Carbazole and rhodanine based donor molecule with improved processability for high performance organic photovoltaics

Despite the great potential of carbazole and rhodanine moieties, donor molecule containing carbazole and rhodanine have received less attention because of their limited processability and poor efficiency. In this work, we synthesized a new donor molecule based on a combination of carbazole as a core-unit and rhodanine as an electron-withdrawing end-unit. We introduced diketopyrrolopyrrole as an additional acceptor at a position of π-linker to increase molecular planarity and the overall molecular weight. Our new donor molecule (named LGC-D073) showed a promising PCE value of 6.6% using chlorobenzene as a solvent. Moreover, LGC-D073 exhibited similar performances for both inverted and conventional structures. These results suggest that designing donor molecules with the combination of carbazole and rhodanine can be an efficient new approach to obtain high performance organic solar cells with improved processability.