title: Effect of Li2O/Al cathode in Alq3 based organic light-emitting diodes.
abstract: An effect of bilayer cathode Li20/Al was studied in Alq3 based organic light-emitting diodes with a variation of Li2O layer thickness. The current-luminance-voltage characteristics of ITO/TPD/Alq3/Li2O/Al device were measured at ambient condition to investigate the effect of Li2O/Al. It was found that when the thickness of Li2O layer is in the range of 0.5-1 nm, there are improvements in luminance, efficiency, and turn-on voltage of the device. A current density and a luminance are increased by about 100 times, a turn-on voltage is lowered from 6 V to 3 V, a maximum current efficiency is improved by a factor of 2.3, and a maximum power efficiency is improved by a factor of 3.2 for a device with a use of thin Li2O layer compared to those of the one without the Li2Otron-barrier height for electron injection from the cathode to the emissive layer.
authors.affiliation: Department of Information Display Engineering, Hongik University, Seoul, 121-791, Korea.
authors.forename: Eun Chul
authors.initials: EC
authors.lastname: Shin
authors.forename: Hui Chul
authors.initials: HC
authors.lastname: Ahn
authors.forename: Wone Keun
authors.initials: WK
authors.lastname: Han
authors.forename: Tae Wan
authors.initials: TW
authors.lastname: Kim
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Jin Woong
authors.initials: JW
authors.lastname: Hong
authors.forename: Dong Hoe
authors.initials: DH
authors.lastname: Chung
authors.forename: Min Jong
authors.initials: MJ
authors.lastname: Song