Berlin 2018 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 23: Organic Photovoltaics I
CPP 23.2: Talk
Tuesday, March 13, 2018, 10:00–10:15, C 243
Developing design criteria for organic solar cells using well-absorbing non-fullerene acceptors — •Lisa Krückemeier1, Pascal Kaienburg1, and Thomas Kirchartz1,2 — 1IEK5 Photovoltaics, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany — 2Faculty of Engineering and CENIDE, University of Duisburg-Essen, Carl-Benz-Str. 199, 47057 Duisburg, Germany
In recent years, a variety of promising, well-absorbing non-fullerene acceptor molecules (NFAs) for bulk heterojunction OPV has been developed, which often achieve higher efficiencies than their fullerene-based counterparts. Unlike fullerene acceptors, these various NFAs have their respective absorption peak at different positions of the visible spectrum, allowing the absorption behavior of the blend to be flexibly adjusted by changing its composition. Thus, the fundamental question arises, how to adjust these two absorption spectra of the acceptor and donor to each other in order to best exploit the incident power of the sun and get high solar cell efficiencies. A series of parameters, such as layer thickness, electronic quality and the amount of non-radiative voltage losses affects this optimum. By using numerical simulations, we have developed design criteria for organic solar cells with well-absorbing non-fullerene acceptors that take these influences into account. Only when the electronic quality of the layer still allows a sufficient charge carrier collection for layer thicknesses around the second interference maximum, a combination of complementary absorbing molecules is more efficient. For smaller thicknesses, a blend of molecules with the same absorption onset achieves higher efficiencies.