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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 71: Organic Electronics and Photovoltaics - OLEDs and Molecular Excitations
CPP 71.8: Vortrag
Donnerstag, 15. März 2018, 17:00–17:15, C 243
Conical intersection dynamics mediating coherent ultrafast singlet fission — •Hong-Guang Duan1,2,3, Ajay Jha1, Vandana Tiwari1, Pabitra Nayak4, Zheng Li1, Michael Thorwart2,3, and R. J. Dwayne Miller1,3,5 — 1MPSD, Hamburg, Germany — 2I. Institut für Theoretische Physik, UH, Germany — 3CUI, Hamburg, Germany — 4University of Oxford, UK — 5University of Toronto, Canada
Carrier multiplication in organic semiconductors by singlet fission holds the key to break the Shockley-Queisser limit. Primary step of singlet fission process is a spin-allowed transition of a singlet exciton to a doubly excited pair of spin-correlated triplets. Consequently, two triplets are formed after the spin decoherence. Despite enormous studies, the mechanism of the primary step is still unclear. Here, we use transient grating spectroscopy to probe the vibrational dynamics of singlet fission process in pentacene thin films. Our observations guide us to propose the existence of the conical intersection mediating singlet state and spin-correlated triplet pair transition. The interplay of vibrational modes mediating this transition will be discussed.