Ultrathin Ag Transparent Conducting Electrode Structure for Next-Generation Optoelectronic Applications

In this study, we report an Ag-based multilayer structure as the bottom transparent conducting electrode (Ag-TCE) by sandwiching an ultrathin Ag film between commonly used organic hole injection layers for organic light-emitting diode (OLED) applications. This electrode structure fabricated using the same inline fabrication system as organic materials exhibited excellent electrical and optical properties. Ag-TCE showed a high transmittance and low sheet resistance of 79.2% and 17.6 Ω/□, respectively, for the ultrathin Ag layer (9 nm). The phosphorescent yellow OLED fabricated with optimized Ag-TCE showed a driving voltage of 4.0 V, an external quantum efficiency of 23.8%, and a current efficiency of 73.2 cd/A. The electroluminescence performance of Ag-TCE OLED is almost similar to the commonly used ITO electrode (25% and 73.2 cd/A). Based on these results, we demonstrate that this electrode structure is a promising alternative to the ITO electrode.