새로운 청색의 인광 물질을 이용한 유기 발광 소자의 전기적 특성 및 수명에 대한 연구

Abstract

A new blue phosphorescent material for organic light emitting diodes (OLEDs), Iridium(Ⅲ)bis[2-(4-fluoro-3-benzonitrile)-pyridinato-N,C2'] picolinate (Firpic-CN), was synthesized and studied. We compared characteristics of Firpic-CN and Bis(3,5-Difluoro- 2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) which has been used for blue dopant materials frequently. The devices structure were indium tin oxide (ITO) (1000 )/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (500 )/4,4'-N,N'- dicarbazole-biphyenyl (CBP) : FIrpic and FIrpic-CN (X wt%)/4,7-diphenyl-1,10- phenanthroline (BPhen) (300 )/lithum quinolate (Liq) (20 )/Al (1000 ). 15 wt% FIrpic-CN doped device exhibits a luminance of 1450 cd/m2 at 12.4 V, luminous efficiency of 1.31 cd/A at 3.58 mA/cm2, and Commission Internationale d’Eclairage (CIEx,y) coordinates of (0.15, 0.12) at 12 V which shows a very deep blue emission. We also measured lifetime of devices and was presented definite difference between devices of FIrpic and FIrpic-CN. Device with FIrpic-CN as a dopant presented lower longevity due to chemical effect of CN ligand.