Multifunctional applications of TiO2 thin films synthesized by sol–gel dip coating technique

• Published in: Journal of sol-gel science and technology 2024-05, Vol.110 (2), p.346-362
• Main Authors: Sunil, Arsha, Gopika, M. S., Jayasudha, S., Nair, Prabitha B.
• Format: Article
• Language: English
• Subjects: Anatase; Annealing; Antimicrobial agents; Biomedical materials; Catalytic activity; Ceramics; Chemistry and Materials Science; Composites; Crystallites; Degradation; Durability; E coli; Fogging; Glass; Immersion coating; Inorganic Chemistry; Materials Science; Methylene blue; Morphology; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper; Pathogens; Phase composition; Phase transitions; Photocatalysis; Photoelectrons; Photomicrographs; Sol-gel processes; Spectrum analysis; Sunlight; Synthesis; Temperature; Thin films; Titanium dioxide; Wetting; X ray photoelectron spectroscopy
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-024-06358-0

Pure TiO 2 thin films were synthesized by non-aqueous sol–gel method using indigenously fabricated programmable low-cost dip coating unit. The structural, morphological, and optical characterizations of the thin films annealed at various temperatures were carried out to investigate the influence of annealing temperature on the film characteristics. Thin film samples were characterized using grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, HR-TEM, FE-SEM, AFM, profilometry, and UV–Vis spectrophotometery. GIXRD patterns shows phase transformation from amorphous to crystalline at 723 K and into a mixed phase at 1223 K. The average crystallite size of thin films increases from 13.45 to 69.24 nm with increase in annealing temperature. XPS analysis confirmed the phase composition of the thin films. HR-TEM and FE-SEM images revealed spherical surface morphology. FE-SEM micrographs showed increase in mean particle size with increase in annealing temperature. UV–Vis optical transmittance spectra indicated a decrease in optical band gap from 3.47 to 3.03 eV with increase in annealing temperature. Photocatalytic activity of thin films was evaluated by monitoring the degradation of aqueous methylene blue (MB) dye under sunlight. The results indicated that thin film annealed at 723 K in anatase phase has the highest photocatalytic activity with 79.35% degradation. This thin film exhibited high antimicrobial activity against gram-negative ( E. coli ) and gram-positive ( S. aureus ) pathogens. Moreover this thin film possesses durability, reusability, hydrophilicity, anti-fogging behavior, and good wetting performance. These findings provide valuable insights into the multifunctional application of TiO 2 thin films, highlighting their potential for environmental and biomedical applications. Graphical Abstract Highlights Synthesis of TiO 2 thin films via the sol–gel method using indigenously fabricated programmable dip coating unit. Structural, optical, and morphological studies of thin films were carried out and optimized thin film for MB degradation under direct sunlight was arrived at. The optimized thin film yielded high antimicrobial activity on gram-negative ( E. coli ) and gram-positive ( S. aureus ) pathogens. Durability, anti-fogging, and wetting performance of optimized thin film was also studied.