Han, Liangliang published the artcileEfficiency phosphorescent OLEDs with a low roll-off based on a hetero-triplet iridium complex, Safety of 1,2-Diphenyl-1H-benzo[d]imidazole, the publication is Dyes and Pigments (2015), 649-654, database is CAplus.
To explore the triplet-triplet annihilation in cyclometalated Ir complexes, a hetero-triplet Ir complex [Ir(ppy)2pbi] employing 2 2-phenylpyridine (Hppy) ligands and one 1,2-diphenyl-1H-benzo[d]imidazole (Hpbi) ligand with similar triplet energies was synthesized. A device based on Ir(ppy)2pbi exhibited high current efficiency 26.7 cd/A at high doping concentration 12%. The current efficiency was still maintained at 25.8 cd/A when the c.d. was >253.2 mA/cm2. The efficiency roll-off was only ∼3.4%, much lower than that of traditional cyclometalated Ir complexes. Probably the complicated energy level and unsym. ligand in Ir(ppy)2pbi may help to suppress the triplet-triplet annihilation.
Dyes and Pigments published new progress about 2622-67-5. 2622-67-5 belongs to imidazoles-derivatives, auxiliary class Benzimidazole,Benzene,Benzimidazole, name is 1,2-Diphenyl-1H-benzo[d]imidazole, and the molecular formula is C19H14N2, Safety of 1,2-Diphenyl-1H-benzo[d]imidazole.
Referemce:
https://en.wikipedia.org/wiki/Imidazole,
Imidazole | C3H4N2 – PubChem