Walls-like structured monoclinic WO3 thin films were obtained by spray deposition method for further integration in gas sensors. For sensing applications, it is very important to achieve a high surface-to-volume ratio surface together with a proper thin films structure. The present communication reports on the effect of the sprayed solution volume variation (as a thickness variation element) on the detailed Raman spectroscopy for WO3 thin films with different thicknesses grown from precursor solutions with two different concentrations. Detailed analysis of the two series of samples shows that the growing thickness strongly affects the films morphology while their crystalline structure is only slightly affected. The Raman analysis contribute to refining the structural features clarifications. It was observed that, for both concentrations, the increase in thickness seems to slightly affect the stoichiometry of material and, in association with surface morphology variations, provide new possibilities for fine tuning of films properties towards enhanced as sensing applications. Further studies are ongoing.

The use of nanoparticles as antimicrobial agents can be one of the strategies to overcome the tendency of microbes to become resistant to antibiotics’ action. In this study, two composites ZnO/Au and ZnO/Ag, having 1% wt. of noble metal content, were synthesized by simple aqueous solution methods. The structure and morphology of the resulting nanocomposites were analyzed by standard structural and optical characterization methods. The formation of Au NPs and Ag NPs in these experiments was also discussed. The antimicrobial properties of ZnO, ZnO/Au and ZnO/Ag nanomaterials were investigated against Gram-negative bacteria (Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus). The electrostatic interaction between ZnO and noble metals nanoparticles have contributed to a better visible light adsorption, which led to an enhanced antimicrobial activity. The photocatalytic tests indicated an improvement in photocatalytic degradation of the methylene blue (MB) under UV irradiation using ZnO/Au and ZnO/Ag nanocomposites compared to bare ZnO. The introduction of noble metallic nanoparticles in ZnO matrix proved to be an effective strategy to increase their antimicrobial activity against P. aeruginosa and S. aureus and their photocatalytic activity evaluated through the degradation of MB dye. Comparing the enhancing effects of Au and Ag, it was found that ZnO/Au was a better antimicrobial agent while ZnO/Ag was more effective photocatalyst under UV irradiation.