A 9.16% Power Conversion Efficiency Organic Solar Cell with a Porphyrin Conjugated Polymer Using a Nonfullerene Acceptor.

A new low-molecular-weight porphyrin-based polymer, , with pyridine-capped diketopyrrolopyrrole (DPP) has been synthesized, and its optical and electrochemical properties were investigated. The polymer is prepared with a low content of homocoupling units and gives a widely spread absorption from 400 to 900 nm with a narrow optical band gap of 1.46 eV. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels are respectively located at -5.27 and -3.78 eV, respectively. was used as the electron donor, whereas [6,6]-phenyl-C-butyric acid methyl ester (PCBM) and bis(rhodanine)indolo-[3,2-]-carbazole (), a nonfullerene small molecule, were used as acceptors for the fabrication of solution-processed bulk heterojunction polymer solar cells. Overall power conversion efficiencies (PCEs) of 7.31 and 9.16% (record high for porphyrin-containing polymers) were obtained for PCBM and , respectively. A high of 1.01 V and a low of 0.45 eV may explain this new record.