Spray pyrolysis-assisted fabrication of Eu-doped ZnO thin films for antibacterial activities under visible light irradiation

This study reports the fabrication and characterization of zinc oxide (ZnO) and europium-doped ZnO (Eu-doped ZnO) films and their antibacterial activities. The spray pyrolysis method was used to synthesize ZnO and 1, 2, 3, and 4% Eu-doped ZnO thin films on the glass substrate. The fabricated Eu-ZnO thin films were characterized using x-ray diffraction, Fourier transforms infrared spectroscopy, UV-vis spectroscopy, field emission scanning electron microscopy, and x-ray photoelectron spectroscopy. These characterization techniques confirm the successful fabrications of the ZnO and Eu-doped ZnO thin films. It was found that the increase in Eu concentration affects the lattice parameters and the crystallite size without changing the ZnO wurtzite structure. Fabricated ZnO and Eu-doped ZnO films were tested for antibacterial activities against Escherichia coli (E. coli, ATCC 25,922) under visible light irradiation. This is the first antibacterial study of the Eu-ZnO films obtained by the spray pyrolysis method. Improved antibacterial activities were found against E. coli by Eu-doped ZnO films under visible light irradiation.