Research Visit to Lawrence Berkeley Laboratory for Metal Oxide/Liquid Interfaces at the Advanced Light Source

目前有大量的研究工作与替代能源技术有关。光收集是一个被大力追求的途径，其目的是将太阳能转化为电能或产生氢气作为便携式燃料。这两种途径都需要催化剂来收集光，二氧化钛是一个关键的模型系统。近紫外光被吸收的过程中，电子被促进通过该半导体的带隙。然后，电子和空穴移动到表面，在那里它们产生电流并进行一些化学反应，例如将水还原为氢。在光伏应用中，TiO2表面的染料也会吸收可见光，从而提高效率。据估计，到2030年，光伏市场的价值将从2010年的200亿美元增长到6000亿美元。这就是为什么包括太阳能在内的能源研究是EPSRC优先考虑的领域之一。虽然光收集过程的现象是众所周知的，但表面反应的细节现在才被揭示出来。已知的一切都是在高度理想的超高真空条件下的实验中确定的。在这个项目中进行的实验将检查与TiO2表面染料相关的分子的几何形状，这些分子是从溶液中沉积下来的。分子对电子结构的影响也将被监测。这些测量是通过特殊的仪器来实现的，这些仪器使用同步辐射来检查液体下的表面。

There is currently a large research effort associated with alternative energy technologies. Light harvesting is one avenue that is being vigorously pursued, where the aim is to convert energy from the sun into either electrical power or to generate hydrogen as a portable fuel. Both routes require a catalyst to harvest the light, with titanium dioxide being a key model system. Near UV-light is absorbed in a process where electrons are promoted across the band gap of this semiconductor. The electrons and holes then travel to surfaces where they create electrical current and do some chemistry, such as reduce water to hydrogen. In the photovoltaic application, a dye at the surface of TiO2 also absorbs visible light, which leads to an increase in efficiency. The photovoltaics market is estimated to be worth US$600 billion by 2030, building from about US$20 billion in 2010. This is one reason why research on Energy, including solar is an EPSRC priority area. Although the phenomenologies of light harvesting processes are well known, the details of the surface reactions are only now being revealed. What is known has been determined from experiments in the highly idealised conditions of ultra high vacuum. Experiments carried out in this project would examine the geometry of molecules related to dyes on the surface of TiO2, where the molecules are deposited from solution. The effect of the molecules on the electronic structure would also be monitored. These measurements are made possible by special instruments that employ synchrotron radiation to examine surfaces under liquid.