Application of optical property-enhancement film to improve efficiency and suppress angle dependence of top-emitting organic light-emitting diodes

Abstract

In this paper, we propose the application of an optical property-enhancement film that complements the angular dependence and total reflection of top-emitting organic light-emitting diodes (TEOLEDs). The optical property-enhancement film is composed of a porous pyramid arrangement applied on a thin-film encapsulation layer of TEOLEDs and is applied to distribute the transmitted light evenly. The results confirm that the change in the electroluminescence spectrum for each angle was effectively reduced because the TEOLEDs demonstrated uniform light distribution. In addition, reducing the total internal reflection in the film structure made it possible to improve the external quantum efficiency by approximately 35% and current efficiency by 38%.

Keywords

• Organic light-emitting diodes
• light extraction
• pyramid structure
• porous surface
• patterning