Sky-blue phosphorescence from bis- and tris-cyclometalated iridium(III) complexes bearing carbazole-based dendrons: fabrication of non-doped multilayer organic light-emitting diodes by solution processing

摘要: Novel phosphorescent bis- and tris-cyclometalated iridium(III) complexes bearing carbazole-appended dendrons were successfully synthesized, fabrication of non-doped multilayer OLEDs by solution processing was demonstrated using these as emitting materials. The exhibited sky-blue photoluminescence (PL) at 460–464 nm with excellent PL quantum yields ca. 0.8, their neat films also emitted photoluminescence: the effectively suppressed aggregation between luminescent cores, although referential core complexes, no dendrons, aggregate-based green even when doped into a model host material dendron in same core–dendron molar ratios present dendritic complexes. As hydrophobic tert-butyl groups are placed on periphery, exhibit good solubility cyclohexane poor 2-propanol. Such special properties allow for solution-processed consisting stack hole-transporting layer (HTL)/emitting (the complex)/electron-transporting (ETL). devices showed electroluminescence electron–hole charge balance factors (γ) 0.9, which much higher than those simple without HTL ETL (γ; 0.1).