High-luminance top-emitting organic light-emitting diodes using Cs/Al/Au as the semitransparent multimetal cathode

作者：Lim J T^*; Jeong C H; Lee J H; Yeom G Y; Shin E C; Lee E H; Kim T W

来源：Journal of the Electrochemical Society, 2007, 154(10): J302-J305.

DOI：10.1149/1.2759842

Top-emitting organic light-emitting diodes (TEOLEDs) using an ultrathin cesium (Cs) layer capped with a semitransparent Al/Au layer as an effective, electron-injecting cathode were fabricated by vacuum evaporation. The optical properties of Cs (20 nm)/Al (20 nm)/Au (20 nm) at a wavelength of 520 nm exhibited a transmittance of 59% and a reflectance of 14%. The Cs/Al/Au cathode showed lower power consumption and higher luminance at the same forward bias voltage than the Cs/Al/Ag cathode. Using a tris (8-quinolinolato) aluminum (III) (Alq3) layer as the emissive material, a TEOLED based on the Cs/Al/Au cathode showed a maximum luminance of 66,200 cd/m2 at 9.8 V. An external quantum efficiency and the power efficiency of 1.6% and 2.1 lm/W, respectively, at a luminance of 1000 cd/m(2) (corresponding to a bias voltage of 6.2 V) was obtained. The good driving performance of this TEOLED was attributed to the excellent optical properties such as high transmittance and efficient-electron injection from the Cs/Al/Au to the adjoining organic layer.

• 出版日期2007