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O: Fachverband Oberflächenphysik

O 22: Ultrafast Surface Dynamics

O 22.1: Hauptvortrag

Dienstag, 17. März 2015, 10:30–11:00, MA 042

Electron dynamics at molecule-semiconductor interfaces — •Katrin R. Siefermann — Leibniz-Institute of Surface Modification (IOM), Leipzig, Germany

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 electron transfer from a molecule to a semiconductor material with sub-picosecond temporal resolution and from the perspective of well-defined atomic sites [1]. 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.

[1] K. R. Siefermann, C. D. Pemmaraju, S. Neppl, A. Shavorskiy, et al., J. Phys. Chem. Lett. 5, 2753-2759 (2014).