Investigation of Cu Doping Concentration on the Structural and Antimicrobial Properties of TiO₂ Thin Films

This study aims to examine the microorganism-fighting properties of the thin layers of TiO2. These TiO2 film as synthesized through a chemical process, in which different concentrations of copper have been added. The ability of films to inhibit the growth of different types of bacteria and fungi was examined using the disk diffusion technique. TiO2 films without additives exhibited mild antibacterial action, with inhibition areas varying according to the dose and type of microorganism. In contrast, the films that received a dose of copper showed significant increases in their ability to inhibit bacterial growth. More prominent detention areas were observed when a dose of 60 µg/mL and a doping concentration of 0.1% were used. According to X-ray diffraction tests, it was revealed that the thin films of TiO2 exhibit a cubic crystalline configuration, indicating their high crystallinity and the variation in the position of the peaks due to the inclusion of copper in their composition. The effectiveness in combating bacteria increased when the size of the crystals was raised from 6.72 nm (undoped) to 8.39 nm in presence of 0.1% copper. Significant changes occurred in the external appearance, as seen in the photographs taken using scanning electron microscopy (SEM). The modifications higher concentration of Cu doping, a transformation from smooth surfaces of pure ZnS to rough and porous layers in the films doped with Cu is observed. Specifically, the study reveals that by adding copper to thin films of zinc sulfide, their effectiveness can be enhanced, paving the way for the advancement of materials with antimicrobial properties.