Intermolecular interactions and their relevance for self-assembly and phase behavior in solution processed organic electronics

The OSC field has been revolutionized through the development of numerous novel non-fullerene acceptors (NFA). The device stability and mechanical durability of these non-fullerene OSCs is critical and developing devices with high performance, long-term morphological stability, and mechanical robustness remains challenging. We will discuss: 1) our current understanding of the phase behavior of OSC donor:acceptor mixtures and the relation of phase behavior and the underlying hetero- and homo-molecule interactions to performance, processing needs (e.g., kinetic quenches), and morphological and mechanical stability; 2) molecular hetero-interactions between the donor and NFA that are not always the geometric mean of the homo-interactions; molecular interactions that are relevant in understanding in rubber-toughening of OSCs with a SEBS additive; and 3) that ~50% of semi-conducting blends investigated so far exhibit re-entrant phase behavior. The results presented and its ongoing evolution are intended to uncover fundamental molecular structure-function relationships that will allow predictive guidance on how desired properties can be targeted by specific chemical design.