Ternary blend organic solar cells with a non-fullerene acceptor as a third component to synergistically improve the efficiency

Ternary blends, where an additional component is added to a donor/acceptor blend, represent a promising route to improve upon the performance of organic solar cells. Non-fullerene acceptor materials are particularly suited for this application due to their relatively stronger absorption coefficients and tuneable molecular energy levels. This paper demonstrates a ternary blend solar cell by incorporating a promising non-fullerene acceptor, IDFBR, into a PffBT4T-20D:PC71BM blend. The addition of IDFBR to this blend leads to the formation of a cascading energy band structure in the device, which is required for the operation of an efficient ternary system. Ternary blend solar cells with an IDFBR concentration of 5 wt% demonstrated improved photovoltaic performance, when compared to the host binary blends. This improved performance was attributed to a reduction in energetic disorder and improved charge carrier transport in the ternary blend.