Berlin 2018 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: Solid-liquid interfaces: Reactions and electrochemisty I (joint session O/CPP)
CPP 15.2: Talk
Monday, March 12, 2018, 15:15–15:30, MA 144
Probing ultrafast processes at electrode-aqueous solution interfaces with laser induced photovoltage measurements — •Yujin Tong, François Lapointe, Martin Wolf, and R. Kramer Campen — Fritz-Haber-Institut, Abt. Physikalische Chemie, 14195 Berlin, Germany
A conventional potentiostat that typically employed for a three electrode electrochemical system has a time resolution of, at best, 1 µ s (bandwidth above 1MHz) [Bard, A.J., Electrochemical methods: fundamentals and applications, New York: Wiley, (1980), Chapter 15]. However, many charge transfer processes happen on pico- to femtosecond time scales. To measure such fast kinetics, all-optical pump probe techniques using ultrafast lasers are usually adopted. In this contribution, we demonstrate that, using a sequence of two ultrashort laser pulses of different photon energies and detection of the laser induced photovoltage by a slow potentiostat as a function of the delay between the two incident pulses, ultrafast charge transfer kinetics on femtosecond timescales can be resolved. For example, we used a UV laser to trigger electron transfer from a gold electrode to Na2SO4 aqueous solution and then a second laser in middle or near infrared region was employed to interact with the species that generated by the freshly generated electron. The life time as well as the spectrum of the transient species is consistent with the solvated electron at the interface.