Supramolecular Design of Donor–Acceptor Complexes via Heteroatom Replacement toward Structure and Electrical Transporting Property Tailoring

A feasible strategy
relies on using heteroatom replacement, namely, chemical modification
of an organic compound. Here we present this design concept for donor–acceptor
complexes, which involves introducing nitrogen atoms to the middle
ring of donor molecules to promote short contacts and reduce steric
effect of the mixed framework. These nitrogen-modified complexes can
possess a shorter molecular distance besides the mixed-stacking pathway,
enlarged π–π interactions, or even a scarce 1:2.5
molar ratio through extra acceptor insertion. As a result, the unique
1:2 complex with nitrogen atoms on the different sides demonstrated
stable electron field-effect mobility performance, whereas the binary
system with no nitrogen replacement or N atoms on the identical sides displayed poor ambipolar properties.
These results confirmed that heteroatom replacement was a powerful
molecular design tool to fine-tune the molecular packing of organic
donor–acceptor complexes and their corresponding electronic
properties.