Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 42: Organic Electronics and Photovoltaics II
(Joint session of CPP, DS, HL and O, organized by CPP)

DS 42.10: Talk

Thursday, March 10, 2016, 12:15–12:30, H40

Influence of the Heterojunction's Interface on the Dynamics of Separated Charges Recombination in Organic Photoactive Materials — •Julien Gorenflot^1,2, Niva Alina Ran³, Mike Heiber³, Guillermo Bazan^3,4, Thuc-Quyen Nguyen^3,4, and Frédéric Laquai^1,2 — ¹Max Planck Institut für Polymerforschung, Mainz, Germany — ²King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia — ³University of California Santa Barbara, Santa Barbara, California, United States — ⁴Faculty of Science King Abdulaziz University, Jeddah, Saudi Arabia

A recent study has indicated that the energetic density of shallow trap states, specifically at the interface between the electron donor and the electron acceptor, could be responsible for the apparent high recombination order observed in organic photoactive blends [1]. In order to elucidate this issue, we carried out investigations on a material system that allows for well-controlled donor/acceptor interactions. Films of the small-molecule donor, H1, can be processed such that H1 molecules are either stacking with their pi-face perpendicular or parallel to the substrate. By evaporating a layer of the acceptor molecule C60 on the films, we study the effect of molecular orientation at the donor/acceptor interface on charge recombination using transient absorption spectroscopy. We compare the two bilayer systems to a bulk heterojunction also using H1, which is expected to have a mixture of face-on and edge-on donor/acceptor interactions as well as a much larger interface area. [1] J. Gorenflot et al., J. Appl. Phys.115, 144502 (2014)