Synthesis, photoluminescence and electroluminescence of triphenylphosphine functionalized cyclometalated iridium(III) complexes

Three greenish-blue iridium (III) phosphorescent complexes with the molecular structure of [Ir(pppy) ₂ (PPh ₃ )L] (Hpppy = 2-(4-phenoxyphenyl)pyridine; L = Cl ⁻ , NCS ⁻ , NCO ⁻ ) were synthesized and characterized. Their photoluminescence spectra are significantly blue-shifted after introducing the strong-field ancillary ligand triphenylphosphine. These compounds exhibit emission peaks in the range of 474–479 nm in solutions at 298 K with quantum yields up to 0.33. The organic light-emitting diodes (OLEDs) were fabricated by thermal evaporation with complex 3. The best OLED D3 was obtained with turn-on voltage of 4.3 V, maximum luminance of 11931 cd m ⁻² under 15.7 V, highest luminance efficiency (η _L ) as 16.6 cd A ⁻¹ , power efficiency (η _P ) as 12.2 lm W ⁻¹ and external quantum efficiency (EQE) as 5.6%.