Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Poster: Towards Molecular Spintronics, Organic Thin Films, Optical Layers, Vibrational Spectroscopy, Tayloring organic interfaces
DS 18.22: Poster
Dienstag, 26. Februar 2008, 14:30–19:30, Poster A
Spectroscopic studies of metal oxide sensitisation by self-assembling light harvesting molecules and photovoltaic applications — •Clare Dyer-Smith1, Jenny Nelson1, Saif A Haque2, Peter Marek3, and T Silviu Balaban3 — 1Dept of Physics, Imperial College, London SW7 2AZ, U.K — 2Dept of Chemistry, Imperial College, London SW7 2AZ, U.K — 3Karlsruhe Institute of Technology, Institute for Nanotechnology, Postfach 3640, D-76021 Karlsruhe
Molecular photovoltaic devices may provide a low-cost alternative to crystalline silicon solar cells with the long-term potential to displace conventional fossil fuels. Naturally occurring within green photosynthetic bacteria are metal porphyrins which self assemble to form a light harvesting antenna architecture enabling exciton transport over longer ranges. This is promising for application in organic solar cells where charge separation requires exciton diffusion to an interfacial site. Self assembly is thought to lead to improved charge transport properties and therefore improved photocurrent generation efficiency. We report studies of functionalised porphyrins acting as the donor component in molecular photovoltaic devices. We study the influence of film morphology, influenced by the porphyrin side groups, on exciton diffusion, charge separation yield and charge transport in porphyrin films on semiconducting metal oxide surfaces. Charge separation and transport properties are measured using transient optical spectroscopy and time of flight techniques and are correlated to film morphology. The structure and energetics of the donor-acceptor interface are key to maximising the potential of such systems for photovoltaic applications.