Fluorinated Zinc Phthalocyanine as Donor for Efficient Vacuum‐Deposited Organic Solar Cells

Abstract Efficient single bulk heterojunction organic solar cells based on blends of a fluorinated zinc phthalocyanine as electron donor and fullerene C 60 as electron acceptor are reported. In comparison to the commonly used absorber zinc phthalocyanine, the fluorination of the molecule to F 4 ZnPc leads to an increase in ionisation potential and subsequently to an improvement of about 170 mV in the open circuit voltage of organic solar cells, while the short circuit current density and fill factor remain nearly unchanged. Similar to ZnPc:C 60 ‐based devices, the device characteristics of F 4 ZnPc:C 60 solar cells can be further enhanced by improving the blend layer morphology by substrate heating during deposition. F 4 ZnPc is an efficient donor material that can achieve a 4.6% power conversion efficiency in single heterojunction organic solar cells.