Impact of end groups on the performance of non-fullerene acceptors for organic solar cell applications
Non-fullerene organic solar cells employing small molecule acceptors have recently crossed the PCE of 17% through the design and synthesis of efficient acceptor materials. One of the greatest advantages of non-fullerene acceptors (NFAs) is the tunability of the absorption spectrum, frontier molecular orbital (FMO) energy levels and solubility via molecular engineering. Electron deficient chromophoric groups play an important role in the synthesis of efficient non-fullerene acceptors. End groups enhance the absorption, electron acceptor properties and overall performance of a molecule as an acceptor after attaching with a π-conjugated backbone. In this review, a number of NFAs are highlighted focusing on the effect of terminal chromophoric groups on the overall performance of organic photovoltaic devices.