Efficient micro-cavity top emission OLED with optimized Mg: Ag ratio cathode

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 Omega/square, an average transmittance of 49.7%, reflectance of 41.4%, and absorbance of 8.9% over the visible spectral region (400 similar to 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. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement