The Effect of Fe-Doping on ZnO Surface Phenomena and Antibacterial Action

ZnO is an important semiconductor used in optoelectronics, pharmaceuticals, solar cells, etc. Nanoscale applications are of particular interest and these are seen to be driven by characteristics of the crystalline free surface. As such, novel applications could be achieved through introduction of specific dopants into the lattice. It is theorized that Fe dopants can stabilize the surface of the ZnO nano- and microparticles through suppression of the internal surface dipole and minimization of the surface reconstruction. This effect renders the material a platform for studies into the fundamentals of the bactericidal mechanisms of ZnO. The origins of ZnO cytotoxicity are still debated, although our recent results indicate that certain surface phenomena lead to Zn²⁺ ion release following interaction at these surface sites with bacteria and/or growth media components. Stabilization of the surface should diminish the abundance of these interaction sites and mitigate the release of Zn²⁺ ions. Therefore, we characterize the bulk and surface defect properties of hydrothermally grown Fe-doped ZnO at various doping percentages via XRD and XPS. To determine the toxicity of pure ZnO and Fe-doped ZnO, we run antibacterial assays with Staphylococcus aureus via absorption measurements. Finally, to determine the chemical bond energy changes due to the addition of Fe, we employ FTIR and Raman spectroscopies, further elucidating the role of surface defects in antibacterial action of our ZnO samples.