A novel deep-red-emitting iridium complex with single-peaked narrow emission band: Synthesis, photophysical properties, and electroluminescence performances

In this paper, we report a novel ligand equipped with both electron-pushing moieties and enlarged conjugation planes, 1-benzo[b]thiophen-2-yl-naphthalene-2-ol (BYNO). Using BYNO as the ancillary ligand, its corresponding Ir(III) complex of Ir(ppy)2(BYNO) (ppy=2-phenyl pyridine) is also synthesized. An efficient deep-red emission peaking at 620 nm with a narrow emission band (full-width-at-half-maximum=65 nm) was finally observed from Ir(ppy)2(BYNO). We discuss the photophysical properties, thermal properties, geometric and electronic structures of Ir(ppy)2(BYNO) in detail. In addition, its electroluminescence performances are investigated and a maximum luminance of 3840 cd/m2 peaking at 618 nm is achieved. All obtained data suggest that Ir(ppy)2(BYNO) is a promising candidate for red-emitting dopants in organic light emitting diodes.