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SYOP: Symposium Organic Photovoltaics: From Single Molecules to Devices

SYOP 2: Organic Photovoltaics: from Single Molecules to Devices

SYOP 2.4: Hauptvortrag

Donnerstag, 26. März 2009, 11:00–11:30, BAR SCHÖ

Modeling exciton diffusion and dissociation at organic-organic interfaces — •David Beljonne — Chemistry of Novel Materials, University of Mons-Hainaut, Place du Parc 20, B 7000 Mons, Belgium

Increasing the performances of organic photovoltaic (OPV) cells requires the simultaneous optimization of various processes involved in their working principle. We will first briefly overview these processes, comment on the theoretical limits for quantum efficiencies and identify possible directions for improvement. Among other factors, the excitation diffusion length and the fraction of excitons undergoing charge generation at the interface are key to the overall OPV quantum yield. We will assess both thermodynamic and kinetic aspects of these phenomena in the case of oligoacenes:C60 bilayer devices. In particular, on the basis of quantum-chemical calculations and phenomenological models, we will discuss the reasons for the unexpected quasi-quantitative external quantum yield for charge generation that has been measured for such devices.