Modification of iridium(III) complexes for fabrication of high-performance non-doped organic light-emitting diode

Abstract Four novel iridium(III) complexes containing 1,2-diphenyl-1 H -benzoimidazole as cyclometalated ligands were successfully synthesized and characterized. The complexes displayed strong emissions around 492 nm with high photoluminescence quantum yields of 70–92% in dichloromethane solution at 298 K. Doped OLEDs based on the complexes were prepared, which showed a peak current efficiency of 34.5 cd A −1 , power efficiency of 40.1 lm W −1 . Non-doped OLEDs using the complexes as emitters were then fabricated for further investigation of their electroluminescence properties. Encouragingly, one non-doped device possessed outstanding performance with a maximum current efficiency of 19.8 cd A −1 and power efficiency of 20.4 lm W −1 whilst simultaneously displaying low efficiency roll-off at high luminance.