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

•Four Ir(III)-based dyes with 1,2-diphenyl-1H-benzoimidazole ligands were prepared.•They displayed green emissions around 492 nm with high quantum yields in CH2Cl2.•Their electroluminescence properties were successfully investigated.•A non-doped device displayed high efficiencies of 19.8 cd A−1 and 20.4 lm W−1.•A device simultaneously displayed low efficiency roll-off at high luminance.

Four novel iridium(III) complexes containing 1,2-diphenyl-1H-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.

Graphical abstractNovel kinds of iridium(III) complexes with 1,2-diphenyl-1H-benzoimidazole ligands were prepared to fabricate high-performance non-doped OLEDs, which showed favorable performance with a maximum ηc of 19.8 cd A−1 and ηp of 20.4 lm W−1 accompanied by low efficiency roll-off at high luminance.Figure optionsDownload full-size imageDownload as PowerPoint slide