Dresden 2020 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 49: Poster Session II
CPP 49.37: Poster
Tuesday, March 17, 2020, 14:00–16:00, P1A
Influence of Morphology on the Density of Charge-Transfer States in Organic Donor/Acceptor Blends — •Anna-Lena Hofmann1, Thomas Zechel1, Theresa Linderl1, Alexander Hofmann1, Tomoya Sato3, Kohei Shimizu2, Hisao Ishii3, and Wolfgang Brütting1 — 1Institute of Physics, University of Augsburg, 86159 Augsburg — 2Graduate School of Science and Engineering, Chiba University, Chiba, Japan — 3Center for Frontier Science, Chiba University, Chiba, Japan
Charge-transfer (CT) states are considered as precursors for charge generation and their energy (ECT) as the upper limit for the open-circuit voltage (VOC) in organic donor/acceptor (D/A) solar cells. In this study the morphological influence of using a crystalline donor diindenoperylene (DIP) versus an amorphous donor tetraphenyldibenzoperiflanthene (DBP) with almost identical ionization energy is investigated. As acceptor material the widely used fullerene C60 is used. Reduced electroluminescence (EL) and reduced external quantum efficiency (EQE) spectra in the visible and near infrared spectrum are used to determine ECT and the character of the CT density of states (CT DOS). This is then related to the morphology of the different D/A systems. In this context we try to verify the necessity of static disorder in the description of CT emission and absorption spectra of small molecule solar cells. Remarkably, the more crystalline donor DIP shows a significant contribution of static disorder, whereas for the amorphous DBP a description without static disorder soley based on Marcus theory is sufficient.