Berlin 2015 – wissenschaftliches Programm
TT 47.1: Hauptvortrag
Dienstag, 17. März 2015, 14:00–14:30, C 130
Ultrafast Coherent Charge Transfer in Solar Cells and Artificial Light Harvesting Systems — •Christoph Lienau1, Ephraim Sommer1, Antonietta de Sio1, Ralf Vogelgesang1, Margherita Maiuri2, Giulio Cerullo2, Angel Rubio3, Carlo A. Rozzi4, and Elisa Molinari4 — 1Carl von Ossietzky University, Oldenburg, Germany — 2Politecnico di Milano, Milano, Italy — 3Universidad del País Vasco, San Sebastian, Spain — 4Dipartimento di Scienze Fisiche, Modena, Italy
To elucidate the fundamental microscopic processes in solar energy conversion, we have recently combined coherent femtosecond spectroscopy and first-principles quantum dynamics simulations [1,2] and have used this approach to explore the primary photoinduced electronic charge transfer in two prototypical structures: (i) a carotene-porphyrin-fullerene triad, an elementary component for an artificial light harvesting system  and (ii) a polymer:fullerene blend as a model for an organic solar cell .
Our results provide strong evidence that in both systems, at room temperature, the driving mechanism of the primary step within the current generation cycle is a quantum-correlated wavelike motion of electrons and nuclei on a timescale of few tens of femtoseconds. They suggest that the strong coupling between electronic and vibrational degrees of freedom is of key importance for the dynamics and yield of the charge separation process. Here, I will discuss our most recent experimental and theoretical findings.  S. M. Falke et al., Science 344, 6187 (2014).  C. A. Rozzi et al., Nature Comm. 4, 1602 (2013)