Transparent Micromesh Patterned OLED Fabricated Using the In-Situ Deposition Process of an Ultrathin Mg:Ag Interconnection Layer.

Abstract

TOLEDs (transparent organic light-emitting diodes) have emerged as one of the most promising ways to implement next-generation display form factors. Transparent OLEDs can provide new added value to HMDs (head mounted displays), automobiles, smart windows, mobile devices, TVs, etc. through their transparency, which allows objects to be seen from the other side. However, previous approaches using metal thin films have faced limitations in attempting to achieve high transmittance. In this study, TOLEDs were designed using a new cathode structure consisting of an interlayer and an emission pattern layer, and these layers connect the light-emitting part and the nonemitting part by themselves without requiring the use of another interconnection layer. This structure, which was intended to improve transmittance, was implemented by applying an in situ evaporation process that adds only one shadow mask without the need to use any difficult methods. Through this process, the optimal condition was found when the light-emitting part was deposited in a mesh pattern with a length of 120 μm and a width of 80 μm, in which case the transmittance of the TOLED improved by up to 83% while maintaining electro-optical performance. It was also confirmed that this new structure can be applied to flexible devices.