Manipulating Molecular Configurations of Organic Charge-Transfer Cocrystals with Programmable Near-Infrared Emission for Dual-Emission Optical Waveguide

Molecular engineering in molecular configuration was
successfully
applied to finely design the advanced organic semiconductors. However,
it has rarely been investigated in organic charge-transfer (CT) cocrystals
with desired optoelectronic properties that could be controllably
prepared via a facile self-assembly process. Herein, the organic benzo[c]phenanthrene (BcP)-based CT cocrystals with a programmable
near-infrared (NIR) emission peak beyond 760 nm were rationally designed
via manipulating the BcP molecular skew angle for an anisotropic packing
mode. Notably, the torsional distortion of BcP molecule induced by
CT interaction leads to a reduced dihedral angle from 11.95°
to 10.78° for a minimized steric hindrance, showing a NIR emission
red-shifted to 875 nm. Furthermore, these NIR cocrystals with high
chemical/structural compatibility were purposefully integrated into
the organic axial-branch heterostructure by adjusting CT interaction
intensity in the horizontally epitaxial-growth process, which demonstrates
a tunable spatial exciton conversion and dual-emission optical waveguide
for optical logic gate. This confinement-assisted CT modulation strategy
presents a versatile route to high-performance NIR emitters and hierarchical
heterostructures for integrated optoelectronics applications.