title: Efficient triplet exciton confinement of blue- and white-organic light emitting diodes using a new host material.
abstract: We have demonstrated lower driving voltage and efficient blue phosphorescent organic light emitting diodes (PHOLEDs) using iridium(III) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate (Flrpic) doped in new host material 9-(4-(triphenylsilyl)phenyl)-9H-carbazole (SPC) and 2,2',2"-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) as double-emitting layer (D-EML) system. The D-EML was employed to have good electron transportability and exciton confinement. Additionally, we fabricated white organic light-emitting diode (WOLED) using a phosphorescent red emitter; bis(2-phenylquinolinato)-acetylacetonate iridium III (Ir(pq)2acac) doped in SPC and TPBi as D-EML. The properties of white device exhibited a maximum luminous efficiency of 19.03 cd/A, a maximum external quantum efficiency of 9.91%, and a maximum power efficiency of 12.30 lm/W. It also showed white emission with CIE(x,y) coordinates of (x = 0.38, y = 0.37) at 8 V.
authors.affiliation: Department of Information Display, Hongik University, Seoul, 121-791, Korea.
authors.forename: Seok Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Ja Ryong
authors.initials: JR
authors.lastname: Koo
authors.forename: Hyunsu
authors.initials: H
authors.lastname: Shin
authors.forename: Wone Keun
authors.initials: WK
authors.lastname: Han
authors.forename: Kum Hee
authors.initials: KH
authors.lastname: Lee
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Yoon
authors.forename: Young Kwan
authors.initials: YK
authors.lastname: Kim