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Tungsten trioxide (WO 3 ) thin films have been prepared via sol-gel spin-coating technique for different concentrations of Al (0, 3, 6, 9 and 12 wt.%) and investigated them by structural, optical, dc electrical and Al:WO 3 /p-Si heterojunction diodes. The XRD analysis reveals that the trivalent impurity of Al effectively influences the WO 3 . The UV–vis analysis shows an increase in the Al dopant that caused the band gap energy (E g ) to decrease. The SEM analysis shows that the size of the plate-like grains has reduced the Al:WO 3 thin films. The composition ratio of W, O and Al elements has been confirmed by EDX spectrum. The dc electrical conductivity analysis has identified that Mott’s 3D variable hopping (VRH) mechanism influences the Al:WO 3 thin films. The Al:WO 3 /p-Si p - n heterojunction diode parameters of ideality factor (n), barrier height (Φ B ) and series resistance (R s ) have been calculated using the J-V method. From the current density-voltage-temperature (J-V-T) analysis, the inhomogeneity of barrier heights was extracted using the thermionic emission mechanism with Gaussian distribution (GD) function. As a result, the 9 wt.% of Al:WO 3 /p-Si diode gives better results compared to the other Al:WO 3 /p-Si diodes. [ABSTRACT FROM AUTHOR]

The ln(J)-V-T characteristics of the p-Si/n-WO 3-x /Ag junction diode have been analyzed by thermionic emission (TE) mechanism with Gaussian distribution (GD) of the barrier heights. The ultra-fine homologous phases of tungsten oxide (WO 3-x ) thin films on the glass substrate can be prepared simply via sol-gel spin coating method. The oxygen reduction of the tungsten trioxide (WO 3 ) thin films was experimentally controlled by various organic acid additives. The organic acid-treated films have hexagonal and monoclinic crystallographic Magneli phases of W n O 3n-2 series (WO 2.92 , WO 2.9 and WO 2.89 ). The morphological changes in the plate-like structure under the strong influence of the organic acids were observed from SEM analysis. In the temperature dependent dc electrical conductivity, the charge transport mechanism of the WO 3-x thin films was analyzed by Arrhenius, Mott’s variable hopping, small polaron mechanisms. From the J-V-T characteristics of the p-Si/n-WO 3-x /Ag diode, the increasing of barrier height (Φ B ) and decreasing of ideality factor (n) reveal that barrier inhomogeneities at the interface, which is assumed by Gaussian distribution. The mean barrier height ( Φ B ) , the standard deviation (σ 0 2 ) and Richardson constant (A*) values were investigated in the temperature range 303−423 K. The better diode performance was acquired to the Si/WO 2.89 /Ag device with the experimentally intended A* value of 34.81 A/cm 2 /K 2 which is near to the well-known value of 32 A/cm 2 /K 2 for p-type Si. [ABSTRACT FROM AUTHOR]

CuO/g-C 3 N 4 nanocomposite photocatalyst has been synthesized by co-precipitation method and analyzed its performance in the photoelectrochemical water splitting application. X-ray diffraction analyses and Raman measurement confirms the presence of CuO. Scanning electron microscope image shows rod shape morphology. The CuO/g-C 3 N 4 nanocomposite exhibit the wide range of visible light absorbance and the bandgap of the material is 1.64 eV. Room temperature photoluminescence measurement reveals the presence of CuO charge transfer emission and LUMO – HUMO transition of g-C 3 N 4. The CuO/g-C 3 N 4 composite shows improved photocatalytic water splitting under visible light illumination. This could be attributed to the higher visible light absorbance and reduction in the recombination rate. The CuO/g-C 3 N 4 nanocomposite electrode shows a highly stable photocurrent response. [ABSTRACT FROM AUTHOR]

The Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) of N-(4-Chloro-3-methylphenyl)-2-phenylacetamide ( N4C3M2P ) were recorded in the regions 4000–400 cm −1 and 4000–100 cm −1 respectively, in the solid phase. The molecular structures, vibrational wave numbers, infrared intensities, Raman scattering activities were calculated using DFT method with B3LYP/6–311 + +G(d,p) basis set. Detailed interpretations of the vibrational spectra have been carried out with the aid of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field methodology. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels are also constructed. The stability of molecule has been analyzed by NBO analysis. The molecule orbital contributions were studied by using the total density of states (TDOS), the sum of α and β electron density of states (α β DOS). Fukui functions, local softness and eletrophilicity indices for selected atomic sites of the title compound are determined. To study the biological activity of the investigation molecule, molecular docking (ligand-protein) stimulations are performed by using autoDock 4.2.6. The hydrogen bond lengths and binding energy values are determined. Finally, the thermal behaviors of the N4C3M2P compound have been calculated by different temperature. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO 3 ) thin films were prepared at room temperature (RT) and at different annealing temperatures of 250, 350, 450 and 550 °C. We also prepared MoO 3 films using additives of water-soluble and water-insoluble organic acids. The thin films were coated using the spin coating technique and annealed at 350 °C temperature. The effects of different annealing temperatures and different organic acid additives on MoO 3 films were characterized by structural and optical studies. From the XRD pattern, the structure of the MoO 3 films is found to vary with respect to increase in the annealing temperature. For RT and 250 °C, the hexagonal structure was observed and for 350, 450 and 550 °C, the orthorhombic structure was observed. The XRD pattern for all the organic acid additive used MoO 3 films exposed the orthorhombic structure. SEM images show hasty variations in the surface morphology for different annealed MoO 3 films and different additive used MoO 3 films. The EDX analysis confirmed the presence of Mo and O elements for all the films. The UV–vis results show the absorbance and transmittance values. The band gap energy was found to be around 3.8 eV for all the MoO 3 films. [ABSTRACT FROM AUTHOR]

We report on the Chip-on-Plate (COP) packaged high power LED assemblies for solid state lighting (SSL) and backlighting display applications from thermal analysis perspective. Three different light modules with different elements (devices) distribution and heatsink design were considered. Thermal resistance circuit (TRC) model and heat diffusion equation were employed in this study of thermal behavior of the assembly elements. Finite element analysis along with 3D modeling and simulations were used for considered lighting modules and assemblies. Also, the effect of thermal uniformity on the emission spectra was evaluated for different operating powers. Comparative study showed that conventional packages with circularly symmetric having non-uniform devices’ distribution per unit area will have temperature differences ∼7 °C among the chip-elements operating around 1.25 W power level. Also, it was predicted that high elements temperature difference could result in over 2 nm redshift in the emission spectra accompanied by ∼ 4% drop in the output power. However, temperature difference was found to be less than 1 °C for the uniform rectangular array module distribution, which ensures uniform output intensity for all devices. Such findings are extremely useful for designing larger area LED packaging where thermal non-uniformity effects are expected to be more severe for devices’ longevity and performance. [ABSTRACT FROM AUTHOR]

Abstract: By finite difference time domain method, a channel drop filter with four-port is designed, analyzed, and theoretically simulated in the hetero-woodpile-structure. Hetero-woodpile-structure includes three parts namely, along the propagation direction, the constant lattice in the core woodpile is different from two cladding woodpiles. This channel drop filter is comprised of two straight waveguides separated by an air-cavity in the same layer. Through simulations, we found that adjustment of the resonant-mode in heterostructure can be achieved in various ways, such as only changing the lattice constants, or changing both lattice constants, and the cavity size. The results also show that this structure can realize the energy transfer between bus and drop waveguides. [Copyright &y& Elsevier]

In this work, FT-IR, FT-Raman and UV–vis spectra of 1 Phenyl Isatin (1PHISA) were carried out by using HF/6-31++G(d,p) and DFT/B3LYP method with 6-31++G(d,p),6-311++G(d,p) basis sets. The geometric parameters and wavenumbers were obtained and the complete assignments of fundamental vibrations were performed on the basis of potential energy distribution (PED) of the vibrational mode, calculated with scaled quantum mechanics (SQM) method. The hyper conjugative interaction leading to the stability of the molecule and delocalization of charge has been analyzed with natural bond analysis (NBO). HOMO-LUMO energy calculations show the charge transfer within the molecule. Molecular electrostatic potential, hyper polarizability calculations and thermodynamic functions of the compound were also calculated. The biological applications of 1PHISA have been screened out for antimicrobial activity such as antibacterial and antifungal activities. Molecular docking studies were also carried out for different receptors. [ABSTRACT FROM AUTHOR]