM AUTHOR]

Abstract New nanocomposite films of polyvinyl alcohol (PVA) doped with different wt% (0.6, 1.6, 2.4) of Se 80 Te 15 Bi 5 glass have been prepared by solution casting method for flexible optical device applications. X-ray diffractogram (XRD) of films exhibit polycrystalline nature. Scanning electron microscope (SEM) images confirmed the formation of nanoclusters having a mean diameter of 60 nm. Elemental composition of the samples was confirmed by energy dispersive X-ray analysis (EDAX) spectra. The optical constants of films were calculated based on the spectral data obtained using UV–Visible spectrophotometer in the wavelength range 200–800 nm. The possible optical transition in these films was found to be allowed indirect transition with energy gap values which decreases from 4.0 eV for pure PVA to 1.6 eV for the nanocomposite with 2.4 wt% of the glass. The calculated refractive index exhibits a normal dispersion and increases from 1.42 for pure PVA to 3.17 for the nanocomposite with 2.4 wt% of the glass. The optical dispersion parameters were determined according to Wemple and DiDomenico (WDD) model. Decrease in optical band gap while the increase in other optical parameters may be attributed to the formation of clusters during the dissolution of glass. Graphical abstract Image Highlights • New nanocomposite films Se 80 Te 15 Bi 5 /PVA have been prepared by solution casting method. • Semi-crystalline nanocomposites with nanoclusters of 60 nm mean diameter were formed. • Increase in refractive index and decrease in optical band gap was observed with increase in glass concentration in polymer matrix. • Tuneable optical properties based on wt% of Se 80 Te 15 Bi 5 glass in PVA, make the new nanocomposites suitable for optical storage and optoelectronic devices. [ABSTRACT FROM AUTHOR]

The effect of Ag doping on some physical properties of CdS thin films prepared by spray technique using perfume atomiser on glass substrates is reported in this paper. The doped films exhibit polycrystalline nature with hexagonal crystal structure similar to that of the undoped film. A (0 0 2) preferential orientation is observed for all the films. The presence of nanoneedles is evinced for the doped films from the SEM images. All the films have high transparency of nearly 80% in the visible region. The optical band gaps of the doped films exhibit a red shift from 2.44 to 2.23 eV which was attributed to Moss–Burstein (MB) effect. All the films have resistivity in the order of 10−2Ω-cm, and with Ag doping it is found to decrease. The obtained results infer that the CdAgS thin films are well suited for optoelectronic applications. [ABSTRACT FROM PUBLISHER]

In 2 S 3 is a III-VI group semiconductor with n-type conductivity and a wide band gap energy, which can be suitable as a buffer layer alternative to CdS in thin film solar cell fabrication. In the present study, In 2 S 3 thin films were grown on glass substrates by the thermal evaporation method at a constant substrate temperature of 200 °C. The deposited layers were post annealed in vacuum in the temperature range of 200–300 °C for 1 h. The grazing incident X-ray diffraction and scanning electron microscopy studies revealed polycrystalline nature of the layers with a good surface morphology. The optical properties of these annealed layers were investigated by using photoacoustic spectroscopy and independently by using conventional optical transmission spectroscopy. The photoacoustic spectra of In 2 S 3 films showed a sharp fall in the photoacoustic signal at photon energies that increased from 1.95 to 2.74 eV with increasing annealing temperature, which corresponds to the band gap energy of corresponding films. The band gap energy and the refractive index values calculated by using photoacoustic spectra are in good agreement with that determined from transmission spectra. [ABSTRACT FROM AUTHOR]

Monoclinic Fe 2 (MoO 4 ) 3 thin films have been prepared by chemical spray technique deposited on glass substrates and investigated their physical properties. The obtained thin films were characterized by X-rays diffraction (XRD) using Rietveld's method which confirm the appearance of pure monoclinic Fe 2 (MoO 4 ) 3 thin films. Moreover, the surface morphological was investigated using scanning electron microscope (SEM), which showed the formation of porous microstructures with rough surfaces and spherical nanoparticles. The spectrophotometer UV–Vis–NIR reveals that the sample presents an optical gap equal to 2.0 eV. Electrical properties dependence on both temperature and frequency of the Fe 2 (MoO 4 ) 3 thin films have been reported. The ac conductivity plot showed a universal power law according to the Jonscher model. Activation energy values deduced from the relaxation frequency is of the order of 0.71 eV. Finally, Fe 2 (MoO 4 ) 3 thin films have been tested as sensitive films against ethanol vapor at different operating temperatures and gas concentrations. The films showed promising ethanol sensing behavior with good reproducibility and especially an excellent sensing performance at 275 °C. [ABSTRACT FROM AUTHOR]

Metal-sulfides semiconductor nanosheets are talented entrant to be applied in electro-optic devices. Hence, the synthesis of PbS nanosheets is achieved in the current work using a simple route. The synthesized nanosheets were characterized by X-ray diffraction (XRD), FT-Raman, scanning electron microscope (SEM), UV-Visible, Photoluminescence (PL) and impedance spectroscopy techniques. XRD pattern and Raman spectrum confirms the formation of crystalline structure of PbS nanosheets. SEM study shows that the synthesized PbS is well defined nanosheets of <5 nm thicknesses. The absorption band edge is found to be remarkably blue shifted in nanosheets compare to bulk. The energy gap is calculated to be 1.16 eV which is about 3 times superior than the bulk value (0.41 eV). The enhancement of band gap indicates the occurrence of quantum confinement effect in PbS nanosheets. A strong violet emission band at ∼405 nm is observed in PL spectrum which is assigned to electrons transition from conduction-band edge to holes, ensnared at interstitial Pb 2+ sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn-doped CuO nanoparticles was developed by a novel coprecipitation technique. • Mn2+ions are successfully introduced into the CuO lattice. • The content of Mn plays a crucial role in the lattice parameters and optical properties. • The Mn-doped CuO sample shows maximum saturation magnetization. • Reduction of energy band gap with Mn content which plays an important role in the photovoltaic applications. Structural, optical, and magnetic properties of Mn-doped CuO nanoparticles with compositional formula Cu 1-x Mn x O (x = 0.00, 0.01, 0.02) were investigated. The monoclinic structure of CuO without a secondary phase has been confirmed by X-ray diffraction (XRD) analysis. The average crystallite size was determined by Debye-Scherer's formula and found in the range of 8 nm to 14 nm. W-H analysis resulted in decreasing microstrain with an increase of Mn doping, indicating Mn incorporation in CuO host lattice. Scanning electron microscope (SEM) images indicate that the pure and Mn-doped CuO nanoparticles have spherical-like morphology. UV–vis spectroscopy measurements revealed absorbance edge as a function of Mn doping. X-ray photoelectronic spectroscopy (XPS) study indicates that both Cu and Mn ions have 2+ valences in the samples. The magnetic hysteresis loops of the nanoparticles showed paramagnetic behavior at room temperature. [ABSTRACT FROM AUTHOR]

In the present study, SnO 2 nanosheets were synthesized via a sol-gel method, where gelatin was employed as the natural polymerization agent. The calcination temperature variables such as 650, 700, and 750 °C were found to influence the resultant optical and structural properties. The structural properties of the SnO 2 nanosheets were investigated, using Raman spectroscopy and X-ray diffraction (XRD) and were analyzed by Williamson-Hall and size strain plot methods. The Raman studies proved the formation of single-phase SnO 2 structure, while there were no SnO or Sn 2 O 3 secondary phases. The XRD results revealed that the samples were crystallized in a tetragonal structure. The morphology of the prepared samples was observed by scanning electron microscope (SEM). Furthermore, the SEM investigations demonstrated that wide-area SnO 2 nanosheets were successfully obtained by using gelatin at the chosen calcination temperatures. The synthesized samples were also characterized by photoluminescence spectrometers (PL), indicating only green emission from the samples. Being a conductive semiconductor, this unique structure will have prospective applications as a conductive transparent substrate. [ABSTRACT FROM AUTHOR]

In the present study, this report discusses the preparation and photocatalytic properties of pure, Ag and Zn doped and Ag-Zn codoped TiO nanoparticles by sol-gel method. The powder X-ray diffraction study showed that crystallite size of doped and codoped TiO nanoparticles was decreased compared with pure TiO. The decreased particles size was confirmed by high resolution transmission electron microscope and the particle size was in the range of 7-19 nm. The influence of codopant on the morphology of Ag-Zn codoped TiO was clearly observed in the field electron scanning electron microscope. From the UV-Vis diffuse reflectance spectrum, it was observed that the doping and codoping of Ag and Zn reduce the energy gap of TiO. The reduced emission intensity of doped and codoped TiO in the photoluminescence spectrum suggests that the Ag and Zn lower the recombination of electron-hole pairs. The increase of Zn dopant level (0.2, 0.4 and 0.6 mol%) at 1 mol% of Ag in the codoped TiO further reduces the emission intensity. The 0.6 mol% of Zn at 1 mol% of Ag in the codoped TiO shows higher photocatalytic degradation ability against Reactive Yellow 145 under visible light compared with all other nanoparticles. [ABSTRACT FROM AUTHOR]

The rare-earth ions (Eu 3+ , Dy 3+ ) doped Y 6 WO 12 phosphors were prepared by a citrate-based sol–gel method. The morphologies and structural properties of the as-prepared and doped samples were analyzed by scanning electron microscope images and X-ray diffraction patterns. The luminescent properties were studied by examining the excitation and emission spectra of the samples. The Eu 3+ and Dy 3+ ions doped samples exhibited their characteristic emission bands in the visible region under ultraviolet light excitation. The temperature-dependent photoluminescence (PL) properties of the samples were also investigated. The PL spectra of the synthesized samples by the sol–gel method were compared with those of the bulk sample prepared by a solid-state reaction. Similarly, the Commission International de I’Eclairage chromaticity coordinates and the decay times of Y 6 WO 12 :Eu 3+ (3 mol%) and Y 6 WO 12 :Dy 3+ (2 mol%) phosphors were studied. [ABSTRACT FROM AUTHOR]

In this research, we have investigated the effects of three samples of carbon-base nanostructures (carbon nanoparticles, carbon nanotubes and silicon carbide nanoparticles) doping on the properties of Y 1 Ba 2 Cu 3 O 7− δ (YBCO) high temperature superconductor. The pure and doped YBCO samples were synthesized by sol–gel method and characterized by resistivity versus temperature (ρ– T ), current versus voltage ( I – V ), through X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis. The results confirmed that for all the samples, the orthorhombic phase of YBCO compound is formed. We found that the pinning energy and critical current density of samples increase by adding carbon nanostructures to YBCO compound. Also critical temperature is improved by adding carbon nanotubes to YBCO compound, while it does not change much for carbon and silicon carbide nanoparticles doped compounds. Furthermore, the samples were characterized by UV–vis spectroscopy in 300 K and the band gap of the samples was determined. We found that the carbon nanotubes doping decreases YBCO band gap in normal state from 1.90 eV to 1.68 eV, while carbon and SiC nanoparticles doping increases it to 2.20 and 3.37 eV respectively. [ABSTRACT FROM AUTHOR]

3-dimensional (3D) rod-like CuO with nanowire hierarchical structure has been synthesized successfully by a facile ultrasound assisted method combined with thermal conversion, using rouaite Cu 2 (OH) 3 NO 3 as the precursor. The product was characterized by XRD, SEM, TEM, HRTEM and FT-IR spectrum. Its optical properties were studied by means of UV–Vis diffuse reflectance absorption spectroscopy and photoluminescence (PL) spectrum. Series of control experiments have been performed to explore influencing factors to the product morphologies and a possible formation mechanism has been proposed. The results show that each CuO rod assembled by tens of nanowires is 200–300 nm in diameter and about 1000 nm in length. Each nanowire contains many interconnected nanoparticles with sizes of about 15 nm. Particularly, ultrasound processing was found beneficial to the formation of the 3D rod-like CuO with nanowire hierarchical structure. [ABSTRACT FROM AUTHOR]

The polycrystalline sample of the Ruddlesden-Popper La(SrCa)MnO phase was synthesized using a sol-gel method. To determine the structural and optical properties as a function of photon energy for this sample, we can use the various techniques of characterization such as X-ray diffraction, SEM, and ellipsometric spectroscopy. Based on structural analysis by Rietveld profile fitting, a single-phase sample with tetragonal I4/mmm space group was obtained. The optical properties were investigated by spectroscopic ellipsometry at room temperature in the spectral range of 300-800 nm. The optical constants: refractive index n and extinction coefficient k were also studied. These measurements revealed that the optical absorption is obtained around 590 nm and the sample has a direct transition corresponding to the energy gap which was equal to 2.25 eV. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA)/CdS and PVA/TiO nanocomposite thin films were prepared at different semiconductor nanoparticles ratio (20, 30, 40 and 50 CC) by employing electrospinning method. For the former, CdS nanoparticles were first synthesized using cadmium nitrate (Cd (NO)) and sodium sulfide (NaS) in a simple and economical way whereas for the latter, TiO was purchased. Morphology and structure of nanocomposites were characterized by X-ray diffraction (XRD) and scanning electron microscope. The results indicated the cubic and anatase structure of CdS and TiO nanoparticles in PVA matrix, respectively, and proved that nanoparticles were successfully coated by PVA molecules. Optical properties of samples were also characterized by diffuse reflectance spectroscopy. Particle sizes of CdS and TiO, <9 and 15 nm, respectively, were calculated with the results obtained from XRD observation and it was found to be in agreement with the absorption spectra of both nanocomposites. The prepared films at 50:50 ratio, in both PVA/CdS and PVA/TiO, were found to be suitable for application in solar cell as a window layer due to the crystalline phase, favorable band gap (2.53, 3.31 eV) and higher optical transmittance. [ABSTRACT FROM AUTHOR]

Photo-driven materials are an emerging research field due to its real-time definable capabilities and wide ranging potential applications. Previous research in the field has been limited to opto-electrical interactions. In this study, we investigated an opto-mechanical composite material of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and titanium oxide phthalocyanine (TiOPc). The characteristics of this developed composite material were examined using SEM, FTIR, and XRD analytical methods. Our results showed that a remnant polarization and coercive field can be increased with a proportional increase of TiOPc in the composite. Experimental results show that the optimal composition of the TiOPc to P(VDF-TrFE) was 10 wt% ( d 33 = 18 pC/N, 30% of impedance variation at 100 Hz). Our developed composite material has good potential as an opto-configurable mechanism for various applications. [ABSTRACT FROM AUTHOR]

The vacuum evaporated thin films of zinc phthalocyanine (ZnPc) were prepared at room temperature and structurally investigated using X-ray diffraction and scanning electron microscope (SEM). The temperature dependence of dark and photoconductivity of as-deposited (i.e. unexposed) and exposed ZnPc films were measured in the temperature range 305-389 K. Some of the optical absorption such as molar extinction coefficient, the oscillator strength, the electrical dipole strength have been evaluated. The optical band gaps of the ZnPc thin films have been determined from α² versus hν graph. These films have been studied as chemical sensors such as methanol and ammonia. [ABSTRACT FROM AUTHOR]

SEM images for GO-PbI 2 nanocomposite, switching behaviour and specific detectivity of the fabricated photodetector. • For the first time, the facile microwave synthesis of GO doped PbI 2 nanoparticles are reported. • X-ray diffraction and FT-Raman studies confirm the formation of GO-PbI 2. • SEM studies confirms morphology in terms of nanoparticles decorated GO nanosheets. • The optical band gap was found to be reduced by Go doping however, still higher than bulk due to confinement effect. • Photoconductivity analysis shows GO-PbI 2 has good photodetector stability and reversibility. Herein, lead iodide (PbI 2) nanorods/graphene oxide (GO) nanocomposites have been successfully achieved at low temperature via microwave-assisted syntheses route. The X-ray diffraction (XRD) analysis confirm good crystallinity and absence of any impurity in the prepared hybrid nanostructures which further confirmed through Raman analysis. The XRD and Raman study also confirm the doping of GO in 2H polytypic PbI 2 structure. The average crystallite size of PbI 2 is calculated to be 20 nm which found to be increased to 53 nm in the case of GO-PbI 2 for high intensity peak. Scanning electron microscope (SEM) images reveal that the GO sheets are decorated with PbI 2 nanoparticles and nanorods. The absorption spectra of PbI 2 was found to broaden whereas energy bandgap of GO-PbI 2 decreases to 2.83 eV in compare to 3.24 eV for PbI 2. The effect of graphene oxide doping on photodetector performance of PbI 2 was elucidated by measuring the I-V characteristics under 532 nm laser light illumination. The pure PbI 2 exhibits a stable and reversible photodetector performance with responsivity of 0.060 AW−1, detectivity of 6.38 × 1010 Jones, EQE of ∼14 % and response time of 224 ms. For GO-doped PbI 2 , these parameters were found to be improved to 0.182 AW−1, 1.79 × 1011 Jones, ∼42 %, and 128 ms, respectively. [ABSTRACT FROM AUTHOR]

Tm–Tb co-substituted Sr–Ba hexaferrite (HFs), Sr 0.5 Ba 0.5 Tm x Tb x Fe 12-2x O 19 (x = 0.00–0.05), were produced by ultrasonic assisted citrate sol-gel approach. The compositions were characterized using diverse characterization techniques including X-rays diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning and transmission electron microscopes (SEM and TEM), diffuse reflectance spectroscopy (DRS), and physical property measurement system with vibrating sample magnetometer head (PPMS-VSM). All products are pure and consist of only hexaferrite phase except x = 0.05 composition, which contains minor impurity Fe 2 O 3 phase. Co-doping of Tm3+ and Tb3+ ions increases the 1.73 eV band gap of Sr 0.5 Ba 0.5 Fe 12 O 19 to maximum value of 2.65 eV belonging Sr 0.5 Ba 0.5 Tm 0.03 Tb 0.03 Fe 11.94 O 19 HF. The magnetic properties were investigated at 300 K (RT) and 10 K. Magnetization measurements indicated ferrimagnetic behaviors for different prepared hexaferrites. It was noticed that the M s (saturation magnetization) and M r (remanence) grew with rising Tb–Tm co-substitution proportion up to x = 0.03 and then started decreasing. The intensification in the M s and M r values up to x = 0.03 was mainly ascribed to the magnetic moments of Tb3+ ions (9.7 μ B) and Tm3+ ions (7.5 μ B) that are superior than that of Fe3+ ions (5 μ B) and to strengthening of exchange coupling among Fe sites. At higher co-substitution contents, the formation of impurity phase resulted in reducing the magnetization. The coercivity is larger for lower Tb–Tm co-substitution level compared to non-substituted one and reduced for highest level. It was revealed that the coercivity is mainly dominated by the magneto-crystalline anisotropy in different prepared hexaferrites. The examination of M-T curves showed ferrimagnetic behavior in the whole temperature range of 325 down to 10K and the existence of super-spin glass-like behavior at very low temperatures. The structure, morphology, optical and magnetic properties of Sr0.5Ba0.5TmxTbxFe12-2xO19 (x = 0.00–0.05) hexaferrites produced via ultrasonic assisted citrate sol-gel approach were investigated. Tb–Tm substitution effect could enhance the magnetic properties of SrBa hexaferrites. Image 1 • Sr 0.5 Ba 0.5 Tm x Tb x Fe 12-2 x O 19 (x = 0.00–0.05) hexaferrites were produced by ultrasonic assisted citrate sol-gel approach. • All products are pure except x = 0.05 composition that contains minor Fe 2 O 3 phase. • Optical band gap energy increased with increasing x up to 0.03 and then decreased. • The produced hexaferrites exhibit ferrimagnetic behavior at both 300 and 10 K. • Lower Tb–Tm substituting contents (x ≤ 0.03) improved the values of M s , M r and H c. [ABSTRACT FROM AUTHOR]

Gas sensing device development is a key field of research in the recent scenario, Hence, in this work, facile fabrication of ZnO films with diverse content of Ag was accomplished as a vapor sensor using a cost-effective successive ionic layer adsorption and reaction (SILAR) process. X-ray diffraction (XRD) analysis provides evidence about the good crystalline nature of grown ZnO: Ag films and crystallite size was decreased from 38 to 27 nm with Ag content increased from 0 to 5 wt.%. Scanning electron microscope (SEM) analysis revealed the remarkable modification in morphology from nanograins (undoped) to nanorods (5 wt.% Ag). Energy dispersive analysis of X-rays (EDX) supports the Zn, O, and Ag content present in the final film. The prepared Ag-doped ZnO films exhibited good optical nature and an improvement in the energy gap from 3.04 to 3.29 eV was noticed. The responsivity, response and recovery time of ammonia vapor sensor were remarkably enhanced to 8260 %, 27 s, and 7 s respectively, for the 5 wt.% Ag doped ZnO nanofilm. The responsivity of 5 wt.% Ag doped film was 15 times that of undoped ZnO film. These results make low cost grown Ag-doped ZnO nanorod a good candidate for high quality vapor sensor. • Facile fabrication of ZnO:Ag films-based ammonia gas sensor has been achieved by SILAR route. • XRD and FT-Raman confirm the monophasic hexagonal ZnO formation. • Morphology was remarkably transformed from nanograins to nanowires. • An improvement in energy gap from 3.04 to 3.29 eV in ZnO was noticed when doped with Ag. • Fabricated ZnO film with 5 wt% Ag is highly sensitive to sensing ammonia gas. [ABSTRACT FROM AUTHOR]

• The prepared Sn 4 Sb 6 S 13 (TAS) thin film on PAA at different deposition temperatures results an evolution in the crystal sizes and shapes at the surface. • XRD and Raman patterns presented an increase in the peak intensity and a change in the peaks position toward higher energy indicating the crystalline quality enhancement. • The average R% spectra decreased significantly from 71.6% for the PAA layer to 59.9%, indicating the large absorbance of the deposited compound on PAA substrates. • The average reflectivity of TAS/PAA multilayered structure increases significantly from 59.9%–61.4% by increasing substrate temperature from 30 to 140 °C, owing to an improvement in the film crystallization. • The refractive index (n), extinction coefficient (k), the real and imaginary dielectric constants, as well as the thickness of TAS/PAA multilayers were estimated from the ellipsometric measurements. In this study, the Sn 4 Sb 6 S 13 (TAS) nanocrystals were grown on the porous anodic alumina (PAA) templates through the vacuum thermal evaporation process at different deposition temperatures. The influence of deposition temperature on the microstructural and optical properties of TAS/PAA was investigated systematically. As the substrate temperature is increased, crystallite size increases while the strain and the dislocation density decrease. An improvement of the crystallinity is deduced from Raman spectra and X-Ray diffraction (XRD) patterns. The homogeneous distribution of TAS nanocrystals on PAA substrates was observed from surface morphology by using atomic force microscopy (AFM) and scanning electron microscope (SEM). The average reflectance of TAS/PAA films decreased significantly from 77 % to 60 % in the visible and near-infrared spectral regions, indicating the large absorbance of the deposited thin film. The optical parameters and thickness of TAS/PAA layers were estimated on the basis of spectroscopic ellipsometry measurements. [ABSTRACT FROM AUTHOR]

In this study, undoped and Ag-doped HfO2 thin films were deposited on glass substrates by means of sol–gel dip coating method. These films were then thermally annealed at 500 °C for 1 h. The structural and optical properties of undoped and Ag-doped HfO2 thin films were characterized by X-ray diffraction, UV–Vis spectrometry and scanning electron microscope. The results of this analysis were compared and interpreted with the results obtained in literature by various methods of coating with HfO2. The X-ray diffraction peaks of the films paired with monoclinic HfO2 crystalline peaks. The refractive indices of the films decreased with doping Ag, at 500 nm wavelengths. The optical band gap values of Ag-doped HfO2 thin films increased with doping Ag. The porous structures were observed on the surface films, especially with 5% Ag doping. [ABSTRACT FROM AUTHOR]

Co-doped CuO nanoparticles were successfully prepared by sol-gel auto combustion technique to investigate structural, optical and magnetic properties. The X-ray diffraction (XRD) analysis studied the structural properties of the nanoparticles and confirms structure of the monoclinic CuO crystal structure. As the Co doping increases the volume of unit cell decrease in Co doped CuO nanoparticles. The mean crystalline size was determined using Scherrer's formula and found in the range of 35–40 nm. The effects of Co doping on the variation of the microstrucutre property in the Co doped CuO nanoparticles were revealed by scanning electron microscope (SEM). The EDX analysis showed that the atomic percentage of Cu decreases with the increasing doping (Co) concentrations, which have confirms that the Cu atoms have successfully replaced their Co counterparts as content. The optical data revealed that with an increase in Co doping level there is an energy band gap increase. The magnetic hysteresis loops of the samples indicated that the samples are super-paramagnetic in nature. The super-paramagnetic behavior of the samples is also discussed. Average crystalline size versus strain of pure and Co doped CuO nanoparticles. Image 1 • Cu 1-x Co x O nanoparticles were synthesized by co-precipitation technique. • Single monoclinic crystal structure was confirmed. • The lattice parameters and volume decreases with increasing Co content. • The crystalline size decreased, whereas strain increased with increasing Co doping. • Cu 1-x Co x O can be used in spintronics device as the nanoparticles have super-paramagnetic behavior at room temperature. [ABSTRACT FROM AUTHOR]

Nano-crystalline Cd0.95−xMn0.05AlxO (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) semiconductors were synthesized by sol-gel technique. These samples are characterized via X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) methods. XRD analyses show that the samples have pure rocksalt structure, which is typical for cadmium oxide (CdO). SEM micrographs show that the Al,Mn-doped CdO nanoparticles are cubic with rocksalt structures. The presence of bands at 499, 615 and 660 cm−1 observed in the FTIR spectrum correspond to the stretching of CdO. In addition, the optical properties of nanoparticles were performed as experimentally and theoretically. The optical band gaps of nanoparticles were measured between 1.87 and 2.34 eV, while calculated as 1.19 eV for Mn-doped CdO nanoparticle and 2.13 eV for Mn,Al-doped CdO nanoparticle at lanl2dz and pm6 basis sets. The optical studies showed that the Mn-doped reduces band gap, while Al-doped increases. [ABSTRACT FROM AUTHOR]

The structural and optical properties of RF sputtered Nb2O5 thin films are studied before and after gamma irradiation. The films are subjected to structural and surface morphological analyses by using X-ray (XRD) and field emission scanning electron microscope techniques. In the wavelength range of 300-2000 nm, the optical parameters for amorphous and crystalline Nb2O5 thin films are estimated at differently exposed γ-irradiation doses (0, 50, 100 and 200 kGy). The optical constants, such as optical energy band gap, absorption coefficient, refractive index and oscillators parameters of amorphous and crystalline Nb2O5 thin films are calculated. The optical band gaps of γ-irradiated amorphous and crystalline Nb2O5 thin films are determined. In the non-absorbing region, the real part of the refractive index of amorphous and crystalline Nb2O5 thin films slightly increases with the increase in the exposed γ-irradiation dose. [ABSTRACT FROM AUTHOR]