ALD-induced TiO2/Ag nanofilm for rapid surface photodynamic ion sterilization

The daily life of people in the intelligent age is inseparable from electronic device, and a number of bacteria on touch screens are increasingly threatening the health of users. Herein, a photocatalytic TiO2/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction. Ultraviolet-visible (UV-Vis) spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO2. The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO2/Ag film against S. aureus and E. coli was 98.2% and 98.6%, under visible light irradiation for 5 min. The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO2 reduced the bandgap of TiO2 from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO2 and Ag. Thus, TiO2/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens. More importantly, the TiO2/Ag film had great biocompatibility with/without light irradiation. The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.随着智能时代的来临, 人们的日常生活日益离不开电子产品, 随之带来的触摸屏上的细菌卫生问题则给使用者的健康产生了严重的威胁。有鉴于此, 本项目通过原子层沉积技术和传统的原位光还原工艺在玻璃基底上制备了TiO2/Ag光催化纳米薄膜。紫外-可见光谱表明, 在TiO2上原位还原Ag使TiO2的带隙从3.44 eV 变为2.61 eV。该纳米薄膜和单独的TiO2薄膜相比能够将TiO2对于光谱的吸收范围从紫外光区域拓宽到可见光区域，从而更有效地吸收模拟太阳光。体外抑菌试验表明, 在可见光照射5分钟后, 复合纳米薄膜对金黄色葡萄球菌和大肠杆菌的杀菌效率分别达到了98.2%和98.6% 。其潜在机制是, 由于TiO2和Ag纳米粒子之间存在接触电位差, 二者在表面界面处的结合形成了肖特基异质结, 在阻碍了电子-空穴复合速率的同时还能够产生活性氧物种 (ROS), 大大提高了光催化效果。更重要的是, TiO2/Ag纳米薄膜在有/无可见光照射的情况下都具有很好的生物相容性。这种基于功函数的肖特基异质结平台不仅为传统的光动力快速杀菌提供了更便捷的选择, 还为其在亿万电子触摸屏领域的应用创造了无限可能。.