Yellow Organic Light-Emitting Diodes from Heteroleptic Iridium(III) Complexes with Avobenzone Ligands as Dopants

Avobenzone as an ancillary ligand was chosen to construct two yellow iridium(III) complexes, named Irdfppyavo and Irbtavo, [dfppy, bt, and avo represent 2‐(2,4‐difluorophenyl)pyridine, 2‐phenylbenzo[d]thiazole, and avobenzone, respectively], which were thoroughly investigated as yellow organic light‐emitting diode dopants. Most importantly, the yellow electroluminescence devices from a luminance of 100–1000 cd m–2 displayed small power efficiency roll‐off values of 28.9 and 21.4 % for Irdfppyavo and Irbtavo, respectively. Two yellow emissive iridium(III) complexes are designed through novel emission color adjustment associated with ancillary ligands. Correspondingly, yellow organic light‐emitting diodes having small power efficiency roll‐off are fabricated and thoroughly characterized in this work. TPBI = 1,3,5‐tris(1‐phenyl‐1H‐benzo[d]imidazol‐2‐yl)benzene, CBP = 4,4′‐bis(9H‐carbazol‐9‐yl)biphenyl, TAPC = 1,1‐bis[(di‐4‐tolylamino)phenyl]cyclohexane, ITO = indium tin oxide.