Enhanced light out-coupling in OLED employing thermal-assisted, self-aggregated silver nano particles

Abstract

Metallic nano-structures in micro-cavity organic light emitting diode (OLED) can significantly enhance light out-coupling efficiency. Nevertheless, they are not widely accepted in conventional devices due to its complicated process and increased manufacturing cost. In this study, we demonstrate a production-ready alternative for increasing the efficiency of OLEDs by implementing thermal-assisted self-aggregated metallic nanoparticles (NPs). Silver NPs are fabricated by thermal annealing of vacuum deposited thin silver layer without any complicated process, which is easily scalable in large area with low cost. Theoretical calculation and dark field microscopy image indicate that these stochastic Ag NPs provide light scattering in broad range. By incorporating Ag NPs to OLED with micro-cavity structure, 11% improvement in the external quantum efficiency was obtained without deteriorating viewing angle.