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

Abstract

Three greenish-blue iridium (III) phosphorescent complexes with the molecular structure of [Ir(pppy)2(PPh3)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 (ηL) as 16.6 cd A−1, power efficiency (ηP) as 12.2 lm W−1 and external quantum efficiency (EQE) as 5.6%.