The Impact of Varying the Number of Layers Deposited Using the Spin-Coating Technique on the Structural, Optical, and Photocatalytic Properties of Polyvinyl Chloride/Zinc Oxide Nanocomposite Films

Spin coating is a key method for thin film preparation due to its simplicity and cost-effectiveness, relying on the number of layers deposited. This study investigates the impact of sample thickness on polyvinyl chloride (PVC) nanocomposites doped with zinc oxide (ZnO) nanoparticles, focusing on structural, optical properties, and photocatalytic activity. Different numbers of layers (15, 20, 25, and 30) were synthesized via sol–gel spin coating using tetrahydrofuran as a solvent. X-ray diffraction revealed ZnO crystallites in 30-layer films, with a wurtzite structure and 32 nm crystallite size. Raman and infrared spectra confirmed ZnO incorporation. Optical transmittance ranged from 75 to 86%, with band gap energies between 3.45 and 3.94 eV. Photoluminescence spectra indicated ultraviolet and green luminescence attributed to ZnO defects. Photocatalytic efficiency, tested with methylene blue under UV irradiation, showed the 30-layer sample achieving 79% removal efficiency at 60 min, outperforming others.