Fast Synthesis of Iridium(III) Complexes Incorporating a Bis(diphenylphorothioyl)amide Ligand for Efficient Pure Green OLEDs

Bis­(diphenylphorothioyl)­amide
(Stpip) containing phosphor–sulfur
(PS) bonds was used as an ancillary ligand for three pure
green iridium­(III) emitters Ir1, Ir2, and Ir3, which were synthesized in few minutes at room temperature
with high reaction yields above 70%. All these complexes show good
thermal stability and excellent sublimation yields of around 80–90%,
which are considered beneficial for industry practical production
and organic light-emitting diode (OLED) fabrication. The emission
profiles of these complexes meet the green standards of CIE1931 with
coordinates of (0.33, 0.63), (0.33, 0.62), and (0.34, 0.62), respectively,
and high photoluminescence quantum yields of up to 98% are achieved.
Utilizing these complexes as emissive dopants, these OLEDs exhibited
high current efficiency up to 91.94 cd A–1, external
quantum efficiency up to 26.52%, and power efficiency up to 92.60
lm W–1 with very small efficiency roll-off, without
adopting internal or external out-coupling methods. These results
indicate that Stpip is a potentially suitable ligand scaffold for
highly efficient phosphorescent Ir­(III) emitters that endow corresponding
OLEDs with high efficiency and small roll-off.