Sintesis filem nipis AG/TIO₂ melalui kaedah sol-gel untuk aplikasi pembersihan diri

Titanium dioxide (TiO₂) thin film coating has attracted tremendous attention from many researchers due to its light absorption and photocatalytic properties, which make it suitable to be used for self-cleaning applications. In this research, the Ag/TiO₂ thin film was produced by using a simple and fast sol-gel spin coating method. By using a developed formulation, the Ag/TiO₂ thin film coating can be produced in 25 minutes of time. The preparation of the Ag/TiO₂ thin film coating can be divided into three different parameters. For the first parameter, the different concentration of AgNO₃ solution was used. The second parameter involved the different annealing temperatures, while the third parameter studied on the influence of polyethylene glycol (PEG) addition onto the formation of the thin film. The synthesized thin film coatings were characterized by using an X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM). The light absorption study was conducted by using a UV-visible (UV-Vis) spectroscopy. The wettability and photocatalytic testing were also conducted. From the results, the addition of 0.1 M of AgNO₃ solution had produced the Ag/TiO₂ thin film with smooth morphology and homogenously coated over the indium thin oxide (ITO) glass substrate. The optical property was enhanced where the light absorption was extended into the visible light range with reducing the energy level from 3.30 eV to 3.10 eV, compared to the TiO₂ thin film that was produced without the addition of AgNO₃. The film also had the lowest water contact angle and exhibited the best self-cleaning behavior with highest decomposition of the methylene blue solution, which is almost 60%. In term of annealing temperature, the optimum temperature for obtaining an anatase (TiO₂) structure with small particles size and homogenous surface morphology was 500 ⁰C. The film light absorption was found to be the highest with lowest energy level, 3.10 eV. The film that was annealed at 500 ⁰C also showed the lowest water contact angle, which is 11.30o and the best self-cleaning properties where more than 70% of the methylene blue solution can be decomposed in 150 minutes. The addition of 0.15 g of PEG resulted in small, homogenous porous structure with 19.6 nm of the particle size. The film had a good absorption in the visible light range with energy level of 2.65 eV and had almost 80% of photocatalytic decomposition of methylene blue in 150 minutes. From this research, it can be concluded that the 0.1 M of AgNO₃ concentration, 500oC of annealing temperature and 0.15 g of PEG became an optimum parameter in producing a good self-cleaning Ag/TiO₂ thin film. It was also found that the produced Ag/TiO₂ thin film had a good optical and photocatalytic behavior and suitable to be used in self-cleaning applications.