Improving the Antibacterial Properties of SnO₂/Mn₃O₄ Hybrid Thin Film Synthesized by Spray Pyrolysis Method

The current study used the spray pyrolysis method to prepare tin oxide, manganese oxide, and SnO₂/Mn₃O₄ hybrid bilayer thin films. The primary solutions for the deposition process were produced utilizing the sol-gel method. X-ray diffraction, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence spectroscopy were used to analyze the grown films. XRD spectrum of SnO_2, Mn₃O₄, and SnO₂/Mn₃O₄ hybrid bilayer thin film shows that SnO₂ thin film has a polycrystalline structure with a tetragonal cassiterite phase, Mn₃O₄ thin film shows a lower crystallinity degree due to the powdery nature of its surface, and XRD pattern of SnO₂/Mn₃O₄ hybrid thin film has a polycrystalline structure. From the FESEM, the surface morphology of SnO₂ thin film is crack-free and regular with incessant grain distribution. FESEM micrographs of the synthesized Mn₃O₄ thin film and the perfectly spherical grains of Mn₃O₄ are uniform and entirely separate, with an average size of less than 50 nm. FESSEM micrographs of SnO₂/Mn₃O₄ hybrid thin film exhibit an uneven and porous polycrystalline structure with polyhedral granulation. The film's antibacterial properties were evaluated for standard gram-negative bacteria (GNB) and gram-positive bacteria (GPB), namely Staphylococcus aureus and Escherichia coli. According to the results, the hybrid bilayers have demonstrated better antibacterial properties than tin oxide and manganese oxide monolayers. These findings ascertain the role the hybrid thin film nanocomposites play in the biomedical field's potential applications.