Enhanced antimicrobial and photocatalytic effects of plasma-treated gallium-doped zinc oxide

• Published in: Applied surface science 2024-05, Vol.655, p.159567, Article 159567
• Main Authors: Rutherford, David, Remes, Zdenek, Kolarova, Katerina, Matolinova, Iva, Cech, Jaroslav, Micova, Julia, Rezek, Bohuslav
• Format: Article
• Language: English
• Subjects: Antibacterial; Doping; Gallium; Photocatalytic; Plasma treatment; Zinc oxide
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.159567

[Display omitted] •Antibacterial effect enhanced by plasma treatment against both gram-negative and gram-positive bacteria.•Photocatalytic effect enhanced by oxygen plasma treatment.•Surface roughness increased by plasma treatment.•Zinc ion release decreased by plasma treatment.•Surface charge influenced by plasma treatment. We characterize gallium-doped zinc oxide (ZnO:Ga) after exposure to hydrogen or oxygen plasma for potential use as a novel antibacterial and photocatalytic material. ZnO:Ga were composed of smooth rods with a thick central portion and tapered nanometre-sized ends alongside clusters of thin disk particles. Plasma treatment removed material from the rod surface and introduced features such as small holes or pits that increased the surface roughness and reduced the zinc ion concentration measured from colloidal suspensions. The surface charge of ZnO:Ga was influenced by plasma treatment: hydrogen plasma induced a positive surface charge whereas oxygen plasma resulted in a negative surface charge. However, electrostatic interactions with negatively charged bacteria were not the predominant mechanism underlying the antibacterial effect of ZnO:Ga. Treatment with oxygen or hydrogen plasma enhanced the antibacterial effect of ZnO:Ga against gram-positive bacteria, yet only oxygen plasma caused an enhancement against gram-negative bacteria. The photocatalytic effect of ZnO:Ga was enhanced after oxygen plasma treatment but supressed by hydrogen plasma treatment. The results indicate that plasma treatment of ZnO:Ga can successfully alter material properties to provide enhancement of the antibacterial and photocatalytic effects, however the type of feed gas used should be carefully chosen based upon the desired application.