Characterization of ultrafast processes at metal/solution interfaces: Towards femtoelectrochemistry
The essential part of electrochemistry is charge transfer. To understand this process in great detail, one needs to probe the relevant kinetics and dynamics on time scales spanning from femtoseconds to seconds or even longer. Although a conventional electrochemical detection scheme is sufficient for nanosecond or slower processes, it does not offer high enough time resolution for probing ultrafast processes, such as solvent reorganization, electron tunneling, and surface isomerization, that occur on faster, for example picosecond or femtosecond, timescales. These are indispensable parameters in the advanced charge transfer theories. In this review, some recent studies using ultrashort lasers to explore the ultrafast dynamics at the metal/solution interface are reviewed. The focus is on optical pump-probe and optical pump-push with electrochemical probe schemes. The connection of these studies with conventional electrochemistry and the limitations of these detection schemes are discussed.