Fabrication by AC Deposition and Antimicrobial Properties of Pyramidal-Shaped Cu2O-TiO2 Heterostructures

Nanoparticulate surfaces possessing antimicrobial and fungicidal properties under visible light illumination have found wide applications in a number of fields. In this study, titania nanotubes, as well as titania compact films were designed with pure Cu2O crystals in a mildly acidic copper acetate solution using a simple alternating current (AC) deposition approach. In this way, the thermally oxidized Ti substrate was coated by densely packed pyramidal and bipyramidal shaped Cu2O crystals with dominant (111) planes and investigated against several types of fungi and bacteria. For comparison, TiO2 nanotube (TiNT) films were also decorated with similar crystals and tested. The results showed that, compared to bare TiO2 films, both Cu2O-in- TiNT and Cu2O-on-TiO2 heterostructures exhibited remarkably enhanced activity against tested fungi and bacteria. We also demonstrated that the high photoactivity of these crystals remained even after 50 h stability tests under bright light illumination. The results obtained from in vitro tests indicated that Cu2O-in/on-TiO2 heterostructures show promise as visible light driven antimicrobial materials.