SYNTHESIS, CHARACTERIZATION, AND ANTIBACTERIAL ACTIVITY OF COBALT DOPED (α-Fe2O3) THIN FILMS

Abstract

0-20 wt % Cobalt doped hematite iron oxide (α-Fe2O3) thin films were deposited on 500°C heated glass substrates via spray pyrolysis method with moving nozzle. The dopant concentration is stepped as 0, 2%, 5%, 10%, and 20%. For the non doped thin film, XRD analyses exhibit the presence of diffraction peaks corresponding to planes (012), (104), (110), (113), (024), (116), (214), and (300) confirming the formation of α-Fe2O3 phase. While for the Co doped α-Fe2O3 thin films, further diffraction peaks corresponding to α-Fe2O3 phase, peaks matching well with the planes (200) and (311) of cobalt oxides CoO and Co3O4 respectively are observed. Co substitution was confirmed by XRD based on peaks shift of hematite towards higher angles. The crystallite size of the hematite increases from 37nm to 47nm with increasing dopant from 0 to 2wt. % Co/Fe. Then it decreases to 28nm for 20wt. % Co doping. While for cobalt oxides CoO and Co3O4, their crystallite sizes were found to be in the range of 29-32nm and 18-43nm, respectively. The optical investigation indicates an increase in transmittance with increasing the dopant level reaching 80% at 600nm with blue shift in the band gap for the doped samples. FTIR study confirms the existence of the cobalt oxides at wave number average 460-542cm-1 . As an application in the areas of the antibacterial test, cobalt doped hematite nanoparticles (NPs) exhibit a good antibacterial activity against E. coli, Listeria innocua, Pseudo monas aeruginosa and Salmonella beyond 5wt. % Co/Fe doping.