Perylene diimide based non-fullerene acceptors: top performers and an emerging class featuring N-annulation

The perylene diimide (PDI) chromophore is a classic polycyclic aromatic hydrocarbon that has been widely used in the field of organic electronics. A combination of strong visible light absorption and low-lying frontier molecular orbital (FMO) energy levels make PDI useful as a photoactive electron transporting material in organic solar cells. Indeed, PDI based molecules and polymers have been studied as so-called non-fullerene acceptors (NFAs) for over 30 years. Recent advances in materials design has enabled solution processed organic solar cell devices based on PDI materials to reach power conversion efficiencies (PCEs) upwards of 12%. This perspective highlights recent PDI design strategies developed to enable such highly performing devices and covers recent work on N-annulated PDIs, which have the potential to deliver roll-to-roll compatible processed solar cells with high operating voltages.