Remotely Modulating the Optical Properties of Organic Charge-Transfer Crystallites via Molecular Packing

Organic charge-transfer complex (CTC) formation has emerged
as
an effective molecular engineering strategy for achieving the desired
optical properties via intermolecular interactions. By synthesizing
organic CTCs with carbazole-based electron donors and a 7,7,8,8-tetracyanoquinodimethane
acceptor and adopting a molecular linker located remotely from the
charge-transfer interface within the donors, we were able to modulate
near-infrared absorptive and short-wavelength infrared emissive properties.
Structural characterizations performed by using single-crystal X-ray
diffraction confirmed that the unique molecular arrangements induced
by the steric hindrance from the remotely located linker significantly
influence the electronic interactions between the donor and acceptor
molecules, resulting in different photophysical properties. Our findings
offer an improved understanding of the interplay between molecular
packing and optoelectronic properties, providing a foundation for
designing advanced materials for optoelectronic applications.