Preparation and electroluminescent application of iridium(III) complexes containing sulfur-containing phenylpyridazine ligands

Abstract

Four iridium(III) complexes (1–4) with sulfur-containing phenylpyridazine ligands were successfully synthesized and characterized. The structure of complex 3 was further confirmed by single X-ray structural analysis. These complexes showed strong green phosphorescence at room temperature with peak wavelengths ranging from 524 to 539 nm in CH2Cl2 solution. These complexes exhibited medium quantum yields of 42 ~ 61% in PMMA films with lifetimes of 1.58 ~ 3.26 μs. These complexes also exhibited good thermal stability with Td > 275 °C. The phosphorescent OLEDs were fabricated using complexes 1 and 2 as dopants. The device using complex 2 displayed good performances with the maximum luminance, current efficiency, power efficiency and external quantum efficiency of 8913 cd m−2, 44.2 cd A−1, 30.7 lm W−1 and 11.8%, respectively. These results indicate excellent application prospects of these iridium(III) complexes as efficient phosphors in OLEDs.