| 초록 |
We fabricated a high efficient organic light-emitting diodes (OLEDs) using phosphorescent host/guest system, which focus on recently developed green electrophosphorescent molecule, bis[(4,6-difluorophenyl)-8-methylpyridinato-N,C2′) iridium pyrazinate [(dfmppy)2Irprz], as the guest and blend of poly(N-vinylcarbazole) (PVK) with 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as the host and different cathode structures such as triple layer of BAlq/LiF/Al and bilayer of CsF/Al. The electrophosphorescence emission was characteristic of (dfmppy)2Irprz, with its maximum at 563 nm with CIE (Commission International de L’Eclairage) coordinates of (0.43, 0.53). The device fabricated with 0.5 wt% of (dfmppy)2Irprz in PVK/PBD (60:40 wt%) using CsF (2 nm)/Al bilayer cathode, which exhibited an external quantum efficiency of 6.2 %, luminescence efficiency of 17.3 cd/A, luminous power efficiency of 24.2 lm/W, and maximum brightness of 10,220 cd/m2. |
