| 초록 |
Organic light-emitting diodes (OLEDs) containing both fluorescent and phosphorescent molecules have been widely studied since it was developed at 1990s. Here we have designed and synthesized new blue phosphorescent Ir(III) complexes. The 2-(2,4-difluorophenyl)pyridine (dfppy) and 2-(2,4-difluorophenyl)-5-methylpyridine (dfpmpy) were synthesized as main ligands and L-proline (prl) and trans-4-hydroxy proline (prlOH) were used as ancillary ligands in phosphorescent heteroleptic Ir(III) complexes; (dfppy)2Ir(prl) (1), (dfppy)2Ir(prlOH) (2), (dfpmpy)2Ir(prl) (3) and (dfpmpy)2Ir(prlOH) (4). The complexes exhibited the photoluminescence peaks at 473 ~ 479 nm and quantum yields of 15.7 ~ 41.6% in solution. We obtained blue-emitting devices with a structure of ITO / PEDOT : PSS (40nm) / host : 10 wt% dopant (50nm) / TmPyPB (30nm) / LiF (1nm) / Al (100nm). The complex 4 showed the best performance with a EQE of 1.05% at a low turn-on voltage (4.5 V) with CIE coordinates of (0.19, 0.38). |
