Superhydrophilic Fe³⁺ Doped TiO₂ Films with Long-Lasting Antifogging Performance

Based on the superhydrophilicity of titanium dioxide (TiO2) after ultraviolet irradiation, it has a high potential in the application of antifogging. However, a durable superhydrophilic state and a broader photoresponse range are necessary. Considering the enhancement of the photoresponse of TiO2, doping is an effective method to prolong the superhydrophilic state. In this paper, a Fe3+ doped TiO2 film with long-lasting superhydrophilicity and antifogging is prepared by sol–gel method. The experiment and density-functional theory (DFT) calculations are performed to investigate the antifogging performance and the underlying microscopic mechanism of Fe3+ doped TiO2. Antifogging tests demonstrate that 1.0 mol % Fe3+ doping leads to durable antifogging performance which lasts 60 days. The DFT calculations reveal that the Fe3+ doping can both increase the photolysis ability of TiO2 under sunlight exposure and enhance the stability of the hydroxyl adsorbate on TiO2 surface, which are the main reasons for a long-lasting superhydrophilicity of TiO2 after sunlight exposure.