Star‐Shaped Beta‐Substituted Porphyrins with Four DPP Arms for Organic Solar Cells

Porphyrins are a very important class of chromophores that have been widely applied in many fields. In recent years, the porphyrins functionalized at the meso‐positions have made much progress in photovoltaic fields, including photodetectors, dye‐sensitized solar cells (DSSCs) and organic solar cells (OSCs). In order to explore the relationship between new chemical structures and the properties of functionalized porphyrins, herein, two star‐shaped β‐substituted porphyrins 4β‐EDPP‐Por and 4β‐DPP‐Por with four DPP arms linked at 2, 8, 12, and 18‐β‐positions of a porphyrin core by ethynylenes and single‐bonds, respectively, are designed and synthesized for OSCs. The two porphyrins exhibit absorption spectra, energy level arrangements, and molecular configurations different from those of the A−D‐A‐type molecules previously functionalized at porphyrin meso‐positions. The power conversion efficiencies (PCEs) of the all‐small‐molecule organic solar cells (ASM‐OSCs) based on the active layers of 4β‐EDPP‐Por:Y6 and 4β‐DPP‐Por:Y6 are 5.64 % and 6.96 %, respectively. This study enriches the diversity of porphyrin optoelectronic materials and provides a practical approach for developing star‐shaped small molecule donor materials for organic optoelectronics.