The effects of side chain engineering on the morphology and charge transport of the A–DA 1 D–A type of non-fullerene acceptor: a multiscale study

, and DD stacking of molecular pairs. With respect to prototype Y6, the introduction of oxygen atoms to outer alkyl side chains could enhance AA stacking but worsen the electrical network and enlarge the reorganization energy during electron transfer, and changing outer side straight alkyl chains to branched chains ruins π-π stacking of all units significantly. Finally, we discover that shortening outer alkyl side chains appropriately or changing inner branched chains to straight chains with the same number of carbon atoms is a good strategy to improve the molecular π-π stacking and electron mobility of Y6 while changing outer straight side chains to branched chains or introducing oxygen atoms to outer straight chains is the opposite. This study provides a new insight into the relationship between morphology and electron mobility and will be helpful for the design of future high-performance non-fullerene acceptors.