Interfacial electron transfer dynamics is important for environmental and catalytic reactions. Extensive ensemble-averaged studies have indicated inhomogeneous and complex dynamics of interfacial ET reaction. To characterize the inhomogeniety and the complex mechanism, we have applied femtosecond ultrafast spectroscopy, single-molecule photon stamping and Raman spectroscopy, and correlated AFM imaging to study the interfacial ET dynamics of dye molecules adsorbed at the surface of TiO2 nanoparticles.

In our density functional theory study combined with the experimental study by the group at IBM Zurich headed by G. Meyer, we have identified a metal-molecule complex that can be used as a molecular switch [1,2]. Using a scanning tunneling microscope, a covalent bond was formed reversibly between a gold atom and a perylene-3,4,9,10-tetracarboxylic dianhydride molecule supported by a thin insulating film.

The water surface is important for a variety of disciplines, including electrochemistry, biology and atmospheric chemistry. The properties of water molecules at interfaces is different from those in the bulk and determine the processes occurring at those interfaces. In bulk water, water molecules are surrounded by other water molecules to which hydrogen bonds can be formed; at the interface, the hydrogen-bonded network is interrupted. We use advanced laser spectroscopies to characterize specifically the outermost monolayer of water molecules.