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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 36: Organic Electronics and Photovoltaics III
CPP 36.7: Talk
Thursday, March 21, 2024, 11:00–11:15, H 0110
Polymer Donors vs. Small Molecule Donors for Solar Cells — •Elifnaz Sağlamkaya and Safa Shoaee — Disordered Semiconductor Optoelectronics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
All small molecule (ASMs) solar cells have great potential to actualize the commercialization of organic photovoltaics owing to their higher solubility, lesser batch-to batch variety and simpler synthesis routes compared to the blend systems that utilize conjugated polymers. However, the efficiency of the ASMs are slightly lacking behind the polymer: small molecule single heterojunctions. To address this discrepancy, we compare a small molecule donor ZR1 and polymer PM7 blended with Y6 acceptor. Our temperature dependent electroluminescence quantum efficiency analysis reveals the same energetic offset between the charge transfer state and the singlet energy (ΔES1 − CT) in PM7:Y6 and ZR1:Y6. Surprisingly, the ZR1:Y6 has noticeably stronger field-dependency of charge generation. Furthermore, charge generation rate constant is significantly lower for ZR1:Y6. Low charge carrier mobilities of ZR1:Y6 measured from the space charge limited currents entail a viable explanation for suppressed charge generation.
Keywords: all small molecule; charge generation barrier; charge carrier mobility; energetic offset; stability