Nanocrystalline Cadmium sulfide (CdS) thin films were prepared by chemical bath deposition technique on a glass substrates at a temperature of 80°C and at different deposition times with composition of cadmium chloride (CdCl 2 ), thiourea (CS (NH 2 ) 2 ), ammonia solution (NH 4 OH) and triethanolamine (TEA) solution. The characterization of thin films was carried out for the structural, morphological and optical properties using X-ray diffraction (XRD), Scanning electron microscope (SEM) and UV-VIS spectrophotometer. XRD studies show that the preferential orientation (002), analysis shows that the prepared samples have hexagonal crystal structure. Scanning electron microscopy (SEM) reveals small nanosized grains tied up in a fibrous-like porous structure uniformly distributed over the surface of the substrate for the CdS films. A UV-VIS optical spectroscopy study was carried out to determine the band gap of the nanocrystalline CdS thin films. The average band gap was found to be 2.25 eV, which is lower than the bulk value (2.4 eV). The increase in absorption coefficient with photon energy makes the deposited CdS thin film a suitable candidate for the fabrication of solar cells.

The influence of dip times on the lead sulphide (PbS) thin films deposited on glass slide substrates via chemical bath deposition (CBD) technique using chemical precursors, nitrate, and thiourea, ) in alkaline medium at 300 K was investigated. The optical, structural and morphological studies were performed by UV-vis spectophotometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The XRD showed films of cubic (galena), crystalline in nature with the preferential (111) orientation. The optical studies showed films of direct band gaps in the range of 1.59-1.65 eV.

We present spectrally-resolved multi-photon induced fluorescence (TPIF) and second harmonic generation (SHG) imaging of porcine arterial wall tissue sections, both native tissues and damaged tissues subject to a proprietary therapy based on photo-activated crosslinking of collagen and other structural proteins in the arterial wall, a proposed treatment for peripheral artery disease termed non-invasive vascular scaffolding (NVS). We employ a spectrally-resolved multi-photon imaging system, based on a closed loop piezoelectric stage, a transmission grating and an EMCCD. From the spectrally-resolved multiphoton emission, we form ratiometric images of select spectral bands associated primarily with collagen (SHG) and elastin (TPIF). The ratiometric images aid in identifying representative regions for comparing the native and treated tissue sections, as well as reducing sensitivity to variations in intensity caused by scattering or attenuation of the excitation beam. Our aim is to use these ratios as a metric of the tissue structure and composition, indicating the relative contribution of collagen and elastin to the observed nonlinear signals. We note the photochemical modification results in a recovery of SHG intensity similar to the native artery, with the hypothesis that cross-linking of the compressed collagen fibrils in the arterial wall during the light activation step results in the formation of the NVS.

The critical current density, Jc  has been the most important parameter used in the design and engineering of effective devices which is one of the implementation of high temperature superconductors (HTSC). In this work, an effort has been made to further improve the critical current density of YBa2Cu3O7-x (YBCO) thin films by preventing the magnetic flux line lattice against the Lorentz force by pinning it in place with the aid of nano-dimensional defects. These defects were generated by distributing nano sized CeO2 islands after YBCO layer was created on LaAlO3 substrates perpendicular to the film using pulsed laser deposition (PLD) technique. Three samples with buffer layers of CeO2 were prepared. CeO2 with 50 pulses, 100 pulses and 150 pulses, after each 1000 pulses of YBCO were prepared five layers for each of the samples. The structural characterization of YBCO/CeO2 and YBCO pristine films were carried out using x-ray diffraction (XRD) and scanning electron microscopy (SEM). Superconducting proprieties were measured using a vibrating sample magnetometer (VSM). Jc  for the pure YBCO and the YBCO/CeO2 films were calculated from magnetization (M) versus Field (H) loops using Bean’s model. Jc  for the 50 pulses of YBCO/CeO2 films was found to be increased slightly by an order of magnitude of about 40% with respect to those of YBCO films without the nano dimensional defects.

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