B. A. Taleatu

Environmental stability of PTB7:PCBM bulk heterojunction solar cell

The short life span of organic photovoltaic (OPV) cell in an ambient laboratory condition is one of the challenges hindering the realization of organic-based devices. The presence of moisture and oxygen in conjugated polymer matrix is the major factors responsible for the degradation of organic molecules. The chemical degradation of OPV cell generally depends on the nature of the semiconductor polymer used in the preparation of the devices. However, the lifespan of unprotected OPV cells often ranges in the order of few hours in simple laboratory environment. We are reporting here the lifetime of organic photovoltaic cell in ambient laboratory condition whose active layer is composed of PTB7:PCBM blend.

Electro-chemical deposition of zinc oxide nanostructures by using two electrodes

One of the most viable ways to grow nanostructures is electro deposition. However, most electrodeposited samples are obtained by three-electrode electrochemical cell. We successfully use a much simpler two-electrode cell to grow different ZnO nanostructures from common chemical reagents. Concentration, pH of the electrolytes and growth parameters like potentials at the electrodes, are tailored to allow fast growth without complexity. Morphology and surface roughness are investigated by Scanning Electron and Air Force Microscopy (SEM and AFM) respectively, crystal structure by X-Ray Diffraction measurements (XRD) and ZnO stoichiometry by core level photoemission spectroscopy (XPS).

Review of 2H-tetraphenylporphyrins metalation in ultra-high vacuum on metal surfaces

The formation and conformational adaptation of self-assembled monolayer of 2H- tetraphenylporphyrins (2H-TPPs) on metal surfaces, as well as their metalation processes in ultra-high vacuum (UHV), are reviewed. By means of XPS, NEXAFS and STM measurements we demonstrate that, after the annealing at 550 K, a temperature-induced chemical modification of 2H-TPP monolayer on Ag(111) occurs, resulting in the rotation of the phenyl rings parallel to the substrate plane. Moreover, independently of the conformation, we report three dierent methods to metalate 2H-TPP monolayers in UHV. Experimental evidence indicates that the presence of a metal atom in the TPP macrocycle influences both the conformation of the molecule and its adsorption distance.

Growth and characterization of V2O5 thin film on conductive electrode

Vanadium pentoxide V2O5 thin films were grown at room temperature on ITO coated glass substrates by electrochemical deposition. The resulting films were annealed at 300, 400 and 500°C for 1 h in ambient environment. The effect of heat treatment on the films properties such as surface morphology, crystal structure, optical absorption and photoluminescence were investigated. The x‐ray diffraction study showed that the films are well crystallized with temperatures. Strong reflection from plane (400) indicated the films preferred growth orientation. The V2O5 films are found to be highly transparent across the visible spectrum and the measured photoluminescence quenching suggested the films potential application in OPV device fabrication.

Synthesis and microstructural studies of annealed Cu2O/CuxS bilayer as transparent electrode material for photovoltaic and energy storage devices

Cu2O thin film and a transparent bilayer have been fabricated by electrodeposition method. The growths were obtained in potentiostatic mode with gradual degradation of anodic current. X‐ray diffraction (XRD) study showed that the bilayer is polycrystalline and it possesses mixture of different crystallite phases of copper oxides. Surface morphology of the films was investigated by scanning electron microscopy (SEM). The SEM images revealed that the films were uniformly distributed and the starting material (Cu2O) had cubical structure. Grains agglomeration and crystallinity were enhanced by annealing. Optical studies indicated that all the samples have direct allowed transition. Energy band gap of the bilayer film was reduced by annealing treatment thus corroborating quantum confinement upshot.

Synthesis and Some Properties of Metal Organic Chemical Vapour Deposited Molybdenum Oxysulphide Thin Films

of oxygen. The large amount of oxygen was attributed to the large abundance of oxygen in the starting material. A direct optical energy gap of 3.31 eV was obtained from the analysis of the absorption spectrum. The scanning electron microscopy (SEM) micrographs of the fllms showed that the fllms were continuous and porous. An estimated average size of the grains was below 5 „m. X-ray difiraction (XRD) showed that the deposited fllms were crystalline in nature.

Metal-organic chemical vapour deposition of lithium manganese oxide thin films via single solid source precursor

Abstract Lithium manganese oxide thin films were deposited on sodalime glass substrates by metal organic chemical vapour deposition (MOCVD) technique. The films were prepared by pyrolysis of lithium manganese acetylacetonate precursor at a temperature of 420 °C with a flow rate of 2.5 dm3/min for two-hour deposition period. Rutherford backscattering spectroscopy (RBS), UV-Vis spectrophotometry, X-ray diffraction (XRD) spectroscopy, atomic force microscopy (AFM) and van der Pauw four point probe method were used for characterizations of the film samples. RBS studies of the films revealed fair thickness of 1112.311 (1015 atoms/cm2) and effective stoichiometric relationship of Li0.47Mn0.27O0.26. The films exhibited relatively high transmission (50 % T) in the visible and NIR range, with the bandgap energy of 2.55 eV. Broad and diffused X-ray diffraction patterns obtained showed that the film was amorphous in nature, while microstructural studies indicated dense and uniformly distributed layer across the substrate. Resistivity value of 4.9 Ω·cm was obtained for the thin film. Compared with Mn0.2O0.8 thin film, a significant lattice absorption edge shift was observed in the Li0.47Mn0.27O0.26 film.

Electronic structure of Fe3Sion Si(100) substrates

The improved performance of large-scale integrated circuits (LSIs) by the shrinking of devices is becoming difficult due to physical limitations. Here we report, the growth and formation of Fe 3 Si on Si(100) and characterized by x-ray photoemission, UV photoemission and low energy electron diffraction to study the electronic structure. The results revealed that the DO3 phase formation is exist and photoemission results also support the electron diffraction outcome.

Electronic structure of Fe3Si on Si(100) substrates

The improved performance of large-scale integrated circuits (LSIs) by the shrinking of devices is becoming difficult due to physical limitations. Here we report, the growth and formation of Fe 3 Si on Si(100) and characterized by x-ray photoemission, UV photoemission and low energy electron diffraction to study the electronic structure. The results revealed that the DO3 phase formation is exist and photoemission results also support the electron diffraction outcome.

Electronic structure of Fe{sub 3}Si on Si(100) substrates

The improved performance of large-scale integrated circuits (LSIs) by the shrinking of devices is becoming difficult due to physical limitations. Here we report, the growth and formation of Fe 3 Si on Si(100) and characterized by x-ray photoemission, UV photoemission and low energy electron diffraction to study the electronic structure. The results revealed that the DO3 phase formation is exist and photoemission results also support the electron diffraction outcome.