Self-assembled nanostructures obtained from various functional
π-conjugated organic molecules have been able to draw substantial
interest due to their inherent optical properties, which are imperative
for developing optoelectronic devices, multiple-color-emitting devices
with color-tunable displays, and optical sensors. These π-conjugated
molecules have proven their potential employment in various organic
electronic applications. Therefore, the stimuli-responsive fabrication
of these π-conjugated systems into a well-ordered assembly is
extremely crucial to tuning their inherent optical properties for
improved performance in organic electronic applications. To this end,
herein, we have designed and synthesized a functional π-conjugated
molecule (
TP
) having phenanthro[9,10-
d
]imidazole with terpyridine substitution at the 2 position and its
corresponding metal complexes (
TPZn
and
(TP)
2
Zn
). By varying the polarity
of the self-assembly medium,
TP
,
TPZn
, and
(TP)
2
Zn
are fabricated
into well-ordered superstructures with morphological individualities.
However, this medium polarity-induced self-assembly can tune the inherent
optical properties of
TP
,
TPZn
, and
(TP)
2
Zn
and generate
multiple fluorescence colors. Particularly, this property makes them
useful for organic electronic applications, which require adjustable
luminescence output. More importantly, in 10% aqueous-THF medium,
TPZn
exhibited H-type aggregation-induced white light emission
and behaved as a single-component white light emitter. The experimentally
obtained results of the solvent polarity-induced variation in optical
properties as well as self-assembly patterns were further confirmed
by theoretical investigation using density functional theory calculations.
Furthermore, we investigated the
I
–
V
characteristics, both vertical and horizontal, using ITO
and glass surfaces coated with
TP
,
TPZn
,
and
(TP)
2
Zn
, respectively,
and displayed maximum current density for the
TPZn
-coated
surface with the order of measured current density
TPZn
>
TP
>
(TP)
2
Zn
. This observed order of current density measurements
was
also supported by a direct band gap calculation associated with the
frontier molecular orbitals using the Tauc plot. Hence, solvent polarity-induced
self-assembly behavior with adjustable luminescence output and superior
I
–
V
characteristics of
TPZn
make it a...