Time: November 10th, 2015, 10 A.M.
Location: Meeting Room 300, State Key Laboratory of Molecular Reaction Dynamics (36#)
Lecturer: Dr. Katrin R. Siefermann
Leibniz Institute of Surface Modification, Leipzig, Germany
Biography:
Katrin Siefermann obtained her PhD in 2010 at the Institute of Physical Chemistry, Georg-August-University Gottingen under the supervision of Prof. Bernd Abel. Subsequently, she worked as a PostDoc in Lawrence Berkeley National Laboratory with Prof. Daniel M. Neumark, Prof. Steven R. Leone and Dr. Oliver Gessner. Since August 2012 she has been working as a group leader at the Leibniz Institute of Surface Modification (IOM). Her current research interests are concerned with the fundamental understanding of ultrafast processes in complex functional materials, with a particular focus on surface and interface dynamics induced by light. Goal is to understand these systems on a molecular level and their dynamics on femtosecond timescales. Her tools to visualize dynamic processes in these complex systems are innovative and unique techniques from the field of ultrafast spectroscopy.
Abstract:
Charge transfer processes across hybrid interfaces, such as formed by the connection of molecules to semiconductors, play an increasingly important role in a variety of emerging technologies. Detailed understanding of interfacial charge transfer in these systems, however, remains a major challenge for experiments and theory. In my talk I will present a new approach to monitor photo-induced electrontransfer from a molecule to a semiconductor material with sub-picosecond temporal resolution and from the perspective of well-defined atomic sites. Combining femtosecond time-resolved X-ray photoelectron spectroscopy with constrained density functional theory, we are able to identify the nature of an intermediate electronic state that precedes free charge carrier generation in a film of dye-sensitized ZnO nanocrystals after photoexcitation of the dye with visible light. The findings demonstrate a new capability to monitor charge transfer in complex hybrid materials. This presentation will further include our latest results of electron dynamics at interfaces.
Contact: Group 1102, Chuanyao Zhou (9701)