Phosphorescent
Iridium(III) Complexes Bearing Fluorinated
Aromatic Sulfonyl Group with Nearly Unity Phosphorescent Quantum Yields
and Outstanding Electroluminescent Properties
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Abstract
A series of heteroleptic functional
Ir<sup>III</sup> complexes
bearing different fluorinated aromatic sulfonyl groups has been synthesized.
Their photophysical features, electrochemical behaviors, and electroluminescent
(EL) properties have been characterized in detail. These complexes
emit intense yellow phosphorescence with exceptionally high quantum
yields (Φ<sub>P</sub> > 0.9) at room temperature, and the
emission
maxima of these complexes can be finely tuned depending upon the number
of the fluorine substituents on the pendant phenyl ring of the sulfonyl
group. Furthermore, the electrochemical properties and electron injection/transporting
(EI/ET) abilities of these Ir<sup>III</sup> phosphors can also be
effectively tuned by the fluorinated aromatic sulfonyl group to furnish
some desired characters for enhancing the EL performance. Hence, the
maximum luminance efficiency (η<sub>L</sub>) of 81.2 cd A<sup>–1</sup>, corresponding to power efficiency (η<sub>P</sub>) of 64.5 lm W<sup>–1</sup> and external quantum efficiency
(η<sub>ext</sub>) of 19.3%, has been achieved, indicating the
great potential of these novel phosphors in the field of organic light-emitting
diodes (OLEDs). Furthermore, a clear picture has been drawn for the
relationship between their optoelectronic properties and chemical
structures. These results should provide important information for
developing highly efficient phosphors