Materials Science

Ni-substituted MnZn mixed ferrite prepared by conventional sol-gel method. Ni substituted MnZn ferrite of molecular formula Mn0.3Zn0.7NixFe2-xO4 in which five samples of x=0.0, x=0.4, x=0.8, x=1.2 and x=1.6 were prepared. The X-ray intensity of (4 0 0) plane were used to calculate particle size and studied its variation with Nickel concentration. XRD, SEM, FTIR and VSM characteristics were presented. The substitution of Ni by replacing Fe reduces the coercivity of the ferrite due to replacement of Ni2+ by Fe3+ in tetrahedral site. Infrared spectroscopies have been discussed so as to bring out the role of nickel substitution in determining structural properties of Zn–Mn ferrites and the role of nitrates in preparation of these compounds.

Cadmium sulphide (CdS) thin films were deposited from different cadmium salts by acidic chemical bath deposition (CBD) method. The effect of cadmium source on CdS thin films by thickness, optical properties, structural properties, functional groups and surface morphology with elemental composition were studied. Film growth rate and band gap were found to the sensitive to the Cd source used. The transmittance data analysis indicates that the optical band gap ranging from 2.37 eV to 2.43 eV was deduced. The XRD study reveals that the films were cubic in nature. SEM with EDS data shows that all the particles were spherical and average atomic ratio of Cd/S increases with the decrease in particle sizes.

The work is devoted to solution of an actual problem – the problem of relation between geometry and natural sciences. Methodological basis of the method of attack is the unity of formal logic and of rational dialectics. It is shown within the framework of this basis that geometry represents field of natural sciences. Definitions of the basic concepts "point", "line", "straight line", "surface", "plane surface", and “triangle” of the elementary (Euclidean) geometry are formulated. The natural-scientific proof of the parallel axiom (Euclid’s fifth postulate), classification of triangles on the basis of a qualitative (essential) sign, and also material interpretation of Euclid’s, Lobachevski’s, and Riemann’s geometries are proposed.

The development of polymer solar cells has improved power-conversion efficiencies from 3% to almost 9% in recent progress. Based on semiconducting polymers, these solar cells are fabricated from solution-processing techniques and have unique prospects for achieving low-cost solar energy harvesting, owing to their material and manufacturing advantages. The potential applications of polymer solar cells are broad, ranging from flexible solar modules and semi transparent solar cells in windows to building applications and even photon recycling in liquid-crystal displays. The various device structures used in organic polymer solar cells are reviewed. The operating principles behind these devices are explained in order to provide the reasoning behind the different structures and bilayer and bulk heterojunction devices discussed.

Co-precipitation method was employed to synthesize the ZnO-ZnS nanocomposites with different ZnO:ZnS ratios. These prepared nanocomposites were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), and Thermogravimetric analysis (TGA). The characterization results reveal that particles in all nanocomposites have similar size of about 30 nm. Zinc oxide may exist in the form of composite with ZnS and free from which can be seen in the XRD patterns. Though zinc oxide may exist in the different form, particles in all samples are relatively similar in size. The presence of ZnS in the composites can be seen clearly in the TGA curves.

In this study, the different film thicknesses of nano silver–clay films were prepared by varying volumes of the composite dispersion for casting. Effect of film thickness on thermal behavior, solid-state crystallinity, water uptake and erosion, and water vapor permeability of the nano composite films were investigated. The film thickness caused a small change in thermal behavior of the films when tested using DSC and TGA. The crystallinity of the thin films increased when compared with the thick films. Water uptake and erosion, water vapor permeation of the thick films were higher than those of the thin films. The results suggest that the evaporation rate of solvent in different volumes of the composite dispersion used in the preparation method could affect crystallinity of the film surface and film bulk of the nano composite films. This led to a change in water vapor permeability of the films.

In the present communication doping of Polypyrrole (Ppy) has been done with a multiligand urea complex of cobalt(II) via in situ oxidative polymerization using FeCl3.6H2O as an oxidant. The dopant has been synthesized and characterized by using elemental analysis, FTIR, XRD and thermogravimetric (TG) analysis. The composite based on the synthesized dopant has been subjected to FTIR and X-ray diffraction techniques.Surface morphology of Ppy and its composite with metal complex is investigated with scanning electron microscope (SEM).Thermal analysis has been done by using TG and DSC technique. The dopant has developed the crystallinityin amorphous Ppy and has increased its thermal stability. XRD results show crystalline nature of composite.Parameters like crystallite size, interplanar distance, micro strain and dislocation density have been calculated by using Bragg’s and other related equations. Moreover lattice parameters a, b, c, ?, ? and ? have also been calculated for the dopant as well as the composite using powder X softwareThermogravimetric analysis reveals that the thermal stability of composite is better to that of pure polypyrrole. 

The organic nonlinear optical (NLO) crystals of thiourea mono acetate were grown by slow evaporation method. The solubility study was carried out for water solvent from 30 to 50 °C. Powder XRD study reveals the crystalline nature of the grown sample. The mode of vibration of different molecular groups present in TMA was identified by FTIR spectral analysis. The UV-vis-NIR spectrum of TMA shows less optical absorption and good transmittance in the entire visible region. The second harmonic generation (SHG) was confirmed by Kurtz powder method. The frequency dependent dielectric studies were carried out. The dielectric constant and dielectric loss of TMA were measured in the frequency range 100 Hz to 5M Hz at different temperatures. The photo current and dark current with applied field were measured. The grown crystal of TMA exhibit negative photoconductivity and reported for the first time.

Asingle-stepenvironmental friendly approach is employed to synthesize silver nanoparticles. The environmental friendly synthesis of nanoparticles process is a revolutionary step in the field of nanotechnology. In this study, the biosynthesis of silver nanoparticles was carried out using Glycyrrhiza Glabra root extract as reducing agent. UV–visible spectroscopy was used for quantification of silver nanoparticle synthesis. The synthesized silver nanoparticles were characterized with Scanning electron microscopy (SEM), Energy dispersive X ray analysis (EDX), X-ray Diffraction (XRD) and Fourier transform Infrared Spectroscopy (FTIR).

The present work envisages the synthesis of polyaniline and its doping with salt of a transition metal (Titanium) and effect of dopant on its optical properties to study changes in band gap. Polyaniline was synthesized by process of chemical oxidative polymerization. Chemical Doping of the dopant has been carried out in synthesized polyaniline by making different concentration of dopant in neutral medium and using THF as solvent. An effort has been done to see the effect of dopant in polyaniline by its properties characterized by UV-Visible spectroscopy and then determining band gap with the help of UV spectra.. A significant change has been observed after doping. UV-Visible study shows that optical parameters change after doping. The study reveals that strong dopant interaction takes place with polyaniline network which is responsible for observed changes.