Doping-Free Inverted Top-Emitting Organic Light-Emitting Diodes With High Power Efficiency and Near-Ideal Emission Characteristics

Author

Yun, Changhun ; Cho, Hyunsu ; Koh, Tae-Wook ; Kim, Ji-Hoon ; Kim, Jeong Won ; Park, Yongsup ; Yoo, Seunghyup

Author_Institution

Dept. of Electr. Eng., Korea Adv. Inst. of Sci. & Technol., Daejeon, South Korea

Volume

59

Issue

1

fYear

2012

Firstpage

159

Lastpage

166

Abstract

Inverted top-emitting organic light-emitting diodes (ITOLEDs) with high power efficiency and near-ideal emission characteristics are demonstrated by using the combination of the following: 1) an electron-injection layer composed of Cs₂CO₃, which lowers the turn-on voltage; 2) an electron-transporting layer with optimal electron mobility, which enhances the electron current and thus improves the carrier balance; and 3) a dielectric/metal/dielectric multilayer electrode that works as a damage-free top transparent anode optimized to achieve high efficiency and ideal emission characteristics. By this approach, ITOLEDs with power efficiency values of 3.8 and 30 lm W^-1 are demonstrated in fluorescent and phosphorescent types, respectively, at a luminance value of 1000 cd m^-2 with little distortion in spectral/angular characteristics.

Keywords

organic light emitting diodes; ITOLED; dielectric-metal-dielectric multilayer electrode; doping-free inverted top-emitting organic light-emitting diodes; electron current; electron-injection layer; electron-transporting layer; high power efficiency; luminance value; near-ideal emission characteristics; optimal electron mobility; Cavity resonators; Charge carrier processes; Dielectrics; Electrodes; Metals; Organic light emitting diodes; Pentacene; Electron injection; inverted geometry; microcavity effect; organic light-emitting diodes (OLEDs); top emitting;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2011.2171488

Filename

6069579