Advancements in Visible Reflection Coatings: Innovations in Dielectric and Nanostructured Thin Films for Photonic and Optoelectronic Applications

This study reports the fabrication of TiO2/SiO2 multilayer coatings via sol-gel spin coating, optimized for high visible light reflectance and hydrophilic functionality. X-ray diffraction confirmed the formation of anatase-phase TiO2 with a dominant (101) peak at 25o -27o, while Fourier-transform infrared spectroscopy revealed strong Si-O-Ti bonding, indicative of robust interfacial adhesion. Cross-sectional FESEM imaging demonstrated a well-defined multilay er stack with measured individual layer thicknesses of 136.8, 147.8, 268.0, 300.8 and 169.5 nm, giving a total thickness of ≈1.02 μ m and ensuring precise thickness uniformity for constructive interference. Optical characterization showed a reflectance exceeding 90% in the 500-600 nm region with complementary transmission suppression, v alidating the multilayer as an efficient dielectric reflector. Contact angle measurements yielded 45o±2o, confirming hydrophilic surface behaviour beneficial for self-cleaning applications. The combination of broadband reflectance, structural integrity and surface wettability highlights the multifunctional potential of the TiO2/SiO2 multilayer for photonic and optoelectronic applications, including dielectric mirrors, optical filters, waveguides, augmented reality display s and self-cleaning solar panels. The scalable sol-gel spin-coating approach establishes a promising route toward low-cost, energy -efficient optical coatings for next-generation dev ices.