SKM 2021 – wissenschaftliches Programm
CPP 10: Organic Electronics and Photovoltaics, Electrical and Optical Properties (joint session CPP/KFM)
CPP 10.5: Vortrag
Donnerstag, 30. September 2021, 14:45–15:00, H3
Thermally Evaporated Donor Molecules Well-Suited for Low-Voltage Loss Organic Solar Cells — •Pascal Kaienburg1, Helen Bristow2, Anna Jungbluth1, Irfan Habib1, David Beljonne3, and Moritz Riede1 — 1Clarendon Laboratory, Department of Physics, University of Oxford, UK — 2Department of Chemistry, University of Oxford, UK — 3Laboratory for Chemistry of Novel Materials, University of Mons, Belgium
Novel molecules are key drivers in the development of efficient organic solar cells (OSCs). Device fabrication via solution-casting, mostly of polymer-blends, and thermal evaporation of small molecule blends in vacuum have proven successful. The advent of non-fullerene acceptors (NFAs) in solution processing pushed OSC efficiency by 50%, outpacing the development of vacuum-deposited OSCs.
We take an important first step towards efficient NFA-based evaporated OSCs by demonstrating that donors commonly used in vacuum deposition benefit from being combined with NFAs. We do so by evaporating donors onto solution-cast NFAs and performing in-depth analysis of voltage losses via sensitive EQE and electroluminescence on the resulting bilayer devices. We find that voltage losses of donor/NFA systems are reduced by up to 400mV compared to corresponding donor/C60 systems, without compromising photocurrent.
Together with evaporated OSCs' advantages such as industrial scalability as proven by OLEDs, our findings highlight the technology's potential and stress the need for evaporable non-fullerene acceptors, which - once available - will significantly increase OSC efficiency.