inclusion. The rutile fraction increased with Mn 2+ concentration due to the creation of surface oxygen vacancies. All the doped catalysts showed red shift in the band gap absorption to the visible region. The photocatalytic activities of these catalysts were evaluated in the degradation of Aniline Blue (AB) under UV/solar light. Among the photocatalysts, Mn 2+ (0.06 at.%)-TiO 2 showed enhanced activity, which is attributed to the synergistic effect in the bicrystalline framework of anatase and rutile. Further the unique half filled electronic structure of Mn 2+ serves as a shallow trap for the charge carriers to enhance the photocatalytic activity. An insight to the mechanism of interfacial charge transfer in the mixed phase of anatase and rutile is explored, taking into consideration the theories of previous models.

Nanosheets of Ti0.87O2 and Ca2Nb3O10 were synthesized and transferred onto Si substrates by Langmuir-Blodgett deposition. Using pulsed laser deposition, SrRuO3 films were formed on top of these samples. The underlying nanosheets determined both the morphology and crystallographic orientation of the films. SrRuO3 grew preferentially in the [110]pc direction on Ti0.87O2 nanosheets, while growth proceeded in the [001]pc direction on Ca2Nb3O10 nanosheets (pc refers to the pseudocubic unit cell of SrRuO3). Besides macroscopic control over the out-of-plane crystal direction, single crystal orientations were measured by electron backscatter diffraction on the level of individual nanosheets, indicating that epitaxial growth was achieved on the nanosheets as imposed by their well-defined crystal lattices. The nanosheets also had a clear effect on the magnetic properties of the films, which showed anisotropic behavior only when a seed layer was used. A monolayer consisting of a mixture of both types of nanosheets was made to locally control the nucleation of SrRuO3. In this context, SrRuO3 was used as model material, as it was used to illustrate that nanosheets can be a unique tool to control the orientation of films on a (sub-)micrometer length scale. This concept may pave the way to the deposition of various other functional materials and the fabrication of devices where the properties are controlled locally by the different crystallographic orientations.

This work presents a study on the surface morphology, structure and optical behavior of stable phase cadmium sulphide (CdS) nanoparticles synthesized via co-precipitation technique. Scanning electron microscopy (SEM) analysis has been employed to study a cluster formation in the aggregated nanoparticles. An image analysis approach using ImageJ has been used to measure the size of nanoparticles from the SEM micrographs. Fourier transform infrared spectroscopic (FT-IR) analysis identified absorption peaks of Cd-S stretching along with moisture content. X-ray diffraction (XRD) analysis showed that CdS nanoparticles crystallized in wurtzite structure with a preferential orientation along (0 0 2) plane. The particle size, microstrain and lattice constants have been evaluated using XRD data. The lattice parameters of these nanoparticles were found to be shorter than the bulk value which led to lattice contraction. The optical absorption study showed a blue shift in the fundamental absorption edge indicating a quantum size effect.

CdS nanofilms of varying thickness (t) deposited by chemical bath deposition technique have been studied for structural changes using x-ray diffractometer (XRD) and transmission electron microscope (TEM). XRD analysis shows polycrystalline nature in deposited films with preferred orientation along (002) reflection plane also confirmed by selected area diffraction pattern of TEM. Uniform and smooth surface morphology observed using field emission scanning electron microscope. The surface topography has been studied using atomic force microscope. The optical constants have been calculated from the analysis of %T and %R spectra in the wavelength range 300 nm-900 nm. CdS nanofilms show a direct transition with red shift. The optical band gap decreases while the refractive index increases with increase in thickness of nanofilms.

Cadmium sulfide (CdS) nanofilms have been deposited on the glass substrate using the chemical bath technique. Cadmium chloride and thiourea have been used as Cd2+ and S2− ion sources with ammonia as a complexing agent in the presence of a nonionic surfactant. The deposited films have been annealed in air at 373 K, 473 K, 573 K, and 673 K ± 5 K temperature. The effect of the annealing on the structure, morphology, and optical properties of CdS nanofilms has been studied. CdS films have been characterized by X-ray diffraction, scanning electron microscopy, energy dispersive x-ray analysis, and UV-Vis-NIR spectrophotometer. The CdS films have been found to be nanocrystalline in nature with the zinc blende structure. The direct bandgap has been determined. Various parameters, viz. the grain size, inter-planer spacing, lattice constant, dislocation density, microstrain, surface morphology, absorption coefficient, and optical bandgap has been calculated and found to vary with annealing. The results have been explained on the basis of structural, surface, and optical changes.

No abstract

Cadmium sulphide nanofilms have been deposited by chemical bath deposition technique on glass substrates. The effect of S/Cd molar ratio on the structural, morphological, and optical properties of CdS nanofilms has been investigated. Structural parameters have been analyzed using x-ray diffractometer. Scanning electron microscope and energy dispersive x-ray analyzer have been used to study surface morphology and elemental composition of nanofilms, respectively. The optical properties of the nanofilms have been studied for varying S/Cd molar ratio. The variation in S/Cd molar ratio induces reorientation in lattice structure of the nanofilms and a phase transition has been observed with changing molar ratios. The modification in properties with varying S/Cd ratio has been discussed in terms of quantum confinement and compared with theoretical results based on effective mass approximation and tight binding model.

Calcium oxide (CaO) is a promising material that works as a glass constituent, catalyst, toxicwaste remediation, poisonous gas absorbent, industrial refectory element for metal smelting, paper bleaching, sulfur neutralization in sugar, cosmetics and drug delivery mediator. This work proposes the synthesis of CaO nanoparticles by direct precipitation technique using an aqueous solution of calcium chloride and sodium hydroxide precursors. The synthesized nanoparticles are characterized for the structure, morphology, chemical composition and optical behavior using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field effect scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and diffuse reflectance spectroscopy. The XRD results show that the CaO nanoparticles have been synthesized in a cubic crystalline structure with the average crystallite size of about 13 nm and display aggregated morphology of nanoclusters. The presence of distinct peaks in the FTIR and EDS spectra reveal that the nanoparticles are successfully formed from the chemical recipe of the precipitation process. The optical bandgap has been estimated from the Kubelka-Munk plot and found to be 3.48 eV. The antibacterial activity of CaO nanoparticles has been tested by the well diffusion technique and observed that it shows good antibacterial action against the gram-negative bacterial strains.