title: Highly efficient phosphorescent organic light emitting diodes based on iridium(III) complex with bulky substituent spacers.
abstract: We developed highly efficient phosphorescent organic light emitting diodes (PHOLEDs) using iridium(III) complex, fac-tris[4-methyl-2-2(4'-trimethylsilylphenyl)pyridine] [Ir(msippy)3]. PHOLEDs based on Ir(msippy)3 complex exhibit the yellowish-green emission with CIE color coordinates of (0.31,0.64). These device performances were compared with those of the green emitting Ir(ppy)3-based devices. The higher external quantum efficiency (EQE) of 25.6% and the current efficiency of 84.4 cd/A were achieved for Ir(msippy)3-based device. The results show that the complete energy and/or charge transfer from the host to Ir(msippy)3 dopant in the emitting layer (EML) of the device resulted in the higher device efficiencies compared with those of Ir(ppy)3-based devices.
authors.affiliation: School of Materials Science and Engineering and Research Institute for Green Energy Convergence Technology (REGET), Gyeongsang National University, Jinju 660-701, South Korea.
authors.forename: Seul-Ong
authors.initials: SO
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Thangaraju
authors.forename: Sungouk
authors.initials: S
authors.lastname: Jung
authors.forename: Wanxiang
authors.initials: W
authors.lastname: Lu
authors.forename: So Min
authors.initials: SM
authors.lastname: Park
authors.forename: Jonghee
authors.initials: J
authors.lastname: Lee
authors.forename: Jeong-Ik
authors.initials: JI
authors.lastname: Lee
authors.forename: Hye Yong
authors.initials: HY
authors.lastname: Chu
authors.forename: Yun-Hi
authors.initials: YH
authors.lastname: Kim
authors.forename: Soon-Ki
authors.initials: SK
authors.lastname: Kwon