Open AccessEfficient micro-cavity top emission OLED with optimized Mg:Ag ratio cathode
Author(s) -
Sun-Kap Kwon,
Eun-Hyung Lee,
Kwan-soo Kim,
HyunChul Choi,
Mi Jin Park,
Seong Keun Kim,
Ramchandra Pode,
Jang Hyuk Kwon
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.029906
Subject(s) - cathode , materials science , oled , transmittance , optics , optoelectronics , brightness , diode , current density , absorbance , visible spectrum , electroluminescence , nanotechnology , chemistry , quantum mechanics , physics , layer (electronics)
Micro-cavity top-emitting organic light emitting diodes (TEOLEDs) are now receiving prominence as a technology for the active matrix display applications. The semi-transparent metal cathode plays the crucial role in realizing TEOLEDs structure. Here, we report the optimization results on Mg:Ag ratio as the semitransparent cathode deposited by vacuum thermal evaporation. The optimized Mg:Ag cathode with 1:10 ratio (wt %) shows a sheet resistance value as low as 5.2 Ω/□, an average transmittance of 49.7%, reflectance of 41.4%, and absorbance of 8.9% over the visible spectral region (400~700 nm). The fabricated red TEOLEDs device implemented using LiF (1nm)/Mg:Ag (1:10) cathode shows the voltage value of 4.17 V at a current density of 10.00 mA/cm 2 , and current efficiencies variation from 55.3 to 50.1 cd/A over the brightness range 2,000 - 12,000 cd/m 2 . The electroluminescence (EL) spectrum displays the light emission at 608 nm wavelength with a half width of 29.5 nm. The narrow half-width of red light emission is attributed to the micro-cavity effects due to the semitransparent cathode.