Design Rules for Donors in Bulk-Heterojunction Solar Cells—Towards 10 % Energy-Conversion Efficiency


  • This work was partially supported by the Commission of the European Community (Project MOLYCELL Contract No. 502783) and the BMBF project EKOS: Förderkennzeichen 03N2023.


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For bulk-heterojunction photovoltaic cells fabricated from conjugated polymers and a fullerene derivative, the relation between the open-circuit voltage (Voc) and the oxidation potential for different conjugated polymers is studied. A linear relation between Voc and the oxidation potential is found (see figure). Based on this relation, the energy-conversion efficiency of a bulk-heterojunction solar cell is derived as a function of the bandgap and the energy levels of the conjugated polymer.