Electrophosphorescence Devices Using Novel Cyclometallated Complexes with Bulky Ligands

摘要

The new green Ir(III) complex fac-tris[2-(5'-trimethylsilylphenyl)pyridine] iridium (III) Ir(sippy)_3-1 and fac-tris[4-methyl-2-(5 '- trimethylsilylphenyl)pyridine] Ir(sippy)_3-2 are synthesized and fabricated phosphorescent light emitting devices using them as triplet emissive dopants in CBP. Ir(sippy)_3-l and Ir(sippy)_3-2 showed absorption centered at 393 nm and 401 run, respectively. The EL devices with configuration of ITO/NPD (40 nm)/CBP : Ir(sippy)_3-l (20 nm) or CBP : Ir(sippy)_3-2 (20 nm) /BAlq (8 nm)/Alq_3 (40 nm)/Al showed the emission maximum at 525 nm and 532 nm, respectively, due to the radiative decay from MLCTstate to ground state. The 6 % doped devices showed the maximum efficiency of 16 cd/A for CBP:Ir(sippy)_3-2 and 12 cd/A for CBP:Ir(sippy)_3-l, respectively, and peak luminance of 13000 cd/m~2 for CBP:Ir(sippy)_3-2 and 11000 cd/m~2 for CBP:Ir(sippy)_3-l, respectively.