Search

In this study, zinc oxide (ZnO) and zinc oxide-zirconium dioxide nanocomposites (ZnO@ZrO2) were synthesized by a low-cost solution combustion route to study their structural, morphological, optical, and photocatalytic performance. The properties of synthesized nanocomposites were characterized by x-ray diffraction (XRD), UV–vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Phase formation and purity were confirmed using XRD and EDS. Optical absorption spectra revealed that the addition of ZrO2 significantly affected optical absorption and band gap energy. The band gap energy increased from 3.01 to 3.24 eV with addition of ZrO2 in ZnO. FTIR spectra confirmed the formation of ZnO and ZnO@ZrO2. SEM micrographs showed a significant change in the morphology of the ZrO2 addition in ZnO. BET analysis showed surface area for sample P3 (ZnO@0.4ZrO2) was 28.9 m2/g while for sample P1 (ZnO) was 22.5 m2/g. In addition, the photocatalytic performance of ZnO and ZnO@ZrO2 for the decomposition of methylene blue (MB) dye was studied for all samples exposed to solar light. The effect of different contents of ZrO2 in ZnO@ZrO2 in terms of degradation efficiency and degradation time are described in detail. The sample P3 showed highest photodegradation efficiency of 84.52 % at degradation time of 240 minutes.

In present work, we report synthesis of molybdenum (Mo) thin films by direct current (DC)-magnetron sputtering method. The structural, optical, morphological, and electrical properties were investigated as a function of target-to-substrate distance. From the results, it is evident that with increase in target-to-substrate distance the thickness of films decreases while its sheet resistance and electrical resistivity increases, which is confirmed by van der Pauw method. Low angle XRD analysis revealed that with increase in target-to-substrate distance preferred orientation of Mo crystallites changes from (211) to (110) and its size decreases. The field emission scanning electron microscope (FE-SEM) analysis revealed a significant change in surface morphology with increase in target-to-substrate distance. UV-Visible spectroscopy analysis showed that Mo films deposited at higher target-to-substrate distance have more reflection than those deposited at lower target-to-substrate. Finally, adhesion test was performed using scotch hatch tape adhesion test which show all Mo films have excellent adhesion over the entire range of target-to-substrate distance studied. The employment of such Mo films as back contact can be useful to improve efficiency of CZTS solar cells.

Abstract We report the synthesis of tungsten sulfide (WS2) films using RF‐magnetron sputtering at different RF powers. X‐ray diffraction (XRD) data confirm the hexagonal crystal structure of WS2 with an average crystallite size of ∼44.54 Å. With increased RF power, the preferred orientation of WS2 crystallites shifts from (002) to (100). Linear sweep voltammetry (LSV) was used to assess the Photoelectrochemical (PEC) activity of WS2 films. The film deposited at 150 W demonstrated the highest photocurrent density of 5.44 mA/cm2. The 150 W film also showed a lower Tafel slope of ∼0.374 V/decade, indicating superior PEC activity. Mott Schottky's (MS) analysis revealed a notable shift in the flat band potential towards the negative side, suggesting a shifting of the Fermi level towards the conduction band. WS2 film grown at 150 W demonstrated a majority charge carrier density of 6.2×1021 cm−3 and a depletion layer width of 1.54 nm. The observed low charge transfer resistance of 155 Ω contributed to the enhanced PEC activity with a relaxation time constant of 37 ms. These properties suggest that WS2 can be suitable for PEC water splitting.