The functionalization of conducting
silicon (Si) substrates with
redox-active probes delivers hybrid semiconducting interfaces whose
electronic functions are parameterized by the molecular conformations
of monolayers. However, it remains challenging to build electronically
homogeneous semiconducting interfaces using flat, π-conjugated
derivatives that are prone to aggregation, as structural heterogeneity
in the solid state unequivocally engenders ill-defined electronic
domains. This limitation has notoriously hampered the development
of n-type semiconducting Si interfaces derived from rylene dyes, which
possess enticing applications in solar energy capture and conversion.
Herein, this challenge is overcome by using supramolecular oligomers
derived from reactive naphthalene diimide (NDI) units as structural
templates to control the electrochemical response of semiconducting
monolayers at Si interfaces. Specifically, conducting Si surfaces
functionalized with NDI noncovalent assemblies exhibit reversible
electrochemical signals and reduction potentials stabilized by more
than 100 mV compared to semiconducting interfaces derived from molecularly
derived precursors. Leveraging density functional theory and molecular
dynamics simulations, the potentiometric properties recorded experimentally
are assigned to discrete NDI conformations, which are parameterized
by the aggregation state of the precursors in solution. These findings
delineate a novel strategy to control the electronic structure homogeneity
of semiconducting interfaces constructed from dyes infamously known
to form ill-defined electronic domains.