Effect of Thickness of SnO_2:F over Layer on Certain Physical Properties of ZnO:Al Thin Films for Opto-electronic Applications

Bilayered FTO/AZO （fluorine doped tin oxide/aluminium doped zinc oxide） films were fabricated using a simple, cost effective spray pyrolysis technique. X-ray diffraction （XRD） profiles of bilayered films showed that in the case of lower thickness FTO over layers, （002） plane of ZnO phase had the highest intensity, whereas the predominance was changed in favour of （200） plane of SnO2 phase for higher thickness FTO over layer. UV studies showed that bilayered FTO/AZO films exhibited a sharp absorption edge as that of AZO film. The decrease in the photoluminescence （PL） peak at 420 nm with increasing FTO over layer thickness indicated a reduction in the zinc vacancies which caused a reduction in the sheet resistance （Rsh）. Electrical studies revealed that, eventhough the Rsh value （916Ω/□） of bilayered FTO （313 nm）/AZO （314 nm） film was found to be higher than that of FTO single layer film （72Ω/□）, it was much lower than that of AZO single layer film （5661Ω/□））. The atomic force microscopy （AFM） images reflect the characteristic features of both zinc oxide and tin oxide films.

Enhancement of Photocatalytic and Antibacterial Activities of ZnO：Ag Nanopowders Through the Addition of Bamboo Charcoal： An Efficient Natural Adsorbent

This research article explains the removal of methylene blue （MB） and malachite green （MG） from aqueous solution using adsorption/photodegradation activity of ZnO：Ag/bamboo charcoal （BC） nanocomposite. In addition, the antibacterial studies of the prepared samples were tested against Staphylococcus aureus （S. aureus） Gram-positive and Escherichia coli （E. coli） Gram-negative bacteria by the well diffusion method. The ZnO：Ag/BC nanocomposite exhibits superior photocatalytic activity compared with ZnO：Ag. Remarkable degradation efficiencies of 93.95% （MB） and 95.75% （MG） were recorded for ZnO：Ag/BC nanocomposite after 45 min. The degradation process follows a pseudo-first-order kinetics. The rate constant of ZnO：Ag/BC nanocomposite is two times greater than that of pristine ZnO nanopowder for the degradation of MB dye, while for MG dye degradation, it is three times. It is found that the ZnO：Ag/BC nanocomposite shows a higher rate of dye removal due to excellent adsorbing properties of bamboo charcoal （BC）. The ZnO：Ag/BC nanocomposite showed better antibacterial properties compared to ZnO：Ag. In this study, the samples were prepared using a simple and low-cost soft chemical route and they were characterized by optical, structural, surface morphological, antibacterial and photocatalytic properties. These characterization studies substantiate the discussions on the photocatalytic and antibacterial activities of the synthesized samples.