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 (J _SC) 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 J _SC as a result of complementary absorption spectra in the near-infrared region. In combination with J _SC 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 J _SC, FF, and thus the performance and photostability of TOSCs.