The Gd doped ceria (CGO) in thin layers is of great interest for low temperature operation. In the present investigation, we report on the use of spray pyrolysis technique for the synthesis of CGO thin films. The process parameters were optimized for synthesizing Gd0.1Ce0.9O1.95 films. Films were characterized by XRD, EDS, SEM, and AFM and are observed to be phase pure and dense with surface roughness of the order of not, vert, similar5 nm. The d.c. conductivity was also measured and is observed to be not, vert, similar0.5 S/cm at 623 K.

Solid electrolyte for intermediate temperature solid oxide fuel cell (IT-SOFC) is a challenge for material researchers. However, Gd doped ceria (CGO) found to be a promising electrolyte among the other competitive materials. In the present investigation, we report the structural and electrical properties of CGO thin films prepared by spray pyrolysis technique. The process parameters were optimized for synthesizing Ce0.9Gd0.1O1.95 (CGO10) films. Films were characterized by XRD and EDS and are observed to be phase pure. The SEM showed the dense and uniform film growth. The dc conductivity measured is of the order of 0.5S/cm at 623K.

Polyhydroxyalkanoates are water-insoluble, hydrophobic polymers and can be degraded by microorganisms that produce extracellular PHA depolymerase. The present work was aimed to evaluate the degradability of Polyhydroxyalkanoate film produced by Halomonas hydrothermalis using Jatropha biodiesel byproduct as a substrate. PHB films were subjected to degradation in soil and compared with the synthetic polymer (acrylate) and blend prepared using the synthetic polymer (acrylate) and PHB. After 50 days, 60% of weight loss in PHB film and after 180 days 10% of blended film was degraded while no degradation was found in the synthetic film. Scanning electron microscopy and confocal microscopy revealed that after 50 days the PHB film and the blended film became more porous after degradation while synthetic film was not porous. The degradative process was biologically mediated which was evident by the control in which the PHB films were kept in sterile soil and the films showed inherent integrity over time. The TGA and DSC analysis shows that the melting temperatures were changed after degradation indicating physical changes in the polymer during degradation.

Transient photoconductivity in microcrystalline silicon thin films prepared by VHF PECVD over a range of [silane] : [silane + hydrogen] concentrations r from 3 to 6.3% has been measured as a function of temperature (210 K - 390 K) and laser pulse density (1013 – 1016 cm3). The behavior of highly crystalline films (r ≈ 3%) bears certain similarities to n-type amorphous silicon, where the power law decay at long times is controlled by hole rather than electron kinetics. As r approaches 6% the decay begins to resemble that of intrinsic amorphous silicon, consistent with structural studies which indicate a transition from crystalline to amorphous character. Transient photocurrent density of states spectroscopy on transitional films suggests a similar deep defect density to high-quality amorphous silicon, but a larger conduction band tail energy of some 30 meV and a tenfold increase in localised state density at a depth of about 0.4 eV.

Measurements of dark conductivity, steady-state and transient photoconductivity in undoped and boron-doped microcrystalline silicon films exposed to room air are reported. Two aging processes are identified: (i) an increase in dark conductivity and mobility-lifetime product occurring over several days, that may be reversed by heating to 160 °C under vacuum, and subsequently re-cycled, (ii) an irreversible change in the density of states occurring over a period of several months. It is proposed that the reversible effect is associated with charge transport in a region of electron accumulation induced by weakly-adsorbed water, whereas the irreversible effect, identified from its transient photocurrent signature, is associated with a true change in the density of states within the transport path, possibly as a result of slow chemical reactions at silicon grain boundaries.

The effects of exposure to atmosphere (ageing) and light-soaking on coplanar dark- and photo-conductivity of silicon films of varying crystallinity are examined. Dark conductivity generally increases on ageing in films with significant amorphous fraction and decreases in largely crystalline films, and may be reversed by annealing under vacuum at 130 °C consistent with adsorption and desorption of atmospheric components. Thinner films are more strongly affected by ageing. Boron doping appears to compensate charge introduced by ageing, though there are disagreements in detail. In comparison with ageing, moderate light-soaking affects dark conductivity in transitional microcrystalline silicon films only slightly. Both processes change the majority carrier mu–tau product in line with shifts in Fermi level position.

A study of the effects of microcrystalline silicon i-layer modification near p/i interface in tandem configuration silicon thin film solar cells is presented. The structural properties of the absorber layers were investigated by Raman spectroscopy at different stages of growth. The results indicate the possibility of improving both the nucleation process and the film homogeneity in the direction of growth, without specific re-optimization of the p-layer, transferred from a single-junction microcrystalline silicon cell. Structural modifications of the i-layer have been correlated with performance of tandem solar cells, leading to improvements in the bottom cell current Jsc (up to 11.4 mA/cm2) and initial tandem-cell conversion efficiency (up to 11.3%).

Nanocrystalline anatase TiO2 films have been prepared using sol–gel spin coating method. The sol has been prepared by mixing titanium isopropoxide with absolute ethanol and acetic acid at room temperature. The structural studies carried out revealed that the pristine films are amorphous in nature. The annealed films have been observed to be nanocrystalline in nature and the crystallinity has been observed to improve on annealing. The films are found to exhibit anatase phase with grain size of 19nm and 22nm for 450 ◦C and 550 ◦C annealed films. The high-resolution transmission electron microscope (HRTEM) image showed lattice fringes corresponding to the anatase phase of TiO2. The Raman spectra of the prepared films has been observed to be distinct without overlapping peaks suggesting that the prepared films have low level of impurity sites. The vibration peaks present in the spectra at 145cm−1, 394cm−1, 513cm−1 and 635cm−1 has been observed to unambiguously correspond to the Raman active modes of the anatase phase of TiO2.

Highly stable silver nanoparticles (Ag NPs) in agar–agar (Ag/agar) as inorganic–organic hybrid were obtained as free-standing film by in situ reduction of silver nitrate by ethanol. The antimicrobial activity of Ag/agar film on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) was evaluated in a nutrient broth and also in saline solution. In particular, films were repeatedly tested for antimicrobial activity after recycling. UV–vis absorption and TEM studies were carried out on films at different stages and morphological studies on microbes were carried out by SEM. Results showed spherical Ag NPs of size 15–25 nm, having sharp surface plasmon resonance (SPR) band. The antimicrobial activity of Ag/agar film was found to be in the order, C. albicans > E. coli > S. aureus, and antimicrobial activity against C. albicans was almost maintained even after the third cycle. Whereas, in case of E. coli and S. aureus there was a sharp decline in antimicrobial activity after the second cycle. Agglomeration of Ag NPs in Ag/agar film on exposure to microbes was observed by TEM studies. Cytotoxic experiments carried out on HeLa cells showed a threshold Ag NPs concentration of 60 lg/mL, much higher than the minimum inhibition concentration of Ag NPs (25.8 lg/mL) for E. coli. The mechanical strength of the film determined by nanoindentation technique showed almost retention of the strength even after repeated cycle.

A soft route for the preparation of catalytically active multilayers of Pt films free from poisoning effects is reported. The SAMs (self-assembled monolayers) were initially formed on the gold substrates and they act as nucleating centers initiating the formation of multilayers of Pt on gold substrates. The nanoscale to mesoscale structures of Pt thus prepared were characterized by SEM and XPS. The SAM-based Pt structures exhibited well-defined hydrogen adsorption, desorption regions associated with very high charge indicating high surface area Pt. The electrocatalytic activity of the multilayers of Pt was characterized by methanol oxidation and a comparison was made with two commercial Pt catalyst preparations.