Integrated Substrate for Enhanced Outcoupling Efficiency in Organic Light-Emitting Diodes

Organic light-emitting diodes (OLEDs) exhibit advantages of wide viewing angle, high contrast ratio, low weight, and power consumption as well as flexibility for applications such as displays and solid state lighting. However, their low light extraction efficiency hampers their overall external quantum efficiency (EQE). OLEDs are also utilize ITO for a transparent electrode where ITO is costly and brittle. In this work, we demonstrate high transparency, high haze glass that may be fabricated via a simple, one-step reactive etching process to improve quantum efficiency. The glass provides for graded refractive index at the substrate/air interface and reduces substrate mode losses. Furthermore, we demonstrate a metal microgrid that may be utilized to replace indium tin oxide (ITO), which is a costly transparent electrode material. The metal microgrid has low index of refraction and may reduce waveguide mode losses. The transmission, haze, and sheet resistance properties of integrated substrates are correlated with OLED performance as characterized by EQE, current density-voltage, radiance-voltage, and EQE-current density. The results demonstrate a pathway to improving the performance of OLEDs as well as lowering their manufacturing costs.