Fluorinated Zinc and Copper Phthalocyanines as Efficient Third Components in Ternary Bulk Heterojunction Solar Cells

Abstract

Fluorinated zinc and copper metallophthalocyanines MPcF48 are synthesized and incorporated as third component small molecules in ternary organic solar cells (TOSCs). To enable the high performance of TOSCs, maximizing short-circuit current density (JSC) is crucial. Ternary bulk heterojunction blends, consisting of a polymer donor PTB7-Th, fullerene acceptors PC70BM, and a third component MPcF48, are formulated to fabricate TOSCs with a device architecture of ITO/PFN/active layer/V2O5/Ag. Employing copper as metal atom substitution in the third component of TOSCs enhances JSC as a result of complementary absorption spectra in the near-infrared region. In combination with JSC enhancement, suppressed charge recombination, improved exciton dissociation and charge carrier collection efficiency, and better morphology lead to a slightly improved fill factor (FF), resulting in a 7% enhancement of PCE than those of binary OSCs. In addition to the increased PCE, the photostability of TOSCs has also been improved by the appropriate addition of CuPcF48. Detailed studies imply that metal atom substitution in phthalocyanines is an effective way to improve JSC, FF, and thus the performance and photostability of TOSCs.