Understanding the effect of number of layers on the optical and wetting properties of titania thin films fabricated by sol-gel spin coating technique

The ubiquitous availability and simplicity of manufacture of titanium thin films make them highly sought after for electrical, electronic, optoelectronic, and mechanical applications. Photon multipliers are used in the form of thin films of the aforementioned material to enhance performance, particularly in the context of solar cells and light-emitting diodes (LEDs). The primary objective of this research is to examine the impact of sol-gel spin coating on the optical properties of a glass substrate by applying multilayers (1, 2, and 3) of titania. The multilayers underwent atomic force microscopy (AFM) tests to evaluate surface roughness. The results revealed surface roughness values of 11, 18, and 26 nm for the one, two, and three layers of titania, respectively. The synthesis of one, two, and three layers of titania with thicknesses of about 182, 200/230, and 180, 220, 230 nm, respectively, was seen using a cross-sectional field emission scanning electron microscopy (FESEM) research. In addition, the investigation of optical properties using ultraviolet-visible (UV-VIS) spectroscopy demonstrated an augmentation in transmittance and a displacement of the optical band towards longer wavelengths. The analysis of water contact angle in single, bilayer, and tri-layer structures indicates that an increase in roughness may lead to a reduction in contact angle. This changes the surface properties from hydrophobic to hydrophilic.