title: High efficiency phosphorescent blue organic light-emitting diodes using double emitting layer.
abstract: We have demonstrated a highly efficient blue phosphorescent organic light emitting diodes (PHOLED) using iridium (111) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate doped in double emitting layers (D-EML), N,N-dicarbazolyl-3,5-benzene (mCP) and p-bis (triphenylsilyly)benzene (UGH2). D-EML layers were employed to broaden the exciton formation zone and confine excitons. The optimized blue PHOLEDs having mCP/UGH2 as D-EML with a thickness of 200/100 A, exhibited a peak external quantum efficiency of 11.44%, power efficiency of 16.8 Im/W, luminous efficiency of 23.14 cd/A, and Commission Internationale de l'Eclairage coordinates of (0.17, 0.33).
authors.affiliation: Department of Information Display, Hongik University, Seoul 121-791, Korea.
authors.forename: Jung Sun
authors.initials: JS
authors.lastname: Park
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Seo
authors.forename: Ja Ryong
authors.initials: JR
authors.lastname: Koo
authors.forename: Bo Min
authors.initials: BM
authors.lastname: Seo
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