Recent advances in non-fullerene organic photovoltaics enabled by green solvent processing

Solution-processed organic photovoltaic (OPV) as a new energy device has attracted much attention due to its huge potential in future commercial manufacturing. However, so far, most of the studies on high-performance OPV have been treated with halogenated solvents. Halogenated solvents not only pollute the environment, but are also harmful to human health, which will negatively affect the large-scale production of OPV in the future. Therefore, it is urgent to develop low-toxic or non-toxic non-halogen solvent-processable OPV. Compared with conventional fullerene OPVs, non-fullerene OPVs exist with stronger absorption, better-matched energy levels and lower energy loss. Processing photoactive layers with non-fullerenes as the acceptor material has broad potential advantages in non-halogenated solvents. This review introduces the research progress of non-fullerene OPV treated by three different kinds of green solvents as the non-halogenated and aromatic solvent, the non-halogenated and non-aromatic solvent, alcohol and water. Furthermore, the effects of different optimization strategies on the photoelectric performance and stability of non-fullerene OPV are analyzed in detail. The current optimization strategy can increase the power conversion efficiency of non-fullerene OPV processed with non-halogen solvents up to 17.33%, which is close to the performance of processing with halogen-containing solvents. Finally, the commercial potential of non-halogen solvent processing OPVs is discussed. The green solvent processing of non-fullerene-based OPVs will become a key development direction for the future of the OPV industry.

Automated summary

Solution-processed organic photovoltaic (OPV) is a new energy device with great potential in future commercial manufacturing. However, most studies on high-performance OPV have used halogenated solvents, which pollute the environment and pose risks to human health. Therefore, there is an urgent need to develop low-toxic or non-toxic non-halogen solvent-processable OPV. Non-fullerene OPVs show stronger absorption, better energy level matching, and lower energy loss compared to conventional fullerene OPVs. This review discusses the research progress of non-fullerene OPV processed with different green solvents and analyzes the effects of optimization strategies on their photoelectric performance and stability. The current optimization strategy can increase the power conversion efficiency of non-fullerene OPV processed with non-halogen solvents up to 17.33%, which is close to the performance of processing with halogen-containing solvents.