Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 61: Organic electronics and photovoltaics III (organized by CPP)

HL 61.9: Talk

Wednesday, April 2, 2014, 11:45–12:00, ZEU 260

On the role of the effectiv mass, ground state complexes and interfacial dipoles on exciton dissocitation in organic donor-acceptor systems — •Anna Köhler — University of Bayreuth, Bayreuth, Germany

Efficient exciton dissociation at a donor-acceptor interface is a necessary condition for obtaining high efficiency polymeric solar cells. Despite its importance, this step is still not fully understood. A central question is how and why, after photoexcitation of the donor and transfer of an electron onto the acceptor, the the e-h pair can overcome their considerable mutual Coulomb potential. Possibilities that are currently discussed include the degree of delocalization of both an exciton and a charge in a conjugated polymer, ground state charge transfer complexes as well as interfacial dipoles that may exist at the donor-acceptor interface in the ground state, and the degree of energetic and structural order/disorder. In this talk I will show how we combine insight gained from ultrafast pump-probe spectroscopy, field dependent photocurrent measurements, photoemission measurements and modeling to assess which factors control the dissociation process.