Optical and Photocatalytic Properties of CuxS/ZnO Composite Thin Films Deposited by Robotic Spray Pyrolysis Deposition

This article reports on VIS-active composite thin films based on zinc oxide (ZnO) and copper sulfide (CuxS) deposited using robotic spray pyrolysis deposition (SPD) for the study of the optical and photocatalytic properties. The first step involves the SPD deposition of a CuxS layer onto the glass substrate at 300°C. The second step consists of the deposition of a ZnO layer onto the CuxS layer to form glass/CuxS-ZnO composites that were further annealed at 400°C. The development of the composite thin films was confirmed by XRD and EDX analyses. The band gap energy ( E g ) of the bare ZnO thin films decreased from 3.15 eV to an activation energy value of 2.8 eV after the deposition of the ZnO thin layer onto the CuxS layer and from 2.8 to 2.08 eV after annealing the CuxS-ZnO composite at 400°C. The UV-VIS irradiation (5.5% of UV, G = 55 W / m 2 ) of a 10 ppm methylene blue solution was used to investigate the photocatalytic properties of the CuxS-ZnO composites. The annealed CuxS-ZnO thin films at 400°C demonstrates better photocatalytic activity compared to CuxS-ZnO composites deposited at 300°C. The enhanced photocatalytic efficiency of the annealed CuxS-ZnO thin films may be the result of the diode structure and the increased crystallinity that prevent the electron-hole recombination.

Structural, Opticaland Morphological Properties Of Zn And Mg Co-Doped V2O5 Thin Filmnanostructures

The research study reveals metallic co-doping of Zinc(Zn) and Magnesium (Mg) on vanadium pentoxide(V2O5) thin film nanostructures by spray pyrolysis deposition technique. The studyfindings have been made into how the morphological, structural and optical properties of the materials change for the different co-doping percentage of 1%,3%,5%10% of Zn-Mg. X-ray diffraction (XRD)clearly showsan orthorhombic crystalline structure with polycrystalline nature.The dopantZn and Mginfused into the V2O5 matrixand is confirmed by EDAX images. A field emission scan electron microscope was used to examine surface morphology whichreveals that grain structure has beenmodified by increasing the doping content. It is evident from theatomic force microscopy (AFM) images that the effect of Zn and Mg on V2O5 thin filmshave enhanced surface roughness.The transmittance and energy bandgap (Eg) of the film found to be decreased with an increase in doping concentration whereas absorbance varieswith doping levels.The research findings suggest that the Zn-Mg co-doped V2O5 thin films could be a potential source for energy,optical and sensor-based device applications.

Influence of Bi1.5Y0.5O3 Active Layer on the Performance of Nanostructured La0.8Sr0.2MnO3 Cathode

The efficiency of solid oxide fuel cell cathodes can be improved by microstructural optimization and using active layers, such as doped bismuth oxides. In this work, Bi1.5Y0.5O3 (BYO) films are prepared by spray-pyrolysis deposition at reduced temperatures on a Zr0.84Y0.16O1.92 (YSZ) electrolyte. The influence of the BYO film on the performance of an La0.8Sr0.2MnO3 (LSM) cathode prepared by traditional screen-printing and spray-pyrolysis is investigated. A complete structural, morphological, and electrochemical characterization is carried out by X-ray diffraction, electron microscopy, and impedance spectroscopy. The incorporation of BYO films decreases the Area Specific Resistance (ASR) of screen-printed cathodes from 6.4 to 2.2 Ω cm2 at 650 °C. However, further improvements are observed for the nanostructured electrodes prepared by spray-pyrolysis with ASRs of 0.55 and 1.15 Ω cm2 at 650 °C for cathodes with and without an active layer, respectively. These results demonstrate that microstructural control using optimized fabrication methods is desirable to obtain high-efficiency electrodes for solid oxide fuel cell (SOFC) applications.

Nanostructured BaCo0.4Fe0.4Zr0.1Y0.1O3-δ Cathodes with Different Microstructural Architectures

Lowering the operating temperature of solid oxide fuel cells (SOFCs) is crucial to make this technology commercially viable. In this context, the electrode efficiency at low temperatures could be greatly enhanced by microstructural design at the nanoscale. This work describes alternative microstructural approaches to improve the electrochemical efficiency of the BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) cathode. Different electrodes architectures are prepared in a single step by a cost-effective and scalable spray-pyrolysis deposition method. The microstructure and electrochemical efficiency are compared with those fabricated from ceramic powders and screen-printing technique. A complete structural, morphological and electrochemical characterization of the electrodes is carried out. Reduced values of area specific resistance are achieved for the nanostructured cathodes, i.e., 0.067 Ω·cm2 at 600 °C, compared to 0.520 Ω·cm2 for the same cathode obtained by screen-printing. An anode supported cell with nanostructured BCFZY cathode generates a peak power density of 1 W·cm−2 at 600 °C.