Highly conductive and transparent thin metal layer for reducing microcavity effect in top-emitting white organic light-emitting diode

The optical and electrical properties of the top electrode are crucial for the structural design of top-emitting organic light-emitting diodes (OLEDs). A uniform metal layer, if obtainable, can be electrically excellent and optically well-tuned. In this study, Ag deposited with Mg at a concentration of 9:1 to form a metal thin film exhibits higher conductivity and higher transmittance than those of a neat Ag thin film within a thickness of 10 nm or less. In addition, the thin Mg:LiF (1:1) layer renders the Mg:Ag metal film more uniform and enhances its electron injection property. If a Mg:LiF/Mg:Ag thin film is applied to top-emitting white OLEDs, the driving voltage is lowered and the efficiency is improved. In addition, color shifts for viewing angles are reduced, and the emission characteristics are close to Lambertian.