Earth-abundant
and cheaper zinc-based organometallic molecules
as luminophores are drawing significant research attention for solid-state
lighting devices. In this paper, we report two air-stable zinc complexes,
where the zinc is coordinated to two sterically encumbered β-diketiminate
ligands in a tetrahedral geometry. In such a geometry, eight phenyl/aryl
rings from the ligand backbones are oriented in a propeller shape,
augmenting the restricted rotation of the putative rings. Such an
architecture harnesses aggregation-induced emission behavior with
an excellent solid-state emission property. The rigidity of these
molecules reduces the possibility of non-radiative transitions and
makes them excellent fluorescence emitters. Both molecules exhibit
electroluminescence (EL) in the yellowish-green region of the visible
spectrum. We have utilized these molecules as emitters to fabricate
multilayered organic light-emitting diode (OLED) devices. The emitter Zn-I in host m-MTDATA exhibits EL with a
maximum external quantum efficiency of 4.4%. Among the handful of
zinc-based OLEDs, the performance of this emitter is very commendable
with power and current efficacies of 15.2 lm W–1 and 12.1 cd A–1, respectively, along with a brightness
of 2426 cd m–2.
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