Regensburg 2019 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 31: Organic Electronics and Photovoltaics II - Non-Fullerene Organic Solar Cells
CPP 31.6: Talk
Wednesday, April 3, 2019, 10:45–11:00, H18
Enthalpy of Charge Transfer Energetics for Organic Photovoltaics based on anthracene-containing PPE-PPVs and ITIC — •Shahidul Alam1,2, Christian Friebe1,2, Johannes Ahner2, Martin Hager1,2, Daniel A. M. Egbe3, Tomas Vary4, Vojtech Nádaždy4, Ulrich S. Schubert1,2, and Harald Hoppe1,2 — 1FSU Jena, Germany — 2IOMC, Jena, Germany — 3JKU, Linz, Austria — 4SUT, Bratislava, Slovak Republic
Lately, NFAs have received increasing attention for use in polymer-based bulk-heterojunction OPVs, as they have demonstrated improved PV performances over classical polymer-fullerene blends. Part of the success of these materials has to be attributed to a considerable contribution to the overall absorption of the solar cells, thanks to relatively low bandgaps in these materials. In this study a systematic comparison between two acceptor materials, the classical fullerene-derivative PCBM and the NFA ITIC was performed in combination with AnE-PVstat. The photo-induced charge transfer occurring at the D-A interface within an organic semiconductor (bulk) heterojunction is considered to be driven by the energy level offset between the corresponding LUMO of the same. Commonly, these energy offsets between LUMO levels of D-A are taken from CV characterization of organic semiconductors in film or solution. While the such derived energy levels seem to suggest successful charge transfer from the polymer to the ITIC, blend films and PV studies show the opposite. Literature, various spectroscopic, morphological and structural characterization methods have been used for finding an explanation.