Resistance against water and acid water (pH = 4.0) via Al-doped ZnO thin films for environmentally friendly glass panels

Thirty nm-thick ZnO (0AZO), Al (3 at%)-doped ZnO (3AZO), and Al (10 at%)-doped ZnO (10AZO) thin films were grown at room temperature on a Gorilla glass substrate via radio-frequency sputtering. The annealed 30 nm-thick 10AZO films showed a high transmittance of approximately 91.7% (at a wavelength of 550 nm), a hydrophobic property, strong antimicrobial activity for various bacteria, and reliable mechanical durability to touches. In particular, AZO thin films also showed a strong killing effect for the molds as well as bacteria. The 10AZO films sufficiently suppressed the release of both Zn and Al ions when they were dipped into water and acid water (pH = 4.0) for 30 days. The main antimicrobial mechanism of the AZO films was governed by the electrostatic interactions between the AZO films and the bacterium cells. The AZO films are strongly attracted for environmentally friendly applications of the glass panels.