Functional properties of transparent ZnO thin films synthetized by using spray pyrolysis for environmental and biomedical applications

Spray pyrolysis is a promising method for producing thin, transparent films on glass substrates. ZnO thin films synthesized by this method exhibit high crystallinity, adhesion and chemical resistance. They also possess the ability to degrade water pollutants and exhibit antibacterial properties under UV light. The crystalline structure of these films has been studied using grazing X-ray diffraction (GIXRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM), while transmission electron microscopy (TEM) has been used to investigate their composition and purity. Other techniques such as X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and ultraviolet–visible spectroscopy were also employed. ICP-OES was used to evaluate photocatalyst leaching. These transparent thin films have exceptional optical properties, with a transmittance of 95%. The photocatalytic degradation of 4-Nitrophenol (4-NP) by ZnO thin films showed a degradation rate of 94% in 270 min with a kinetic constant value of 3.1 × 10−3 mM/min. The films are also highly durable and reusable, exhibiting superior performance compared to other ZnO photocatalysts. The bactericidal activity of these transparent films was also evaluated, with a value of 60.6% being obtained using Escherichia coli after irradiating the films with UV light for 3 h.